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


Therapeutics

Angioplasty for single-vessel coronary artery disease

ACP J Club. 1992 July-Aug;117:5. doi:10.7326/ACPJC-1992-117-1-005


Source Citation

Parisi AF, Folland ED, Hartigan P. A comparison of angioplasty with medical therapy in the treatment of single-vessel coronary artery disease. N Engl J Med. Jan


Abstract

Objective

To compare percutaneous transluminal coronary angioplasty (PTCA) with medical therapy for single-vessel coronary artery disease.

Design

6-month randomized controlled trial.

Setting

8 Veterans Affairs medical centers.

Patients

The inclusion criteria were clinical (stable angina pectoris, an exercise test with ST-segment depression ≥ 3 mm, or myocardial infarction in previous 3 mo); angiographic (70% to 99% stenosis in the proximal two thirds of 1 major epicardial coronary artery or its branches [index lesions]); and exercise test (ST-segment depression ≥ 1 mm during exercise testing off medication, or evidence of a reversible defect corresponding to the index lesion on thallium scanning). 9573 patients were screened and 212 included in the study.

Intervention

PTCA done within 3 days of randomization with repeat PTCA as required, or stepped-care medical therapy including nitrates, β-blocking agents, calcium-channel-blocking agents, or a combination of these drugs. All patients received aspirin, 325 mg/d. Exercise testing and angiography were repeated after 6 months or ≥ 3 months after repeat PTCA.

Main outcome measures

Change in exercise tolerance, frequency of angina attacks, and use of nitroglycerin.

Main results

PTCA was done in 100 of 105 patients allocated to receive it; 80 procedures were initially clinically successful (> 20% decrease in stenosis where dilation was attempted, no myocardial infarction, and no need for emergency surgery). For the 94% of patients with complete exercise-test data, the PTCA group had a greater increase in duration of exercise at 6 months (2.1 min vs. 0.5 min; P < 0.001). The mean decrease in episodes of angina per month was 15 for PTCA and 7 for medical patients (P = 0.06). More patients with PTCA were free of angina after 6 months (64% vs. 46%; P = 0.01 {95% CI, 3.8% to 31.1%}[numbers calculated from data in article]). The groups did not differ in nitroglycerin use. By 6 months, 5 patients with PTCA (5%) had myocardial infarctions and 7 (7%) had coronary bypass surgery; 3 medical patients (3%) had myocardial infarctions, 11 (10%) had PTCA (1 died), and none had coronary bypass surgery. During follow-up, 19 repeat PTCA procedures were done in 16 patients.

Conclusion

Patients with single-vessel coronary artery stenosis had better exercise test results and were more likely to be free of angina 6 months after PTCA compared with patients receiving medical therapy.

Source of funding: Department of Veterans Affairs.

Address for article reprint: Dr. A.F. Parisi, Miriam Hospital, 164 Summit Avenue, Providence, RI 02906.


Commentary

This study addresses whether coronary angioplasty for mild symptomatic, single-vessel disease is better than medical therapy alone. The study has a number of noteworthy aspects. The condition they were studying, mild angina and single-vessel disease, is rare. Just 2.2% of those screened for the study were eligible. Such patients may not normally be referred for intervention. The end point chosen to determine sample size was also interesting (a 1-min advantage in total exercise duration) in that it was not particularly ambitious. Greater differences would have required lesser numbers but may have been unachievable. The results show an increase in exercise time of 0.5 minutes for the medically treated patients at 6 months compared with an increase of 2.1 minutes for the PTCA group (P < 0.001). Although more patients with PTCA were free of angina at each stage of the exercise test, it is unclear whether patients with PTCA achieved extra stages. Patients in the PTCA group also complained less about angina.

Although exercise stress testing and patient symptoms have been shown to be unreliable at indicating outcome from PTCA in single-vessel disease, this study suggests that with these end points PTCA is better than medical treatment. But at what cost? Apart from the financial implications, 2 patients in the PTCA group needed emergency coronary surgery, 5 had infarctions, 19 required repeat PTCA, and 5 required nonurgent surgery. Although 3 patients in the medical group had infarctions, none required coronary surgery.

Currently, the clinical and financial costs of PTCA may militate against it being the treatment of choice in patients with mild coronary artery disease, despite the fact that it appears to have greater value in terms of symptom treatment.

A. H. Gershlick, MD
University of Leicester Leicester, England


Author's Response

A 1-minute advantage in exercise endurance historically has been used to validate efficacy of new antianginal drugs. Figure 1 of the article shows that at 6 months 15% more patients in the PTCA group were angina-free at 9 minutes on the treadmill, achieving stage 3. Single-vessel disease and chronic stable angina may be less "rare" outside of the U.S. veteran population.

Alfred F. Parisi, MD