Prognostic differences between routine invasive and conservative strategies for the management of high-risk, non-ST segment acute coronary syndromes: Experience from two consecutive periods in a single center

Abstract

Background The optimal revascularization strategy for non-ST elevation acute coronary syndromes (NSTE-ACS) remains controversial, especially in a real world context. The objective of this work was to assess differences at 1 year in all-cause mortality and the composite endpoint of mortality or acute myocardial infarction (MI) between two management strategies for NSTE-ACS: a conservative strategy (CS) versus a routine invasive strategy (RIS). Methods Of 799 consecutive patients admitted to our institution, 369 were treated with CS (from January 2001 to October 2002); 430 patients admitted with the same diagnosis were treated with RIS (from November 2002 to November 2004). A propensity score (PS) matched sample was created and included 694 patients (87% of the original population). The event rate was compared between each paired member of the PS-matched sample, one receiving RIS and the other CS, and their differences were tested by Cox proportional analysis. Results No significant differences in baseline characteristics were noted between the two management cohorts. By design, the rate of in-hospital catheterization and revascularization procedures increased in RIS compared with CS. The mortality rate was lower, but not significant, in RIS (HR: 0.76, 95% CI = 0.51–1.11; p = 0.155). For the composite of death or MI, RIS showed a relative risk reduction of 29% (HR: 0.71, 95% CI = 0.53–0.94); p = 0.018) compared with CS, differences that become non-significant ( p = 0.680) if we adjust for differences in rate of revascularization procedures and changes in medication prescription. Conclusions RIS was associated with a 1-year lower risk of the combined endpoint of all-cause death and MI in patients with NSTE-ACS, attributable to changes in frequency of revascularization procedures and in medical treatment.