Drug Cuts Surgical Ischemia Risk in Heart Patients

A medication used to treat high blood pressure has been shown to reduce the incidence and severity of myocardial ischemia in surgery patients with heart disease or at risk of heart attacks. Called clonidine, the drug works by inhibiting the release of a group of hormones called catecholamines, which raise blood pressure and heart rate by constricting blood vessels. The study, reported at the annual meeting of the American Society of Anesthesiologists, was conducted by researchers at the University of California-San Francisco (UCSF, USA).

The study involved 200 patients, all of whom had heart disease, peripheral vascular disease or two serious risk factors for heart disease (age 65 or over, hypertension, smoking history, or elevated cholesterol). Those who received oral clonidine before surgery and wore a timed-release clonidine patch the day of surgery and four days afterward had about one-tenth the incidence of myocardial ischemia within the 12 hours before surgery (2 out of 131), compared to those who received placebo (7 out of 66).
For the entire perioperative period, clonidine was found to cut the incidence of myocardial ischemia in half (23 out of 131, or 18% for the clonidine group, versus 25/66, or 38%, for the placebo group).

The fact that more than 10% of patients in the control group had an episode of myocardial ischemia in the 12 hours before surgery emphasizes the importance of protecting patients throughout the entire perioperative period, not just during surgery, noted Arthur Wallace, M.D., a UCSF anesthesiologist and a member of the research team. The team is conducting an analysis of perioperative clonidine's long-term benefits.