Impact of age on clinical outcome and postlytic management strategies in patients treated with intravenous thrombolytic therapy. Results from the TIMI II Study. TIMI II Investigators.

BACKGROUND

Few thrombolytic studies have assessed whether patient age is an indication for routine postlytic cardiac catheterization and revascularization or evaluated the impact of age on 1-year outcome differences after acute myocardial infarction.

METHODS AND RESULTS

A secondary analysis of 3339 patients enrolled in the TIMI II trial was performed to identify differences in clinical and coronary angiographic findings and 1-year cardiac event rates among 841 patients < 50 years old, 1639 patients 50 to 64 years old, and 859 patients 65 to 75 years old. Differences in 1-year clinical outcome were assessed among patients randomly assigned to an invasive or a conservative postlytic strategy within each age group. The percentages of patients with a prior history of myocardial infarction, angina, congestive heart failure, hypertension, or diabetes mellitus or an infarction complicated at the time of study entry by shock, pulmonary edema, hypotension, rales more than one third of lung fields, or atrial fibrillation as well as the percentage of female patients (all P < .001) increased with age. Fewer older patients (65 to 75 years) received early (ie, < or = within 2 hours after symptom onset) treatment with recombinant tissue-type plasminogen activator (rTPA), and fewer were eligible for random assignment to immediate or deferred beta-blocker therapy (P = .01). The location of the infarct-related artery and the percentage of patients with patent (ie, TIMI flow grade 2 or 3) or "complete" (ie, TIMI flow grade 3) infarct-related artery flow did not vary with age. The percentage of patients with multivessel disease was greatest in the older patients (P = .001). Cumulative 1-year mortality was low in the youngest patients (2.8%; 99% confidence interval [CI], 1.6% to 4.7%) regardless of whether the infarct location was anterior (3.7%) or nonanterior (1.6%). The highest 1-year mortality occurred in the older patients (13.6%; 99% CI, 10.9% to 16.9%), particularly when the infarct location was anterior (18%). The 42-day rates of reinfarction (P = .85), death (P = .95), or death or reinfarction (P = .99) were similar in patients assigned to the invasive or conservative postlytic treatment strategy, regardless of age group.

CONCLUSIONS

Among patients with acute myocardial infarction treated with intravenous rTPA, heparin, and aspirin, there were age-related differences in time to treatment with thrombolytic therapy, use of beta-blockers, extent of coronary artery disease, and 1-year cardiac event rates. Routine use of cardiac catheterization and coronary revascularization does not improve immediate or 1-year outcome in terms of mortality or reinfarction compared with a more conservative strategy in young, middle-aged, or elderly patients similar to those enrolled in TIMI II.