Valva mitral heteróloga sem suporte: resultados clínicos a médio prazo

Heterologous mitral stentless valve: mid-term clinical results

ARTIGOS ORIGINAIS

Valva mitral heteróloga sem suporte: resultados clínicos a médio prazo

Heterologous mitral stentless valve: mid-term clinical results

Mario O. Vrandecic; Bayard Gontijo Filho; Fernando Antônio Fantini; Idail Costa Martins Jr.; Marcelo H. Oliveira; Sandra O. S. Avelar; Ozanam Oliveira; Erika Vrandecic; Ektor Vrandecic; João Alfredo Paula e Silva

Do Biocór Instituto. Belo Horizonte

^{Endereço para correspondência}

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.

Descritores: Valva mitral, cirurgia, resultado clínico. Valvas cardíacas, próteses, resultados clínicos. Biopróteses.

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.

Descriptors: Mitral valve, surgery, clinical results. Heart valves, prostheses, clinical results. Bioprostheses.

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Full text available only in PDF format.

Trabalho realizado no Biocór Instituto de Belo Horizonte. MG, Brasil

Apresentado ao 23º Congresso Nacional de Cirurgia Cardiaca. Recife, PE, 20 a 23 de março, 1996.

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Endereço para correspondência:

Mário Vrandecic

Caixa Postal 106. Belo Horizonte, MG, Brasil. CEP: 30161-970

Tel. [phone]. Fax [phone]

Datas de Publicação

• Publicação nesta coleção
  07 Dez 2010
• Data do Fascículo
  Set 1996