RESUMO
In animal models using left ventricular assist systems over long time periods, myocardial cellular atrophy has been reported, raising concern that prolonged clinical use of such systems might lead to deterioration in left ventricular function. At the University of Pittsburgh, long-term clinical use of the Novacor (Baxter Healthcare Corp., Novacor Div., Oakland, Calif.) left ventricular support system for patients awaiting heart transplants has allowed study of the effects of long-term mechanical support on human subjects. This study determined that cardiac myocyte dimension is initially greater in patients with end-stage cardiac disease who require support rather than in patients with the same disease who do not require such support. Although myocyte dimension does decrease within a few days of the inception of support, this decrease merely brings cell size closer to the values usual in patients with chronic end-stage cardiac disease, and no further shrinkage is observed. Thus the Novacor left ventricular assist system does not appear associated with left ventricular atrophy, and its long-term use may not be detrimental to left ventricular function.
Assuntos
Coração Auxiliar , Miocárdio/patologia , Cardiomiopatias/patologia , Cardiomiopatias/terapia , Doença das Coronárias/patologia , Doença das Coronárias/terapia , Transplante de Coração , Humanos , Pessoa de Meia-Idade , Fatores de TempoRESUMO
Most reports concerning the use of streptokinase (SK) for thrombolysis in myocardial infarction (MI) have employed doses over 1,000,000 units. We evaluated the efficacy of a dose of 500,000 U in 40 patients with acute MI who received full heparin dose before, during and after SK. Thrombolytic effect, as measured by the protamine neutralized thrombin time was shown to be strong in 60% of cases, moderate in 17% and weak in 22%, and this was not modified by larger SK doses. A patent culprit artery was demonstrated at coronary arteriography performed 3 days after SK in 90% of patients. Only one instance of severe bleeding was observed. Thus, a reduced SK dose in association to heparin provides adequate lytic effect and artery patency rate in patients with MI.