This work was supported by a grant from the Swiss Cardiovascular Foundation to RT.

<ol>
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O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Focused+update+incorporated+into+the+ACC/AHA+2006+guidelines+for+the+management+of+patients+with+valvular+heart+disease:+A+report+of+the+American+College+of+Cardiology/American+Heart+Association+Task+Force+on+Practice+Guidelines+(Writing+Committee+to+Revise+the+1998+Guidelines+for+the+Management+of+Patients+With+Valvular+Heart+Disease):+endorsed+by+the+Society+of+Cardiovascular+Anesthesiologists,+Society+for+Cardiovascular+Angiography+and+Interventions,+and+Society+of+Thoracic+Surgeons.">Focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons.</a> Circulation. 118 (15), e523-e661 (2008).</li><li>Rahimtoola, S. 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G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemodynamic+and+clinical+impact+of+prosthesis-patient+mismatch+in+the+aortic+valve+position+and+its+prevention.">Hemodynamic and clinical impact of prosthesis-patient mismatch in the aortic valve position and its prevention.</a> J. Am. Coll. Cardiol. 36 (4), 1131-1141 (2000).</li><li>Kang, Y. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+hypertrophy:+a+risk+factor+for+QT-prolongation+and+cardiac+sudden+death.">Cardiac hypertrophy: a risk factor for QT-prolongation and cardiac sudden death.</a> Toxicol. Pathol. 34 (1), 58-66 (2006).</li><li>Castro, L. J., Arcidi, J. M., Fisher, A. L., Gaudiani, V. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Routine+enlargement+of+the+small+aortic+Root:+a+preventive+strategy+to+minimize+mismatch.">Routine enlargement of the small aortic Root: a preventive strategy to minimize mismatch.</a> Ann. Thorac. Surg. 74 (1), 31-36 (2002).</li><li>Kunihara, T., Schmidt, K., Glombitza, P., Dzindzibadze, V., Lausberg, H., Sch&#228;fers, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Root+replacement+using+stentless+valves+in+the+small+aortic+root:+A+propensity+score+analysis.">Root replacement using stentless valves in the small aortic root: A propensity score analysis.</a> Ann. Thorac. Surg. 82 (4), 1379-1384 (2006).</li><li>Yacoub, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fourteen-year+experience+with+homovital+homografts+for+aortic+valve+replacement.">Fourteen-year experience with homovital homografts for aortic valve replacement.</a> J. Thorac. Cardiovac. Surg. 110 (1), 186-194 (1995).</li><li>Sommers, K. E., David, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aortic+valve+replacement+with+patch+enlargement+of+the+aortic+annulus.">Aortic valve replacement with patch enlargement of the aortic annulus.</a> Ann. Thorac. Surg. 63, 1608-1612 (1997).</li><li>El-Hamamsy, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rate+of+progression+and+functional+significance+of+aortic+root+calcification+after+homograft+versus+freestyle+aortic+root+replacement.">Rate of progression and functional significance of aortic root calcification after homograft versus freestyle aortic root replacement.</a> Circulation. 120 (Suppl 1), S269-S275 (2009).</li><li>Bach, D. S., Kon, N. D., Dumesnil, J. G., Sintek, C. F., Doty, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ten-year+outcome+after+aortic+valve+replacement+with+the+Freestyle+stentless+bioprosthesis.">Ten-year outcome after aortic valve replacement with the Freestyle stentless bioprosthesis.</a> Ann. Thorac. Surg. 80 (2), 480-487 (2005).</li><li>Ennker, I. C., Albert, A., Dalladaku, F., Rosendahl, U., Ennker, J., Florath, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Midterm+outcome+after+aortic+root+replacement+with+stentless+porcine+bioprostheses.">Midterm outcome after aortic root replacement with stentless porcine bioprostheses.</a> Eur. J Cardio-thorac. Surg. 40 (2), 429-434 (2011).</li><li>Tavakoli, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Full-root+aortic+valve+replacement+with+stentless+xenograft+achieves+superior+regression+of+left+ventricular+hypertrophy+compared+to+pericardial+stented+aortic+valves.">Full-root aortic valve replacement with stentless xenograft achieves superior regression of left ventricular hypertrophy compared to pericardial stented aortic valves.</a> J. Cardiothorac. Surg. 10, 15 (2015).</li><li>Kon, N. D., Cordell, A. R., Adair, S. M., Dobbins, J. E., Kitzman, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aortic+root+replacement+with+the+Freestyle+stentless+porcine+aortic+root+bioprosthesis.">Aortic root replacement with the Freestyle stentless porcine aortic root bioprosthesis.</a> Ann. Thorac. Surg. 67 (6), 1609-1616 (1999).</li><li>Dapunt, O. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stentless+full-root+bioprosthesis+in+surgery+for+complex+aortic+valve-ascending+aortic+disease:+a+single+center+experience+of+over+300+patients.">Stentless full-root bioprosthesis in surgery for complex aortic valve-ascending aortic disease: a single center experience of over 300 patients.</a> Eur. J. Cardiothorac. Surg. 33 (4), 554-559 (2008).</li><li>Saxena, A., Dinh, D., Smith, J. A., Reid, C. M., Shardey, G., Newcomb, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Training+surgeon+status+is+not+associated+with+an+increased+risk+of+early+or+late+mortality+after+isolated+aortic+valve+replacement+surgery.">Training surgeon status is not associated with an increased risk of early or late mortality after isolated aortic valve replacement surgery.</a> Cardiol. J. 21 (2), 183-190 (2014).</li><li>D'Agostino, R. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Society+of+Thoracic+Surgeons+Adult+Cardiac+Surgery+Database:+2016+Update+on+Outcomes+and+Quality.">The Society of Thoracic Surgeons Adult Cardiac Surgery Database: 2016 Update on Outcomes and Quality.</a> Ann. Thorac. Surg. 101 (1), 24-32 (2016).</li><li>Fries, R., Wendler, O., Schieffer, H., Sch&#228;fers, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+rest+and+exercise+hemodynamics+of+23-mm+stentless+versus+23-mm+stented+aortic+bioprostheses.">Comparative rest and exercise hemodynamics of 23-mm stentless versus 23-mm stented aortic bioprostheses.</a> Ann. Thorac. Surg. 69 (3), 817-822 (2000).</li></ol>

