Switching from Enoxaparin to Bivalirudin in Patients with Acute Coronary Syndromes without ST-segment Elevation who Undergo Percutaneous Coronary Intervention. Results from SWITCH--a multicenter clinical trial.

Background. Enoxaparin is an established therapy for the treatment of patients with acute coronary syndrome (ACS), and bivalirudin is commonly used as the antithrombotic agent during percutaneous coronary intervention (PCI). This study was designed to examine the safety of switching from enoxaparin to bivalirudin in these patients. Methods. The Switching from Enoxaparin to Bivalirudin in Patients with Acute Coronary Syndromes without ST-segment Elevation Undergoing Percutaneous Coronary Intervention (SWITCH) trial was a prospective, open-label, multicenter study including 91 patients who presented with an ACS without ST-segment elevation, and who had received ≥ 1 dose of enoxaparin (1 mg/kg SC) within the 12 hours prior to PCI. Patients were enrolled into 3 time categories: Group 1: 0-4; Group 2: 4-8; and Group 3: 8-12 hours from last enoxaparin dose to PCI. The primary endpoint of the study was major bleeding complications. Results. Baseline characteristics and average number of enoxaparin injections prior to PCI were similar in all 91 patients and among the groups. There was no occurrence of death, Q-wave myocardial infarction (MI), or acute revascularization in any group and no incidence of intracranial or retroperitoneal bleeding. The overall rate of major bleeding (7.7%) was comparable among groups (p = 0.39), as was the incidence of periprocedural non-Q-wave MI (overall 12%; p = 0.58), irrespective of the time interval between enoxaparin and bivalirudin administration. Conclusions. Switching from enoxaparin to bivalirudin for patients with ACS undergoing PCI appears to be clinically safe without increased risk of major bleeding complications, regardless of the time of enoxaparin administration, and is safe enough to warrant testing it in larger numbers.