RESUMO
From March 1990 to May 1993,309 patients underwent redo cardiac surgery operation at the Shahid Rajai Heart Hospital in Tehran. Early mortality rates in these patients showed a significant increase in comparison to patients undergoing open heart surgery for the fast time. Late mortality [at least one month after surgery] in the patients was slightly increased also but less than early mortality rates. The causes and factors involved in mortality of the patients are discussed in detail. Comparison of mortality rates in our patients with that reported in the literature reveals similar mortality in these patients, and thus the presence of definite and irrefutable factors which influence this risk. These factors consist of the patients' function class, age, surgical procedure, number of prosthetic valves in place, duration of cardiopulmonary bypass, degree of hypothermia and duration of myocardial ischemia. These factors are evaluated in this report