ANGIOGRAPHIC AND CLINICAL OUTCOME FOLLOWING CORONARY STENTING OF SMALL VESSELS - A COMPARISON WITH CORONARY STENTING OF LARGE VESSELS

Objectives. Stent implantation reduces restenosis in vessels greater t han or equal to 3 mm compared with balloon angioplasty, but few data a re available for stents implanted in vessels <3 mm. The aim of this st udy was to evaluate immediate and follow-up patient outcomes after ste nt implantation in vessels <3 mm compared to stent implantation in ves sels greater than or equal to 3 mm. Methods. Between March 1993 and Ma y 1996, a total of 1,298 consecutive patients (1,673 lesions) underwen t coronary stenting. The study population was divided into two groups based on angiographic vessel diameter. In case of multivessel stenting , patients were randomly assigned only one lesion. Group I included 69 6 patients (696 lesions) in whom stents were implanted in vessels grea ter than or equal to 3 mm, and group II included 602 patients (602 les ions) in whom stents were implanted in vessels <3 mm. Results. There w as no difference in procedural success (95.4% in group I and 95.9% in group II), or subsequent subacute stent thrombosis (1.5% in group I an d 1.4% in group II p = NS). The postprocedure residual diameter stenos is was 3.31 +/- 12.4% in group I and -2.45 +/- 16.2% in group II. Angi ographic follow-up was performed in 75% of patients, restenosis occurr ed in 19.9% of patients in group I and 32.6% in group II (p <0.0001). Absolute lumen gain was significantly higher in group I compared to gr oup II, but absolute late lumen loss was similar in the two groups (1. 05 +/- 0.91 mm in group I vs. 1.11 +/- 0.85 mm in group II, p NS). Sub sequently, the loss index was more favorable in group I [0.45 vs. 0.56 ; p = 0.0006). Independent predictors of freedom from restenosis by mu ltivariate logistic regression in the total population were: larger ba seline reference diameter (odds ratio 2.032 p = 0.006, larger postproc edure minimal stent cross-sectional area (odds ratio 1.190, p = 0.0001 ) and shorter lesions (odds ratio 1.037, p = 0.01). At long term clini cal follow up, patients with small vessels had a low er rate of event free survival (63% vs. 71.3%, p = 0.007), Conclusions. Coronary stenti ng can be performed in small vessels with a high success rate and low incidence of stent thrombosis. However, the long-term angiographic and clinical outcome of patients undergoing stent implantation in small v essels is less favorable than that of patients with large vessels. (J Am Coll Cardiol 1998;32:1610-8) (C)1998 by the American College of Car diology.