This work was supported by a grant (N&#176; 32119) of the Swiss Cardiovascular Foundation to RT.

The protocol follows our institutional guidelines of the human research ethics committee.
1. Patient Selection (Table 1)
<ol>
	<li>Identify patients necessitating isolated aortic valve replacement14.</li>
	<li>Select among these patients a subgroup without major chest deformities (Kypho-scoliosis), previous history of irradiation or surgery of the right hemi-thorax, need for emergency operation, and operation for active endocarditis.</li>
	<li>Perform a chest computed tomography (CT) scan to exclude patients with ascending aortic aneurysm &#8805;4.5 cm.</li>
	<li>Make the final decision according to the measurements provided by the chest CT (Figure 1 and 2 and Table 1). Choose between the second or third intercostal space, based on closer distances to the aortic cannulation site and the aortic annulus.</li>
</ol>
2. Preparation for Surgery
<ol>
	<li>Prepare the patients for surgery following the institutional guidelines and recommendations for adult cardiac surgery patients, as previously described14.</li>
	<li>Place the external defibrillator pads on the back and left chest anteriorly prior to draping.</li>
</ol>
3. Surgery
<ol>
	<li>Access to the heart through a right anterior mini-thoracotomy
	<ol>
		<li>Incise the skin transversally over 8 cm with an 18-blade knife over the chosen intercostal space, starting 1 cm to the right of the right sternal edge.</li>
		<li>Cut the pectoralis and the superficial layers of the intercostal muscles using the electrocautery. To avoid injury to the right lung, enter the right pleura first with Metzenbaum scissors. Then enlarge the opening of the intercostal muscles with electrocautery.</li>
		<li>Preserve the right internal thoracic pedicle by freeing it from the fascia and soft tissue around it using Metzenbaum scissors.</li>
		<li>Insert the soft tissue retractor into the right pleura and fix it onto the wound. Take care not to injure the right internal thoracic pedicle.</li>
		<li>Place the minimal access retractor over the soft tissue retractor and open it gently and gradually.</li>
		<li>Grab the cranially overlying fat with Carpentier forceps and cut it with electrocautery. Take care not to injure the right phrenic nerve.</li>
		<li>Open the pericardium over the right atrium with electrocautery and place 2/0 polyglactin stay sutures on both sides of the opening in order to spread the pericardium.</li>
		<li>Continue opening the pericardium cranially over the ascending aorta and caudally over the right atrium. Place 2/0 polyglactin stay sutures on both sides of the opening to spread the pericardium.</li>
		<li>Check the distal pericardial reflection line over the ascending aorta and the basis of the aortic root to prepare for the placement of the aortic cannulation purse-strings.</li>
		<li>Verify the anatomy of the right superior pulmonary vein for the placement of the left ventricular vent.</li>
		<li>To expose the distal part of the ascending aorta, gently push down the ascending aorta using a peanut gauze mounted on an Allis clamp.</li>
		<li>Place the first purse-string for aortic cannulation just below the distal pericardial reflection line over the ascending aorta using 4/0 polypropylene suture. Complete the preparation for aortic cannulation by adding a second purse-string around the first one using 4/0 polypropylene suture.</li>
		<li>Give 300 I.U. of heparin/kg (concentration 5,000 U/mL) through the IV line.</li>
	</ol>
	</li>
	<li>Connect the patient to the cardiopulmonary bypass
	<ol>
		<li>First puncture the right femoral vein and place the guidewire through the needle into the vein. Enlarge the skin opening with an 11-blade knife. Dilate the puncture site with successive dilators and introduce percutaneously the femoral venous cannula over the guidewire under transesophageal echocardiographic control (Figure 3).</li>
		<li>Gently push down the ascending aorta using a peanut gauze mounted on an Allis clamp and puncture the ascending aorta in the middle of the purse-strings. Cannulate the aorta over the guidewire.</li>
		<li>Start the cardiopulmonary bypass and cool down the patient to 30 &#176;C (Figure 4). To improve the venous return, let the perfusionnist apply assisted negative pressure of -50 mmHG.</li>
		<li>Gently push the superior vena cava towards the left side and place a purse-string on the right upper pulmonary vein with a 4/0 polypropylene monofilament suture. Insert the left ventricular vent through the purse-string to unload the left heart.</li>
	</ol>
	</li>
	<li>Prepare for valve resection and replacement
	<ol>
		<li>Cross-clamp the ascending aorta just below the aortic cannula using a flexible clamp with a retractable rigid shaft.</li>
		<li>Perform an inverted-L aortotomy parallel and at the level of the sino-tubular junction, extending to the non-coronary Valsalva sinus. Retract the inferior ridge of the aortotomy with an Allis clamp.</li>
		<li>In case of aortic regurgitation, deliver the antegrade crystalloid cardioplegia directly into the coronary ostia.</li>
		<li>Extend the aortotomy through the non-coronary sinus to 1 cm above the aortic annulus. Check the left and right coronary ostia.</li>
		<li>Place a 5/0 polypropylene suture on the inferior ridge of the aortotomy and fix it superficially to the anterior aspect of the right ventricle to improve the exposure of the aortic valve.</li>
		<li>Place another 5/0 polypropylene suture on the superior ridge of the aortotomy and fix it superficially to the pericardium to improve the exposure of the aortic valve.</li>
		<li>Grab in turn the right, non-coronary, and left coronary cusp with endo-forceps and excise them with endo-scissors. Check the mitral valve through the aortotomy.</li>
		<li>Use commercially available valve sizers to determine the labeled size of the valve to be inserted. Choose a sizer which comfortably passes through the aorto-ventricular junction.</li>
		<li>Place the first braided polyester 2/0 with pledget U-suture on the commissure between the left and right coronary sinuses, using an endo-needle holder. Pass the suture from the ventricle up so that the pledget is on the ventricle side.</li>
		<li>Continue the placement of the braided polyester 2/0 with pledget U-sutures clockwise to complete the right coronary sinus.</li>
		<li>Place clockwise braided polyester 2/0 with pledget U-sutures on the non-coronary sinus.</li>
		<li>Complete the annulus sutures by placing counter-clockwise braided polyester 2/0 with pledget U-sutures on the left coronary sinus, starting at the commissure between the right and left coronary sinuses.</li>
		<li>Pass the braided polyester 2/0 sutures onto the sewing ring of the valve prosthesis using a Ryder needle holder.</li>
		<li>Slide down the valve prosthesis and remove the valve holder. Tie the sutures and check for any gap between them and the aortic annulus. Verify that the left and right coronary ostia are unobstructed.</li>
		<li>Cut the tied sutures using Metzenbaum scissors. Remove the 5/0 exposure sutures on the inferior and superior ridge of the aortotomy.</li>
		<li>Close the aortotomy by two 5/0 polypropylene running hemi-sutures. Place the first one on the nadir of the aortotomy in the non-coronary sinus and tie it. Then come up to the angle of inverted L-aortotomy. Put the end of the suture under slight tension.</li>
		<li>Continue the closure of the aortotomy by the second 5/0 polypropylene running hemi-suture starting on the left end and coming towards the right side to meet the end of the first hemi-suture. Tie the two ends together and cut them.</li>
		<li>Place the ventricular pacing wires on the right ventricle before unclamping the aorta.</li>
		<li>Let the operating table tilt in the Trendelenburg position. Reduce the pump flow to 50% of the full flow. Under gentle aspiration of the left ventricular vent, slowly remove the aortic cross-clamp14.</li>
		<li>Resume the full flow of the cardio-pulmonary bypass. Check the hemostasis of the aortotomy closure. Remove the left ventricular vent and tie its purse-string. Check for hemostasis.</li>
		<li>Rewarm the patient to 37 &#176;C. Separate the patient from the cardio-pulmonary bypass. When a stable blood pressure is reached, neutralize the heparin by a protamine-infused IV in a 1:1 ratio (3 mg/kg corresponding to 300 U/kg of heparin)14.</li>
		<li>Prepare for removal of the aortic cannula by tying down the first purse-string. Let the assistant gently remove the aortic cannula and finish tying the purse-strings.</li>
		<li>Double-secure the aortic cannulation site with a figure of eight 4/0 polypropylene suture. Cut the sutures.</li>
		<li>Remove the femoral venous cannula and secure the hemostasis by manual compression for 20 min.</li>
		<li>Place one pericardial and one right pleural chest tube. Adapt the pericardium with three loosely tied braided 2/0 polyglactin sutures.</li>
		<li>Adapt the ribs with two braided 0 polyglactin sutures. Close the wound in layers in a standard fashion.</li>
	</ol>
	</li>
</ol>
4. Post-Operative Patient Care
<ol>
	<li>Following the transfer to the intensive care unit, provide the patient with standard post-operative care for cardiac surgical operations14.</li>
</ol>