The authors have nothing to disclose.

This study reports a detailed description of the surgical technique of full-root aortic valve replacement using stentless aortic xenografts in patients with small aortic roots. Early morbidity and mortality are very low and compare favorably with other reports7. Heavily calcified coronary ostia constitute an anatomical limitation to this technique. Another drawback to this technique is represented by patients with a poor general condition who would not tolerate longer operative times. In these cases, a standard stented pericardial aortic valve replacement, with or without aortic root enlargement, should be preferred to the more demanding full-root stentless aortic xenograft implantation6.
This protocol calls for six running 4/0 polypropylene sutures for the proximal anastomosis. Similarly to multiple interrupted sutures used by other authors14,15, this technique for the proximal anastomosis leads to a better distribution of tension on the proximal anastomosis and thus avoids pleating of the suture line. Compared to multiple interrupted sutures, the use of six semi-continuous running sutures is slightly time-saving. Moreover, it makes the use of reinforcement of the suture line by pericardial or polytetrafluoroethylene strips for the control of postoperative bleeding7,12,14 unnecessary. In these patients, no resternotomy was necessary for bleeding. A potential disadvantage of a single running suture for the proximal anastomosis advocated by some authors7,12 is the risk of pleating of the valve substitute and the left ventricular outflow tract.
Besides the potential of increased postoperative bleeding, coronary anastomotic problems constitute another major concern of cardiac surgeons who are not willing to use the full-root technique for the implantation of stentless aortic xenografts. Possible coronary anastomotic problems can arise, from kinking of patient&#39;s coronaries after re-implantation to tissue tear related to excessive tension on the anastomosis. To adapt the placement of the coronary neo-ostia of the graft to the coronary ostia of the patient, the left coronary neo-ostium is first created in the graft by extending the existing left coronary hole or ligated artery towards the commissure between the left and non-coronary sinus of the stentless graft. Upon completion of the proximal suture line and re-connection of the left coronary anastomosis, the place of re-connection of the right coronary ostium of the patient is adjusted according to the right coronary sinus of the graft. To do so, the right coronary neo-ostium in the graft is created by extending the existing right coronary hole or ligated artery towards the commissure between the right and non-coronary sinus of the stentless graft. Proximal mobilization over 1-2 cm of the main coronary arteries further helps in eliminating excessive tension on the coronary anastomoses and thus the potential for tissue tear and bleeding. This technique avoids the rotation of the stentless graft suggested by other authors12.
The cross-clamp, cardio-pulmonary bypass, and operative times for this technique are expectedly longer than those for standard aortic valve replacements with stented valves16. However, they compare favorably with those reported by Kunihara et al.7 for the full-root implantation of stentless aortic xenografts. Despite the prolongation of the operative times in our patients, the perioperative morbidity and mortality are not adversely affected, as compared to those reported in the STS Adult Cardiac Surgery database17 for isolated aortic valve replacement. In particular, the incidence of re-exploration for bleeding, complete heart block requiring definitive pace maker implantation, stroke, deep sternal infection, or early mortality are very low and similar to those reported by Kunihara et al.7 for the full-root implantation of stentless aortic xenografts and by ourselves for the isolated aortic valve replacement by stented pericardial valves13.
The labelled size of all commercially available mechanical and biological valve substitutes indicates the global (external) diameter of the valve. However, for stented valve substitutes, including mechanical and biological stented pericardial valves, the sewing ring of the valve occupies between 3 and 4 mm of the global (external) diameter of the valve and correspondingly reduces the functionally useful internal diameter. Biological stentless aortic xenografts are devoid of similar obstructive sewing rings. Hence, the functionally useful internal diameter of these valve substitutes is very close to their global (external) diameter as commercially labelled. As a result, for a given labelled size, biological stentless valves offer a functionally useful internal diameter larger than biological stented pericardial valves. A larger functionally useful internal diameter allows for a greater opening area of the valve, known as the effective orifice area of the valve. A better opening area of the valve, adjusted for the body surface area, known as the indexed effective orifice area, provides for superior hemodynamics and potentially for better functional relief of the patient. In this regard, a comparison between 23 mm stented and stentless valves implanted by the full-root technique showed better hemodynamics in the latter in terms of transvalvular gradients. As a consequence, better patient outcomes were observed in terms of regression of left ventricular hypertrophy18.
The selection of adult patients with small aortic roots for full-root stentless aortic xenograft implantation was based on the projected (i.e., preoperatively expected) EOAI. In concrete terms, in patients with an aortic annulus diameter of less than 20 mm, estimated on preoperative echocardiography, a subgroup with a body surface area of greater than 1.6 m2 was identified. These patients are at risk of PPM if they receive a stented pericardial valve offering an effective orifice area of 1.28 cm2, with a resulting indexed orifice area of 0.8 cm2/m2. It has been shown that projected EOAI of less than 0.85 cm2/m2 predicts PPM, with adverse effects on postoperative, long-term transvalvular gradients and patient outcomes3,4.
Another option to accommodate a larger aortic valve prosthesis into a small aortic root is represented by patch enlargement of the aortic annulus6. However, this technique is not devoid of drawbacks, even in experienced hands9. Increased postoperative bleeding requiring resternotomy and enhanced early mortality following patch enlargement of the aortic annulus have been reported by Sommers and David9.
In conclusion, in patients with small aortic roots, we recommend the full-root implantation of stentless aortic xenografts to avoid PPM. This technique can be performed without adversely affecting the early morbidity or mortality. The additional time necessary for the full-root implantation of stentless valves compared to the implantation of pericardial stented valves is therefore not detrimental to the early clinical outcomes and could be rewarded by better mid- and long-term outcomes. Limitations to this technique are represented by heavily calcified coronary ostia and patients in poor general condition who would not tolerate longer operative times.

