CHRONOLOGIE ET INCIDENCE DE LA RESTENOSE APRES ANGIOPLASTIE CORONAIRE. COMPARAISON DES PATIENTS PRESENTANT UN ANGOR STABLE A CEUX PRESENTANT UN ANGOR INSTABLE

The aim of this prospective study was to compare the incidence of restenosis after percutaneous transluminal coronary angioplasty (PTCA) in patients with stable and unstable angina before the procedure. Between January 1984 and February 1986, 344 patients with stable angina and 228 patients with unstable angina underwent PTCA. The primary success rate was 86.3 per cent in patients with stable angina (297 patients) and 87.7 per cent in patients with unstable angina (200 patients). The patients were recalled for systematic control coronary arteriography at 30, 60, 90, 120 or 150 days, and was obtained in 83.8 per cent of patients with stable angina and in 86 per cent of patients with unstable angina. The degree of stenosis before and the angiographic changes after PTCA and at control coronary arteriography were evaluated by a computer-assisted automatic contour detection system. The three criteria of restenosis were : 1) over 50 per cent loss of the benefit of PTCA, 2) residual post-PTCA stenosis increasing from less than 50 per cent to more than 50 per cent at control arteriography, 3) a decrease in the minimum intraluminal diameter of at least 0.72 mm with respect to the immediate post-PTCA result. A comparison between the two groups of patients showed that the average age was slightly greater in patients with unstable angina (56 ± 9 years vs 58 ± 9 years, p = 0.047). Apart from this difference, the two groups were comparable with regards to the average number of lesions dilated per patient, the date of control arteriography, the severity of the coronary artery disease and previous bypass surgery, angioplasty and infarction. A significant improvement in the intraluminal diameter and percentage stenosis was observed in both groups of patients after PTCA (p < 0.0001). The analysis of the incidence of restenosis showed a large variation in the percentage of restenosis depending on which angiographic criterion was used. On the other hand, the incidence of restenosis was identical in the two groups of patients (stable and unstable angina) irrespective of the criteria used. The results of multivariate analysis of the timing of restenosis showed that the relative risk of restenosis was higher in the group with stable angina between 30 and 60 days after PTCA. Patients with unstable angina had a higher risk of restenosis between the 60th and 90th day after angioplasty.