Background: At 30 days, it is recognized that 12-hour periprocedural abciximab infusion protects against reinfarction and the need for revascularization in percutaneous coronary intervention (PCI) in acute myocardial infarction (MI). However, it is controversial whether the benefit to patients continues or fades away subsequently. We investigate whether abciximab provides a persistent advantage in terms of life-years gained in large trials of abciximab in PCI.
Methods and results: We identified four eligible randomized, controlled studies of PCI and adjunctive abciximab therapy in acute MI enrolling a total of 3,183 patients. Using the published time course of survival, we calculated the life-years gained at a series of time points over the following year. The weighted mean value and standard error for life-years gained at 1 year was 0.0034 +/- 0.0005. For abciximab-treated patients, life-years gained increases non-linearly for the first 90 days (gain = y = 0.003t(2) + 0.0016t - 3E-05; R(2) = 0.998; p < 0.05 for non-linear term) then linearly thereafter (gain = y = 0.004t - 0.0005; R(2) = 0.9998). The "number needed to treat" to gain 1 life-year is twenty-fold lower at the 1-year time point than at the 60-day time point.
Conclusion: When viewed across trials, benefit to the patient in terms of gain in life-years grows, rather than shrinks, with the passage of months. Initially, growth is significantly greater than linear, suggesting that a single periprocedural infusion continues to help prevent events from occurring up to 3 months post procedure. Evaluation of benefit at early time points may therefore underestimate the benefit of abciximab.