Twelve-month outcome after coronary stent implantation without predilatation.

S tent implantation has traditionally been performed after predilatation of the stenotic lesion with a conventional catheter balloon, thus allowing the lesion to be crossed easily. As a result of the improved design of the stent delivery systems with lower crossing profiles and greater flexibility and better stent stability on the balloon, predilatation may not be necessary in some cases. The clinical feasibility, efficacy, and procedural safety of direct stenting in selected groups of patients have been shown in recent reports. This technique reduces the procedure time and radiation exposure times and costs. In addition, it may cause less myocardial ischemia due to a decrease in balloon inflations. However, there are few reports about midand long-term outcome after direct stenting. The purpose of the present study was first, to know the clinical and angiographic restenosis rate in patients in whom direct stenting was successfully implanted and also to identify clinical, lesional, and procedural variables predictive of angiographic restenosis after direct stent implantation. • • • From September 1998 to October 1999, 107 patients with significant coronary stenosis were eligible for primary direct coronary stenting. The study population represented 20% of patients undergoing percutaneous transluminal coronary angioplasty in our center during this period. Direct stenting was not attempted in patients with (1) severe calcified lesions, (2) long lesions ( 20 mm), (3) total occlusions, (4) severe tortuosity of the vessel proximal to the stenosis, (5) severe angulation within the lesion, and (6) contraindication to acetylsalicylic acid or ticlopidine. Patients in whom a direct stent was deployed in a vein graft were also excluded. The presence of intraluminal thrombus and the type of symptomatology at onset (stable angina, unstable angina, and acute myocardial infarction) were not considered exclusion criteria. Before angioplasty, oral acetylsalicylic acid and an intravenous bolus of sodium heparin were administered in all patients. After placing a soft guiding catheter into the coronary ostium, intracoronary nitroglycerin, 0.2 to 0.8 mg, was administrated. Another bolus of intracoronary nitroglycerin, 0.2 to 0.4 mg, was given after crossing the lesion with the guidewire to revert a potential associated vasoconstriction and to reach the maximum vasodilatation of the vessel for correct calculation of the stent size. A ratio stent/ reference diameter of 1.1-to-1.0/1.0 was chosen. The stent was then positioned in the target lesion with moderate pushing or proximal intubation of the guiding catheter when necessary. The balloon was slightly inflated over nominal pressures to assess an adequate stent deployment. When the expansion was incomplete, higher pressures with the same balloon or another balloon were performed. At least 2 orthogonal projections were performed for analysis. Quantitative analysis was performed by computer using a coronary detection border analysis system (Integris HM 3000, Phillips Medical System, Leiden, The Netherlands). Angiographic measurements were obtained during diastole after intracoronary nitroglycerin administration using the guiding catheter for calibration. The percentage of stenosis and minimum luminal diameter (MLD) were measured at the basal stage, immediately after stent implantation, and at follow-up. We calculated the following variables: (1) acute gain, defined as an increase in MLD of the stented artery immediately after the procedure; (2) late loss, defined as subsequent reduction in luminal diameter of the treated artery at follow-up angiography; and (3) loss index, as the average ratio of the late loss to acute gain. Coronary angiography was performed no earlier than 6 months after angioplasty, except in cases of recurrent angina. If angiography was performed within 4 months of angioplasty and the lesion was not redilatated, it was repeated 6 months after the procedure. Clinical, procedural, and angiographic data were evaluated as potential determinants of restenosis as a binary variable (defined as 50% diameter stenosis at follow-up in the stented segment) and as a continuous variable (as absolute late MLD and late loss). The unpaired Student’s t test was used to detect differences in continuous variables and chi-square test for categorical variables between the restenotic and nonrestenotic groups. Logistic regression multivariate analysis using the stepwise procedure was performed to identify significant independent risk variables of binary restenosis. Multiple regression analysis was performed to evaluate the potential determinants of restenosis considered as continuous variables (late loss and late MLD). Data are expressed as mean SD. A p value 0.05 was considered statistically significant. Of the 107 patients for whom a primary direct stent was electively indicated, the lesion could not be crossed in 7 (6.5%), and they were excluded from the study. In these patients, predilatation of the lesion with From the Interventional Cardiology Unit, Department of Cardiology and Cardiac Surgery, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. Dr. Marti’s address is: Interventional Cardiology Unit, Hospital de la Santa Creu i Sant Pau, Sant Antoni M. Claret 167, 08025 Barcelona, Spain. E-mail: 18461vmc@comb.es. Manuscript received March 14, 2001; revised manuscript received and accepted May 18, 2001.