Monobloc Aorto-Mitral Homograft: Report of Two Cases Sidney Chocron, MD, PhD, Dimitrios Buklas, MD, Christian Taberlet, MD, Djamel Kaili, MD, Pierre Emmanuel Falcoz, MD, and Joseph-Philippe Etievent, MD Departments of Thoracic and Cardiovascular Surgery, and Anesthesiology, Jean-Minjoz Hospital, Besançon, France
Cryopreserved monobloc aorto-mitral homograft implantation to treat complex recurrent endocarditis involving the intervalvular fibrous body and both aortic and mitral orifices, as previously described, remains a technically demanding procedure. We report two cases of recurrent destructive aorto-mitral endocarditis treated by a monobloc aortomitral homograft implantation with encouraging results. (Ann Thorac Surg 2007;84:e14 – 6) © 2007 by The Society of Thoracic Surgeons
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urgery for recurrent endocarditis is more demanding when the infection involves the intervalvular fibrous body. First, removing the intervalvular fibrous body involves removing at least part of both the aortic and mitral valve annuli, which makes reconstruction more difficult to achieve. In addition, infection of the intervalvular fibrous body is often associated with infection of other cardiac structures, which also have to be removed. A monobloc aorto-mitral homograft implantation is an alternative that provides enough tissue to compensate for the lack of substance. Moreover, it molds well to the rigid tissues involved in the redo operation, it resists infection well [1], it is hemodynamically effective, and it does not require anticoagulation treatment.
Case Reports Surgical Technique (A video of this procedure can be viewed on the Internet at http://ats.ctsnetjournals.org/ content/vol84/issue4/images/data/e14/DC1/chocron.mpg) The surgical technique is based on the works of Obadia and colleagues [2, 3]. The procedure was performed under standard cardiopulmonary bypass. Myocardial protection is provided by intermittent antegrade cold (8°C) hyperkalemic blood cardioplegia with 2 minutes of warm reperfusion before aortic unclamping. Selective caval cannulation for the superior septal approach (Guiraudon’s approach) is performed and the left ventricle is vented through the apex. After opening the right atrium, the interatrial septum is opened through the fossa ovalis and the incision is extended to the left atrial roof. The mitral lesions are evaluated and all infected tissue and prosthetic material is removed. The native papillary muscles are identified. The aorta is then transected 1 cm above the sinotubular junction, the aortic lesions or the prosthesis is removed, and the coronary ostias are separated into buttons. An oblique aortotomy is performed from the commissure between the left and
Fig 1. The infected intervalvular fibrous body has been removed leaving only one opening, with the aortic annulus at the upper part and the mitral annulus at the bottom. (IS ⫽ interatrial septum; LCA ⫽ left main coronary artery; L-NC ⫽ commissure between the left and noncoronary cusps; LV ⫽ left ventricle; RA ⫽ right atrium; R-NC ⫽ commissure between the right and noncoronary cusps.)
noncoronary cusps down to the aortic annulus and the intervalvular fibrous body. The infected intervalvular fibrous body is then removed, leaving only one opening, with the aortic annulus at the upper part and the mitral annulus at the bottom (Fig 1). The monobloc aorto-mitral homograft, provided by a public homograft tissue bank based in Lyon (France), was prepared by trimming the excess of tissue. The papillary muscles of the homograft are sutured with Gore-Tex U sutures (W.L. Gore, Flagstaff, AZ) and reinforced with Teflon pledgets (Impra Inc, Tempe, AZ) to the corresponding papillary muscle of the native heart. The homograft is then slid down and the stitches are tied. Six reference 4-0 polypropylene threads are used to keep the homograft from twisting (ie, three on the mitral annulus, two at the upper part of the intervalvular fibrous body that correspond to the two commissures next to the noncoronary cusp that was removed, and one more at the third commissure). Running sutures are then done between the reference stitches, and a Carpentier-Edwards ring (Edwards Lifesciences, Irvine, CA) is inserted as for any mitral valvuloplasty. Next, both the left and right coronary ostia are implanted with five monofilament running sutures. The sutures and the competence of the mitral valve are tested by filling the left ventricle through the venting catheter when clamping the aorta of the homograft after the air is removed. The access route is then closed, beginning with the roof of the left atrium, which is sutured to the corresponding tissue of the homograft. Should it be insufficient, a piece of autologous pericardium can be sutured to close the roof of the left atrium. Finally, the interatrial septum and the right atrium are closed, and the aorta of the homograft is sutured to the native aorta.
Patient 1 A 34-year-old drug-addicted man, presented to our department with a staphylococcal endocarditis. A complex
Accepted for publication June 11, 2007. Address correspondence to Dr Chocron, University Hospital, Department of Thoracic and Cardiovascular Surgery, Pole Coeur-Poumon, Bd Fleming, Hopital Jean Minjoz, Besancon, Cedex 25030, France; e-mail:
[email protected].
