Current issues of ACP Journal Club are published in Annals of Internal Medicine


Therapeutics

Bypass surgery and angioplasty led to similar 5-year mortality rates in multivessel coronary artery disease

ACP J Club. 1997 Jan-Feb;126:12. doi:10.7326/ACPJC-1997-126-1-012


Source Citation

The Bypass Angioplasty Revascularization Investigation (BARI) Investigators. Comparison of coronary bypass surgery with angioplasty in patients with multivessel disease. N Engl J Med. 1996 Jul 25;335: 217-25.


Abstract

Objective

To compare the effectiveness of coronary artery bypass grafting (CABG) with percutaneous transluminal coronary angioplasty (PTCA) in patients with multivessel coronary artery disease (CAD).

Design

Randomized controlled trial with a mean follow-up of 5.4 years.

Setting

16 U.S. and 2 Canadian centers.

Patients

1829 patients (mean age 62 y, 73% men) with angiographically documented multivessel CAD and clinically severe angina or objective evidence of ischemia that required revascularization who were suitable candidates for CABG or PTCA. Vital status was ascertained for 1792 patients (98%).

Intervention

914 patients were assigned to CABG, and 915 were assigned to PTCA.

Main outcome measures

All-cause mortality, cumulative survival, Q-wave myocardial infarction (MI), survival free of Q-wave MI, and subsequent revascularization.

Main results

1796 patients (98%) had the assigned treatment. In-hospital death (1.3% vs 1.1%, { P = 0.67}*) and in-hospital stroke (0.8% vs 0.2%, { P = 0.09}*) were similar between the CABG and PTCA groups. Patients assigned to CABG were more likely to have an in-hospital Q-wave MI than patients assigned to PTCA (4.6% vs 2.1%, P < 0.01). No difference existed between the CABG and PTCA groups in the 5-year mortality rate (12.1% vs 14.3%, P = 0.19), the 5-year cumulative survival rate (89.3% vs 86.3%, CI for the 3% absolute difference -0.2% to 6.0%, P = 0.19), the rate of survival free of Q-wave MI (80.4% vs 78.7%, CI for the 1.6% absolute difference -2.2% to 5.4%, P = 0.84), or the cumulative rate of Q-wave MI (11.7% vs 10.9%, P = 0.45). At 5 years, 8% of the patients assigned to CABG had subsequent revascularization compared with 54% of those assigned to PTCA (P < 0.001). Patients treated for diabetes who were assigned to CABG had a greater 5-year survival rate than those who were assigned to PTCA (80.6% vs 65.5%, CI for the 15.1% absolute difference 1.4% to 28.9%, P = 0.003).

Conclusions

Mortality rates were similar among patients with multivessel coronary artery disease who were assigned either to CABG or to an initial strategy of PTCA. Patients treated with PTCA, however, were more likely to receive subsequent CABG. CABG improved survival in patients with diabetes.

Source of funding: National Heart, Lung, and Blood Institute.

For article reprint: Dr. R.L. Frye, c/o BARI Coordinating Center, University of Pittsburgh, Rm. 127, Parran Hall, 130 DeSoto Street, Pittsburgh, PA 15261, USA. FAX 507-284-8137.

*Numbers calculated from data in article.


Commentary

The Bypass Angioplasty Revascularization Investigation (BARI) brings the number of reported randomized trials comparing PTCA with CABG for the treatment of CAD to 9 (1). It is the largest study to date and the only multicenter, North American trial. The authors conclude that PTCA is an acceptable alternative to CABG for the treatment of all patients with CAD except those with diabetes. Although this result is similar to that reported in the other studies, it does not mean that there was no difference, as noted in an accompanying editorial (2). CABG was associated with a survival advantage of 2.9% at 5 years, largely because of its benefit in patients with diabetes. However, perhaps because of the lower-than-expected mortality rates, the study was underpowered to show statistically significant differences.

Anticipating concerns about generalizability, the BARI investigators compared the current practice of revascularization in the BARI centers with a sample of U.S. hospitals (3). The patients and the choice of revascularization procedures were found to be similar. The investigators estimated that 12% of candidates for revascularization would meet eligibility criteria for the BARI. Unfortunately, no information was available on whether success or complication rates were comparable. Also relevant to the generalizability of the study is that options for revascularization have changed. Stents have been shown to improve the outcomes of percutaneous interventions, and surgeons are becoming more aggressive with the use of arterial conduits.

Trials comparing treatment strategies are difficult to do, and the first-rate work of the BARI investigators is commendable. It is hoped that additional trials will assess the newer options for revascularization. In the interim, the BARI provides us with important insights that can guide our practice of evidence-based medicine.

David J. Malenka, MD
Dartmouth-Hitchcock Medical CenterLebanon, New Hampshire, USA


References

1. Pocock SJ, Henderson RA, Richards AF, et al. Lancet. 1995;346:1184-9.

2. Simoons ML. N Engl J Med. 1996;335: 275-7.

3. Detre KM, Rosen AD, Bost JE, et al. J Am Coll Cardiol. 1996;28:609-15.