Angioplasty Compared to Medicine - Two-Vessel Disease - ACME-2
Angioplasty Compared to Medicine - Two-Vessel Disease (ACME-2) was a multicenter, randomized Veterans Affairs-based study that sought to assess outcomes of men with double-vessel coronary artery disease assigned to treatment by percutaneous transluminal coronary angioplasty (PTCA) or medical therapy, compared with previously reported outcomes for men with single-vessel disease.
The goal of the study was to compare the relative benefit of PTCA versus medical therapy in patients with double-vessel disease and also to compare this benefit to patients with single-vessel disease.
Patients Screened: 9,398
Patients Enrolled: 328
Mean Follow Up: Median 60 months
Patients screened for the study included all those who underwent diagnostic coronary angiography for a primary diagnosis of coronary artery disease at the participating centers.
• Clinical requirements: history of angina, MI within three months, or ≥3 mm horizontal ST-segment depression on an exercise ECG.
• Angiographic requirements: ≥70% diameter stenosis in the proximal two-thirds of one or two major coronary arteries. Lesions in at least one of the arteries had to be technically amenable to PTCA, and all patients were required to be suitable candidates for potential CABG.
• Patients meeting the above requirements then underwent exercise stress testing with nuclear imaging, and were enrolled if they met the following requirements: ≥1 mm horizontal or downsloping ST-segment depression with exercise; or, in the absence of ST-segment depression, exercise-induced angina with a reperfusing thallium-201 image defect at the location of the patient’s arterial disease.
Medically refractory unstable angina; previous coronary artery revascularization; primary cardiac diagnosis other than coronary artery disease; left main coronary artery stenosis ≥50%; ≥70% stenosis of more than two major coronary arteries (three-vessel disease); or left ventricular ejection fraction ≤30%
Changes in angina frequency during each 30-day follow-up time period compared with baseline; percent of patients free from angina during the last month of follow-up compared with that at baseline month; changes in total duration of exercise, time to onset of angina and maximal rate–pressure product; and change in mean percent diameter stenosis of the index lesions (potential targets for baseline PTCA) from baseline to the follow-up angiogram
PTCA or medical treatment into the following randomization strata:
1) Single-vessel disease, ≤99% stenosis
2) Single-vessel disease, 100% occlusion
3) Double-vessel disease, both vessels amenable to PTCA
4) Double-vessel disease, only one vessel amenable to PTCA
Patients assigned to PTCA treatment were given aspirin and calcium channel blocking agent therapy and underwent dilation as soon as possible. Patients assigned to medical treatment received aspirin plus individualized therapy utilizing nitrates, beta-adrenergic blocking agents, and calcium channel blockers in a progressive, stepped-care approach similar to usual clinical practice for treatment of angina.
A total of 328 patients were enrolled in the overall trial, with 101 patients with double-vessel disease and 227 with single-vessel disease. Baseline characteristics were similar between patients with single- and double-vessel disease. Of the 51 double-vessel disease patients assigned to PTCA, only five did not undergo the procedure.
At six months, fewer double-vessel disease patients assigned to PTCA versus medical therapy were on antianginal medications (62% vs. 96%), similar to results in patients with single-vessel disease (53% vs. 97%). Rates of death/myocardial infarction (MI) were similar between patients assigned to PTCA versus medical therapy. PTCA-treated and medically treated patients with double-vessel disease experienced a comparable improvement in exercise duration (+1.2 vs. +1.3 minutes, respectively, p=0.89), freedom from angina (53% and 36%, p=0.09), and improvement of overall quality of life score (+1.3 vs. +4.4, p=0.32) at six months compared with baseline. This contrasts with the results from the single-vessel disease patients favoring PTCA by these criteria.
At angiographic follow-up among PTCA-treated patients, patients with double-vessel dilation had less complete initial revascularization (45% vs. 83%) and greater average stenosis of worst lesions at six months (74% vs. 56%) compared to patients with single-vessel disease. PTCA-treated patients with double-vessel disease had follow-up myocardial perfusion image changes that were not statistically different from those of medically treated patients, while patients with single-vessel disease treated by PTCA had significantly more improvement and less worsening than those treated by medical therapy. At long-term follow-up, there were no significant differences between PTCA and medical therapy in double-vessel disease patients.
In this multicenter study of clinically stable patients with two-vessel coronary artery disease, the initial strategy of PTCA or medical therapy produced comparable decreases in symptoms and improvement in exercise performance, with similar adverse outcomes. However, as the authors state, the study was not adequately powered to compare differences between medical therapy and PTCA in double-vessel disease patients (it was powered for single-vessel disease patients, as reported in the initial ACME trial). The lack of incremental benefit related to PTCA versus medical therapy may be related to the higher prevalence of incomplete revascularization in the PTCA arm (compared to patients with single-vessel disease), as well as the greater restenosis rates with two-vessel dilation.
Folland ED, Hartigan PM, Parisi AF. Percutaneous transluminal coronary angioplasty versus medical therapy for stable angina pectoris: outcomes for patients with double-vessel versus single-vessel coronary artery disease in a Veterans Affairs Cooperative randomized trial. Veterans Affairs ACME InvestigatorS. J Am Coll Cardiol 1997;29:1505-11.
Keywords: Coronary Artery Disease, Myocardial Infarction, Coronary Angiography, Quality of Life, Constriction, Pathologic, Electrocardiography, Angioplasty, Balloon, Coronary, Exercise Test
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