ABSTRACT

The concept of using extracardiac conduits, to establish an outflow tract between the right ventricle and the pulmonary artery was developed on the sixties. Between 1971 and 1986, 335 patients received extracardiac conduits for the right heart, at The Hospital for Sick Children, London; 176 were antibiotic preserved aortic homografts (Hancock, Ross, Carpentier-Edwards, lonescu-Shiley) and 19 non-valved tubes. These conduits were used for the repair of complex congenital heart defects. The mean age of these groups was 6.34 ± 4.6 years and the mean weight 17.8 ± 10.8 kg. The internal diameter of the conduits varied from 8 to 30 mm. The hospital mortality was 29.2% and long-term follow-up of the survivals had a maximum period of 14,39 years. Sixty patients (17.9%) were submited to 60 reoperations, being only 40% conduit related. The actuarial survival cun/e of freedom from obstruction was significant when analyzed the homografts, without Dacron, versus each group of heterografts (p < 0.005). The more important risk factors were the number of postoperative complications, for late deaths; the severity of associated lesions for reoperation, the date of surgery for the replacement of the extracardiac conduit, and the date of surgery and severity of associated lesions for the obstruction of the extracardiac conduits. We conclude that on long-term the use of extracardiac valved conduits has good results specially when using antibiotic preserved aortic homografts and therefore they are our first choice in the reconstruction of the pulmonary ventricle outflow tract.

RESUMO

O conceito do uso de um conduto extracardíaco para estabelecer uma via de saída, conectando o ventrículo direito com o tronco pulmonar, ou seus ramos, foi desenvolvido na década de 60. Entre 1971 e 1986, 335 pacientes receberam, no The Hospital for Sick Children, de Londres, condutos extracardíacos para o lado direito do coração; 176 destes foram homoenxertos aórticos, preservados em solução antibióticonutriente; 140 heteroenxertos (Hancock, Ross, Carpentier-Edwards, lonescu-Shiley e 19 tubos não valvulados. Estes condutos foram usados na correção de defeitos cardíacos complexos. A idade média foi de 6,34 anos e o peso médio, de 17,8 kg. O diâmetro interno dos condutos variou de 8 a 30 mm. A mortalidade hospitalar foi de 29,2% e o seguimento dos sobrevivente teve uma duração máxima de 14,3 anos, sendo que apenas 40% delas foram relacionadas ao conduto extracardíaco. A curva atuarial, livre de obstrução, dos condutos extracardíacos foi significativa, quando se analisaram os homoenxertos, face a cada grupo de heteroenxertos (p < 0,005). Os fatores de risco mais importantes foram: o número de complicações pós-operatórias, para óbitos tardios; a severidade das lesões associadas, para as reoperações; a data da cirurgia, para a troca do conduto extracardíaco, e a severidade das lesões associadas, para a obstrução. Assim, conclui-se que, a longo prazo, o uso de condutos valvulados extracardíacos tem bons resultados, especialmente no que se refere aos homoenxertos. Pelos dados apresentados, os homoenxertos aórticos, preservados em solução antibiótico-nutriente, continuam a ser nossa primeira escolha na reconstrução da via de saída ventrículo-pulmonar.

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