To the Editor:
I first became aware of the recent paper published in this journal not by my reading of Anesthesiology, but through National Public Radio's Web site and the American Society of Anesthesiologists E-Newsletter of October 6, 2010. The National Public Radio story began with the following sentence: “Patients at risk of a heart attack who are having surgery can cut their death risk 35% by simply taking a drug called a β-blocker.”*
I write from the perspective of an anesthesiologist in private practice. Over the past several years, the hospital with which I am affiliated has eagerly adopted protocols for perioperative care. All Surgical Care Improvement Project mandates have become required. Currently, reimbursement from our largest private payer is tied to the World Health Organization Surgical Safety Checklist—an instrument whose utility has been presented but has not been clearly validated for hospitals such as ours.1
Despite such pressures from administration, physicians must insist that mandated protocols dictating pathways of perioperative care require unequivocal evidence demonstrating overall benefit to patients.
The article published by Wallace in this journal's October 2010 issue looks back at San Francisco Veterans Administration Medical Center patients who had inpatient or outpatient surgery from 1996 to 2008.2During that time, a protocol for perioperative β-blockade was instituted at the San Francisco Veterans Administration Medical Center by Dr. Wallace, the author of the analysis. The protocol was not universally followed; it was voluntary. The protocol was based largely on evidence from a trial that had enrolled 200 patients, authored by Mangano, Layug, Wallace, and Tateo in 1996.3
The patients in the analysis were not studied based on their participation in the author's protocol. They were studied in groups defined by their receipt of “at least one dose of B-blocker medication after surgery, either as an in-patient or out-patient.”
During the time of the analysis, 30-day mortality decreased, as did 1-yr mortality. Over the time of the analysis, β-blocker use increased. Through regression and propensity analysis, the author concludes that the addition of a single dose of β-blocker during the perioperative period was independently associated with a reduction in 30-day and 1-yr mortality.
However, patients having vascular surgery did not share this benefit at the 1-yr mark, which stands in contrast to the results of a small prospective, randomized trial that showed remarkable benefit for vascular patients (odds ratio for cardiac death or nonfatal myocardial infarction over 22 months with β-blockade of 0.16 vs. placebo).4
During the period of the analysis, other investigators conducted three large prospective, randomized trials of perioperative β-blockade that enrolled a total of 9,768 patients. None of these three prospective, randomized, controlled trials found overall benefit (decreased mortality) of the investigated protocol.5–7
One statement in the Wallace article requires particular scrutiny. Wallace states in his conclusion that “appropriate use of the PCRRT protocol is clearly associated with a reduction in 30-day and 1-yr mortality.” The analysis associates the addition of a single dose of any β-blocker with benefit, not the Perioperative Cardiac Risk Reduction Therapy protocol with benefit; this protocol was not an arm of this analysis.
Wallace's analysis does deserve careful study; in particular, regarding the hazard of withdrawing β-blockers during the perioperative period. In addition, the article suggests that some β-blockers administered to patients at risk may be helpful, and that patients who should have been taking β-blockers for medical indications, outside of any perioperative considerations, may present for surgery.
However, it cannot be argued that this analysis provides evidence for benefit of a particular protocol for perioperative β-blockade, certainly not one eligible for mandated care.
Anesthesia Services of Lynchburg, Lynchburg, Virginia. firstname.lastname@example.org