An estimated 6 million people undergo non-cardiac surgery each year, and up to a quarter of these procedures (eg, major intra-abdominal, thoracic vascular, and orthopedic procedures) are associated with significant risk of perioperative cardiovascular morbidity and mortality. The American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) issued a practice guideline for the utilization of β-blockade in non-cardiac surgery. The update, published in the November 24, 2009 issue of Circulation and the Journal of the American College of Cardiology, identifies important new information regarding the risks and benefits of perioperative β-blockade.
“Non-cardiac surgery represents a stress to the heart, particularly if the procedure is high risk or if patients have underlying risk factors for cardiac complications,” says Kirsten E. Fleischmann, MD, MPH, who chaired the committee that generated the focused update. As the aging population rises and the number of non-cardiac surgeries performed in them continues to increase, steps must be taken to minimize the risk of cardiac complications associated with these surgeries.
Clinical Trial Evidence Drives Update
Another impetus for the ACCF/AHA update was the publication of new randomized trial data, most notably the POISE (PeriOperative Ischemic Evaluation) and DECREASE (Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography)-IV trials. POISE confirmed that β-blocker therapy reduces perioperative cardiac events, but also clarified that routine perioperative β-blockade—particularly in fixed, higher-dose regimens initiated the day of surgery—was associated with risk. In POISE, the reduction in cardiac events was offset by a higher risk of stroke and death when using fixed higher-doses of metoprolol started on the day of surgery.
The DECREASE-IV trial assigned intermediate cardiac risk patients to bisoprolol, fluvastatin, combination treatment, or control therapy before surgery. It confirmed a reduction in cardiac risk with perioperative bisoprolol started well before surgery and titrated to blood pressure and heart rate, but no increase in stroke rate was observed in this trial or in pooled analyses of all the DECREASE trials. “The update generally suggests that the higher the cardiac risk, the more likely β-blockade will be of benefit,” Dr. Fleischmann explains. “Initiation of therapy requires careful risk-benefit assessments, and patients should be started on β-blocker therapy well before an elective surgery, focusing on careful titration to heart rate and blood pressure perioperatively. The goal is to avoid bradycardia or hypotension.”
Prior to administration of β-blockade, active cardiac conditions that require intensive management—and which may delay or cancel surgery—must be evaluated (Figure 1). In addition, the surgery-specific cardiac risk of non-cardiac surgery must be considered (Figure 2).
Some of the major recommendations in the ACCF/AHA update include:
|β-blockers should generally be continued perioperatively in those already receiving them (Class I).|
|β-blockers titrated to heart rate and blood pressure are probably recommended for those undergoing vascular surgery at high cardiac risk owing to coronary artery disease or cardiac ischemia on preoperative testing (Class IIa).|
|It is reasonable to consider β-blockade titrated to heart rate and blood pressure in patients with multiple risk factors for complications undergoing vascular surgery or in those with coronary disease and/or multiple risk factors undergoing intermediate-risk surgery (Class IIa).|
|The usefulness of β-blockers is uncertain for patients undergoing intermediate-risk procedures or vascular surgery with one clinical risk factors in the absence of established coronary disease or those without clinical risk factors undergoing vascular surgery that are not currently taking β-blockers (Class IIb).|
“β-blockers should still be continued perioperatively as much as feasible in those already receiving them for good indications,” Dr. Fleischmann emphasizes. The update also provides Class III recommendations that indicate when β-blocker therapy should not be administered. These include using β-blockers in individuals who have contraindications for them and routine use of high-dose β-blockers in the absence of dose titration in patients not currently taking them.
The Provider’s Role
Different types of providers or specialists may be involved in decision-making for perioperative β-blocker use. “The key is that physicians assess cardiac risk thoroughly and weigh the risks and benefits of β-blockade,” says Dr. Fleischmann. Patient compliance in the perioperative period will affect the success rate of β-blockade in non-cardiac surgery. Good communication, patient education, and clear instructions are also important in maximizing adherence.
In the future, clinicians need more research to guide the use of β-blockers in the presence of newer techniques such as percutaneous or endovascular vascular procedures. In addition, studies to determine the best regimens for β-blockade and the optimal duration of therapy are lacking. Dr. Fleischmann says, “We still have some gaps in our knowledge regarding β-blockade, but this update can serve as a bridge for clinicians until more research emerges.”
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Dunkelgrun M, Boersma E, Schouten O, et al. Bisoprolol and fluvastatin for the reduction of perioperative cardiac mortality and myocardial infarction in intermediate-risk patients undergoing noncardiovascular surgery: a randomized controlled trial (DECREASE-IV). Ann Surg. 2009;249:921-926.
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