Perioperative BP control reduces mortality

Maintaining tight blood pressure (BP) control in cardiac surgery patients during the 24-hour perioperative period is associated with less 30-day mortality, reported Solomon Aronson, MD, at the American College of Cardiology's 56th annual scientific session. "Blood pressure excursions of 1 mm Hg/min outside a targeted range are correlated with a 20% increased mortality risk," he said.

There have been no previous studies showing a link between active BP control during the perioperative period and improved clinical outcomes, said Dr. Aronson, executive vice chairman, division of anesthesiology, Duke University Health System, Durham, N.C.

He analyzed BP data from phase III ECLIPSE (Effectiveness and Cost effectiveness of Levonorgestrel containing Intrauterine system in Primary care against Standard treatment for Menorrhagia) clinical trials for the calcium channel blocker, clevidipine. A total of 1,512 cardiac surgery patients were included in the trials and were randomized to receive clevidipine, nitroglycerin, sodium nitroprusside, or nicardipine to control perioperative BP. Median patient age was 65, 86% had preexisting hypertension, and 77% were undergoing bypass surgery.

Medication was administered as needed to maintain systolic blood pressure (SBP) within 85 to 145 mm Hg both pre- and postoperatively and within 75 to 135 mm Hg intraoperatively. Medication was continued for at least 24 hours after surgery or until discharge from the intensive care unit. Use of other antihypertensive agents during this period was strongly discouraged, Dr. Aronson said.

Data from the clinical trials was examined to determine the duration and magnitude of any SBP reading outside of the targeted range. Pooled data showed that patients displaying BP excursions outside of the specified range of only 1 mm Hg/minute over 60 minutes had a 20% increased risk of death during the first postsurgical month and the risk increased with each additional 1 mm Hg excursion outside the target range.

Patients having a 2 mm Hg/minute departure from the target range over an hour had a 43% increased risk of 30-day mortality. The risk for 3 mm Hg/minute, 4 mm Hg/minute, and 5 mm Hg/minute excursions outside target range were associated with increased mortality of 71%, 105%, and 146% respectively.

"Acute fluctuations in blood pressure are common, especially among patients undergoing cardiac procedures," Dr. Aronson said. "Poor blood pressure control is associated with poor outcomes, especially among those with preexisting hypertension."