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.