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The authors have nothing to disclose.

In this protocol, we describe in detail the technique of right anterior mini-thoracotomy for isolated aortic valve replacement, and highlight the patient selection criteria for this procedure. As for any other therapeutic intervention, proper patient selection is the key to successful accomplishment of the procedure. The optimal CT measurements for consideration of patients for this technique are precisely described in this protocol, and are based on experience and consider the extensive work of Dr. Glauber and coworkers in this field10. These optimal CT measurements add some valuable criteria, i.e., the annulus size, distances of the coronary ostia from the aortic annulus, to the recommendations of Glauber et al., who find patients suitable for this technique only if: (1) the ascending aorta is rightward (more than one half located on the right in respect to the right sternal border) at the level of the main pulmonary artery, (2) the distance between the ascending aorta and the sternum does not exceed 10 cm, and (3) the angle between the&#160;midline and the inclination of ascending aorta (&#945; angle) is larger than 45&#176;10. These CT selection criteria differ somewhat from those recommended by Glauber et al.10. First, the 3-D CT reconstruction of the distance from the mid-clavicular line of the second and third intercostal spaces to the origin of the right innominate artery is of utmost importance in this protocol. The shorter this distance is, the safer the central arterial cannulation. Second, beside the configuration of the chest 3-D CT measurements of the distance from the mid-clavicular line of the second and third intercostal spaces to the aortic valve annulus are mandatory for estimation of the ease of the valve procedure itself. Thus, selection of patients for this protocol is based on two key distances, i.e. working distances to the aortic valve and the central arterial cannulation site. As a consequence, the criteria of distance from the intercostal space to the aortic annulus and the aortic cannulation site give more precise information and are more helpful for selection and pre-operative planning of patients than the formulation of distance of ascending aorta to the sternum used by Glauber and co-workers10. Other groups do not routinely use CT measurements for selection of patients for right anterior mini-thoracotomy16,17,18. However, in order to compensate for skipping this step, these authors manage a dislocation of the ribs during entry to the pleural space followed by refixation of the dislocated rib(s) with a plate at the end of the operation16,17,18. However, this strategy may reduce patient comfort and could potentially lead to more bleeding from broken bone surfaces.
An important aspect of the present protocol is that the arterial perfusion is done through central aortic cannulation. The site of arterial perfusion during minimal access heart valve surgery in general, and during right anterior mini-thoracotomy in particular, remains controversial. While a number of centers and surgeons have reported an increased risk of stroke following peripheral femoral arterial cannulation as compared to central aortic cannulation19,20, other authors have reported an increased risk of stroke following central aortic cannulation21, or no difference is reported between the two strategies22. This disparity might be due not only to different definitions of stroke, but also to associated comorbidities such as older age and peripheral arterial vascular disease20,23. Other potential complications related to peripheral femoral arterial perfusion are infection, lymphoid fistula, arterial wall dissection, and distal limb ischemia24. In contrast to Glauber and colleagues, who used short-tipped aortic cannulas for central aortic cannulation25, we used commercially available arterial cannulas long enough so that the tip of the cannula could be placed at the origin of the descending aorta. The rationale of this strategy is to avoid the jet of the arterial perfusion into the aortic arch with potential dislocation and embolization of the arch vessels.
In this protocol, we gain access to the pleural space and the heart without deliberate fracture or dislocation of the ribs, in contrast to other protocols16,17,18. Based on copious experience, a gentle and gradual opening of the spreader avoids inadvertent fracture of the ribs. In the same line of tissue preservation, we do not systematically ligate the right internal thoracic vessels and reserve the ligation for anatomical variations of these vessels where they are laterally more than 1 cm to the right of the sternal edge. Systematic fracture of the ribs could potentially increase the amount of bleeding from the fractured bone surfaces and cause patients discomfort, despite the fixation at the end of the operation25.
Early mortality of patients operated on according to the present protocol of right anterior mini-thoracotomy (1.5%) compares favorably with those undergoing full sternotomy (1.8%) (Table 4) and with the reported outcomes for isolated aortic valve replacement in the STS Database (2.4%)26. Compared to full sternotomy, right mini-thoracotomy did not increase early postoperative complications, including reoperation for bleeding and stroke. The rate of reoperation in the two groups of patients (RAMT 2%, FS 2.3%) was slightly less than that reported in the STS database (3.9%), whereas the incidence of stroke was slightly higher (RAMT 2.6%, FS 3.5%, STS 1.1%)26. The reason for this difference might lie in the definition of stroke used in these patients and in the STS Database. In this protocol, all clinically diagnosed peri-operative cerebrovascular events, including reversible transient deficits were computed as stroke, while the STS Database reported on permanent stroke26. Further, in the studied patients, the incidence of new onset atrial fibrillation was reduced by RAMT approach (18%) compared to the FS group (30%, p=0.02) and the STS Database (31%)26. This finding is in accordance with the study of Glauber et al. reporting 18.1% and 27.9% of new onset atrial fibrillation in RAMT versus FS patients (p = 0.03)27. This difference might be due to the elimination of direct cannulation of the right atrium in the RAMT compared to the FS approach. In fact, the scar of the cannulation site of the right atrium may be the local origin of atrial arrhythmias. This hypothesis warrants further investigation. Another improvement in early patient outcomes achieved by the RAMT (0%) compared to FS approach (1.2%, p=0.02) was the disappearance of deep wound infection. In comparison to FS, RAMT access significantly lowered the need for pain medication and transfusion requirements in this protocol. As a result of reducing the incidence of post-operative new onset atrial fibrillation, transfusion requirements, and deep wound infection, as well as of enhancing patient comfort by reducing pain medication, the RAMT approach significantly shortened the length of hospital stay as compared to the FS approach. This observation is in accordance with other studies reporting similar reduction in the length of hospital stay, which could potentially contribute to cost savings16,27.
In this protocol, excision of the aortic valve and implantation of the new valve prosthesis remain unchanged compared to the full sternotomy. This may explain the achievement of the same good results of conventional AVR through full sternotomy, and makes this approach an attractive alternative to TAVI in the intermediate risk subgroup of patients28.
The limitations of the comparisons between the RAMT and FS cohorts in this protocol are due to the retrospective nature of these&#160;data. Although the risk profiles of the two groups reflected by Euroscore15 were comparable between these groups, other uncontrolled parameters might have affected the reported comparison. The limitations of the reported technique in this protocol are represented by the optimal CT measurements and other criteria reported in Table 1. In these patients, aortic valve replacement should be performed by conventional full or partial sternotomy access.
In conclusion, right anterior mini-thoracotomy as described in this protocol can be done in selected patients according to the described criteria with comparably good results achieved with the full sternotomy approach. The additional operative times required are not detrimental to the patients and are rewarded by improved patient comfort and accelerated early recovery. This minimally invasive approach can be a viable alternative to TAVI in intermediate risk patient populations needing an aortic valve replacement.