Biological aortic valve replacement is recommended for patients older than 65 years1. In patients with small aortic roots, the implantation of a stented biological valve substitute based on the labelled size given by the manufacturer might not meet the functional needs. In this situation, Rahimtoola first described the prosthesis-patient mismatch (PPM) as follows: &#34;mismatch can be considered to be present when the effective prosthetic valve area, after insertion into the patient, is less than that of a normal human valve&#34;2. The effective orifice area of the valve prosthesis is to be related to the patient&#39;s body size and, more commonly, to the patient&#39;s body surface area. The hemodynamic consequence of a too-small prosthetic valve is an abnormally high transvalvular gradient3. It has been shown that the relationship between the transvalvular gradient and the effective orifice area indexed to the body surface area (EOAI) is curvilinear and that gradients increase exponentially when the indexed EOA is less than 0.8 to 0.9 cm2/m2. On the basis of this relation, an EOAI less than 0.85 cm2/m2 is generally regarded as the threshold for PPM in the aortic position4. The impact of the PPM on early and late clinical outcomes is controversial. However, it has been reported that PPM negatively affects the regression of left ventricular hypertrophy and thus the normalization of left ventricular function and the alleviation of symptoms4. Persistent left ventricular hypertrophy is associated with an increased risk of arrhythmias and sudden cardiac death5.
It is therefore advisable to avoid PPM as much as possible4. In the case of a predictable PPM for a planned aortic valve replacement with a biological valve substitute, the options are: 1) to accept the PPM resulting from the implantation of a stented pericardial valve when comorbidities of the patient forbid a more technically demanding operative technique to implant a larger prosthesis, 2) to enlarge the aortic root to accommodate a larger stented valve substitute6, or 3) to implant a stentless biological valve7 or homograft8.
Aortic root enlargement has been reported to enhance perioperative bleeding, necessitating a re-sternotomy and increasing early mortality9. Aortic homografts may have excellent hemodynamic profiles and good long-term outcomes when implanted by experienced surgeons8. However, their limited availability and the accelerated rate of calcification make aortic homografts less suitable biological valve substitutes than their counterpart, porcine stentless aortic xenografts10.
The shortage and drawbacks of homografts have prompted the conception and development of alternative biological valve substitutes. To this purpose, stentless aortic xenografts were introduced into clinical practice11. On one hand, thanks to the elimination of the cumbersome sewing ring, stentless aortic xenografts can reproduce the hemodynamic advantages of homografts. On the other hand, as a result of the application of anti-calcification technology, the durability of stentless aortic xenografts has been optimized to match and even exceed the longevity of homografts11. Hemodynamic advantages of stentless aortic xenografts are entirely attained by full-root implantation12. In contrast to subcoronary and root inclusion techniques, full-root implantation places the stentless aortic xenograft on top of the aortic annulus, and not inside it. This fact underlies the rationale to opt for the full-root implantation technique, which grants the implementation of the largest internal functional diameter of the stentless valve substitute. In addition, the preservation of the Valsalva sinuses en-bloc with the valve leaflets favors more physiological opening and closing movements and hence a longer life expectancy of the leaflets. This advantage further contributes to the amelioration of long-term results12.
However, concerns regarding the increased potential for bleeding and for the possible distortion of coronary ostia anastomoses prevent a number of cardiac surgeons from shifting from a classical aortic valve replacement with a stented biological valve to the more technically demanding procedure represented by full-root replacement with 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 (Table 1). In these patients, the aim is to attain a projected EOAI of greater than 0.85 cm2/m2 for the newly implanted aortic valve. This intention is based on the reports of Pibarot and co-workers showing an unacceptably high transvalvular gradients for valve substitutes having a projected EOAI of less than 0.85 cm2/m2, with the subsequent incomplete relief of symptoms and the persistent risk of adverse outcomes3,4. Following the initial identification of adult patients with an aortic annulus diameter of less than 20 mm on their pre-operative echocardiography, patients are further selected to have a body surface area of greater than 1.6 m2. In this subgroup of patients, the implantation of a 19-mm stented pericardial aortic valve (EOA: 1.28 cm2) would result in a projected EOAI of less than 0.85 cm2/m2. In this protocol, these patients are candidates for the full-root implantation of stentless aortic xenografts. The final decision is made intra-operatively after the removal of the aortic valve. If a 19-mm valve sizer for the stented pericardial aortic valve passes too-tightly through the aortic annulus and the patient is hemodynamically stable and can tolerate a longer operation, the full-root implantation of a stentless aortic xenograft is performed.
For the stentless aortic xenografts, we use two commercially available valve substitutes interchangeably (for details, see the Table of Materials). Both valves are procured from the porcine aortic root bearing the aortic valve. They are prepared using a low-pressure (0-2 mmHg) fixation process, with anti-calcification (e.g., XenoLogiX) treatment for one valve and alpha amino oleic acid (AOA) anti-calcification treatment for the other. In those patients for whom the 19 mm sizer for the stented pericardial valves passes too-tightly through the aortic annulus, the 23 mm sizer for the stentless aortic xenograft fitting well in the aortic annulus denotes that the stentless aortic xenograft size of 23 mm is to be chosen. This protocol describes in detail the technique of 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.

