Diverging associations of an intended early invasive strategy compared with actual revascularization, and outcome in patients with non-ST-segment elevation acute coronary syndrome: The problem of treatment selection bias
AimsIn several observational studies, revascularization is associated with substantial reduction in mortality in patients with non-ST-segment elevation acute coronary syndrome (nSTE-ACS). This has strengthened the belief that routine early angiography would lead to a reduction in mortality. We investigated the association between actual in-hospital revascularization and long-term outcome in patients with nSTE-ACS included in the ICTUS trial.Methods and resultsThe study population of the present analysis consists of ICTUS participants who were discharged alive after initial hospitalization. The ICTUS trial was a randomized, controlled trial in which 1200 patients were randomized to an early invasive or selective invasive strategy. The endpoints were death from hospital discharge until 4 year follow-up and death or spontaneous myocardial infarction (MI) until 3 years. Among 1189 patients discharged alive, 691 (58) underwent revascularization during initial hospitalization. In multivariable Cox regression analyses, in-hospital revascularization was independently associated with a reduction in 4 year mortality and 3 year event rate of death or spontaneous MI: hazard ratio (HR) 0.59 [95 confidence interval (CI) 0.37-0.96] and 0.46 (95 CI 0.31-0.68). However, when intention-to-treat analysis was performed, no differences in cumulative event rates were observed between the early invasive and selective invasive strategies: HR 1.10 (95 CI 0.70-1.74) for death and 1.27 (95 CI 0.88-1.85) for death or spontaneous MI.ConclusionThe ICTUS trial did not show that an early invasive strategy resulted in a better outcome than a selective invasive strategy in patients with nSTE-ACS. However, similar to retrospective analyses from observational studies, actual revascularization was associated with lower mortality and fewer MI. Whether an early invasive strategy leads to a better outcome than a selective invasive strategy cannot be inferred from the observation that revascularized patients have a better prognosis in non-randomized studies.
|Keywords||Prognosis, Revascularization, Treatment strategy, Unstable angina|
|Persistent URL||dx.doi.org/10.1093/eurheartj/ehn438, hdl.handle.net/1765/24643|
Hirsch, A., Windhausen, F., Tijssen, J.G.P., Oude Ophuis, A.J.M., van der Giessen, W.J., van der Zee, P.M., … de Winter, R.J.. (2009). Diverging associations of an intended early invasive strategy compared with actual revascularization, and outcome in patients with non-ST-segment elevation acute coronary syndrome: The problem of treatment selection bias. European Heart Journal, 30(6), 645–654. doi:10.1093/eurheartj/ehn438