Among heart valve lesions diagnosed as hemodynamically relevant and clinically receiving particular attention, aortic valve stenosis is the most common valvular pathology in the United States and developed countries1,2. In the Cardiovascular Health Study, 2% of patients had frank aortic stenosis, with a clear increase in prevalence with growing age: 1.3% in patients aged 65-75 years, 2.4% in those aged 75-85 years, and 4% in patients older than 85 years1. For symptomatic patients presenting with severe aortic valve stenosis, aortic valve replacement is a Class I recommendation in the guidelines of the American Heart Association for the management of patients with valvular heart disease3.
Conventional surgical aortic valve replacement through median full sternotomy (FS) has been established as the gold standard for treating aortic valve stenosis with excellent results in terms of morbidity and mortality4. These results have encouraged the extension of therapeutic indications to older patients and patients with a higher risk profile. A number of treatment strategies have been implemented in these patient subsets to maintain the same good results achieved by conventional surgical aortic valve replacement in the general population. Among these alternative treatment modalities, transcatheter aortic valve implantation (TAVI) was introduced in 2002 by Cribier and colleagues5. Performed initially in moribund patients, TAVI has rapidly emerged as the treatment of choice for patients with severe aortic stenosis who are not suitable for conventional surgical aortic valve replacement6,7, or as a less invasive approach for surgery for patients at high risk8,9.
Despite the improved outcomes of TAVI in selected patient subsets, many patients with symptomatic aortic valve stenosis are still candidates for surgical aortic valve replacement. In these patients, FS aortic valve replacement is the most frequently used approach by cardiac surgeons. Nevertheless, various &#39;minimally invasive&#39; techniques have been developed with the rationale of reducing surgical trauma10. All these minimal-access techniques have aimed at improving patient comfort by reducing post-operative pain and accelerating patient recovery by shortening the hospital stay and potentially saving global costs10. Among minimally invasive incisional approaches upper hemi-sternotomy (UHS) and right anterior mini-thoracotomy (RAMT) have become the predominant techniques reported in the literature11. Right anterior mini-thoracotomy for aortic valve replacement was initially reported by Benetti et al.12, and upper hemi-sternotomy was first described by several authors11. In addition to incisional alternatives, two arterial perfusion strategies are currently used: i) peripheral femoral arterial cannulation, which is more frequently employed than ii) central aortic cannulation.
In spite of reported improvement in patient outcomes following minimally invasive aortic valve replacement, concerns about the disadvantages of restricted operative field and peripheral arterial perfusion strategies13 lead many cardiac surgeons to not let their patients benefit from potential advantages of minimal access approaches for aortic valve replacement. The goal of this protocol is to describe in detail this technique of minimally invasive aortic valve replacement through a right anterior mini-thoracotomy without rib resection/fracture, and with central aortic cannulation for arterial perfusion. By following this protocol, a larger number of cardiac surgeons can perform right anterior mini-thoracotomy for aortic valve replacement in certain patient groups. Patient selection and limitations of the technique are discussed. Early results are compared to those of a cohort of patients undergoing isolated aortic valve replacement by full sternotomy.

<table><tbody><tr><td>&lt;strong&gt;Heart surgery infrastructure:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Heart Lung Machine</td><td>Stockert</td><td>SIII</td><td></td></tr><tr><td>EOPA 24Fr. arterial cannula</td><td>Medtronic</td><td>77624</td><td></td></tr><tr><td>FemFlex arterial cannula</td><td>Edwards</td><td>FEMII20A</td><td></td></tr><tr><td>Quickdraw 25Fr. femoral venous cannula</td><td>Edwards</td><td>QD25</td><td></td></tr><tr><td>Biomedicus 25Fr. Nextgen venous cannula</td><td>Medtronic</td><td>96670-125</td><td></td></tr><tr><td>LV vent catheter 17Fr.</td><td>Edwards</td><td>E061</td><td></td></tr><tr><td>Antegrade 9Fr. cardioplegia cannula</td><td>Edwards</td><td>AR012V</td><td></td></tr><tr><td>Coronary artery ostial cannula 90&amp;deg;</td><td>Medtronic</td><td>30155</td><td></td></tr><tr><td>Coronary artery ostial cannula 45&amp;deg;</td><td>Medtronic</td><td>30255</td><td></td></tr><tr><td>&lt;strong&gt;Soft tissue retractor&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>STAR soft tissue atraumatic retractor</td><td>Estech</td><td>EC400220</td><td></td></tr><tr><td>Soft tissue retractor</td><td>Edwards</td><td>TRM</td><td></td></tr><tr><td>Electrocautery</td><td>Covidien</td><td>Force FX&lt;sup&gt;TM&lt;/sup&gt;</td><td></td></tr><tr><td>&lt;strong&gt;Sutures:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Polypropylene 4/0</td><td>Ethicon</td><td>8871H</td><td></td></tr><tr><td>Polypropylene 5/0</td><td>Ethicon</td><td>8870H</td><td></td></tr><tr><td>Braided polyesther 2/0 ligature with polybutylate coating&amp;nbsp;</td><td>Ethicon</td><td>X305H</td><td></td></tr><tr><td>Braided polyesther2/0 with pledgets V5</td><td>Ethicon</td><td>MEH7715N</td><td></td></tr><tr><td>Braided polyglactin 2/0 suture</td><td>Ethicon</td><td>V114H</td><td></td></tr><tr><td>Braided polyglactin 0 suture</td><td>Ethicon</td><td>W9996</td><td></td></tr><tr><td>&lt;strong&gt;Drugs:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Midazolam</td><td>Roche Pharma</td><td>N05CD08</td><td></td></tr><tr><td>Rocuronium</td><td>MSD Merck Sharp &amp;amp; Dohme&amp;nbsp;</td><td>M03AC09</td><td></td></tr><tr><td>Propofol</td><td>Fresenius Kabi</td><td>N01AX10</td><td></td></tr><tr><td>Fentanil</td><td>Actavis</td><td>N01AH01</td><td></td></tr><tr><td>Heparin</td><td>Braun</td><td>B01AB01</td><td></td></tr><tr><td>Protamin</td><td>MEDA Pharmaceutical</td><td>V03AB14</td><td></td></tr><tr><td>Custodiol cardioplegia solution</td><td>Dr. F. K&amp;ouml;hler Chemie GmbH</td><td>B05CX10</td><td></td></tr><tr><td>&lt;strong&gt;Instruments:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Window access retractor SI</td><td>Estech</td><td>400-400</td><td></td></tr><tr><td>SI retractor blade 40W50L</td><td>Estech</td><td>400-172</td><td></td></tr><tr><td>Ceramo atraumatic forceps 2.8x15/350</td><td>Fehling</td><td>FE-MRA-3</td><td></td></tr><tr><td>Ceramo HCR valve forceps 3.0x15/350</td><td>Fehling</td><td>FE-MRA-0</td><td></td></tr><tr><td>Ceramo HCR needle holder 2x10/340</td><td>Fehling</td><td>FE-MRB-2</td><td></td></tr><tr><td>Ceramo TC HCR needle holder curved 3x10/340</td><td>Fehling</td><td>FE-MRG-9</td><td></td></tr><tr><td>Ceramo HCR valve scissors 350</td><td>Fehling</td><td>FE-MRA-7</td><td></td></tr><tr><td>Ceramo HCR curved scissors 350</td><td>Fehling</td><td>FE-MRA-6</td><td></td></tr><tr><td>Cygnet flexible arched aortic clamp</td><td>Vitalitec</td><td>V10143</td><td></td></tr><tr><td>Intrack insert set double traction</td><td>Vitalitec</td><td>N10122</td><td></td></tr><tr><td>Dissection forceps Carpentier</td><td>Delacroix-Chevalier</td><td>DC13110-28&amp;nbsp;</td><td></td></tr><tr><td>Scissors Metzenbaum</td><td>Delacroix-Chevalier</td><td>B351751</td><td></td></tr><tr><td>Needle holder Ryder</td><td>Delacroix-Chevalier</td><td>DC51130-20&amp;nbsp;</td><td></td></tr><tr><td>Dissection forceps DeBakey</td><td>Delacroix-Chevalier</td><td>DC12000-21&amp;nbsp;</td><td></td></tr><tr><td>Lung retractor</td><td>Delacroix-Chevalier</td><td>B803990</td><td></td></tr><tr><td>Allis clamp</td><td>Delacroix-Chevalier</td><td>DC45907-25&amp;nbsp;</td><td></td></tr><tr><td>O&amp;rsquo;Shaugnessy Dissector</td><td>Delacroix-Chevalier</td><td>B60650</td><td></td></tr><tr><td>18 blade knife</td><td>Delacroix-Chevalier</td><td>B130180</td><td></td></tr><tr><td>11 blade knife</td><td>Premiere</td><td>9311-2PK</td><td></td></tr><tr><td>Leriche haemostatic clamp</td><td>Delacroix-Chevalier</td><td>B86555</td><td></td></tr><tr><td>&lt;strong&gt;Data analysis&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Mann-Whitney and Chi-square tests</td><td>GraphPad</td><td>Prism 7</td><td></td></tr></tbody></table>

