Mario O VrandecicI; Bayard Gontijo FilhoI; Fernando Antônio FantiniI; Idail Costa Martins JrI; Marcelo H OliveiraI; Sandra O. S AvelarI; Ozanam OliveiraI; Erika VrandecicI; Ektor VrandecicI; João Alfredo Paula e SilvaI
DOI: 10.1590/S0102-76381996000300003
ABSTRACT
The concept of replacing diseased mitral valve with porcine mitral stentless valve allowed to address the "idiosyncrasy" of the left ventricular flow and contractility. From March 92 to December 95, 108 patients had their mitral valves replaced by stentless mitral valves. Their age varied from 11 to 65 years (mean 35.22 ± 14.98). There were 67 (62%) females and 41 (38%) males. The predominant ethiology was rheumatic heart disease 94 (87%) cases, followed by a prosthetic dysfunction 6 (5.6%) cases, myxomatous disease 5 (4.6%) cases, infective endocarditis 2 (1.9%) cases and ischemic lesion 1 (0.9%) case, 26 (24.1%) patients had mitral stenosis, 24 (22.2%) mitral regurgitation and the remaining 58 (53.7%) mixed lesions; 21.3% of the patients had previous open heart operations. The great majority of the operated patients (97.2%) were in functional class III and IV (NYHA). Associated procedures were performed in 9.3% (10) of the cases. RESULTS: Hospital mortality occurred in 7 (6.5%) patients non valved related with exception of one whom developed early endocarditis. Of the 101 remaining 3 required reoperations, in two due to valved size mismatch and 1 due to papillary muscle tear. Of the 98 remaining patients, 2 were lost to follow-up, 96 patients have been followed for 3.2 to 45 months. During the late follow-up there were six (6.25%) deaths, of the 3 patients with late prosthetic endocarditis, 2 had their valves replaced with standard bioprosthesis, with one death. The third patient expired before reoperation. The late death patient (mitral insufficiency) died early after reoperation. The other 3 patients expired: 1 due to myocardial infarction, 1 due to stroke and 1 with pancreatitis. LATE REOPERATIONS: There were 12 patients reoperated, in 8 due to mitral regurgitation with one death, in 2 due to decrease of the mitral valve area, and 2 late endocarditis with one death. CURRENT CLINICAL FOLLOW-UP: 80 patients are being currently followed. The ecodopplercardiographic studies have shown 63 patients with normal functioning mitral stentless valves, 15 with mild but stable mitral regurgitation and two with reduction on the mitral valve area by the pressure half time. In all but two, serial echocardiographic studies have shown improvement in the left ventricular function, with decreased end systolic and end diastolic volumes. CONCLUSION: Porcine mitral stentless valves have shown better performance, are hemodynamicaly superior with greater possibility of maintaining normal ventricular size and function. Although this study showed a distinct "learning curve" related to the new product and technique, these can be overcome by training and following current described operative technique.RESUMO
OBJETIVO: O uso da prótese mitral porcina sem suporte ("Stentless") propicia manutenção das características de fluxo e contratilidade do ventrículo esquerdo. No presente estudo, são analisados os resultados a médio prazo com o uso desse substituto valvar. CASUÍSTICA E MÉTODOS: No período de março de 1992 a dezembro de 1995, 108 pacientes foram submetidos a implante de valva mitral "Stentless". A idade variou de 11 a 65 anos (média 35,22 ± 14,98). A etiologia predominante foi a doença reumática (94 casos), seguida da disfunção de bioprótese mitral (6), degeneração mixomatosa (5), endocardite infecciosa (2) e lesão isquêmica (1). Vinte e seis (24,1%) tinham estenose mitral, 24 (22,2%) insuficiência mitral e 58 (53,7%) dupla lesão. Operações cardíacas prévias haviam sido realizadas em 21,3% dos pacientes. Procedimentos associados foram necessários em 10 (9,3%) casos. RESULTADOS: A mortalidade hospitalar foi de 6,5% (7 pacientes); em apenas 1 caso a endocardite precoce foi relacionada à valva. Dos 101 restantes, 3 foram reoperados, 2 devido a erro na medida da valva e 1 devido a deiscência da fixação ao músculo papilar. Com 2 pacientes perdidos no seguimento, 96 foram seguidos por 3,2 a 45 meses. No seguimento tardio ocorreram 6 óbitos devidos a: endocardite (1), infarto agudo do miocárdio (1), pancreatite (1), acidente vascular cerebral (1) e reoperações para retroca valvar (2). Foram reoperados tardiamente 12 pacientes, 8 devido a insuficiência mitral (1 óbito), 2 devido a diminuição da área valvar mitral e 2 a endocardite profética (1 óbito). Atualmente, 80 pacientes têm sido avaliados trimestralmente. Os estudos ecodopplercardiográficos têm mostrado 63 pacientes com valvas funcionalmente normais, 15 com insuficiência mitral discreta e estável e 2 com redução da área valvar. Com exceção destes 2 últimos pacientes, todos os outros têm mostrado melhora da função ventricular esquerda, com redução dos volumes sistólico e diastólico final, em avaliações ecocardiográficas seriadas.CONCLUSÃO: As valvas mitrais porcinas sem suporte têm mostrado melhor performance hemodinâmica, com maior possibilidade de manutenção da função e do tamanho do ventrículo esquerdo. Embora este estudo tenha demonstrado uma curva de aprendizado bem definida relacionada a um novo substituto valvar e à técnica cirúrgica, estes fatores são superados com treino e aderência à técnica atualmente em uso.REFERENCES
1. Carabello B A - Preservation of left ventricular function in patients with mitral regurgitation: a realistic goal for the nineties. J Am Cardiol, 1990; 15: 564-5.