<table border="0" cellpadding="0" cellspacing="0" width="761">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:368px;">Heart surgery infrastructure:</td>
			<td style="width:163px;"></td>
			<td style="width:151px;"></td>
			<td style="width:80px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Heart Lung Machine</td>
			<td>Stockert</td>
			<td>SIII</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">EOPA 24Fr. arterial cannula</td>
			<td>Medtronic</td>
			<td>77624</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Atrial caval venous cannula 34/48Fr.</td>
			<td>Medtronic</td>
			<td>93448</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">LV vent catheter 17Fr.</td>
			<td>Edwards</td>
			<td>E061</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Antegrade 9Fr. cardioplegia cannula</td>
			<td>Edwards</td>
			<td>AR012V</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Retrograde 14Fr. cardioplegia cannula&#160;</td>
			<td>Edwards</td>
			<td>NPC014&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Coronary artery ostial cannula 90&#176;</td>
			<td>Medtronic</td>
			<td>30155</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Coronary artery ostial cannula 45&#176;</td>
			<td>Medtronic</td>
			<td>30255</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Valve subsitutes:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Stentless aortic xenograft Prima Plus 23mm</td>
			<td>Edwards</td>
			<td>2500P-23</td>
			<td>anti-calcification XenoLogiX treatment</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Stentless aortic xenograft Sizer 23mm</td>
			<td>Edwards</td>
			<td>1170</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Stentless aortic xenograft Freestyle 23 mm</td>
			<td>Medtronic</td>
			<td>FR995-23</td>
			<td>alpha amino oleic acid (AOA) anti-calcification treatment</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Stentless aortic xenograft Sizer 23mm</td>
			<td>Medtronic</td>
			<td>7900</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Electrocautery</td>
			<td>Covidien</td>
			<td>Force FXTM</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sutures:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Polypropylene 4/0</td>
			<td>Ethicon</td>
			<td>8871H</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Polypropylene 5/0</td>
			<td>Ethicon</td>
			<td>8870H</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Polypropylene 6/0</td>
			<td>Ethicon</td>
			<td>EH7400H</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Braided polyesther 2/0 ligature with polybutylate coating&#160;</td>
			<td>Ethicon</td>
			<td>X305H</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Micro knife Sharpoint&#160;</td>
			<td>TYCO Healthcare PTY&#160;</td>
			<td>78-6900</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Drugs:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Midazolam</td>
			<td>Roche Pharma</td>
			<td>N05CD08</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Rocuronium</td>
			<td>MSD Merck Sharp &#38; Dohme&#160;</td>
			<td>M03AC09</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Propofol</td>
			<td>Fresenius Kabi</td>
			<td>N01AX10</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Fentanil</td>
			<td>Actavis</td>
			<td>N01AH01</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Heparin</td>
			<td>Braun</td>
			<td>B01AB01</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Protamin</td>
			<td>MEDA Pharmaceutical</td>
			<td>V03AB14</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Instruments:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cooley vascular aortic clamp</td>
			<td>Delacroix-Chevalier</td>
			<td>DC40810-16</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Dissection forceps Carpentier</td>
			<td>Delacroix-Chevalier</td>
			<td>DC13110-28&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Scissors Metzenbaum</td>
			<td>Delacroix-Chevalier</td>
			<td>B351751</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Needle holder Ryder</td>
			<td>Delacroix-Chevalier</td>
			<td>DC51130-20&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Dissection forceps DeBakey</td>
			<td>Delacroix-Chevalier</td>
			<td>DC12000-21&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Micro needle holder Jacobson</td>
			<td>Delacroix-Chevalier</td>
			<td>DC50002-21&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Micro scisors Jacobson</td>
			<td>Delacroix-Chevalier</td>
			<td>DC20057-21&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Lung retractor</td>
			<td>Delacroix-Chevalier</td>
			<td>B803990</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Allis clamp</td>
			<td>Delacroix-Chevalier</td>
			<td>DC45907-25&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">O&#8217;Shaugnessy Dissector</td>
			<td>Delacroix-Chevalier</td>
			<td>B60650</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">18 blade knife</td>
			<td>Delacroix-Chevalier</td>
			<td>B130180</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Leriche haemostatic clamp</td>
			<td>Delacroix-Chevalier</td>
			<td>B86555</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Data analysis:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Mann-Whitney and Chi-square tests</td>
			<td>GraphPad</td>
			<td>Prism 7</td>
			<td></td>
		</tr>
	</tbody>
</table>

