Prótese de pericárdio bovino PB IMC: 11 anos em posiçäo mitral / IMC - bovine pericardial valve: 11 years mitral position

Objetivo - Avaliar o resultado pós-operatório de pacientes com prótese valvular de pericárdio bovino em posição mitral. Métodos - De 1977 a 1988, 10.812 próteses de pericárdio bovino foram produzidas pela IMC Biomédica e implantadas em diversos serviços. Destas, 1.193foram implantadas por nosso grupo no IMC. Dos 663 pacientes. com troca mitral, 586 eram adultos e 77 eram jovens (abaixo de 21 anos). A febre reumática, com índice de 76,5%, foi a causa primária mais freqüente da doença valvar. Das lesões que levaram à troca mitral, a estenose (23%) e a insuficiência (20,7%) apresentaram-se as mais freqüentes. Consideraram-se, nesse estudo, 602 pacientes que deixaram o hospital, nos quais foram empregadas 666 biopróteses ao longo de 11 anos. As cirurgias foram realizadas com circulação extracorpórea convencional com o uso de cardioplegia cristalóide nos primeiros sete anos e cardioplegia sangüínea hipotérmica ou normotérmica, enriquecida com aminoácidos nos últimos anos. Resultados - A mortalidade hospitalar de 9,2%, isto é, 13,2% para os primeiros 5,5 anos (grupo I) e 6,3% para os 5,5 anos seguintes (grupo II). O seguimento de 98,8% em 11 anos, com média de 3,8 anos. O estudo atuarial revelou um índice de 74,3 ± 6,5% para os jovens e 73,0 ± 3,7% para os adultos, com 95,0 ± 1,0% de pacientes livres de complicações fatais relacionadas à válvula, correspondendo a um evento por 100 paciente-ano (endocardite 0, 6%; calcificação 0,1%; tromboembolismo 0,3%). O índice atuarial de complicações tardias não fatais relacionadas à válvula de 55,2 ± 8,6% de pacientes livres de qualquer complicação, correspondendo a 2,9 eventos por 100 paciente-ano (endocardite 0,5%; calcificação 1,8 tromboembolismo 0,3%; vazamento paravalvular 0,2% e ruptura 0,08%). Nesse período, 95,8 ± 1,6% do pacientes ficaram livres do tromboembolismo; 99,1± 0,6% livres de ruptura; 90,1 ± 4,08% livres de endocardite no grupo de jovens (1,5°/a/pacienteano) e 95,2 ± 1,03% entre os adultos (1,0%/paciente-ano). Para a calcificação, 43,1 + 12,3% dos jovens ficaram livres dessa complicação em 11 anos (7,5%/paciente-ano) e entre adultos esse índice foi de 68,8 ± 9,3% (1,1%/paciente-ano). Conclusão - A bioprótese PB IMC teve um bom desempenho no período de 11 anos, com índices baixos de complicações fatais, rupturas, tromboembolismo sem uso deanticoagulantes. A calcificação foi a maior complicação, principalmente em jovens.

Purpose - To evaluate the postoperative results of patients with valvular bovine pericardial prosthesis in mitral position. Methods - From 1977 to 1988, 10.812 bovine pericardial valves were produced by IMC Biomédica and implanted. Our group at IMC implanted 1,193. Of the 663 patients with mitral change, 586 were adults and 77 were youngsters (under 21). The rheumatic fever was the most frequent primary cause of valvar disease (76.5%). The stenosis (23.0%) and the insufficiency (20.7%) were the most common of the damages that led to mitral exchange. We studied 602 patients that left the Hospital, representing 666 bioprostheses in 11 years. The surgeries were performed with standard cardiopulmonar bypass with cristalloid cardioplegia in the first seven years and hipothermic or normothermic blood cardioplegia enriched with aminoacids in the last four years. Results - Hospital mortality was 9.2%; 13.2% for the first 5.5 years (group I) and 6.3%for the last 5.5 years (group II). Eleven-year follow-up was 98.8% and the mean time was 3.8 years. The actuarial study showed a survival rate of 74.3 ± 6.5%for the youngsters and 73.0 ± 3.7%for the adults, with 95.0 ± 1.0% of the patients free from valve-related fatal complications corresponding to one event % patient-years (endocarditis 0. 6%; calcification 0.1%; thromboembolism 0.3%). The actuarial rate of non fatal valve-related late complications was 55.2 + 8.6% of patientsfrce from all complications, corresponding an incidence of 2.9% / patient-year (endocarditis 0.5%; calcification 1.8%; thromboembolism 0.3%; periprosthetic leakage 0.2% and rupture 0.08%). In this period 95.8 ± 1. 6% of the patients were free from thromboembolism; 99.1 ± 0.6%free from rupture; 90.1 ± 4.08% free from endocarditis in the young group (1.5%/patient-year) and 95.2 ± 1.03% for adults (1.0%/patient-year). For calcification, the actuarial rate was 43.1 ± 12.3% for youngsters (7.5/ patient-year) and 68.8 ± 9.3% for adults (1.1°/a/ Conclusion - IMC pericardial bioprosthesis performed well in a period of 11 years with low rates of fatal complications; ruptures and thromboembolism without the use of anticoagulants. Calcification was the major complication mainly in youngsters

A Clinical Study of Tissue Valve Failure

On reoperations for tissue valve failure from December 1981 to December 1989, we had diagnosed 71 cases as primary tissue failure. In those cases we found out risk factors of accelerated primary tissue failure and increased thrombogenecity. We reviewed also long-term follow-ups of 542 patients after tissue valve replacement from 1978 to 1982, and durability of tissue valve was evaluated with the freedom rate from primary tissue failure. The results were as follows. 1) Eight patients had undergone reoperation by Dec. 1989 ; 71 cases(80.7%) for primary tissue failure, 11 cases(12.5%) for prosthetic valve endocarditis, 4 cases(4.5%) for thromboembolism, and 2 cases(2.3%) for paravalvular leakage. primary tissue failure was the main cause(80.7%) of tissue valve failure. 2) Primary tissue failure occurred at a mean postoperative interval of 89.7 months(range : 19.9-143.2 months). 3)In children under the age of 18, mean implantation time was 62 months, and in adults mean implantation time was 96 months. In the child group primary tissue failure occurred earlier than in the adult group by 34 months(p<0.01) 4) Actuarial freedom from primary tissue failure was 97.6%+/-0.6% at 5 years and 84.4%+/-2.2% at 10 years. 5) The types and locations of prosthetic tissue valves resulted in no significant difference in durability. 6) Primary tissue failure was mainly caused by calcification of the cusps(76%) 7) In atrial fibrillation the incidence of atrial thrombi was 31.3% and left atrial thrombi was the most common finding(60%) In conclusion, 1) Durability of tissue valve for 10 years is acceptable, but the limited durability of tissue may be a major concern after 10 years. 2) In children under the age of 18, tissue valve should be avoided due to accelerated tissue failure. 3) Atrial fibrillation clearly increases the risk of thromboembolism and anticoagulation is considered to be required in patients with atrial fibrillation.