Restenosis following elective implantation of single Palmaz-Schatz stents in de-novo lesions in native vessels

Abstract

Restenosis is the main limitation of long-term success after coronary angioplasty. Intracoronary stent implantation may reduce restenosis by producing a larger initial lumen and eliminating recoil. The objective of this study was to determine the frequency of and features associated with restenosis after elective single Palmaz-Schatz stent implantation in de-novo lesions in native vessels. Eighty consecutive patients were studied. Angiographic follow-up was performed in 79 out of 80 (99%) 6.5 +/- 3.4 months after the procedure. Angiographic measurements were performed using an automated computerized quantitative angiographic analysis system. Restenosis (> or = 50% stenosis) at follow-up occurred in 26 out of 79 patients (33%). The frequency of complex lesion morphology was higher (50% versus 19% American College of Cardiology/American Heart Association classification B2; P = 0.005), the reference vessel diameter larger (3.0 +/- 0.5 mm versus 2.8 +/- 0.6 mm, P = 0.049), and the lesion length longer (10.9 +/- 3.5 mm versus 8.5 +/- 3.5 mm, P = 0.009) in the restenosis group compared with the non-restenosis group. The population was divided into three groups according to the reference vessel diameter: (1) greater than 3.0 mm (n = 27), (2) 2.5-3.0 mm (n = 29), and (3) less than 2.5 mm (n = 22). One patient was excluded from this subgroup analysis because of difficulty in determining the reference vessel diameter before the procedure. The restenosis rates were 52%, 37%, and 11%, respectively, for the three groups (P = 0.02). The relative acute gain was greater in the smaller vessels, (0.66 in the < 2.5 mm vessels, 0.53 in the 2.5-3.0 mm vessels, and 0.48 in the > 3.0 mm vessels; P = 0.006). This was associated with a relative oversizing of the final stent balloon in the smaller vessels (balloon-to-vessel ratio of 1.33 in the vessels < 2.5 mm diameter, 1.16 in the 2.5-3.0 mm vessels, and 0.98 in the > 3.0 mm vessels; P = 0.001). The frequency of restenosis in single electively implanted Palmaz-Schatz stents in de-novo lesions in native vessels was 33%. The degree of restenosis was lower in smaller vessels, in which a better initial result was associated with relative oversizing of the final stent balloon. More aggressive dilation within the stented segment may result in a lower restenosis rate.