technique and patient selection criteria of right anterior mini-thoracotomy for minimal access aortic valve replacement

Aortic valve stenosis has become the most prevalent valvular heart disease in developed countries, and is due to the aging of these populations. The incidence of the pathology increases with growing age after 65 years. Conventional surgical aortic valve replacement through median sternotomy has been the gold standard of patient care for symptomatic aortic valve stenosis. However, as the risk profile of patients worsens, other therapeutic strategies have been introduced in an attempt to maintain the excellent results obtained by the established surgical treatment. One of these approaches is represented by transcatheter aortic valve implantation. Although the outcomes of high-risk patients undergoing treatment for symptomatic aortic valve stenosis have improved with transcatheter aortic valve replacement, many patients with this condition remain candidates for surgical aortic valve replacement. In order to reduce the surgical trauma in patients who are candidates for surgical aortic valve replacement, minimally invasive approaches have garnered interest during the past decade. Since the introduction of right anterior thoracotomy for aortic valve replacement in 1993, right anterior mini-thoracotomy and upper hemi-sternotomy have become the predominant incisional approaches among cardiac surgeons performing minimal access aortic valve replacement. Beside the location of the incision, the arterial cannulation site represents the second major landmark of minimal access techniques for aortic valve replacement. The two most frequently used arterial cannulation sites include central aortic and peripheral femoral approaches. With the purpose of reducing surgical trauma in these patients, we have opted for a right anterior mini-thoracotomy approach with a central aortic cannulation site. This protocol describes in detail a technique for minimally invasive aortic valve replacement and provides recommendations for patient selection criteria, including cardiac computer tomography measurements. The indications and limitations of this technique, as well as its alternatives, are discussed.

