Heparin Versus Bivalirudin in Patients with Non ST-elevation Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention - a Report from SCAAR

Purpose: To compare the outcome of treatment with unfractionated heparin/low-molecular weight heparin (heparin) alone versus bivalirudin in patients with non ST-elevation acute coronary syndrome (NSTE-ACS) undergoing percutaneous coronary intervention (PCI). Methods: We extracted data for all consecutive PCI procedures due to NSTE-ACS between 2005 and 2011 from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR). Patients that received GPIIb/IIIa inhibitors were excluded. Multilevel logistic regression and instrumental variable analysis (for hidden selection bias) adjusted for propensity score were used to compare the groups in regard to 30-days mortality. The analyses were performed on patients with complete data and using multiple imputation method. Background characteristics and procedural data including year of the procedure were used to calculate propensity score. Administrative region was employed as instrumental variable using two-stage least squares regression. Results: In total, there were 41,537 consecutive patients treated with heparin alone (n=31,351) or bivalirudin (n=10,186) between 2005 and 2011. After adjustment with propensity score, the baseline characteristics of the two groups were well balanced. Treatment with heparin alone was associated with lower 30-days mortality in complete case analysis (p<0.01) and in multiple imputation model (p=0.02). There was no difference between the groups after instrumental variable analysis (p=0.27). See figure. Odds ratio 30-day mortality Conclusions: Our large observational study, questions the superiority of bivalirudin over heparin in the absence of GP IIb/IIIa blockade in patients with NSTE-ACS undergoing PCI. A prospective randomized trial evaluating bivalirudin vs heparin is highly warranted.