SAN DIEGO – Since 2007, the use of preoperative beta-blockers has been a quality standard for patients undergoing coronary artery bypass graft surgery. However, a study by Dr. William T. Brinkman of the Cardiopulmonary Research Science and Technology Institute, Dallas, and his colleagues found no evidence that perioperative beta-blocker usage before CABG was beneficial.
Using data from the STS National Database for the period from 2000 to 2008, Dr. Brinkman and his colleagues compared outcomes between two propensity-matched groups obtained from their overall study group. These propensity-matched groups comprised 4,474 patients who received preoperative beta-blockers and 4,474 who did not.
In the propensity-matched groups, there was no difference between event rates in patients treated with beta-blockers and those who were not. However, significantly more beta-blocker-treated patients required intraoperative blood product use. Calculating the adjusted odds ratios showed that in the propensity-matched groups, the preoperative use of beta-blockers was not an independent predictor of mortality, Dr. Brinkman said January 31 at the annual meeting of the Society of Thoracic Surgeons.
In the remaining unmatched cohort from the overall group study patients, only deep sternal infection (0.3% vs. 0.5% without beta-blockers), pneumonia (1.9% vs. 2.4% without beta-blockers) and intraoperative blood usage (37.2% vs. 34.1% without beta-blockers) reached statistical significance.
"We were unable to substantiate any benefit to routine use of preoperative beta-blocker therapy. Our findings do not support continued use of preoperative beta-blockade as a quality indicator for CABG," Dr. Brinkman said in an interview.
"This illustrates the importance of cardiac surgeon participation in decisions regarding quality and value in cardiac surgery."
Dr. Brinkman reported being on the speakers bureau of the Medicines Company; all authors had an ownership interest in the Heart Hospital Baylor Plano. Some of the authors had a financial relationship with heart device companies
Discussant Dr. David M. Shahian, chair of the STS National Database Workforce – which has advocated beta-blocker use as a quality control measure, stated that he disagreed with the conclusions of Dr. Brinkman’s study. "There are now almost 30 randomized clinical trials that demonstrate on average a 60% reduction in the odds of postoperative atrial fibrillation with the use of perioperative beta-blockade," he said.
Because of this and other benefits for patients with various heart conditions, the use of these drugs has had long-standing support, unless contraindicated. "For beta–blockade naive patients, beginning therapy as far in advance of surgery as possible, and titration to optimal heart rate, are the safest and most efficacious strategies," Dr. Shahian added.
An audience member pointed out – and Dr. Brinkman concurred – that the issue is not the value of beta-blockade as a therapy but its use for all patients as a quality indicator. This is especially problematic because there are no controls as to whether beta-blockade is properly used (as Dr. Shahian described) and administered to appropriate patients, as opposed to simply being part of a checklist of necessary prescriptions. Dr. Brinkman advocated further study of the issue before making blanket recommendations.
Dr. Shahian had no relevant disclosures regarding his comments.