Statistical analysis is done for continuous variables (presented as means &#177; SD) in Table 2, Table 3, and Table 4 using the non-parametric Mann Whitney test. Categorical variables are presented as percentages in Table 2, Table 3, and Table 4, and are compared by the Chi-square test. The statistical analyses are performed using commercially available software, with a statistical significance threshold set at p&#60;0.05.
Table 2 depicts patient characteristics. Aortic valve replacement was done according to the described protocol of right anterior mini-thoracotomy in 196 patients who fulfilled the selection criteria (Table 1). Patient characteristics were similar to 171 patients undergoing aortic valve replacement through full sternotomy during the same period. The adoption of the approach was dictated by the choice of the patient, and fulfillment of the selection criteria, including technical feasibility according to the CT measurements (Table 1).
Intra operative data are shown in Table 3. Based on the pre-operative planning CT, access to the pleural space and the heart was secured through the third intercostal space in 80%, and the second in 20%, of the patients. In one patient, after the start of the cardio-pulmonary bypass, increasing perimeter of the abdomen and volume loss was observed. With the suspicion of an abdominal problem, a laparotomy was performed and an iatrogenic tear in the iliac vein of the percutaneously cannulated side was repaired. In order to shorten the cardiac and global operative times, the incision was extended by a transverse sternotomy and the aortic valve replacement performed afterwards in standard manner. The patient did well post-operatively. The data from this patient are included in the right mini-thoracotomy group. As expected, compared to the full sternotomy approach, a right anterior mini-thoracotomy necessitated significantly longer ischemic, cardio-pulmonary, and operative times. The proportion of biological versus mechanical valve substitutes did not differ between the groups.
Table 4 demonstrates early post-operative outcomes. In spite of longer operation times, with the exception of a peripheral cannulation complication, right anterior mini-thoracotomy did not increase the rate of major adverse cardiovascular and cerebrovascular events in comparison to full sternotomy incision. Patients undergoing right anterior mini-thoracotomy tended to be extubated earlier and stayed for a shorter period in the intensive care unit than those operated through full sternotomy, although the differences were not statistically significant. However, compared to full sternotomy, right anterior mini-thoracotomy significantly reduced the need for pain medication and transfusion requirements, the incidence of new onset atrial fibrillation and deep wound infection as well as the global length of hospital stay. In addition, patients reported great satisfaction with the cosmetic results (Figure 5).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57323/57323fig1.jpg" /> 
Figure 1:3-D chest CT reconstruction for pre-operative planning. Measurements from the mid-clavicular line to the aortic cannulation site (origin of the right innominate artery) and to the aortic valve of the second and third intercostal spaces (ICS) are reported on this image (1 mm in scale = 2.9 mm). In this case, the second ICS is chosen for incisional approach of the mini-thoracotomy while with comparable distances to the aortic valve, the distance to the cannulation site is shorter for the second compared to the third ICS. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57323/57323fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57323/57323fig2.jpg" /> 
Figure 2: CT measurements for pre-operative planning from the same patient as in Figure 1. (A) Annulus sizing. The largest and shortest aortic annulus are both greater than the 20 mm criterium for selection of the patients given in Table 1. (B) Distance from the left coronary ostium to the aortic annulus. This distance is greater than 12 mm criterium for selection of the patients given in Table 1. (C) Distance from the right coronary ostium to the aortic annulus. This distance is greater than 12 mm criterium for selection of the patients given in Table 1 (1 mm in scale = 2.9 mm). CT measurements of this patient fulfills the CT criteria for selection of the patients for right anterior mini-thoracotomy with pleural entry in the second ICS. RV = right ventricle, LA = left atrium, dAo = descending Aorta, LMCA = left main coronary artery, LV = left ventricle, RCA = right coronary artery, Ao = ascending aorta. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57323/57323fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57323/57323fig3.jpg" /> 
Figure 3: Bi-atrial view by transesophageal echocardiography. The venous cannula is inserted percutaneously through the right femoral vein and placed through the inferior vena cava (IVC) up to the origin of the superior vena cava (SVC) (1 mm in scale = 2.9 mm). LA = left atrium, RA = right atrium. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57323/57323fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57323/57323fig4.jpg" /> 
Figure 4: Global view of the cardiopulmonary set-up. The head of the patient is to the left of the picture. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57323/57323fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57323/57323fig5.jpg" /> 
Figure 5: Wound cosmetic. One week after aortic valve replacement through right anterior mini-thoracotomy, the general appearance of the wound is satisfactory. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57323/57323fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table fo:keep-together.within-page="1">
	<tbody>
		<tr>
			<td colspan="2">Absence of:</td>
		</tr>
		<tr>
			<td>chest deformities</td>
			<td></td>
		</tr>
		<tr>
			<td>previous right hemi-thorax surgery or irradiation</td>
			<td></td>
		</tr>
		<tr>
			<td>aneurysm of the ascending aorta</td>
			<td></td>
		</tr>
		<tr>
			<td>emergency operation</td>
			<td></td>
		</tr>
		<tr>
			<td>active endocarditis</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td colspan="2">Optimal measurements&#160; calculated from chest CT</td>
		</tr>
		<tr>
			<td>Intercostal space to aortic valve</td>
			<td>&#60; 120 mm</td>
		</tr>
		<tr>
			<td>Intercostal space to aortic cannulation site*</td>
			<td>&#60; 120 mm</td>
		</tr>
		<tr>
			<td>Aortic valve annulus diameter</td>
			<td>&#62; 20 mm</td>
		</tr>
		<tr>
			<td>Right coronary ostium to aortic valve annulus</td>
			<td>&#62; 12 mm</td>
		</tr>
		<tr>
			<td>Left coronary ostium to aortic valve annulus</td>
			<td>&#62; 12 mm</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td colspan="2">* Origin of the right innominate artery</td>
		</tr>
	</tbody>
</table>
Table 1: Selection criteria for right anterior mini-thoracotomy for isolated aortic valve replacement. After exclusion of patients with major chest deformities, previous right hemi-thorax irradiation or surgery and ascending aortic aneurysms, optimal measurements provided by chest CT allow the selection of the patient for the procedure and the choice of intercostal space for incision.
<table fo:keep-together.within-page="1">
	<tbody>
		<tr>
			<td></td>
			<td>Right anterior mini-thoracotomy</td>
			<td>Full sternotomy</td>
			<td>p value</td>
		</tr>
		<tr>
			<td>N</td>
			<td>196</td>
			<td>171</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Age, years</td>
			<td>70&#177;10</td>
			<td>68&#177;13</td>
			<td>0.26</td>
		</tr>
		<tr>
			<td>LVEF &#60; 0.35 (%)</td>
			<td>2 (1)</td>
			<td>4 (2.3)</td>
			<td>0.2</td>
		</tr>
		<tr>
			<td>Hematocrit %</td>
			<td>38.9&#177;2</td>
			<td>37.2&#177;1.6</td>
			<td>0.09</td>
		</tr>
		<tr>
			<td>Native valve disease</td>
			<td></td>
			<td></td>
			<td>0.16</td>
		</tr>
		<tr>
			<td>AS</td>
			<td>155</td>
			<td>135</td>
			<td></td>
		</tr>
		<tr>
			<td>AI</td>
			<td>34</td>
			<td>27</td>
			<td></td>
		</tr>
		<tr>
			<td>AS+AI</td>
			<td>7</td>
			<td>9</td>
			<td></td>
		</tr>
		<tr>
			<td>COPD (%)</td>
			<td>13 (6.6)</td>
			<td>14 (8.2)</td>
			<td>0.8</td>
		</tr>
		<tr>
			<td>CVD (%)</td>
			<td>17 (8.7)</td>
			<td>16 (9.4)</td>
			<td>0.9</td>
		</tr>
		<tr>
			<td>PVD (%)</td>
			<td>10 (5.1)</td>
			<td>11 (6.4)</td>
			<td>0.14</td>
		</tr>
		<tr>
			<td>Diabetes mellitus (%)</td>
			<td>29 (14.8)</td>
			<td>18 (10.5)</td>
			<td>0.42</td>
		</tr>
		<tr>
			<td>Arterial hypertension (%)</td>
			<td>91 (46)</td>
			<td>105 (61)</td>
			<td>0.27</td>
		</tr>
		<tr>
			<td>CHF (%)</td>
			<td>3 (1.5)</td>
			<td>8 (4.7)</td>
			<td>0.26</td>
		</tr>
		<tr>
			<td>Euroscore*</td>
			<td>3.8&#177;2.0</td>
			<td>2.6&#177;2.4</td>
			<td>0.7</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td colspan="4">LVEF: left ventricular ejection fraction</td>
		</tr>
		<tr>
			<td colspan="4">AS: aortic stenosis</td>
		</tr>
		<tr>
			<td colspan="4">AI: aortic insufficiency</td>
		</tr>
		<tr>
			<td colspan="4">COPD: chronic obstructive pulmonary disease</td>
		</tr>
		<tr>
			<td colspan="4">CVD: cerebro-vascular disease</td>
		</tr>
		<tr>
			<td colspan="4">PVD: peripheral vascular disease</td>
		</tr>
		<tr>
			<td colspan="4">CHF: congestive heart failure</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td colspan="4">* Reference 15</td>
		</tr>
	</tbody>
</table>
Table 2: Patients&#39; characteristics. The pre-operative condition of the patients undergoing right anterior mini-thoracotomy is comparable to that of patients operated by a full sternotomy approach.
<table fo:keep-together.within-page="1">
	<tbody>
		<tr>
			<td></td>
			<td>Right anterior mini-thoracotomy</td>
			<td>Full sternotomy</td>
			<td>p value</td>
		</tr>
		<tr>
			<td>N</td>
			<td>196</td>
			<td>171</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Operative time (min)</td>
			<td>274&#177;60</td>
			<td>209&#177;48</td>
			<td>0.0001</td>
		</tr>
		<tr>
			<td>CPB time (min)</td>
			<td>157&#177;36</td>
			<td>110&#177;27</td>
			<td>0.0001</td>
		</tr>
		<tr>
			<td>Cross-clamp time (min)</td>
			<td>108&#177;23</td>
			<td>62&#177;15</td>
			<td>0.0001</td>
		</tr>
		<tr>
			<td>Biological valve (%)</td>
			<td>161 (82)</td>
			<td>121 (71)</td>
			<td>0.09</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td colspan="4">CPB: cardiopulmonary bypass</td>
		</tr>
	</tbody>
</table>
Table 3: Intra-operative data. Operation times and type of the valve substitute of the two cohorts of right anterior mini-thoracotomy and full sternotomy approaches.
<table fo:keep-together.within-page="1">
	<tbody>
		<tr>
			<td></td>
			<td>Right anterior mini-thoracotomy</td>
			<td>Full sternotomy</td>
			<td>p value</td>
		</tr>
		<tr>
			<td>N</td>
			<td>196</td>
			<td>171</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Early mortality (%)</td>
			<td>3 (1.5)</td>
			<td>3 (1.8)</td>
			<td>0.1</td>
		</tr>
		<tr>
			<td>Re-op. for bleeding (%)</td>
			<td>4 (2)</td>
			<td>4 (2.3)</td>
			<td>0.6</td>
		</tr>
		<tr>
			<td>Peri-op. MI (%)</td>
			<td>1 (0.5)</td>
			<td>2 (1.2)</td>
			<td>0.3</td>
		</tr>
		<tr>
			<td>Stroke (%)</td>
			<td>5 (2.6)</td>
			<td>6 (3.5)</td>
			<td>0.7</td>
		</tr>
		<tr>
			<td>Ventilation time (h)</td>
			<td>10.2&#177;6.3</td>
			<td>14.4&#177;20</td>
			<td>0.09</td>
		</tr>
		<tr>
			<td>ICU stay (d)</td>
			<td>2&#177;3.3</td>
			<td>3.7&#177;14</td>
			<td>0.4</td>
		</tr>
		<tr>
			<td>New onset Afib (%)</td>
			<td>35 (18)</td>
			<td>51 (30)</td>
			<td>0.02</td>
		</tr>
		<tr>
			<td>RBC&#8217;s (pack/patient)</td>
			<td>1.6&#177;2.8</td>
			<td>2.1&#177;2.1</td>
			<td>0.002</td>
		</tr>
		<tr>
			<td>MS (mg/day)*</td>
			<td>39.7&#177;22.8</td>
			<td>52.5&#177;26.3</td>
			<td>0.007</td>
		</tr>
		<tr>
			<td>Deep wound infection (%)</td>
			<td>0 (0)</td>
			<td>2 (1.2)</td>
			<td>0.02</td>
		</tr>
		<tr>
			<td>Hospital stay (d)</td>
			<td>8.2&#177;2.7</td>
			<td>10.2&#177;7.3</td>
			<td>0.04</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td colspan="4">MI: myocardial infarction</td>
		</tr>
		<tr>
			<td colspan="4">ICU: intensive care unit</td>
		</tr>
		<tr>
			<td colspan="4">Afib: atrial fibrillation</td>
		</tr>
		<tr>
			<td colspan="4">RBC: Red blood cells</td>
		</tr>
		<tr>
			<td colspan="4">MS: Morphine sulfate for the first 5 post-operative days&#160;</td>
		</tr>
		<tr>
			<td colspan="4">* for the first 3 days</td>
		</tr>
	</tbody>
</table>
Table 4: Early outcomes. In spite of longer operation times, right anterior mini-thoracotomy resulted in better early outcomes without increasing major adverse events.

