Medical and surgical management of myocardial infarction

Abstract

The in-hospital and long-term mortality (18 to 56 months) of two groups of patients treated concurrently for acute transmural myocardial infarction are retrospectively compared. Group I ( no. = 200) was given medical therapy, whereas Group II ( no. = 187) underwent early coronary arterial bypass grafting. The groups were comparable in average age, incidence of previous myocardial infarctions, initial electrocardiographic findings (S-T segment elevation), area of electrocardiographic involvement, initial cardiac enzyme activity, coronary anatomy (when known) and Killip classes I to III on admission to the study. Significantly more patients in Group II were in Killip clinical class IV. In-hospital mortality was lower in Group II than in Group I without (5.8 versus 11.5 percent) and with (1.2 versus 9.3 percent [ P < 0.003]) exclusion of class IV patients from both groups. Long-term mortality during the observation period (18 to 56 months) was also lower in Group II without and with exclusion of class IV patients (11.7 versus 20.5 percent [ P < 0.03] and 7.1 versus 18.1 percent [ P < 0.005], respectively). Group II was arbitrarily classified into two subgroups. Patients in subgroup IIA (no. 110) had abnormally elevated total creatine kinase (CK) activity (more than 90 IU) preoperatively and were placed on cardiopulmonary bypass 9.3 ± 2.6 hours (mean ± standard error of the mean) from the onset of symptoms. The in-hospital and long-term mortality rates were not significantly different from those in Group I (8.1 versus 11.5 percent and 17.2 versus 20.5 percent, respectively). Patients in subgroup IIB ( no. = 77) had normal serum CK activity preoperatively and were placed on cardiopulmonary bypass 5.3 ± 1.4 hours from the onset of symptoms. The in-hospital and long-term mortality rates were significantly lower than those in Group I (2.6 versus 11.5 percent [ P < 0.01] and 3.9 versus 20.5 percent [ P < 0.001], respectively). In the 100 patients in Group II placed on cardiopulmonary bypass within 6 hours of symptoms regardless of CK activity, in-hospital and long-term mortality rates were significantly lower than in patients receiving medical therapy (2.0 versus 11.5 percent [ P < 0.01] and 6.0 versus 20.5 percent [ P < 0.001), respectively. Of the 100 patients, 46 were from subgroup IIA and 54 from subgroup IIB. The inhospital mortality rate was 2.1 percent (1 of 46) and 1.8 percent (1 of 54), respectively. These preliminary data suggest that if the result of surgical reperfusion as treatment for acute evolving myocardial infarction is to be significantly different from that of medical management, reperfusion must be performed early in the course of infarction. A controlled randomized trial is suggested