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. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+problem+of+valve+prosthesis-patient+mismatch.">The problem of valve prosthesis-patient mismatch.</a> Circulation. 58 (1), 20-24 (1978).</li><li>Pibarot, P., Dumesnil, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prosthesis-patient+mismatch:+definition,+clinical+impact,+and+prevention.">Prosthesis-patient mismatch: definition, clinical impact, and prevention.</a> Heart. 92 (8), 1022-1029 (2006).</li><li>Pibarot, P., Dumesnil, J. 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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 cas...

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><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>Atrial caval venous cannula 34/48Fr.</td><td>Medtronic</td><td>93448</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>Retrograde 14Fr. cardioplegia cannula&amp;nbsp;</td><td>Edwards</td><td>NPC014&amp;nbsp;</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;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Valve subsitutes:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Stentless aortic xenograft Prima Plus 23 mm</td><td>Edwards</td><td>2500P-23</td><td>anti-calcification XenoLogiX treatment</td></tr><tr><td>Stentless aortic xenograft Sizer 23 mm</td><td>Edwards</td><td>1170</td><td></td></tr><tr><td>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><td>Stentless aortic xenograft Sizer 23 mm</td><td>Medtronic</td><td>7900</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;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</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>Polypropylene 6/0</td><td>Ethicon</td><td>EH7400H</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>Micro knife Sharpoint&amp;nbsp;</td><td>TYCO Healthcare PTY&amp;nbsp;</td><td>78-6900</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</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>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Instruments:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Cooley vascular aortic clamp</td><td>Delacroix-Chevalier</td><td>DC40810-16</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>Micro needle holder Jacobson</td><td>Delacroix-Chevalier</td><td>DC50002-21&amp;nbsp;</td><td></td></tr><tr><td>Micro scisors Jacobson</td><td>Delacroix-Chevalier</td><td>DC20057-21&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>Leriche haemostatic clamp</td><td>Delacroix-Chevalier</td><td>B86555</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</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>

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-para...

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

Universidad de Cartagena UDEC

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 ...

Transplantation of Pulmonary Valve Using a Mouse Model of Heterotopic Heart Transplantation

Tissue engineered heart valves, especially decellularized valves, are starting to gain momentum in clinical use of reconstructive surgery with mixed results. However, the cellular and molecular mechanisms of the neotissue development, valve thickening, and stenosis development are not researched extensively. To answer the above questions, we developed a murine heterotopic heart valve transplantation model. A heart valve was harvested from a valve donor mouse and transplanted to a heart donor mouse. The heart with a new valve was transplanted heterotopically to a recipient mouse. The transplanted heart showed its own heartbeat, independent of the recipient&#8217;s heartbeat. The blood flow was quantified using a high frequency ultrasound system with a pulsed wave Doppler. The flow through the implanted pulmonary valve showed forward flow with minimal regurgitation and the peak flow was close to 100 mm/sec. This murine model of heart valve transplantation is highly versatile, so it can be modified and adapted to provide different hemodynamic environments and/or can be used with various transgenic mice to study neotissue development in a tissue engineered heart valve.

In order to understand the cellular and molecular mechanisms underlying neotissue formation and stenosis development in tissue engineered heart valves, a murine model of heterotopic heart valve transplantation was developed. A pulmonary heart valve was transplanted to recipient using the heterotopic heart transplantation technique.

Tissue engineered heart valves, especially decellularized valves, are starting to gain momentum in clinical use of reconstructive surgery with mixed ...

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 ...

A Simplified Model for Heterotopic Heart Valve Transplantation in Rodents

There is an urgent clinical need for heart valve replacements that can grow in children. Heart valve transplantation is proposed as a new type of transplant with the potential to deliver durable heart valves capable of somatic growth with no requirement for anticoagulation. However, the immunobiology of heart valve transplants remains unexplored, highlighting the need for animal models to study this new type of transplant. Previous rat models for heterotopic aortic valve transplantation into the abdominal aorta have been described, though they are technically challenging and costly. For addressing this challenge, a renal subcapsular transplant model was developed in rodents as a practical and more straightforward method for studying heart valve transplant immunobiology. In this model, a single aortic valve leaflet is harvested and inserted into the renal subcapsular space. The kidney is easily accessible, and the transplanted tissue is securely contained in a subcapsular space that is well vascularized and can accommodate a variety of tissue sizes. Furthermore, because a single rat can provide three donor aortic leaflets and a single kidney can provide multiple sites for transplanted tissue, fewer rats are required for a given study. Here, the transplantation technique is described, providing a significant step forward in studying the transplant immunology of heart valve transplantation.

This protocol describes a simple and efficient method for the transplantation of aortic valve leaflets under the renal capsule to allow for the study of alloreactivity of heart valves.

