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 cl inical implications of Palmaz-Schatz stent implantation on coronary bl ood flow in side branches arising from a stented coronary artery segme nt. Background. The occlusion of a side branch is a well defined risk after balloon angioplasty. However, the impact of stenting on the coro nary flow in side branches arising within the stented segment is unkno wn. Methods. Forty six stented coronary artery segments with 79 side b ranches emerging from the stented segment were analyzed. Angiographic studies were performed before angioplasty, after balloon dilation, imm ediately after stenting and 24 h later. Side branches were classified as follows: type A (greater than or equal to 1 mm in diameter, with os tial narrowing), type B (greater than or equal to 1 mm in diameter, wi thout ostial narrowing), type C (<1 mm in diameter, with ostial narrow ing) and type D (<1 mm in diameter, without ostial narrowing). Quantit ative 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 ste nts, 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 Throm bolysis in Myocardial Infarction (TIMI) trial flow grade 3; 10 had gra de 2; and 1 had grade 1. Flow worsened (TIMI grade greater than or equ al 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 impairm ent after stenting. Three patients experienced transient angina, but n o acute myocardial infarction occurred as a result of a side branch oc clusion. Conclusions. Coronary artery stenting does not modify anterog rade flow in 90% of side branches. Coronary flow is reduced after sten ting in a few branches, but this does not appear to have major clinica l relevance.