A Volumetric Intravascular Ultrasound Comparison of Early Drug-Eluting Stent Thrombosis Versus Restenosis

ObjectivesWe compared intravascular ultrasound findings of drug-eluting stent (DES)–treated lesions that developed thrombosis versus in-stent restenosis (ISR).BackgroundStent underexpansion is a predictor of both DES thrombosis and ISR. However, all underexpanded DES may not be equal.MethodsIntravascular ultrasound findings from 20 definite DES thrombosis patients (representing all definite thromboses from 1,407 consecutive DES patients undergoing intravascular ultrasound imaging) were compared with 50 risk-factor-balanced ISR patients with no evidence of stent thrombosis and 50 risk-factor-balanced “no-event” patients with neither thrombosis nor ISR.ResultsMinimum stent area (3.9 ± 1.0 mm2 vs. 5.0 ± 1.7 mm2, p = 0.008), mean stent area (5.3 ± 1.0 mm2 vs. 7.2 ± 2.0 mm2, p = 0.001), and both focal (55.4 ± 13.2% vs. 74.9 ± 19.9%, p < 0.001) and diffuse stent expansion (77.4 ± 19.3% vs. 109.5 ± 23.1%, p < 0.001) were significantly smaller in the stent thrombosis group versus ISR and in both groups versus the “no-event” group. Minimum stent area <4.0 mm2 (65% vs. 32%, p = 0.01) or <5.0 mm2 (85% vs. 52%, p = 0.01) was more common in the stent thrombosis versus the ISR group and in both groups vs. “no-event” patients; and the relative length of the stent area <5 mm2 was greatest in the stent thrombosis group (36.6 ± 37.7%), intermediate in the ISR group (22.8 ± 35.6%), and least in the “no-event” group (10.9 ± 26.4%), p = 0.04. In the stent thrombosis group, the minimum stent area site occurred in the proximal stent segment in 50% versus 24% in the ISR group (p = 0.03). There were no differences in edge dissection, stent fracture, or stent-vessel-wall malapposition among the groups.ConclusionsThe DES-treated lesions that develop thrombosis or restenosis are often underexpanded, but underexpansion associated with thrombosis is more severe, diffuse, and proximal in location.