Objectives: This study sought to examine the incidence, temporal profile and clinical implications of shock in a large trial of thrombolytic therapy for acute myocardial infarction.
Background: Despite advances in the treatment of acute ischemic syndromes, cardiogenic shock remains associated with significant morbidity and mortality.
Methods: Patients who presented within 6 h of symptom onset were randomized to four treatment strategies: 1) streptokinase plus subcutaneous heparin; 2) streptokinase plus intravenous heparin; 3) accelerated recombinant tissue-type plasminogen activator (rt-PA) plus intravenous heparin; or 4) streptokinase and rt-PA plus intravenous heparin. The primary end point was 30-day all-cause mortality.
Results: Shock occurred in 2,972 patients (7.2%): 315 (11%) had shock on arrival, and 2,657 (89%) developed shock after hospital admission. Reinfarction occurred in 11% of patients who developed shock compared with 3% of patients without shock. The mortality rate was significantly higher in patients who presented with (57%) or developed (55%) shock than in those without shock (3%) (p < 0.001). Shock developed significantly less frequently in patients receiving rt-PA. There were fewer deaths in patients who presented with shock and were treated with streptokinase plus intravenous heparin or who developed shock and were treated with streptokinase plus subcutaneous heparin. Patients who developed shock had a significantly lower 30-day mortality rate if angioplasty was performed.
Conclusions: Because cardiogenic shock occurred most often after admission and with recurrent ischemia and reinfarction, recognizing signs of incipient shock may improve outcome. Fewer patients treated with rt-PA developed shock, yet those developing shock had the same high mortality rate as those presenting with shock, regardless of treatment. Only angioplasty was associated with a significantly lower mortality rate.