Geographical miss during catheter-based intracoronary beta-radiation: Incidence and implications in the BRIE study

Objectives We sought to determine the incidence and causes of geographical miss (GM) and to evaluate its impact on edge restenosis after intracoronary beta-radiation therapy. Background Edge restenosis is a limitation of intracoronary beta-radiation therapy. Geographical miss is the situation in which the radiation source d oes not fully cover the injured segment and may lead to edge restenosis. Methods We analyzed 175 vessels treated according to the Beta-Radiation In Europe (BRIE) study protocol. The effective irradiated segment (EIRS) and b oth edges were studied with quantitative coronary angiography. The edges of the FIRS that were injured constituted the GM edges. Restenosis was define d as diameter stenosis >50% at follow-up. Geographical miss was determined by simultaneous electrocardiographic-matched, side-by-side projection of th e source and balloons deflated at the injury site, in identical angiographi c projections surrounded by contrast. Results Geographical miss affected 41.2% of the edges and increased edge re stenosis significantly compared with non-GM edges (16.3% vs. 4.3%, respecti vely, p = 0.004). Restenosis was increased both in the proximal (p = 0.05) and distal (p = 0.02) GM edges compared with noninjured edges. Geographical miss associated with scent injury significantly increased edge restenosis (p = 0.006)> whereas GM related to balloon injury did not significantly inc rease edge restenosis (p = 0.35). The restenosis in the FIRS was similar be tween vessels with and without GM (24.3% and 21.6%, respectively, p = 0.8). Conclusions Geographical miss is strongly associated with restenosis at the edges of the EIRS. This effect is more prominent when caused by scenting. Geographical miss does not increase restenosis in the EIRS. (J Am Coll Card iol 2001;38:415-20) (C) 2001 by the American College of Cardiology.