Rationale and design of the PeriOperative ISchemic Evaluation-2 (POISE-2) trial: an international 2 × 2 factorial randomized controlled trial of acetyl-salicylic acid vs. placebo and clonidine vs. placebo in patients undergoing noncardiac surgery.

BACKGROUND: Worldwide, 200 million adults undergo major noncardiac surgery annually, and 10 million of these patients will have a major vascular complication. Low-dose clonidine and low-dose acetyl-salicylic acid (ASA) may prevent major perioperative vascular complications. We therefore initiated the POISE-2 trial to establish the perioperative effects of these 2 interventions.

METHODS: The POISE-2 trial is a 2 × 2 factorial randomized controlled trial of low-dose ASA vs. placebo and low-dose clonidine vs. placebo in 10,000 patients at risk for a perioperative cardiovascular event who are undergoing noncardiac surgery. Both study drugs are initiated prior to surgery (goal 2-4 hours) and are continued after surgery. Patients, health care providers, data collectors, and outcome adjudicators are blinded to treatment allocation. The primary outcome is a composite of mortality and nonfatal myocardial infarction at 30 days after randomization.

RESULTS: To date, the POISE-2 trial has recruited more than 9,000 patients from 135 centers in 23 countries. Among the first 7,500 patients recruited, patients' mean age was 68.2 years, 53.4% were male, 34.0% had a history of vascular disease, and 38.3% had diabetes that was treated. Participants had orthopedic (38.1%), general (27.0%), urologic or gynecologic (17.2%), vascular (6.6%), thoracic (5.7%), and other (5.4%) surgery.

CONCLUSIONS: POISE-2 is a large international trial that will rigorously evaluate the effects of low-dose clonidine and ASA in patients having noncardiac surgery.