Watch this Scientific Journal Video about Technique and Patient Selection Criteria of Right Anterior Mini-Thoracotomy for Minimal Access Aortic Valve Replacement at JoVE.com

Technique and Patient Selection Criteria of Right Anterior Mini-Thoracotomy for Minimal Access Aortic Valve Replacement

The goal of this protocol is to describe in detail the technique of minimally invasive aortic valve replacement through a right anterior mini-thoracotomy and central aortic cannulation. This technique can potentially enhance patients&#39; comfort and, by reducing post-operative morbidity, promote lowering the length of stay and global costs.

Aortic valve stenosis has become the most prevalent valvular heart disease in developed countries, and is due to the aging of these populations. The ...

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Nanyang Technological University

Research

JoVE Journal

Medicine

11.6K Views.  Institut de Cardiologie. Het doel van dit protocol is in detail te beschrijven de techniek van minimaal invasieve aortaklep vervanging door middel van een direct anterieure mini Thoracotomie en centrale aorta cannulation. Deze techniek kan potentieel versterken van patiëntenverenigingen comfort en, door het verminderen van post-operatieve morbiditeit, bevordering van de lengte van verblijf en globale kosten te verlagen.

Video: Technique and Patient Selection Criteria of Right Anterior Mini-Thoracotomy for Minimal Access Aortic Valve Replacement

Minimally Invasive Transverse Aortic Constriction in Mice

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard open-chest transverse aortic constriction (TAC). Although transverse aortic constriction is a highly functional method for the induction of high pressure in the left ventricle, it is a more difficult and lengthy procedure due to its use of artificial ventilation with tracheal intubation. TAC is oftentimes also less survivable, as the newer method, MTAC, neither requires the cutting of the ribs and intercostal muscles nor tracheal intubation with a ventilation setup. In MTAC, as opposed to a thoracotomy to access to the chest cavity, the aortic arch is reached through a midline incision in the anterior neck. The thyroid is pulled back to reveal the sternal notch. The sternum is subsequently cut down to the second rib level, and the aortic arch is reached simply by separating the connective tissues and thymus. From there, a suture can be wrapped around the arch and tied with a spacer, and then the sternal cut and skin can be closed. MTAC is a much faster and less invasive way to induce left ventricular hypertension and enables the possibility for high-throughput studies. The success of the constriction can be verified using high-frequency trans-thoracic echocardiography, particularly color Doppler and pulsed-wave Doppler, to determine the flow velocities of the aortic arch and left and right carotid arteries, the dimension of the blood vessels, and the left ventricular function and morphology. A successful constriction will also trigger significant histopathological changes, such as cardiac muscle cell hypertrophy with interstitial and perivascular fibrosis. Here, the procedure of MTAC is described, demonstrating how the resulting flow changes in the carotid arteries can be examined with echocardiography, gross morphology, and histopathological changes in the heart.

Minimally invasive transverse aortic constriction (MTAC) conserves the essentials of regular transverse aortic constriction (TAC) while eliminating the use of a ventilator with tracheal intubation. It proves to be a highly desirable method for high-throughput studies on left ventricular overload, particularly in translational studies.

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard ...

Full-root Aortic Valve Replacement by Stentless Aortic Xenografts in Patients with Small Aortic Roots

In patients with small aortic roots who need an aortic valve replacement with biological valve substitutes, the implantation of the stented pericardial valve might not meet the functional needs. The implantation of a too-small stented pericardial valve, leading to an effective orifice area indexed to a body surface area less than 0.85 cm2/m2, is regarded as prosthesis-patient mismatch (PPM). A PPM negatively affects the regression of left ventricular hypertrophy and thus the normalization of left ventricular function and the alleviation of symptoms. Persistent left ventricular hypertrophy is associated with an increased risk of arrhythmias and sudden cardiac death. In the case of predictable PPM, there are three options: 1) accept the PPM resulting from the implantation of a stented pericardial valve when comorbidities of the patient forbid the more technically demanding operative technique of implanting a larger prosthesis, 2) enlarge the aortic root to accommodate a larger stented valve substitute, or 3) implant a stentless biological valve or a homograft. Compared to classical aortic valve replacement with stented pericardial valves, the full-root implantation of stentless aortic xenografts offers the possibility of implanting a 3-4 mm larger valve in a given patient, thus allowing significant reduction in transvalvular gradients. However, a number of cardiac surgeons are reluctant to transform a classical aortic valve replacement with stented pericardial valves into the more technically challenging full-root implantation of stentless aortic xenografts. Given the potential hemodynamic advantages of stentless aortic xenografts, we have adopted full-root implantation to avoid PPM in patients with small aortic roots necessitating an aortic valve replacement. Here, we describe in detail a technique for the full-root implantation of stentless aortic xenografts, with emphasis on the management of the proximal suture line and coronary anastomoses. Limitations of this technique and alternative options are discussed.