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.

Statistical analysis
The values of projected effective orifice area indexed to the body surface area (EOAI, cm2/m2) for implanted stentless aortic xenografts sized 23 mm are expressed as means &#177; SD and compared to the calculated EOAI of stented pericardial valves 4 mm smaller (i.e., 19 mm) using the non-parametric Mann Whitney test. In Table 2, continuous variables are compared using the non-parametric Mann Whitney test and categorical variables by Chi-square test. Statistical analysis is performed using commercially available software, with the statistical significance set at p&#60;0.05.
Effective orifice area indexed
In patients with small aortic roots (Figure 1), the implantation of a 19 mm-sized stented pericardial valve would have resulted in moderate to severe PPM4 by an EOAI of 0.7 &#177; 0.09 (range 0.55 - 0.84) cm2/m2 (Figure 1). With this technique, the implantation of a stentless aortic xenograft in these patients yielded a significantly higher EOAI of 1.09 &#177; 0.14 cm2/m2 (range 0.87-1.31 cm2/m2, p &#60;0.0001), thus eliminating any PPM (Figure 2).
Intraoperative and early postoperative data
As expected, the cross-clamp, cardio-pulmonary bypass, and operative times for the full-root implantation of stentless aortic xenografts in our patients were longer than those reported for isolated aortic valve replacement with stented valves13,14. Nevertheless, perioperative morbidity and mortality were very low and not adversely affected by the prolongation of the operative times (Table 2)13.
<img alt="Figure 1" src="/files/ftp_upload/55632/55632fig1.jpg" /> 
Figure 1: Internal Anatomy of the Heart. The anterior aspect of the heart is partially removed to depict the four cardiac chambers and valves. The anterior leaflet of the mitral valve is in continuity with the left and non-coronary cusps of the aortic valve. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55632/55632fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" src="/files/ftp_upload/55632/55632fig2.jpg" /> 
Figure 2: Effective Orifice Area Indexed. In patients with small aortic roots (N = 22), the projected effective orifice area indexed to the body surface area (EOAI, cm2/m2) for implanted stentless aortic xenografts sized 23 mm is significantly higher than the calculated EOAI if they had received a stented pericardial valve 4 mm smaller (i.e., 19 mm). The projected EOAI is calculated by dividing the effective orifice area (cm2) of the valve substitute provided by the manufacturer by the body surface area of the patient (m2). The values are expressed as means &#177; standard deviations.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td></td>
			<td>Full root Stentless Xenografts</td>
		</tr>
		<tr>
			<td>N</td>
			<td>22</td>
		</tr>
		<tr>
			<td>Age, years (mean&#177;SD)</td>
			<td>63&#177;10</td>
		</tr>
		<tr>
			<td>Female gender</td>
			<td>18 (82%)</td>
		</tr>
		<tr>
			<td>Body surface&#160; area, m2 (mean&#177;SD)</td>
			<td>1.85&#177;0.24</td>
		</tr>
		<tr>
			<td>Ejection Fraction (%) (mean&#177;SD)</td>
			<td>53&#177;11</td>
		</tr>
		<tr>
			<td>Aortic regurgitation</td>
			<td>5 (22%)</td>
		</tr>
	</tbody>
</table>
Table 1: Patients&#39; Characteristics. Patients&#39; characteristics are depicted in this table. The decision to implant a full-root stentless aortic xenograft is based on the body surface area to avoid a projected effective orifice area of less than &#60;0.85 cm2/m2, considered a prosthesis-patient mismatch.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td></td>
			<td>Full-root Stentless Xenografts 23 mm</td>
			<td>Isolated aortic valve replacement with stented pericardial valves1</td>
			<td>p</td>
		</tr>
		<tr>
			<td>N</td>
			<td>22</td>
			<td>36</td>
			<td></td>
		</tr>
		<tr>
			<td>Cross-clamp time (min)</td>
			<td>83 &#177;9</td>
			<td>62.3 &#177;9.4</td>
			<td>0.0001</td>
		</tr>
		<tr>
			<td>CPB time (min)</td>
			<td>134 &#177;32</td>
			<td>101 &#177;27.2</td>
			<td>0.0001</td>
		</tr>
		<tr>
			<td>OP time (min)</td>
			<td>242&#177;48</td>
			<td>191.7 &#177;53.2</td>
			<td>0.0001</td>
		</tr>
		<tr>
			<td>Re-exploration for bleeding</td>
			<td>0</td>
			<td>1(3%)</td>
			<td>ns</td>
		</tr>
		<tr>
			<td>Pace maker</td>
			<td>0</td>
			<td>0</td>
			<td>ns</td>
		</tr>
		<tr>
			<td>Stroke</td>
			<td>1(4.5%)</td>
			<td>1(3%)</td>
			<td>ns</td>
		</tr>
		<tr>
			<td>Sternal infection</td>
			<td>0</td>
			<td>0</td>
			<td>ns</td>
		</tr>
		<tr>
			<td>Early mortality</td>
			<td>0</td>
			<td>1(3%)</td>
			<td>ns</td>
		</tr>
		<tr>
			<td>1 Adapted with permission from Biomed Central from reference 13</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ns = not significant</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>
Table 2: Comparison of Intraoperative Data and 30-day Morbidity and Mortality to Previously Reported Data. Cross-clamp, cardio-pulmonary bypass (CPB), and operative times are reported (mean values &#177; standard deviation), along with 30-day morbidity and mortality in the presented group of patients, and are compared with previously reported data for stented pericardial aortic valves. Adapted with permission from Biomed Central from reference13.

