This study was designed to determine: 1) whether a routine invasive (RI) strategy
reduces the long-term frequency of cardiovascular death or nonfatal myocardial infarction
(MI) using a meta-analysis of individual patient data from all randomized studies
with 5-year outcomes; and 2) whether the results are influenced by baseline risk.
Pooled analyses of randomized trials show early benefit of routine intervention, but
long-term results are inconsistent. The differences may reflect differing trial design,
adjunctive therapies, and/or limited power. This meta-analysis (n = 5,467 patients)
is designed to determine whether outcomes are improved despite trial differences.
Individual patient data, with 5-year outcomes, were obtained from FRISC-II (Fragmin
and Fast Revascularization during Instability in Coronary Artery Disease), ICTUS (Invasive
Versus Conservative Treatment in Unstable Coronary Syndromes), and RITA-3 (Randomized
Trial of a Conservative Treatment Strategy Versus an Interventional Treatment Strategy
in Patients with Unstable Angina) trials for a collaborative meta-analysis. A Cox
regression analysis was used for a multivariable risk model, and a simplified integer
model was derived.
Over 5 years, 14.7% (389 of 2,721) of patients randomized to an RI strategy experienced
cardiovascular death or nonfatal MI versus 17.9% (475 of 2,746) in the selective invasive
(SI) strategy (hazard ratio [HR]: 0.81, 95% confidence interval [CI]: 0.71 to 0.93;
p = 0.002). The most marked treatment effect was on MI (10.0% RI strategy vs. 12.9%
SI strategy), and there were consistent trends for cardiovascular deaths (HR: 0.83,
95% CI: 0.68 to 1.01; p = 0.068) and all deaths (HR: 0.90, 95% CI: 0.77 to 1.05).
There were 2.0% to 3.8% absolute reductions in cardiovascular death or MI in the low-
and intermediate-risk groups and an 11.1% absolute risk reduction in highest-risk
patients.
An RI strategy reduces long-term rates of cardiovascular death or MI and the largest
absolute effect in seen in higher-risk patients.