Full-root aortic valve replacement by stentless aortic xenograft is a viable option in patients with small aortic roots. We describe, a technique for the full-root implantation of stentless aortic xenografts, with emphasis on the management of the proximal suture line and coronary anastomoses, and discuss its limitations and alternative options.

In patients with small aortic roots who need an aortic valve replacement with biological valve substitutes, the implantation of the stented pericardial ...

Technique of Minimally Invasive Transverse Aortic Constriction in Mice for Induction of Left Ventricular Hypertrophy

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure overload-induced left ventricular hypertrophy (LVH) and its progression to heart failure. In the majority of the reported investigations, this procedure is performed with intubation and ventilation of the animal which renders it demanding and time-consuming and adds to the surgical burden to the animal. The aim of this protocol is to describe a simplified technique of minimally invasive TAC without intubation and ventilation of mice. Critical steps of the technique are emphasized in order to achieve low mortality and high efficiency in inducing LVH.
Male C57BL/6 mice (10-week-old, 25-30 g, n=60) were anesthetized with a single intraperitoneal injection of a mixture of ketamine and xylazine. In a spontaneously breathing animal following a 3-4 mm upper partial sternotomy, a segment of 6/0 silk suture threaded through the eye of a ligation aid was passed under the aortic arch and tied over a blunted 27-gauge needle. Sham-operated animals underwent the same surgical preparation but without aortic constriction. The efficacy of the procedure in inducing LVH is attested by a significant increase in the heart/body weight ratio. This ratio is obtained at days 3, 7, 14 and 28 after surgery (n = 6 - 10 in each group and each time point). Using our technique, LVH is observed in TAC compared to sham animals from day 7 through day 28. Operative and late (over 28 days) mortalities are both very low at 1.7%.
In conclusion, our cost-effective technique of minimally invasive TAC in mice carries very low operative and post-operative mortalities and is highly efficient in inducing LVH. It simplifies the operative procedure and reduces the strain put on the animal. It can be easily performed by following the critical steps described in this protocol.

The aim of this protocol is to describe step-by-step the technique of minimally invasive transverse aortic constriction (TAC) in mice. By elimination of intubation and ventilation which are mandatory for the commonly used standard procedure, minimally invasive TAC simplifies the operative procedure and reduces the strain put on the animal.

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure ...

Standardized Technique of Aortic Valve Re-implantation for Valve-sparing Aortic Root Replacement

Despite the obvious advantages of the preservation of a normal aortic valve during aortic root replacement, the complexity of valve sparing procedures prevents a number of cardiac surgeons from incorporating them into their practice. The aim of this protocol is to describe a simplified and user-friendly technique of an aortic valve-sparing root replacement (VSRR) procedure by re-implantation of the aortic valve. Proper selection of patients and limitations of the technique are discussed.
In 54 consecutive patients, normal appearing aortic valves were re-implanted in a commercially available polyester prosthesis with pre-shaped sinuses by a simplified and standardized technique. Placement of the first row of the proximal suture line, choice of the prosthesis size, and adjustment of the height of the commissures of the patient to the fixed height of the sinus portion of the prosthesis were slightly modified from the reference techniques with the aim of increasing its feasibility for use by other cardiac surgeons. Early mortality and morbidity as well as 5-year survival, freedom from aortic valve reoperation, and freedom from recurrent moderate regurgitation were collected in all patients.
Thirty-day mortality, re-sternotomy for bleeding, re-sternotomy for mediastinitis, and the incidence of stroke were very low, 1.8% for each (1 of 54). No patient required permanent pace-maker implantation. At 5 years, survival, freedom from aortic valve reoperation, and freedom from recurrent moderate regurgitation were 97.5%, 95.2%, and 91.6%, respectively.
Mid-term results of our standardized technique of re-implantation of the aortic valve for valve-sparing aortic root replacement are very good and compare with more complex techniques reported by experienced surgeons. By following the present protocol of the standardized re-implantation technique, a greater number of cardiac surgeons can perform this procedure with comparable good results.

Valve-sparing aortic root replacement has the advantage of preserving the patient&#39;s own aortic valve. The complexity of the reported techniques to date restricts their use to a limited number of cardiac surgeons. This protocol describes step-by-step a standardized technique reproducible by a greater number of cardiac surgeons.

Despite the obvious advantages of the preservation of a normal aortic valve during aortic root replacement, the complexity of valve sparing procedures ...

Semi-Minimal Invasive Method to Induce Myocardial Infarction in Rats and the Assessment of Cardiac Function by an Isolated Working Heart System

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily and highly reproducible MI induction procedure is required to obtain further insight and better understanding of the underlying pathological changes. This procedure can also be used to evaluate the effects or potency of new and promising treatments (as drugs or interventions) in acute MI, subsequent remodeling and heart failure (HF). After intubation and pre-operative preparation of the animal, an anesthetic protocol with isoflurane was performed, and the surgical procedure was conducted&#160;quickly. Using a minimally invasive approach, the left anterior descending artery (LAD) was located and occluded by a ligature. The occlusion can be performed acutely for subsequent reperfusion (ischemia/reperfusion injury). Alternatively, the vessel can be ligated permanently to investigate the development of chronic MI, remodeling or HF. Despite common pitfalls, the drop-out rates are minimal. Various treatments such as remote ischemic conditioning can be examined for their cardioprotective potential pre-, peri- and post-operatively. The post-operative recovery was quick as the anesthesia was precisely controlled and the duration of the operation was short. Post-operative analgesia was administered for three days. The minimally invasive procedure reduces the risk of infection and inflammation. Furthermore, it facilitates rapid recovery. The &#8220;working heart&#8221; measurements were performed ex vivo and enabled precise control of preload, afterload and flow. This procedure requires specific equipment and training for adequate performance. This manuscript provides a detailed step-by-step introduction for conducting these measurements.

This article presents an efficient method to perform myocardial ischemia and subsequent chronic reperfusion in rats using a minimally invasive approach. In addition, left ventricular hemodynamic function of rats is assessed by echocardiography and isolated working heart methods.&#160;

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily ...

Intravascular Lithotripsy-Assisted Transfemoral Transcatheter Aortic Valve Implantation

During the last decade, transcatheter aortic valve implantation (TAVI) has evolved as a well-established therapy for aging patients suffering from symptomatic severe aortic valve stenosis. This is also reflected in the recently updated international guidelines on managing patients with valvular heart disease. A transfemoral&#160;(TF) TAVI&#160;approach has proven superior to alternative access strategies. With the introduction of intravascular lithotripsy (IVL), patients with calcified iliofemoral vascular disease and borderline intraluminal diameters have also become candidates for percutaneous TF-TAVI. Moreover, IVL reduces the risk of major vascular complications by modifying the superficial and deep vascular calcium, thereby changing the vessel compliance and controlling luminal expansion. In this way, IVL has shown to safely facilitate TF delivery of TAVI devices in patients with calcified peripheral artery disease. The present article aims to provide a detailed step-by-step description on how to perform IVL-assisted TF-TAVI safely and efficiently. Furthermore, a literature review on the outcomes obtained with this technology is included, along with a concise discussion on this unique TAVI approach.