Watch this Scientific Journal Video about Full-root Aortic Valve Replacement by Stentless Aortic Xenografts in Patients with Small Aortic Roots at JoVE.com

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

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 ...

full-root-aortic-valve-replacement-stentless-aortic-xenografts

Nanyang Technological University

Research

JoVE Journal

Medicine

11.2K Views.  University of Zurich. 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.

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

Orthotopic Aortic Transplantation in Mice for the Study of Vascular Disease

Vascular procedures involving anastomoses in the mouse are generally thought to be difficult and highly dependent on the skill of the individual surgeon. This is largely true, but there are a number of important principles that can reduce the difficulty of these procedures and enhance reproducibility. Orthotopic aortic transplantation is an excellent procedure in which to learn these principles because it involves only two end-to-end anastomoses, but requires good suturing technique and handling of the vessels for consistent success. This procedure begins with the procurement of a length of abdominal aorta from a donor animal, followed by division of the native aorta in the recipient. The procured aorta is then placed between the divided ends of the recipient aorta and sutured into place using end-to-end anastomoses. To accomplish this objective successfully requires a high degree of concentration, good tools, a steady hand, and an appreciation of how easily the vasculature of a mouse can be damaged, resulting in thrombosis. Learning these important principles is what occupies most of the beginner's time when learning microsurgery in small rodents. Throughout this protocol, we refer to these important points. This model can be used to study vascular disease in a variety of different experimental systems1-8. In the context shown here, it is most often used for the study of post-transplant vascular disease, a common long-term complication of solid organ transplantation in which intimal hyperplasia occurs within the allograft. The primary advantage of the model is that it facilitates quantitative morphometric analyses and the transplanted vessel lies contiguous to the endogenous vessel, which can serve as an additional control9. The technique shown here is most often used for mice weighing 18-25 grams. We have accumulated most of our experience using the C57BL/6J, BALB/cJ, and C3H/HeJ strains.

We describe a technique in which a section of the abdominal aorta from a mouse is transplanted orthotopically to just below the renal arteries in an allogeneic or syngeneic recipient. This technique can be useful in studies in which transplantation of large arteries of uniform size is deemed advantageous.

Vascular procedures involving anastomoses in the mouse are generally thought to be difficult and highly dependent on the skill of the individual surgeon. ...

