EARLY ANGIOGRAPHIC CHANGES OF SIDE BRANCHES ARISING FROM A PALMAZ-SCHATZ STENTED CORONARY SEGMENT - RESULTS AND CLINICAL IMPLICATIONS

Objectives. The purpose of this study was to assess the effects and clinical implications of Palmaz-Schatz stent implantation on coronary blood flow in side branches arising from a stented coronary artery segment. Background. The occlusion of a side branch is a well defined risk after balloon angioplasty. However, the impact of stenting on the coronary flow in side branches arising within the stented segment is unknown. Methods. Forty six stented coronary artery segments with 79 side branches emerging from the stented segment were analyzed. Angiographic studies were performed before angioplasty, after balloon dilation, immediately after stenting and 24 h later. Side branches were classified as follows: type A (greater than or equal to 1 mm in diameter, with ostial narrowing), type B (greater than or equal to 1 mm in diameter, without ostial narrowing), type C (<1 mm in diameter, with ostial narrowing) and type D (<1 mm in diameter, without ostial narrowing). Quantitative angiography was used to assess the diameter of the side branches. Results. Stents were implanted electively in lesions with restenosis (41 stents, 89%) or with a suboptimal result after angioplasty (5 stents, 11%). Nine side branches (11%) were type A, 25 (32%) type B, 7 (9%) type C and 38 (48%) type D. At baseline, 68 side branches had Thrombolysis in Myocardial Infarction (TIMI) trial flow grade 3; 10 had grade 2; and 1 had grade 1. Flow worsened (TIMI grade greater than or equal to 1) in six side branches (8%) after balloon dilation and in four side branches (5%) after stenting. One additional side branch (1%) was occluded at 24 h. Of the 34 side branches greater than or equal to 1 mm in diameter (mean diameter 1.5 +/- 0.3 mm), 2 (6%) had flow impairment after stenting. Three patients experienced transient angina, but no acute myocardial infarction occurred as a result of a side branch occlusion. Conclusions. Coronary artery stenting does not modify anterograde flow in 90% of side branches. Coronary flow is reduced after stenting in a few branches, but this does not appear to have major clinical relevance.