Side branch occlusion during direct stent implantation. Incidence and related factors

The aim of the study was to evaluate the compromise of side branches when jailed by a coronary stent implanted without balloon predilation. 56 patients in which at least a coronary stent was implanted without balloon predilation and covering a side brach (58 stents, 1.04 +/- 0.19 per patient) were studied. The effect of direct coronary stent implantation over side branch flow, as well as the characteristics associated were studied. The main vessel was left anterior descending in 63%, left circumflex in 21%, right coronary in 14%, and left main in one case. An angiographic successful result in the main vessel was obtained in all cases. Coronary flow was TIMI 3, 2, 1, and 0 in 95%, 3%, 0%, and 2% before the procedure, in comparison with 86%, 2%, 3%, and 9% after stent implantation (p = 0.204). The incidence of side branch occlusion was 12% (7/58). In one case, the side branch was dilated across the stent struts, and thus the rate of side branch loss at the end of the procedure was 10% (6/58). In cases of side branch occlusion, there was a more severe stenosis at its origin before stent implantation (30.2 +/-31.3% vs 16.8 +/- 11.1%, p = 0.028). Fifty percent of side branches occluded after direct coronary stent implantation and angiographically re-evaluated at follow-up became patent, and 88% of side branches not affected after stent implantation remained patent at 6.2+/-1.9 months. The rate of side branch occlusion after direct stent implantation in our series was 12%, that is not different from that reported for conventional stent implantation. Thus, the decision of using direct or conventional coronary stenting should not be conditioned by the presence of side branches arising from the target lesion.