• Interventional Techniques & Devices
• Myocardial Infarction
• Cardiology Clinical Trials

• Interventional Techniques & Devices
• Myocardial Infarction
• Cardiology Clinical Trials
• Cardiology

Clonidine, a centrally acting α-agonist, does not reduce the risk of perioperative myocardial infarction or death in noncardiac surgery; however, it did cause clinically significant bradycardia and hypotension. The findings of the Perioperative Ischemic Evaluation-2 Trial [POISE-2; Devereaux PJ et al. N Engl J Med 2014] were presented by Daniel I. Sessler, MD, Cleveland Clinic, Cleveland, Ohio, USA.

The trial randomized patients (aged >45 years) scheduled for noncardiac surgery to “low-dose” (0.2 mg) clonidine (n=5009) versus placebo (n=5001). Clonidine was started orally 2 to 4 hours before surgery and continued by patch for 72 hours. The primary outcome was a composite of death or MI at 30 days. The secondary outcome was death, MI, or stroke at 30 days.

Patients in both arms were similar. The mean age was 68.5 years. Approximately one third of subjects had a history of any vascular disease but few patients had a history of coronary revascularization (recent stenting was an exclusion). Vascular surgery comprised only 6% of the total surgeries. Approximately 30% of subjects were also taking β-blockers during the perioperative period. Over 96% of patients were randomized within 24 hours of the operation.

The primary and secondary outcomes were similar in patients receiving clonidine or placebo (Table 1).

Throughout the 30-day follow-up period, the composite of death or MI was greater, but not statistically significant, with clonidine versus placebo (HR, 1.08; 95% CI, 0.93 to 1.26; p=0.29). Of the assessed tertiary outcomes, nonfatal cardiac arrest was significantly more frequent in those given clonidine (n=16, 0.3%) versus placebo (n=5, 0.1%; HR, 3.20; 95% CI 1.17 to 8.73; p=0.02). Clinically important hypotension and bradycardia, but not stroke, were statistically more frequent in patients given clonidine (Table 2).

Hypotension was an independent predictor of MI (adjusted HR, 1.37; 95% CI, 1.16 to 1.62; p<0.001). Hypotension was always more prevalent in patients given clonidine than placebo, especially during surgery and recovery, and decreasing over the next 3 days (Table 3). The duration of hypotension was markedly shorter during surgery and recovery, compared with the following 3 days (Table 3).

The ineffectiveness of clonidine in reducing postoperative MI or death combined with the increase in frequency and duration of hypotension means that low-dose clonidine should not be given to patients having noncardiac surgery in an effort to lessen perioperative mortality or MI.

Consistent with the results of POISE-1 (β-blockers in noncardiac surgery), starting drugs that may have potent hemodynamic effects (eg, antihypertensive, sympatholytic) within 24 hours of major noncardiac surgery is not effective in a broad population of patients undergoing noncardiac surgery.

• © 2014 MD Conference Express®