731-4 Vascular Remodeling of Balloon-induced Intimal Dissection: Long-term Angiographic Assessment

Healing of intimal dissections after balloon angioplasty (PTCA) was prospectively assessed by morphologic and quantitative coronary analysis in a restenosis trial of PTCA vs coronary stenting (STRESS). The population for this substudy consisted of 202 patients assigned to balloon PTCA of de novo native coronary lesions. Based on NHLBI criteria, dissection after PTCA was present in 72 patients (35%). Baseline lesion characteristics were similar in patients with and without dissection except for higher frequency of bends ≥ 45° in the dissection group (28 vs 12%, p<0.01). Compared to lesions without dissection, the presence of a dissection was associated with significantly less acute gain from PTCA (0.98±0.56 vs 1.26±0.44mm, p<0.0001) and greater residual percent diameter stenosis (45±20 vs 33±10%, p<0.001), Accordingly, bailout stenting to treat a failed PTCA result was used in 13/72 (18%) patients with dissection in contrast to only 1/130 (0.8%) patients without dissection (p<0.0001). Follow-up angiography was performed at 6.6±2.3 months in 83% of eligible patients. Of the 44 patients restudied by late angiography who had post-PTCA dissection (but no bailout stenting), complete resolution of the intimal flap was observed in 41 or 93.2%. Late loss was similar in lesions with and without post-PTCA dissection (0.46±0.31 vs 0.43±032mm, p=ns). Angiographic restenosis ≥50% diameter stenosis) was present in 45% (20/44) of lesions with dissection and in 40% (43/107) of lesions without dissection (p=ns). In conclusion, although coronary dissection remains a critical determinant of acute PTCA failures, nonocclusive intimal tears characteristically heal with complete resolution within 6 months. Furthermore, the presence of an intimal dissection does not influence the restenosis rate