Reperfusion Strategies in Elderly Patients with Acute MI: Angioplasty is the Winner
Abstract & Commentary
Synopsis: Angioplasty patients may benefit compared to thrombolysis, but more attention needs to be focused on the early recognition of AMI and the rapid delivery of either reperfusion therapy.
Source: Berger AK, et al. JAMA 1999;282:341-348.
Controversy remains whether direct angioplasty or thrombolysis is the best therapy for acute myocardial infarction (AMI). Individual clinical trial experiences and meta-analyses suggest that angioplasty may be superior to thrombolytic therapy; this is particularly true in younger patients but has not been convincingly proven in individuals older than 70. This analysis from the Medicare-based Cooperative Cardiovascular Project (CCP) assessed almost 21,000 older patients with AMI between 1994 and 1996 who were eligible for reperfusion therapy, and reported short-term (30-day) and long-term (1-year) survival as well as a variety of secondary end points. The individuals received direct angioplasty, thrombolysis, or neither reperfusion strategy. Furthermore, hospitals were assessed as to whether they are high or low volume (number of yearly AMI patients) with respect to outcome. An "ideal" subgroup of individuals who presented within six hours with ST elevation or left bundle branch block (LBBB) were separately analyzed. A wide variety of predictive variables for outcome were also assessed. The results favored angioplasty for both short- and long-term survival, although when only "ideal" patients were analyzed, the differences between the two strategies were minimal. Both reperfusion approaches resulted in considerably better survival than the majority of patients in the CCP database who did not receive either reperfusion strategy. Approximately 18,645 individuals (23%) received thrombolysis (76% TPA), and 2038 patients underwent angioplasty within the six-hour time frame from the onset of AMI.
Thus, approximately 75% of the entire database did not receive either reperfusion strategy. The overall cohort had a mean age of 73; 58% were male. The angioplasty group was more likely to have prior coronary revascularization and presented later to the hospital. Time to angioplasty was substantially longer than time to thrombolysis. Nevertheless, the angioplasty patients had a significantly lower 30-day mortality (8.7% vs 11.9%; P = 0.001) as well as one-year mortality (14.4% vs 17.6%; P = 0.001). There were no differences when adjusted for age and sex; the survival advantage of angioplasty over thrombolyis persisted for at least 18 months. Furthermore, angioplasty patients had substantially lower incidence of stroke and cerebral hemorrhage, as well as less postinfarction angina, but there was somewhat more bleeding in these individuals. In the thrombolytic cohort, 40% ultimately underwent cardiac catheterization and 12% received an angioplasty. After adjustments for baseline characteristics, direct angioplasty demonstrated a robust improvement in survival, with a 26% reduction in mortality at 30 days and 12% at one year. Of interest, diabetes, prior heart failure, and nonanterior infarction were not associated with benefit with angioplasty compared to thrombolysis. Among "ideal" candidates who were treated within six hours and had ST segment elevation or LBBB, angioplasty still was better than thrombolysis but the differences were less marked than in the overall cohort and were small at one year (16.2% mortality vs 17.8%; P = 0.18). Hospitals with high-volume AMI (> 150 per year) had better results than lower volume institutions, but angioplasty remained the better strategy in both. Of great importance, either reperfusion strategy resulted in a 30-day mortality of 11.8% vs. 17.2% with more (P = 0.0001). At one year, the mortality was 33% in nonreperfused subjects vs. 17.6% in the angioplasty or one-year cohort (P = 0.001).
Berger and colleagues comment that the results are concordant with a recent meta-analysis showing an advantage to primary angioplasty over thrombolysis; prior studies have shown a trend with similar outcomes in the elderly. They note the obvious limitations of a retrospective analysis, although the shear size and careful analysis of multiple-risk parameters make a distorted outcome unlikely. Lower mortality rates were associated with primary angioplasty in all subgroups except diabetics and were not directly related to catherization volume. Berger et al suggest that the higher mortality in thrombolysis patients is related to greater complication rates in these patients. The discussion emphasizes that too often, reperfusion therapy is not used at all in elderly patients (less than half of "ideal" candidates received either therapy within 6 hours of hospital arrival). While they conclude that angioplasty patients may benefit compared to thrombolysis, they stress that "more attention needs to be focused on the early recognition of AMI and the rapid delivery of either reperfusion therapy." They suggest that triage of patients to angioplasty is less important than insisting that reperfusion be provided for all appropriate candidates.
Comment by Jonathan Abrams, MD
This is a convincing analysis of a large number of elderly patients, demonstrating that at the very least, primary angioplasty in skilled hands does not increase morbidity and mortality. Furthermore, there is support for this revascularization strategy across almost all cohorts. In patients older than 75, in diabetics, and in nonanterior infarctions, there were minimal differences in outcome between the two reperfusion approaches. Thus, in hospitals that have both thrombolytic and angioplasty capability, choice of reperfusion strategy should be driven by patient characteristics and physician choice. I agree that the failure to provide either reperfusion approach for eligible AMI patients older than the age of 65 is a significant problem, given the major survival benefits demonstrated in this database. For instance, 30-day mortality at high-volume centers was only 8.1% for primary angioplasty and 11.5% for thrombolysis. However, for all comers who did not undergo reperfusion, one-year mortality was a remarkable 33.3% compared to 17.6% for either reperfusion approach.
This analysis provides more support for proceeding directly to the cath lab in selected older subjects with AMI. In that the elderly have a higher absolute risk of dying with AMI, the number of lives saved in such individuals is substantial. Efforts should be redoubled to provide reperfusion, either thrombolytic or direct angioplasty, in all eligible older individuals that present with ST segment elevation within six hours of MI.
A Medicare database study of survival after AMI in patients older than age 70 concluded regarding survival that:
a. thrombolytic therapy is superior to direct angioplasty.
b. both reperfusion strategies are superior to no reperfusion therapy.
c. about three-fourths of the patients received neither therapy.
d. b and c.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content