Invasive versus conservative strategy after thrombolytic therapy for acute myocardial infarction in patients with antecedent angina. A report from Thrombolysis in Myocardial Infarction Phase II (TIMI II).

OBJECTIVES

This study was designed to assess the possibility that a subgroup of patients at high risk for recurrent ischemia and reinfarction after thrombolytic therapy might benefit from early intervention.

BACKGROUND

The Thrombolysis in Myocardial Infarction Phase II (TIMI II) study recently concluded that an obligatory invasive strategy after thrombolytic therapy offered no advantage over a more conservative strategy.

METHODS

Data from the 3,534 patients enrolled in the TIMI II trial were analyzed to determine whether a history of antecedent angina before myocardial infarction identifies patients at high risk for subsequent ischemia and whether these patients might benefit from an invasive strategy.

RESULTS

Within the TIMI II population, antecedent angina identified patients at increased risk for recurrent chest pain in the hospital (32.3% vs. 22.1%, p < 0.001) and recurrent infarction during the 1st year of follow-up (11.2% vs. 7.9%, p = 0.001) compared with that of patients without antecedent angina. Among patients assigned to the invasive strategy, coronary arteriography revealed that those with antecedent angina had a more severe residual stenosis of the infarct-related artery after thrombolytic therapy (77.1 +/- 0.7% vs. 73.0 +/- 0.9%, p < 0.001) and more multivessel disease (37.9% vs. 26.4%, p < 0.001). The clinical outcome of the patients with antecedent angina assigned randomly to either the invasive or the conservative strategy were compared. The invasive strategy patients had a slightly lesser incidence of recurrent chest pain in the hospital (29.9% vs. 34.8%, p = 0.13) and more negative (normal) findings on exercise tolerance tests (24.7 vs. 18.9%, p = 0.003), but there was no difference between the treatment strategies in the end point variable of recurrent myocardial infarction or death.

CONCLUSIONS

These data demonstrate that antecedent angina identifies patients at increased risk for recurrent ischemic events after thrombolytic therapy. However, similar to the results for the overall population, the invasive strategy does not alter the risk of reinfarction or death compared with the conservative approach.