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Therapeutics

Bypass surgery and angioplasty were comparable for preventing ischemic outcomes

ACP J Club. 1995 Mar-April;122:31. doi:10.7326/ACPJC-1995-122-2-031


Source Citation

King SB 3d, Lembo NJ, Weintraub WS, et al. A randomized trial comparing coronary angioplasty with coronary bypass surgery. N Engl J Med. 1994 Oct 20;331:1044-50.


Abstract

Objective

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

Design

Randomized controlled trial with 3-year follow-up.

Setting

3 hospitals in Atlanta.

Patients

Of the 5118 patients who were screened for eligibility, 842 were eligible for enrollment, and 392 patients (mean age 62 y, 74% men) referred for revascularization because of stable or unstable angina or because of objective signs of ischemia with 2- or 3-vessel disease participated. Exclusion criteria were previous CABG or PTCA.

Intervention

194 patients were assigned to CABG, and 198 patients were assigned to PTCA.

Main outcome measures

A composite of death, Q-wave myocardial infarction (MI), and a large ischemic defect identified on thallium scanning; clinical and angiographic status; and need for additional revascularization.

Main results

The composite outcome occurred in 27.3% of patients assigned to CABG compared with 28.8% of those assigned to PTCA (P = 0.81) (Table). Death occurred in 6.2% of patients in the CABG group compared with 7.1% of patients in the PTCA group (P = 0.73) (Table). Subsequent revascularization with either PTCA or CABG was required in 13% of patients in the CABG group compared with 54% of patients in the PTCA group (P < 0.001) (Table). CABG provided more successful revascularization than did PTCA. At 3 years, angina was more prevalent in the PTCA group than in the CABG group (20% vs 12%, P = 0.039). Patients in the PTCA group were also more likely to be taking antianginal medication (66% vs 51%, P = 0.005).

Conclusions

Coronary artery bypass surgery and percutaneous transluminal coronary angioplasty did not differ with respect to the occurrence of a composite outcome of death, myocardial infarction, and a large ischemic defect on thallium scanning at 3 years in patients with multivessel coronary artery disease. Patients who had initial angioplasty, however, had more frequent angina, were more likely to be taking antianginal drugs, and were more likely to have subsequent revascularization.

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

For article reprint: Dr. S.B. King 3d, Emory University Hospital, Suite F606, 1364 Clifton Road Northeast, Atlanta, GA 30322, USA. FAX 404-712-5622.


Table. Percutaneous transluminal coronary angioplasty (PTCA) vs coronary artery bypass grafting (CABG) for multivessel coronary artery disease*

Outcomes at 3 y PTCA CABG RRI (95% CI) NNH (CI)
Combined end point† 29% 27% 5.4% (-23 to 45) Not significant
Death 7.1% 6.2% 14% (-45 to 137) Not significant
Subsequent revascularization 54% 13% 320% (188 to 521) 3 (3 to 4)

*Abbreviations defined in Glossary; RRI, NNH, and CI calculated from data in article.
†Combined rates of death, Q-wave myocardial infarction, and a large ischemic defect identified on thallium scanning.


Commentary

Bypass surgery and angioplasty were similarly effective in relieving angina

Medical therapy, PTCA, and CABG are competitive and complementary techniques for treating symptomatic CAD. Medical therapy includes nitrate, β-blockers, and calcium channel blockers. Balloon angioplasty is superior to these drugs to relieve angina and improve exercise duration (1) but is not very successful for diffuse disease or chronic total occlusions and is limited by acute closure and restenosis. CABG has the same advantages as angioplasty relative to drug therapy and also has been shown to reduce mortality in patients with significant left main disease or 3-vessel disease and left ventricular dysfunction. Surgery is superior to angioplasty for revascularizing arteries that are diffusely diseased or chronically occluded but is limited by perioperative complications, prolonged convalescence, and bypass graft atherosclerosis. Increasing data support the use of coronary revascularization rather than medical therapy for selected patients with CAD, but the choice of angioplasty or surgery has only recently been studied in 6 randomized studies, 2 of which are abstracted here and 4 of which are reported elsewhere (2-5).

The early results from these trials have produced no major surprises. No differences existed in mortality, MI, left ventricular ejection fraction, exercise time, or employment status. Angioplasty was easier to schedule, required shorter hospital stays and convalescent periods, and was less expensive initially. Patients were, however, more likely to have recurring angina, increased need for antianginal medications, and repeat revascularizations. Surgery resulted in more complete and sustained revascularization but was associated with more in-hospital complications and longer recovery periods.

The patients enrolled in these studies were carefully selected, representing < 10% of those screened. Patients with left main disease, significant valvular heart disease, previous angioplasty or surgery, recent MI, total occlusions, long lesions, or significant left ventricular dysfunction were excluded. Thus, the results only apply to patients who are suitable candidates for either procedure.

Individually, these trials are underpowered for addressing several important revascularization questions, but future analysis of the pooled results and the nonrandomized registries may prove enlightening. Does partial revascularization give the same clinical outcome as total revascularization for large subsets of patients? Are the techniques equivalent in patients with left ventricular dysfunction? How does vein graft failure 5 to 10 years after surgery influence the long-term comparison? Will the early economic advantage for angioplasty be maintained? The potential benefit of selectively using coronary atherectomy or endoluminal stenting to improve the angioplasty results is not addressed by these studies.

Clinically, it continues to seem reasonable to offer angioplasty initially to patients with low-risk anatomy (1-vessel disease, multivessel disease with dilatable lesions, reasonable left ventricular function) who wish to avoid major surgery and are willing to risk the need for further interventions. Patients with left main disease, complex multivessel disease, and significant left ventricular dysfunction have a proven survival benefit with surgery. Another important role for angioplasty is in revascularizing patients who are at high risk for surgery because of cerebrovascular, renal, or pulmonary disease or who have poor target arteries, inoperable valvular heart disease, or severe left ventricular dysfunction.

Eric Bates, MD
The University of Michigan Medical CenterAnn Arbor, Michigan, USA


Commentary Update

The results of the 8-year follow-up of the trial by King and colleagues confirm the 1994 results (6).


References

1. Parisi AF, Folland ED, Hartigan P. A comparison of angioplasty with medical therapy in the treatment of single-vessel coronary artery disease. Veterans Affairs ACME Investigators. N Engl J Med. 1992;326:10-6.

2. Protocol for the Bypass Angioplasty Revascularization Investigation. Circulation. 1991;84 (Suppl V):V1-27.

3. RITA Trial Participants. Coronary angioplasty versus coronary artery bypass surgery: the Randomized Intervention Treatment of Angina (RITA) trial. Lancet. 1993;341:573-80.

4. Rickards A. Coronary Angioplasty vs Bypass Revascularization Investigation (CABRI). Presented at the European Society of Cardiology XVth Congress. Nice, France; September 1993.

5. Rodriguez A, Boullon F, Perez-Baliño N, et al. Argentine randomized trial of percutaneous transluminal coronary angioplasty versus coronary artery bypass surgery in multivessel disease (ERACI): in-hospital results and 1-year follow-up. ERACI Group. J Am Coll Cardiol. 1993;22:1060-7.

6. King SB 3d, Kosinski AS, Guyton RA, Lembo NJ, Weintraub WS. Eight-year mortality in the Emory Angioplasty versus Surgery Trial. J Am Coll Cardiol. 2000;35:1161-21.