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Johns Hopkins Medical Institutions, Baltimore, Maryland, and University of Michigan School of Medicine, Ann Arbor, Michigan
Address correspondence to Lee A. Fleisher, MD, The Johns Hopkins Hospital, 600 N. Wolfe St. Carnegie 280, Baltimore, MD 21202. Address e-mail to lfleishe{at}jhmi.edu
In March 1996, a Committee convened by the American College of Cardiology/American Heart Association published Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery (1). As outlined in the original guideline process, the Committee was queried every year since publication to determine if significant new information had been published which would warrant updating the Guidelines. In 2000, the Committee deemed there was sufficient new information, the culmination of which is published in this issue of Anesthesia & Analgesia (2). Using a MEDLINE search, the committee identified and reviewed over 400 relevant new articles.
When the original Guidelines were developed, the number of randomized trials addressing perioperative cardiovascular evaluation and therapy was extremely limited. Most of the literature reported on the relationship between adverse events and known risk factors or interventions. To develop a meaningful document, we incorporated these data with information from the nonsurgical arena to make recommendations. The goal of the final document was to define those situations in which testing and perioperative interventions may benefit patients and situations in which those interventions are not indicated. Using a Delphi approach, the Committee proposed an algorithm to define the need the further diagnostic testing before noncardiac surgery, incorporating patient and surgery-specific factors and exercise tolerance.
Considering the nature of the original guidelines, what should be the basis of any update? Clearly, the proposed algorithm needs validation. In fact, several nonrandomized studies published during the intervening years demonstrated low morbidity and mortality using an approach either identical or similar to the one advocated in the Guidelines (3,4). Importantly, no randomized trials have been published during the intervening period. In reviewing the components of the decision to perform further diagnostic testing (clinical factors, surgical risk, and exercise tolerance), there have been numerous papers to refine or confirm the previous designations. For example, chronic renal insufficiency is now considered an intermediate risk marker, but recent myocardial infarction (more than 7 days but less than or equal to 1 mo before examination) with evidence of important ischemic risk by clinical symptoms or noninvasive study is a major predictor. Finally, a recent report confirmed the value of self-reported exercise tolerance and its association with an increased incidence of perioperative morbidity and mortality (5). This is an important finding in light of statements made in the Guidelines published by the American College of Physicians in 1997, in which the use of self-reported exercise tolerance is questioned because of the lack of evidence (6).
The greatest advancements have been made in the area of perioperative interventions. Numerous randomized clinical trials have been published during the intervening years (7). These include trials of beta-adrenergic blocking drugs, alpha-2 agonists and other medical therapies. Based on this stronger evidence, the Committee was able to rate the strength of evidence and provide formal recommendations using a classification schema:
In assessing any medical practice, the goal is the appropriate utilization. The RAND Medical Outcomes Study demonstrated the frequency with which different surgical procedures are performed without appropriate indications (8). There are also data to support the contention that many medical interventions are underutilized. For example, the underuse of beta-blockers in elderly patients after myocardial infarction has been associated with worse survival (9). Recent evidence suggests that beta-blocker therapy is effective in reducing perioperative morbidity and mortality in high risk patients, yet many of these patients present to surgery without being prescribed these medications (7,10-12). Publications of these Guidelines will hopefully highlight the group for whom the evidence of the advantages of beta-blocker therapy is well established (Class I), and therefore care can be improved. Similarly, the potential harms of interventions can be disseminated, such as recent evidence, albeit from a small series of patients, suggesting that coronary stent placement within 30 days of surgery (and particularly within 2 wk) may lead to a frequent incidence of adverse events (13).
It is important to recognize that the Committee’s goal was to create Guidelines that are intended for "physicians who are involved in the preoperative, operative, and postoperative care of patients undergoing noncardiac surgery." The Guidelines were originally intended for use by all of the physicians involved, rather than restricted to any one group. To that end, the Committee sought and obtained endorsements from numerous societies, including the Society of Cardiovascular Anesthesiologists and the Society of Vascular Surgeons. Additionally, the Executive Summary was published in several journals, including Anesthesia & Analgesia. Pocket versions were made available from the American College of Cardiology which included a one-page laminated card of the algorithm. It is our belief that the wide dissemination of the Guidelines helped to facilitate communication among the different relevant specialties. With the development of the Update, we are grateful to the Editorial Board of Anesthesia & Analgesia for publishing the new Executive Summary.
Where do we go from here? Clearly, additional work is required to further define best practices. A section of the executive summary and complete document (which can be found at http://www.acc.org/clinical/guidelines/perio/update/periupdate_index. htm) outlines some of these projects. By providing a framework for practice, these Guidelines will hopefully allow for the best outcomes for our patients by fostering knowledge and communication.
References
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