OBJECTIVETo identify underlying mechanical risk factors of that developed in-stent restenosis (ISR) or early stent thrombosis in sirolimus-eluting stent (SES)-treated lesions using intravascular ultrasound (IVUS).

METHODSIVUS were performed in 60 (ISR, n = 43; early stent thrombosis, n = 17) patients (event group) and in 34 patients without ISR and early stent thrombosis (no-event group) underwent SES implantations.

RESULTSCompared with the no-event group, minimum stent area [MSA, (4.6 +/- 1.6) mm(2) vs. (5.8 +/- 1.6) mm(2), P < 0.01], minimum stent diameter [(2.2 +/- 0.5) mm vs. (2.5 +/- 0.4) mm, P < 0.01], and stent expansion [(69.2 +/- 20.7)% vs. (80.6 +/- 17.2)%, P < 0.01] were significantly smaller, and longitudinal stent symmetry index (MSA/maximum stent area, 2.0 +/- 0.6 vs. 1.7 +/- 0.6, P < 0.05) was significantly larger in the event group. Incidence of MSA < 4.0 mm(2) (43.3% vs. 14.7%, P < 0.01) and stent expansion < 60% (40.7% vs. 11.8%, P < 0.01) were more frequent in the event group than that in no-event group. Furthermore, proximal residual plaque burden was significantly higher compared to the no-event group [(49.0 +/- 15.5)% vs. (38.4 +/- 17.6)%, P < 0.01]. Independent predictors of post SES ISR or early thrombosis were MSA (OR:0.7, 95%CI:0.5 - 0.8, P < 0.01) and proximal residual plaque burden (OR: 280.7, 95%CI: 17.2 - 40 583.6, P < 0.01).

CONCLUSIONSmaller MSA and higher proximal residual plaque burden are independent predictors of ISR or early thrombosis post SES implantations.