Background: Clinical follow-up after percutaneous transluminal coronary angioplasty (PTCA) of an infarct-related lesion has demonstrated a low incidence of recurrent symptoms and repeated revascularization. In the absence of systematic angiographic follow-up, this low rate of clinical restenosis may reflect either a truly lower incidence of anatomic restenosis or the lack of recurrent symptoms in patients with extensive infarction in the territory of the restenotic vessel.
Methods and results: We studied 300 consecutive patients who, after a thrombolysis for myocardial infarction, underwent delayed (10.5 +/- 6 days after the myocardial infarction) PTCA of the infarct-related lesion. Procedural success was obtained in 253 patients (84%), and angiographic follow-up was performed in 205 of this group (81%) at a mean of 7.3 +/- 1.9 months. Restenosis (defined as the recurrence of > 50% stenosis) was present in 105 patients (51%). Only 34 of the 105 patients (32%) with angiographic restenosis were symptomatic; the other 68% had clinically silent restenosis. Of these 105 patients, 27 (13% of the total population undergoing follow-up angiography) had reocclusion at the dilated site at follow-up. The severity of the stenosis at follow-up and the late loss in minimal lumen diameter followed a nearly Gaussian distribution if the lesions that were totally occluded at follow-up were excluded. By multivariate analysis, two independent predictors of reocclusion were identified: a small reference diameter (P < .0005) and the presence of collateral vessels before the procedure (P < .01). Only one factor was associated with restenosis in the 178 patients who did not have reocclusion at follow-up; a Thrombolysis in Myocardial Infarction grade < or = 2 before the procedure (P < .0001). At follow-up, there was a significantly (P < .01) higher ejection fraction in patients without restenosis (56.1 +/- 13.4%) and in patients with restenosis without total occlusion (56.0 +/- 13.8%) than in patients with reocclusion (46.4 +/- 13.0%).
Conclusions: Despite a satisfactory clinical outcome, delayed PTCA of an infarct-related lesion is associated with a high rate of angiographic recurrence. Two distinct mechanisms account for recurrent stenosis: progressive luminal renarrowing as documented after angioplasty of stable lesions and reocclusion of the infarct-related lesion. Only reocclusion is associated with a deterioration in left ventricular function at follow-up.