Dr. Modest makes several valid points with which we concur. First, clinical practice guidelines must be continuously updated to reflect advances in knowledge. Second, data on the efficacy of coronary bypass surgery are relatively old and may not accurately reflect current practices and outcomes. Third, data are emerging to indicate that aggressive lipid-lowering therapy is an important component of regimens to manage symptoms of ischemia as well as to prevent future complications.

With regard to updating clinical guidelines, the American Heart Association and the American College of Cardiology require that updates and revisions be performed regularly. In fact, the guideline on the management of chronic stable angina by the American Heart Association, American College of Cardiology, and American College of Physicians–American Society of Internal Medicine, on which our article was based, is currently being updated. The rules require that any new information or recommendations included in the updated guidelines be based on high-quality evidence.

As Dr. Modest points out, some of the data from which recommendations for surgery are derived were collected in trials conducted over a decade ago, when results of both surgical and medical therapy were probably poorer than they are today. In keeping with our rules of evidence, however, these trials were methodologically sound and demonstrated important differences in mortality and control of symptoms for certain specific subgroups of patients. To date, these findings have not been supplanted by newer data from randomized trials, and a recent decision analysis indicates that there have been similar improvements in mortality due to advances in medical and surgical therapy for chronic stable angina (1). In our review, we specifically stated that such studies "must be interpreted cautiously," in part because "advances such as aggressive lipid lowering ... were often not assessed" (2). As we also noted, similar concerns apply to comparisons of percutaneous coronary interventions because many earlier randomized trials did not incorporate the latest advances, such as intracoronary stents (with or without drug coating).

In reference to studies suggesting that aggressive lipid lowering may alleviate anginal symptoms, we share Dr. Modest's excitement. The major trial he cites, however, enrolled patients who were at very low risk for acute coronary events, had mainly absent or mild anginal symptoms, and would probably not have been candidates for surgery under any circumstances (3). Thus, the results of that trial have little relevance to recommendations for surgical intervention. Nonetheless, we share Dr. Modest's implied optimism that future trials involving higher-risk patients with more severe symptoms will show that aggressive medical therapy can obviate the need for invasive procedures in at least some patients.