2. Gams E, Hagl S, Shcad H, Heimisch W, Mendler N, Sebening F - Importance of the mitral apparatus for left ventricular function: an experimental approach. Eur J Cardiothorac Surg 1983: 6: (Suppl.1): 17-24.
3. Hertz R, Bouriouskas G, Franz M, Borst H G - Mitral valve replacement with preservation of papillary muscles and chordae tendineae: revival of a seemingly forgotten concept. Thorac Cardiovasc Surg 1963; 31: 291-6.
4. Lillehei C W, Levy M J, Bonnabeau R C - Mitral valve replacement with preservation of papillary muscles and chordae tendinae. J Thorac Cardiovasc Surg 1964: 47: 532-43. [MedLine]
5. Rozich J D, Carabello B A, Usher B W, Krata J M, Bell A E, Ziler M R - Mitral valve replacement with and without chordae preservation in patients with chronic mitral regurgitation. Circulation 1992; 86: 1718-26. [MedLine]
6. Straub U J, Huwer H, Petzold T, Kalweit G, Volkmer I, Gams E - Preservation of the mitral subvalvular apparatus in multiple valve procedures. J Heart Valve Dis 1995; 4: 477-83. [MedLine]
7. David T E, Armstrong S, Sun Z - Left ventricular function after mitral valve surgery. J Heart Valve Dis 1995; 4 (Suppl.2): S175-80. [MedLine]
8. David T E, Burns R F, Bacchus C M, Druck M N - Mitral valve replacement for mitral regurgitation with and without preservation of the chordae tendinae. J Thorac Cardiovasc Surg 1984; 88: 718-25. [MedLine]
9. David T E & HO T W - The effect of preservation of chordae tendinae on mitral valve replacement for post-infarction mitral regurgitation. Circulation 1986; 74 (Suppl.1): 116-20.
10. Rusted I E, Scheifley C H. Edwards J E - Estudies of the mitral valve: I. Anatomic features of the normal mitral valve and associated structures. Br Heart J 1958; 6: 825-31.
11. Yankah A C, Sievers H H, Lange P E, Bernhard A - Clinical report on stentless mitral allografts. J Heart Valve Dis 1995; 4: 40-4. [MedLine]
12. Anderson R H - Surgical anatomy of the mitral valve (Editorial comments). J Heart Valve Dis 1995; 4: 76-7.
13. Anderson R H & Wilcox B R - Understanding cardiac anatomy: the prerequisite for optimal cardiac surgery. Ann Thorac Surg 1995; 59: 1366-75. [MedLine]
14. Kunzelman K S, Cochran R P, Verrier E D, Eberhart R C - Anatomic basis for mitral valve modelling. J Heart Valve Dis. 1994; 3: 491-6. [MedLine]
15. Vrandecic M, Fantini F A, Gontijo B et al. - Surgical technique of implanting the stentless porcine mitral valve. Ann Thorac Surg 1995; 60: S439-42. [MedLine]
16. Vrandecic M, Gontijo B, Fantini F A et al. - Heterologous mitral valve transplant: the first 50 patients clinical analysis. Eur J Cardio-Thorac Surg 1995; 9: 69-74.
17. Vrandecic M, Gontijo B, Fantini F A et al. - Anatomically complete heterograft mitral valve substitute: surgical technique and immediate results. J Heart Valve Dis 1992; 1: 254-9.
18. Vrandecic M, Gontijo B, Fantini F A et al. - Porcine stentless mitral heart valve substitute: short term clinical data. J Cardiovasc Surg 1994; 35 (Suppl.1 to No.6): 41-5.
19. Vrandecic M, Gontijo B, Fantini F A et al. - Heterologous stentless mitral valve transplant: a new aproach for mitral valve replacement. Cor Europeaum 1994; 3:130-3.
20. Vrandecic M, Gontijo B, Fantini F A et al. - Heterologous mitral valve transplant. New alternative for mitral valve replacement: one year clinical follow-up. In: D'Alessandro L C, ed. Heart surgery 1993. Roma: Casa Editrice Scientifica Internazionale 1993: 57-68.
21. Vrandecic M O, Gontijo Filho B, Fantini F A et al. - Transplante de valva mitral heteróloga. Nova alternativa cirúrgica: estudo clínico inicial. Rev Bras Cir Cardiovasc 1993; 8: 83-90.
22. Carpentier A - Valve reconstruction in predominant mitral valve incompetence. In: Duran C, ed. Recent progress in mitral valve disease. London: Butterworths & Co. (Publishers) Ltd., 1984; 265-74.
23. Acar C, Farge A, Ramsheyi A et al. - Mitral valve replacement using a cryopreserved mitral homograft. Ann Thorac Surg 1994; 57: 746-8. [MedLine]