A New Murine Model of Endovascular Aortic Aneurysm Repair

Endovascular aneurysm exclusion is a validated technique to prevent aneurysm rupture. Long-term results highlight technique limitations and new aspects of Abdominal aortic aneurysm (AAA) pathophysiology. There is no abdominal aortic aneurysm endograft exclusion model cheap and reproducible, which would allow deep investigations of AAA before and after treatment. We hereby describe how to induce, and then to exclude with a covered coronary stentgraft an abdominal aortic aneurysm in a rat. The well known elastase induced AAA model was first reported in 19901 in a rat, then described in mice2. Elastin degradation leads to dilation of the aorta with inflammatory infiltration of the abdominal wall and intra luminal thrombus, matching with human AAA. Endovascular exclusion with small covered stentgraft is then performed, excluding any interactions between circulating blood and the aneurysm thrombus. Appropriate exclusion and stentgraft patency is confirmed before euthanasia by an angiography thought the left carotid artery. Partial control of elastase diffusion makes aneurysm shape different for each animal. It is difficult to create an aneurysm, which will allow an appropriate length of aorta below the aneurysm for an easy stentgraft introduction, and with adequate proximal and distal neck to prevent endoleaks. Lots of failure can result to stentgraft introduction which sometimes lead to aorta tear with pain and troubles to stitch it, and endothelial damage with post op aorta thrombosis. Giving aspirin to rats before stentgraft implantation decreases failure rate without major hemorrhage. Clamping time activates neutrophils, endothelium and platelets, and may interfere with biological analysis.

Histological and biochemical modifications after aneurysm endograft exclusion are still unclear. We describe a new model of endograft implantation on a murine aneurysm. Through thrombus analysis with and without persistant circulating blood stream interface, and new endovascular biomaterials evaluation, this model will help to better understand endovascular aneurysm exclusion pathobiology.

Endovascular aneurysm exclusion is a validated technique to prevent aneurysm rupture. Long-term results highlight technique limitations and new aspects of ...

Reproducible Arterial Denudation Injury by Infrarenal Abdominal Aortic Clamping in a Murine Model

Percutaneous vascular interventions uniformly result in arterial denudation injuries that subsequently lead to thrombosis and restenosis. These complications can be attributed to impairments in re-endothelialization within the wound margins. Yet, the cellular and molecular mechanisms of re-endothelialization remain to be defined. While several animal models to study re-endothelialization after arterial denudation are available, few are performed in the mouse because of surgical limitations. This undermines the opportunity to exploit transgenic mouse lines and investigate the contribution of specific genes to the process of re-endothelialization. Here, we present a step-by-step protocol for creating a highly reproducible murine model of arterial denudation injury in the infrarenal abdominal aorta using external vascular clamping. Immunocytochemical staining of injured aortas for fibrinogen and &#946;-catenin demonstrate the exposure of a pro-thrombotic surface and the border of intact endothelium, respectively. The method presented here has the advantages of speed, excellent overall survival rate, and relative technical ease, creating a uniquely practical tool for imposing arterial denudation injury in transgenic mouse models. Using this method, investigators may elucidate the mechanisms of re-endothelialization under normal or pathological conditions.

Understanding the cellular and molecular mechanisms of re-endothelialization following arterial denudation injury is of paramount importance in preventing thrombosis and restenosis of arteries. Here we describe a protocol for reproducible arterial denudation injury of the infrarenal abdominal aorta. The procedure was developed to investigate the underlying mechanisms that regulate endothelial regeneration using mouse models.

Percutaneous vascular interventions uniformly result in arterial denudation injuries that subsequently lead to thrombosis and restenosis. These ...

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 ...

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 ...

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.

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 ...

Improved Registration of 3D CT Angiography with X-ray Fluoroscopy for Image Fusion During Transcatheter Aortic Valve Implantation

The fusion of 3D anatomical models derived from high-fidelity pre-interventional computed tomography angiography (CTA), and x-ray (XR) fluoroscopy to facilitate anatomical guidance is of huge interest for complex cardiac interventions like TAVI procedures with cerebral protection. Co-registration of CTA and XR has been introduced either based on additional intraoperative non-/contrast-enhanced cone-beam computed tomography (CBCT) or two separate aortograms. With the related increase of radiation exposure and/or contrast agent (CA) dose, a potential additional risk for the patient is introduced. Here, we propose a modified co-registration approach making use of arteriograms of the iliofemoral arteries, routinely performed during the femoral puncture and sheath introduction. On-the-fly refinement of the co-registration during the on-going procedure enables accurate co-registration without any additional angiograms, thus reducing CA, XR dose and procedure time, while simultaneously improving operator confidence and procedure safety.

The aim of this study was to improve the co-registration for image fusion (IF) of pre-interventional CT data with real-time x-ray (XR) fluoroscopy during transfemoral transcatheter aortic valve implantation (TAVI).

The fusion of 3D anatomical models derived from high-fidelity pre-interventional computed tomography angiography (CTA), and x-ray (XR) fluoroscopy to ...