There is an urgent clinical need for heart valve replacements that can grow in children. Heart valve transplantation is proposed as a new type of ...

A Rodent Model of The Ross Operation: Syngeneic Pulmonary Artery Graft Implantation in A Systemic Position

The Ross operation for aortic valve disease has regained new interest due to its outstanding long-term results. Nonetheless, when employed as freestanding root replacement, the possible dilation of the pulmonary autograft and subsequent aortic regurgitation is described. Several animal models have been proposed. However, these are usually limited to ex-vivo models or in-vivo experiments with relatively expensive large animal models. In this study, we sought to establish a rodent model of pulmonary artery graft (PAG) implantation in a systemic position. A total of 39 adult Lewis rats were included. Immediately after euthanasia, the pulmonary root was harvested from a donor animal (n=17). Syngeneic recipient (n=17) and sham-operated (n=5) rats were sedated and ventilated. In the recipient group, the PAG was implanted with an end-to-end anastomosis in infra-renal abdominal aortic position. Sham-operated rats underwent only transection and re-anastomosis of the aorta. Animals were followed with serial ultrasound studies for two months and post-mortem histological analysis. The median PAG diameter in the native position was 3.20 mm (IQR=3.18-3.23). At follow-up, the median diameter of the PAG was 4.03 mm (IQR=3.74-4.13) at 1 week, 4.07 mm (IQR=3.80-4.28) at 1 month, and 4.27 mm (IQR=3.90-4.35) at 2 months (p&lt;0.01). Peak systolic velocity was 220.07 mm/s (IQR=210.43-246.41) at 1 week, 430.88 mm/s (IQR=375.28-495.56) at 1 month, and 373.68 mm/s (IQR=305.78-429.81) at 2 months (p=0.02) and did not differ from the sham-operated group at the end of the experiment (p=0.5). Histological analysis did not show any sign of endothelial thrombosis. This study showed that rodent models may allow for the evaluation of the long-term adaptation of the pulmonary root to a high-pressure system. A systemically placed syngeneic PAG implantation represents a simple and feasible platform for the development and evaluation of novel surgical techniques and drug therapies to further improve the outcomes of the Ross operation.

We demonstrate how to establish a murine model of pulmonary root implantation into the descending aorta to simulate the Ross procedure. This model enables the medium/long-term evaluation of pulmonary autograft remodeling in a systemic position, representing the basis of developing therapeutic strategies to promote its adaptation.

The Ross operation for aortic valve disease has regained new interest due to its outstanding long-term results. Nonetheless, when employed as freestanding ...

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 ...

Transcatheter Pulmonary Valve Replacement from Autologous Pericardium with a Self-Expandable Nitinol Stent in an Adult Sheep Model

Transcatheter pulmonary valve replacement has been established as a viable alternative approach for patients suffering from right ventricular outflow tract or bioprosthetic valve dysfunction, with excellent early and late clinical outcomes. However, clinical challenges such as stented heart valve deterioration, coronary occlusion, endocarditis, and other complications must be addressed for lifetime application, particularly in pediatric patients. To facilitate the development of a lifelong solution for patients, transcatheter autologous pulmonary valve replacement was performed in an adult sheep model. The autologous pericardium was harvested from the sheep via left anterolateral minithoracotomy under general anesthesia with ventilation. The pericardium was placed on a 3D shaping heart valve model for non-toxic cross-linking for 2 days and 21 h. Intracardiac echocardiography (ICE) and angiography were performed to assess the position, morphology, function, and dimensions of the native pulmonary valve (NPV). After trimming, the crosslinked pericardium was sewn onto a self-expandable Nitinol stent and crimped into a self-designed delivery system. The autologous pulmonary valve (APV) was implanted at the NPV position via left jugular vein catheterization. ICE and angiography were repeated to evaluate the position, morphology, function, and dimensions of the APV. An APV was successfully implanted in&#160;sheep J. In this paper, sheep J was selected to obtain representative results. A 30 mm APV with a Nitinol stent was accurately implanted at the NPV position without any significant hemodynamic change. There was no paravalvular leak, no new pulmonary valve insufficiency, or stented pulmonary valve migration. This study demonstrated the feasibility and safety, in a long-time follow-up, of developing an APV for implantation at the NPV position with a self-expandable Nitinol stent via jugular vein catheterization in an adult sheep model.

This study demonstrates the feasibility and safety of developing an autologous pulmonary valve for implantation at the native pulmonary valve position by using a self-expandable Nitinol stent in an adult sheep model. This is a step toward developing transcatheter pulmonary valve replacement for patients with right ventricular outflow tract dysfunction.

Transcatheter pulmonary valve replacement has been established as a viable alternative approach for patients suffering from right ventricular outflow ...

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 ...