© 2007 by The Society of Thoracic Surgeons Published by Elsevier Inc
A video of this procedure can be viewed on the Internet at http://ats.ctsnetjournals.org/content/vol84/ issue4/images/data/e14/DC1/chocron.mpg
0003-4975/07/$32.00 doi:10.1016/j.athoracsur.2007.06.058
Ann Thorac Surg 2007;84:e14 – 6
mitral valvuloplasty was performed with resection of the infected segment of the posterior leaflet, and reconstruction of the perforated anterolateral commissure was performed by sliding both leaflets. Then a 30 CarpentierEdwards ring (Edwards Lifesciences) was inserted. The patient recovered well and was dismissed without complications from the department. Six months later he presented with an aorto-mitral streptococcus endocarditis involving the intervalvular fibrous body. The echocardiography showed vegetation in both the aortic and mitral valves. The aortic regurgitation was severe, and the mitral regurgitation was mild. We decided to perform a monobloc aorto-mitral homograft implantation. The technical aspects were previously described. There was a large abscess of the intervalvular fibrous body and a tear on the free edge of the noncoronary cusp. We identified a large vegetation obstructing the mitral orifice that was stuck to the Carpentier-Edwards ring (Edwards Lifesciences), which had been inserted during the first operation. Cardiopulmonary bypass time was 219 minutes, and aortic cross-clamp time was 201 minutes. The postoperative echocardiography showed trivial mitral regurgitation and no aortic regurgitation. There was a floating structure in the left ventricle that corresponded to the septum of the homograft that had not been sutured. The Doppler showed no obstruction caused by the floating structure. Wires for a permanent pacemaker were placed at the end of the procedure due to the high likelihood of postoperative heart block. Surprisingly, even with a negative p wave, the patient was discharged in sinus rhythm. The postoperative course was uneventful and the patient was discharged to the infectious disease department on postoperative day 8. After 11 months the patient is doing well with no regurgitation on either valve and no recurrence of endocarditis.
Patient 2 A 34-year-old man presented to our department with an aorto-mitral staphylococcal endocarditis and a concomitant abscess of the noncoronary part of the aortic annulus. Regurgitation of both the aortic and mitral valves was severe due to perforations with vegetations. Both valves were replaced with mechanical prostheses. Autologous pericardium was used to reconstruct the aortic annulus. The patient returned 2 months later, presenting an aorto-mitral endocarditis with partial prosthesis detachment. Echography showed vegetations of the intervalvular fibrous body and the posterior commissure. Both prostheses were removed, along with all damaged surrounding tissue and the intervalvular fibrous body. A monobloc aorto-mitral homograft was implanted. Total cardiopulmonary bypass time was 254 minutes and aortic cross-clamp time was 191 minutes. Postoperative echography showed mild paramitral homograft regurgitation due to a leak in the running suture and no aortic dysfunction. This patient was also discharged in sinus rhythm. His postoperative course was uneventful, and the patient was discharged to the infectious disease department on postoperative day 10. After 6
CASE REPORT CHOCRON ET AL MONOBLOC AORTO-MITRAL HOMOGRAFT
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months, the patient has a mild paramitral regurgitation and no recurrence of endocarditis.
Comment Recurrent destructive aortic and mitral native or prosthetic valve endocarditis remains a technically demanding procedure. Wide resection of all the septic tissue is mandatory [4 – 6], as well as replacement of the resected cardiac structures. Some surgeons prefer prosthetic valve implantation, in which the defect created by the resection is patched with fresh autologous or glutaraldehyde-fixed bovine pericardium, both for small defects (1 or 2 cm wide) in the aortic root and left ventricular outflow tract, and also for larger defects [6, 7]. Some also use Dacron fabric (Vascutek LTD, Renfrewshire, Scotland) to reconstruct the aortic root [8]. Another replacement technique using separate aortic and mitral homografts has shown encouraging results [9]. We have opted to use a single aorto-mitral monobloc homograft to replace all of the resected structures and thus avoid all prosthetic material, except the Carpentier ring. We inserted a Carpentier ring because we believe there is a genuine risk of the mitral annulus of the homograft being deformed by the surrounding tissues, which are much more rigid. The monobloc aorto-mitral homograft implantation is a reliable technique. However, several key issues need to be addressed. Myocardial protection was provided with antegrade intermittent cold blood cardioplegia. As the heart chambers are opened wide, it is as easy to use either the antegrade or retrograde way of delivery. Due to the long aortic cross-clamping time, continuous blood cardioplegia may be an alternative way of myocardial protection. This kind of operation is only indicated for recurrent aorto-mitral endocarditis involving the intervalvular fibrous body. Tissue banks need to be able to guarantee readily available monobloc homografts. Care must be taken when preparing and trimming the homograft, as stated above. Care should be taken to avoid twisting of the subvalvular apparatus of the homograft. Reference alignment sutures for the mitral and aortic valve annulus placement must also be used to avoid twisting. A left ventricular filling test through the apical vent can be used to evaluate mitral competence and suture leaks. Atrioventricular heart block is a main concern after these large resections. However, both patients were discharged in sinus rhythm.
The authors thank Nancy Richardson-Peuteuil for her editorial assistance.
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CASE REPORT CHOCRON ET AL MONOBLOC AORTO-MITRAL HOMOGRAFT
surgical option for extensive bivalvular endocarditis. J Thorac Cardiovasc Surg 2006;131:243–5. 3. Obadia JF, Raisky O, Sebbag L, Chocron S, Saroul C, Chassignolle JF. Monobloc aorto-mitral homograft as a treatment of complex cases of endocarditis. J Thorac Cardiovasc Surg 2001;121:584 – 6. 4. David TE. The surgical treatment of patients with prosthetic valve endocarditis. Semin Thorac Cardiovasc Surg 1995;7:47–53. 5. d’Udekem Y, David TE, Feindel CM, Armstrong S, Sun Z. Long-term results of operation for paravalvular abscess. Ann Thorac Surg 1996;62:48.
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