Antônio F Ramires

Bioeffects of albumin-encapsulated microbubbles and real-time myocardial contrast echocardiography in an experimental canine model

Myocardial contrast echocardiography has been used for assessing myocardial perfusion. Some concerns regarding its safety still remain, mainly regarding the induction of microvascular alterations. We sought to determine the bioeffects of microbubbles and real-time myocardial contrast echocardiography (RTMCE) in a closed-chest canine model. Eighteen mongrel dogs were randomly assigned to two groups. Nine were submitted to continuous intravenous infusion of perfluorocarbon-exposed sonicated dextrose albumin (PESDA) plus continuous imaging using power pulse inversion RTMCE for 180 min, associated with manually deflagrated high-mechanical index impulses. The control group consisted of 3 dogs submitted to continuous imaging using RTMCE without PESDA, 3 dogs received PESDA alone, and 3 dogs were sham-operated. Hemodynamics and cardiac rhythm were monitored continuously. Histological analysis was performed on cardiac and pulmonary tissues. No hemodynamic changes or cardiac arrhythmias were observed in any group. Normal left ventricular ejection fraction and myocardial perfusion were maintained throughout the protocol. Frequency of mild and focal microhemorrhage areas in myocardial and pulmonary tissue was similar in PESDA plus RTMCE and control groups. The percentages of positive microscopical fields in the myocardium were 0.4 and 0.7% (P = NS) in the PESDA plus RTMCE and control groups, respectively, and in the lungs they were 2.1 and 1.1%, respectively (P = NS). In this canine model, myocardial perfusion imaging obtained with PESDA and RTMCE was safe, with no alteration in cardiac rhythm or left ventricular function. Mild and focal myocardial and pulmonary microhemorrhages were observed in both groups, and may be attributed to surgical tissue manipulation.

Estudo da preservação do pulmão de cão mantido em autoperfusão

Foram estudados 14 blocos coracao-pulmao (BCP), nos quais os pulmoes foram mantidos em sistema de autoperfusao em periodo de duas ate oito horas. Realizaram-se biopsias pulmonares a cada duas horas. Dez blocos mantiveram-se preservados ate a quarta hora com pequena intensidade de alteracao, demonstrada semiquantitativamente atraves de estudo estrutural. A partir desse tempo, edema intra-alveolar, hemorragia perivasculo-bronquial, hemorragia intra-alveolar, enfisema perivasculo-bronquia e rotura alveolar ocorreram com maior intensidade.

Revascularização do miocárdio no idoso: fatores de risco para morbidade e mortalidade hospitalar

Com a finalidade de determinar os principais fatores de risco para a morbidade e mortalidade hospitalar de pacientes coronarianos idosos (idade > 65 anos), submetidos a revascularizacao isolada, eletiva do miocardio, estudamos prospectivamente 72 pacientes consecutivos, que possuiam observacoes completas no InCor, no periodo compreendido entre janeiro e dezembro de 1988. No roteiro do protocolo foram incluidos fatores clinicos, radiologicos, hemodinâmicos, operatorios e de pos-operatorios (Tabela 1). Os resultados foram analisados utilizando-se o teste do Qui quadrado de Pearson e a Prova Exata de Fisher, atraves do SPSS (Statistical Package for Social Science). Dentre os fatores analisados, apresentaram significância estatistica: o tabagismo, o numero de vasos coronarios acometidos, o tempo de duracao da circulacao extracorporea, o tempo de pincamento da aorta, o numero total de enxertos realizados, a presenca de anastomose mamaria coronaria e o indice de movimentacao da parede ventricular esquerda.

A utilização da artéria torácica interna aumenta a mortalidade hospitalar do paciente coronariano idoso revascularizado

At the Heart Institute, we performed a study to evaluate if the internal thoracic artery modified the nosocomial mortality of elderly coronary patients (age 70 years), submitted to elective isolated revascularization of the myocardium. Clinical, hemodynamic, radiologic, operative and postoperative parameters were included in the protocol. In a prospective study one hundred consecutive patients, with complete observations were analysed. The statistical analysis was performed using Pearsons X 2 test. The results of this study showed that there was a statistically significant difference between the groups, the nosocomial mortality being higher in that in which autogenous saphenous vein grafts were used. The role of the surgeon as a screener regarding obtention of results is also discussed.

Revascularização direta do miocárdio com as duas artérias mamárias internas: análise de 442 casos

From June 1984 to November 1989, 4958 patients (pts) were submitted to myocardial revascularization in the Heart Institute, and in 54% at least one internal mammary artery was used. In 442 (8,9%) pts both intenal mammary arteries, right (RIMA) and left (LIMA) were used, isolated or associated to ther grafts. The age ranged from 30 to 78 years old (52,7y) and 399 were male. The pts were separated in 4 groups, being: G I 232 (52,4%) pts - LIMA to left anterior descending artery (LAD) and RIMA to LAD branches or circumflex (Cx) branches in retroaortic position; G II 135 (30,5%) pts - LIMA to LAD and RIMA to right coronary artery (RCA); G III 48 (10,8%) pts - LIMA to Cx branches and RIMA to LAD as a free graft; G IV 27 (6,1%) pts - different associations with both arteries. The LIMA was used in situ in 440 pts and as free graft in 2; the RIMA was used in situ in 379 pts and as free graft in 63; The average number of grafts/pts was 3,17, considering the association with saphenous vein and other grafts. Respiratory insufficiency and low cardiac output syndrome were the main complications in 37 (8,3%) and 23 (5,2%) pts, respectively; 16 (3,6%) pts had post operatory myocardial infarction and 15 (3,3%) had wound closure complications. The mortality rate was 4,91% (22 pts) and the main causes of deaths were multiple system organ failure in 7 (31,8%) and myocardial insufficiency in 6 (27,3%). The mortality rate was higher in pts with severe myocardial dysfunction and older than 60 years old and the best graft patency was observed when the LIMA was anastomosed to the LAD (93,8%). The use of both intenal mammary arteries showed good results and acceptable morbidity and mortality.