Randomized trials of myocardial revascularization

Over the past two decades there has been considerable refinement in randomized cardiovascular clinical trials. The common aim of randomized clinical trials of myocardial revascularization has been to understand the relative benefits of each technique on survival and nonfatal end points. The bypass surgery versus medicine trials that began in the 1970s provided evidence that the patients with advanced ischemic heart disease--three-vessel disease and/or substantially impaired LV function--have the most to gain from aggressive therapy (i.e., bypass surgery). In these cases, surgical revascularization provides survival benefit and has emerged as the reference standard for providing the most definitive revascularization. In long-term follow-up, however, surgery does not reduce the occurrence of myocardial infarction or angina compared with medical therapy. For patients with less extensive atherosclerosis and/or preserved ventricular function, trials comparing medical therapy, percutaneous coronary interventions, and bypass surgery have shown similar medium-term rates of death and infarction. In general, patients undergoing bypass surgery require the fewest subsequent antianginal medications, whereas patients undergoing PTCA require a moderate amount of antianginal medications, and patients treated solely with medical therapy require the most antianginal medications. Regardless, during long-term follow-up a similarly high number of patients are angina-free, although patients in the PTCA group require reintervention more often. Among patients treated percutaneously, techniques such as balloon angioplasty, directional atherectomy, stenting, rotablation, and laser may be considered. Compared with balloon angioplasty, greater acute gains in angiographic lumen have been obtained after directional atherectomy and stenting, but at the expense of increased periprocedural infarction after atherectomy, increased peripheral vascular complications after stenting, and increased late loss of lumen after both. Elective stenting has been associated with improved clinical outcome, whereas laser and rotational atherectomy have not, in comparison to balloon angioplasty. Restenosis remains the major limitation of all percutaneous approaches. Guidance for the individual patient is often less straightforward. Although general conclusions can be derived from patients cohorts in randomized trials, only a "gestalt" can be provided for the individual patient. For example, we have poor predictive capacity for restenosis, especially when this is recurrent despite repeated intervention. Only the demographic criteria of severe unstable angina and insulin-dependent diabetes mellitus are helpful in categorizing patients as "restenosis-prone." A substantial number of patients do not fit into the criteria adopted for entry into the revascularization trials--a point that is all too frequently forgotten.(ABSTRACT TRUNCATED AT 400 WORDS)