Transcatheter aortic valve implantation (TAVI) has been shown to generate the best clinical outcomes when performed by the percutaneous transfemoral approach. Intravascular lithotripsy (IVL) can facilitate a transfemoral process in patients with calcified iliofemoral vascular disease and borderline intraluminal diameters. The present protocol describes IVL-assisted transfemoral TAVI.

During the last decade, transcatheter aortic valve implantation (TAVI) has evolved as a well-established therapy for aging patients suffering from ...

Chronic Ovine Model of Right Ventricular Failure and Functional Tricuspid Regurgitation

The pathophysiology of severe functional tricuspid regurgitation (FTR) associated with right ventricular dysfunction is poorly understood, leading to suboptimal clinical results. We set out to establish a chronic ovine model of FTR and right heart failure to investigate the mechanisms of FTR. Twenty adult male sheep (6-12 months old, 62 &#177; 7 kg) underwent a left thoracotomy and baseline echocardiography. A pulmonary artery band (PAB) was placed and cinched around the main pulmonary artery (PA) to at least double the systolic pulmonary artery pressure (SPAP), inducing right ventricular (RV) pressure overload and signs of RV dilatation. PAB acutely increased the SPAP from 21 &#177; 2 mmHg to 62 &#177; 2 mmHg. The animals were followed for 8 weeks, symptoms of heart failure were treated with diuretics, and surveillance echocardiography was used to assess for pleural and abdominal fluid collection. Three animals died during the follow-up period due to stroke, hemorrhage, and acute heart failure. After 2 months, a median sternotomy and epicardial echocardiography were performed. Of the surviving 17 animals, 3 developed mild tricuspid regurgitation, 3 developed moderate tricuspid regurgitation, and 11 developed severe tricuspid regurgitation. Eight weeks of pulmonary artery banding resulted in a stable chronic ovine model of right ventricular dysfunction and significant FTR. This large animal platform can be used to further investigate the structural and molecular basis of RV failure and functional tricuspid regurgitation.

Right ventricular failure and functional tricuspid regurgitation are associated with left-sided heart disease and pulmonary hypertension, which contribute significantly to morbidity and mortality in patients. Establishing a chronic ovine model to study right ventricular failure and functional tricuspid regurgitation will help in understanding their mechanisms, progression, and possible treatments.

The pathophysiology of severe functional tricuspid regurgitation (FTR) associated with right ventricular dysfunction is poorly understood, leading to ...

Fully Endoscopic Mitral Valve Repair with Percutaneous Cannulation of Groin Vessels

Endoscopic mitral valve surgery (EMS) has become a standard of care at specialized heart centers, further reducing surgical trauma compared to a traditional minimally invasive, thoracotomy-based approach. Exposure of the groin vessels for the establishment of cardiopulmonary bypass (CPB) via surgical cutdown in minimally invasive surgery (MIS) may result in wound healing disorders or seroma formation. The avoidance of surgical exposure of the groin vessels by using fully percutaneous techniques for the insertion of a CPB cannula with the implementation of vascular pre-closure devices has the potential to reduce these complications and improve clinical results. Herein, we present the utilization of a novel plug based vacsular closure device with a resobable collagen plug and the absence of suture material for closure of the arterial access for CPB in MIS. While this device was initially predominantly used in transcatheter aortic valve implantation (TAVI) procedures, with its safety and feasibility shown, we herein show that it can be used in CPB cannulation, since it is capable of closing arterial access sites up to 25 French (Fr.) in size. This device may be suitable to significantly reduce groin complications in MIS and simplify the establishment of CPB. Here, we describe the fundamental steps of EMS, including percutaneous groin cannulation and decannulation using a vascular closure device.

This protocol demonstrates in detail how to perform fully endoscopic mitral valve surgery (EMS) with percutaneous cannulation of the groin vessels, using a percutaneous plug-based vascular closure device. Fundamental steps and useful instructions are described in detail for each step.

Endoscopic mitral valve surgery (EMS) has become a standard of care at specialized heart centers, further reducing surgical trauma compared to a ...

Ascending Aortic Banding for Studying Pressure-Overload Induced Heart Failure

A Minimally Invasive Model of Aortic Stenosis in Swine

Large animal models of heart failure play an essential role in the development of new therapeutic interventions due to their size and physiological similarities to humans. Efforts have been dedicated to creating a model of pressure-overload induced heart failure, and ascending aortic banding while still supra-coronary and not a perfect mimic of aortic stenosis in humans, closely resembling the human condition.
The purpose of this study is to demonstrate a minimally invasive approach to induce left ventricular pressure overload by placing an aortic band, precisely calibrated with percutaneously introduced high-fidelity pressure sensors. This method represents a refinement of the surgical procedure (3Rs), resulting in homogenous trans-stenotic gradients and reduced intragroup variability. Additionally, it enables swift and uneventful animal recovery, leading to minimal mortality rates. Throughout the study, animals were followed for up to 2 months after surgery, employing transthoracic echocardiography and pressure-volume loop analysis. However, longer follow-up periods can be achieved if desired. This large animal model proves valuable for testing new drugs, particularly those targeting hypertrophy and the structural and functional alterations associated with left ventricular pressure overload.

Author Spotlight: Development of a Minimally Invasive Large-Animal Model for Reliable and Reproducible Cardiovascular Research 

This protocol describes a minimally invasive surgical procedure for ascending aortic banding in swine.

Large animal models of heart failure play an essential role in the development of new therapeutic interventions due to their size and physiological ...

A Modified Technique for Transverse Aortic Constriction in Mice

Transverse aortic constriction (TAC) is a frequently used surgery in research regarding heart failure and cardiac hypertrophy based on the formation of pressure overload in mouse models. The main challenge of this procedure is to clearly visualize the transverse aortic arch and precisely band the target vessel. Classical approaches perform a partial thoracotomy to expose the transverse aortic arch. However, it is an open-chest model that causes a rather large surgical trauma and requires a ventilator during the surgery. To prevent unnecessary trauma and simplify the operating procedure, the aortic arch is approached via the proximal proportion of the sternum, reaching and binding the target vessel using a small self-made retractor that contains a snare. This procedure can be conducted without entering the pleura cavity and does not need a ventilator or microsurgical operation, which leaves the mice with physiological breathing patterns, simplifies the procedure, and significantly reduces operation time. Due to the less invasive approach and less operation time, mice can undergo fewer stress reactions and recover rapidly.

The present protocol describes a modified and simplified technique with a minimally invasive transverse aortic constriction (TAC) procedure using a self-made retractor. This procedure can be conducted without a ventilator or microscope and introduces pressure overload, eventually leading to cardiac hypertrophy or heart failure.

Transverse aortic constriction (TAC) is a frequently used surgery in research regarding heart failure and cardiac hypertrophy based on the formation of ...

Technique and Patient Selection Criteria of Right Anterior Mini-Thoracotomy for Minimal Access Aortic Valve Replacement

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