Studying Left Ventricular Reverse Remodeling by Aortic Debanding in Rodents

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, mice undergo RR upon removal of the aortic constriction. In this paper, we describe a step-by-step procedure to perform a minimally invasive surgical aortic debanding in mice. Echocardiography was subsequently used to assess the degree of cardiac hypertrophy and dysfunction during LV remodeling and RR and to determine the best timing for aortic debanding. At the end of the protocol, terminal hemodynamic evaluation of the cardiac function was conducted, and samples were collected for histological studies. We showed that debanding is associated with surgical survival rates of 70-80%. Moreover, two weeks after debanding, the significant reduction of ventricular afterload triggers the regression of ventricular hypertrophy (~20%) and fibrosis (~26%), recovery of diastolic dysfunction as assessed by the normalization of left ventricular filling and end-diastolic pressures (E/e&#39;&#160;and LVEDP). Aortic debanding is a useful experimental model to study LV RR in rodents. The extent of myocardial recovery is variable between subjects, therefore, mimicking the diversity of RR that occurs in the clinical context, such as aortic valve replacement. We conclude that the aortic banding/debanding model represents a valuable tool to unravel novel insights into the mechanisms of RR, namely the regression of cardiac hypertrophy and the recovery of diastolic dysfunction.

Here we describe a step-by-step protocol of surgical aorta debanding in the well-established mice model of aortic-constriction. This procedure not only allows studying the mechanisms underlying the left ventricular reverse remodeling and regression of hypertrophy but also to test novel therapeutic options that might accelerate myocardial recovery.

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, ...

Porcine Model of Infrarenal Abdominal Aortic Aneurysm

Large animal models to study abdominal aortic aneurysms are sparse. The purpose of this model is to create reproducible, clinically significant infrarenal abdominal aortic aneurysms (AAA) in swine. To achieve this, we use a combination of balloon angioplasty, elastase and collagenase, and a lysyl oxidase inhibitor, called &#946;-aminopropionitrile (BAPN), to create clinically significant infrarenal aortic aneurysms, analogous to human disease.
Noncastrated male swine are fed BAPN for 7 days prior to surgery to achieve a steady state in the blood. A midline laparotomy is performed and the infrarenal aorta is circumferentially dissected. An initial measurement is recorded prior to aneurysm induction with a combination of balloon angioplasty, elastase (500 units)/collagenase (8000 units) perfusion, and topical elastase application. Swine are fed BAPN daily until terminal procedure on either postoperative day 7, 14, or 28, at which time the aneurysm is measured, and tissue procured. BAPN + surgery pigs are compared to pigs that underwent surgery alone.
Swine treated with BAPN and surgery had a mean aortic dilation of 89.9% &#177; 47.4% at day 7, 105.4% &#177; 58.1% at day 14, and 113.5% &#177; 30.2% at day 28. Pigs treated with surgery alone had significantly smaller aneurysms compared to BAPN + surgery animals at day 28 (p &#60; 0.0003). The BAPN + surgery group had macroscopic and immunohistochemical evidence of end stage aneurysmal disease.
Clinically significant infrarenal AAA can be induced using balloon angioplasty, elastase/collagenase perfusion and topical application, supplemented with oral BAPN. This model creates large, clinically significant AAA with hallmarks of human disease. This has important implications for the elucidation of AAA pathogenesis and testing of novel therapies and devices for the treatment of AAA. Limitations of the model include variation in BAPN ingested by swine, quality of elastase perfusion, and cost of BAPN.&#160;

This novel model creates robust infrarenal abdominal aortic aneurysms in swine using a combination of balloon angioplasty, elastase/collagenase perfusion, topical elastase application, and oral compound &#946;-aminopropionitrile administration, which interferes with collagen cross-linking.

Large animal models to study abdominal aortic aneurysms are sparse. The purpose of this model is to create reproducible, clinically significant infrarenal ...

Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy

Based on twice transverse aortic constrictions (TACs) in mice, it is proved that myocardial hypertrophic preconditioning (MHP) could attenuate cardiomyocyte hypertrophy and slow down progression to heart failure. For novices, however, the MHP model is usually quite difficult to establish because of the technical obstacles in ventilator operation, opening the chest repeatedly, and bleeding caused by debanding. To facilitate this model, to increase the surgical success rate and to reduce the incidence of bleeding, we switched to absorbable sutures for the first TAC combing with a ventilator-free technique. Using a 2-week absorbable suture, we demonstrated that this procedure could cause significant myocardial hypertrophy in 2 weeks; and 4 weeks after surgery, myocardial hypertrophy was almost completely regressed to the baseline. Using this protocol, the operators could master the MHP model easily with a lower operation mortality.

This protocol presents an improved method to obtain transient myocardial hypertrophy with absorbable suture, simulating left ventricular hypertrophy decrease after removing pressure overload. It could be valuable for the studies on myocardial hypertrophic preconditioning.