Approximately 7.5 percent of all acute myocardial infarctions which are diagnosed in an emergency room or in-hospital lead to cardiogenic shock and an in-hospital death rate of 70 to 80 percent, usually within one to two days of diagnosis of cardiogenic shock. The high death rate has not changed in the last two decades. Non-random clinical series and animal studies suggest that rapid revascularization following cardiogenic shock complicating acute myocardial infarction may substantially improve survival. However, the apparent benefit reported in the non-random clinic studies could have resulted partly from a selection bias towards patients with a better prognosis.
Randomized, multicenter, Phase III, controlled clinical trial. Patients with shock due to left ventricular failure complicating myocardial infarction were randomly assigned to emergency revascularization or initial medical stabilization. Revascularization was accomplished by either coronary-artery bypass grafting or angioplasty. A total of 152 patients were randomized to early revascularization and 150 patients to conventional therapy consisting of thrombolytics and a possible late attempt at revascularization. Intraaortic balloon counterpulsation was performed in 86 percent of the patients in both groups. The primary endpoint was mortality from all causes at 30 days. Secondary endpoints included all-cause mortality at six months and assessment of the quality of life in survivors after discharge.
All patients with a clinically suspected diagnosis of cardiogenic shock complicating myocardial infarction formed a registry, with limited information collected on in-hospital procedures, medications, length of stay and vital status at discharge.
The study has been extended through June, 2005 for patient follow-up and data analyses. Long-term survival rates (6 to 11 years post-MI) will be estimated and the quality of life of survivors of acute MI complicated by cardiogenic shock will be studied. Extended trial data analyses will be conducted: a) To determine the early echocardiographic parameters which are associated with one year survival in cardiogenic shock patients, and to assess the interaction of these parameters with early revascularization; b) To examine differences in disease course and patient outcome as a function of age, gender, national practice, and changes in serial hemodynamic measurements, as well as to better characterize the related conditions and complications of cardiogenic shock.