Direct coronary stent implantation: Safety, feasibility, and predictors ofsuccess of the strategy of direct coronary stent implantation

This prospective study was designed to evaluate the feasibility, safety, pr edictive factors of success, and 6-month follow-up of stent implantation wi thout balloon predilatation (direct stenting) in 250 patients undergoing el ective stent implantation. Balloon dilatation prior to stent implantation w as a prerequisite to facilitate passage and deployment of the stent. Stent technology has changed tremendously, resulting in stents with improved prop erties, which may allow stent placement without prior balloon dilatation. P atients with coronary lesions suitable for elective stent implantation were included in this trial. Coronary interventions were undertaken predominant ly via the transradial route using 6 Fr guiding catheters. Direct stent imp lantation was attempted using AVE GFX II coronary stent delivery systems. U pon failure, predilatation was undertaken before reattempting stent implant ation. Patient data and ECGs were obtained from case records and from perso nal or telephone interviews 6 months after the procedure. Values were prese nted as mean +/- standard deviation. Student's t-test, two-tailed at 5% lev el of significance, was used to compare the difference of two means. Multiv ariate logistic regression analysis was performed to establish predictive f actors for failure of direct stenting. Two hundred and sixty-six direct ste nt implantations were attempted in 250 patients. Direct stenting was succes sful in 226 (85%) cases. Out of 40(15%) cases where direct stenting failed, balloon predilatation facilitated stent implantation in 39. In one lesion, stent implantation was not possible despite adequate predilatation. Predic tive factors for failure of direct stenting on multivariate analysis were L Cx lesions (P < 0.01), complex lesions (P < 0.01), and longer stents (P < 0 .001). Minimal luminal diameter and percentage diameter stenosis of lesions in the successful and the failure group were not significantly different ( 0.94 <plus/minus> 0.39 mm vs. 0.84 +/- 0.41 mm, P = NS, and 70.2 +/- 11.2 v s. 73.2 +/- 11.2, P = NS). Stent loss occurred in five (2.0%) cases, with s uccessful retrieval in four. one stent was lost permanently in a small bran ch of the radial artery. Post-percutaneous coronary intervention (post-PCI) myocardial infarction occurred in four (1.6%) patients. There were no othe r in-hospital events. Six-month-follow up information was obtained in 99% o f patients. Subacute stent thrombosis was noted in four (1.6%) cases. Targe t vessel-related myocardial infarction rate was 3.2%, of which half was cau sed by subacute stent thrombosis. The overall reintervention rate (coronary artery bypass grafting or PCI) was 9.7%. Target lesion revascularization b y PCI occurred in only 4.0%. At 6 months, overall mortality was 2.0%, of wh ich 1.2% was due to coronary events. Direct stent implantation is safe and feasible in the majority of cases with low rate of complications. Unfavorab le factors include circumflex lesion, more complex lesion morphology, and i ncreasing length of stent. Severity of stenosis does not appear to be of pr edictive value. Long-term outcome is favorable with a low target lesion rev ascularization rate. (C) 2001 Wiley-Liss, Inc.