Comparison of Coronary-Artery Stenting with Angioplasty for Isolated Stenosis of the Proximal Left Anterior Descending Coronary Artery - Comparison of Coronary-Artery Stenting with Angioplasty for Isolated Stenosis of the Proximal Left Anterior Descending Coronary Artery
The goal of this randomized trial was to evaluate the angiographic and clinical outcomes associated with an approach of primary stent implantation versus balloon angioplasty (PTCA) for a symptomatic, isolated stenosis of the left anterior descending coronary artery (LAD).
Compared to PTCA, primary stent implantation would be associated with a reduction in the rate of angiographically assessed restenosis at 12 months.
Patients Enrolled: 120
Mean Follow Up: 12 months
Mean Patient Age: mean 57 yrs
Mean Ejection Fraction: mean 53% (patients with EF<40% were excluded)
Typical angina, documented myocardial ischemia, or both; a newly diagnosed, isolated stenosis of the proximal portion of the LAD (>50 percent reduction of the luminal diameter, as measured by quantitative computerized angiography, extending less than 15 mm in length in a vessel more than 3 mm in diameter); and a left ventricular ejection fraction of ≥ 40%.
MI within the previous month; a contraindication to oral anticoagulation, antiplatelet therapy, or both; and anatomical contraindications, including ostial lesions, major branching of the vessel within the target lesion, total occlusion, and severe tortuosity.
Angiographic: 12 month angiographic restenosis
Clinical: composite of freedom from death, myocardial infarction, or recurrence of angina
Rates of procedural success; rate of CABG; in-hospital complications
Patients were randomly assigned to undergo either primary stent implantation or PTCA. Before randomization could be performed, a consensus that both procedures were feasible had to be reached by two physicians experienced in invasive cardiology who were not involved in the study.
Stent Implantation: A pre-mounted stent-delivery system was used after predilation in the first 40 patients. In the remaining patients, the stent was manually mounted on a balloon that matched the angiographically determined reference diameter. Stents were dilated at high pressure. Heparin was restarted 2-4 hours after sheath removal. Warfarin was started within 24 hours after the procedure, and patients continued to receive heparin until an INR of 2.5-3.5 was achieved. After discharge, warfarin was continued for three months and aspirin and diltiazem were continued indefinitely.
PTCA: Monorail balloon catheters were used. The management of acute/threatened closure was left to the discretion of the operator, and crossover to stent implantation was permitted. After discharge, aspirin and diltiazem were given indefinitely.
Patients received aspirin and diltiazem on the day before the procedure. At the beginning of the procedure, 10,000 IU of heparin was administered intra-arterially; supplemental doses were then given to maintain an ACT of >300 seconds.
120 patients were randomized. The two study groups were well-balanced with respect to baseline clinical and angiographic characteristics. Overall the patient population was relatively low-risk, with <20% of patients having unstable angina, and < 20% of patients having diabetes mellitus.
The procedural success rate was similar in both arms (>93%), and only 2 patients assigned to undergo PTCA crossed over to stent implantation. Stented patients had greater minimal luminal diameter (2.8 vs. 2.1 mm, p=0.001), and less severe residual stenoses (17% vs. 34%, p=0.001) immediately following the procedure.
At 12 months, the rate of freedom from death/MI/recurrent angina was higher among patients who were randomized to stent implantation compared to PTCA (87% vs. 80%, p=0.04), driven almost entirely by a greater frequency of recurrent angina among patients randomized to PTCA (25% vs. 10%). Among the patients who underwent angiographic follow-up (79% of the cohort), the rate of restenosis was lower among patients randomized to stent implantation (19% vs. 40%, p=0.02), and these patients additionally had greater follow-up minimal luminal diameter (1.8 vs. 1.4 mm, p=0.028) despite a greater reduction in minimal luminal diameter from immediately following the procedure (0.7 mm vs. 0.4 mm, p=0.035).
In this randomized controlled trial, a primary strategy of bare metal stent implantation for an isolated stenosis of the LAD was associated with improved outcomes when compared to a strategy of PTCA. This improvement was largely due to a lower rate of recurrent angina during the 12-month follow-up period, which presumably was related to the higher rate of restenosis in patients randomized to PTCA. The results of this trial are consistent with other trials conducted with bare metal stents, which have demonstrated reduced rates of restenosis with stenting compared to PTCA, despite more intense neointimal proliferation.
Versaci F, Gaspardone A, Tomai F, et al. A Comparison of Coronary-Artery Stenting with Angioplasty for Isolated Stenosis of the Proximal Left Anterior Descending Coronary Artery. N Engl J Med 1997;336:817-822.
Keywords: Diltiazem, Warfarin, Heparin, Stroke Volume, Constriction, Pathologic, Coronary Vessels, Angioplasty, Balloon, Coronary, Diabetes Mellitus, Stents
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