Clinical Alert: Bypass Over Angioplasty for Patients with Diabetes
Before PTCA, CABG was the traditional revascularization strategy. But PTCA, first performed in the United States in 1977, has grown rapidly in use. In 1993, about 362,000 PTCAs were done in the United States, compared with about 309,000 CABG surgeries.
However, PTCA use has expanded not just in number but also in the type of patient treated. Initially, PTCA was done on patients with one obstructed vessel. But, with increased physician expertise and an improved technology, PTCA use has rapidly expanded to include patients with more complex, multivessel coronary obstructions, once treated exclusively with CABG. This has led to uncertainties about the long-term effectiveness and safety of PTCA compared with CABG and prompted the NHLBI to fund a rigorous evaluation of the two methods.
That rigorous investigation -- the BARI study -- tests whether the use of PTCA as an initial treatment compromised the clinical outcome for patients with multivessel coronary artery disease who needed revascularization and could be treated by either PTCA or CABG. BARI did not test outcomes for repeat procedures. It also studied only PTCAs performed with the standard balloon technique.
The trial is the largest randomized study of its type, with enough patients to be able to address key endpoints, both overall and in predetermined patient subgroups. The subgroups were based on patients' anginal status, number of diseased vessels, and left ventricular function. Also studied are various demographic factors such as gender, age, race, and the presence of diabetes.
The primary endpoint is mortality after 5 years of follow-up. Other important endpoints include the occurrence of a myocardial infarction, need of repeat revascularization procedures, angina, functional status, quality of life, and utilization of health-care resources. (Both quality of life and utilization of health-care resources are studied in detail in a separately funded ancillary study.)
Patients were eligible for the trial if they had coronary artery disease with a 50 percent or more luminal obstruction (as measured by calipers) in at least two of the coronary vessels supplying two or three major coronary territories. They also had to have clinically severe ischemia but not a prior revascularization. Patients were ineligible for the trial if they had, for example, insufficient angina or ischemia, required emergency revascularization, left main stenosis of 50 percent or greater, a noncardiac illness expected to result in limited survival, primary coronary spasm, or a poor quality angiogram. Baseline angiograms were reviewed and classified by the Central Radiographic Laboratory (Dr. Edwin L. Alderman, director) at the Stanford University Medical Center in Palo Alto, CA.