Intravascular ultrasound assessment of the incidence and predictors of edge dissections and intramural hematomas after drug-eluting stent implantation

Objective We used intravascular ultrasound (IVUS) to assess incidence, predictors, morphology, and angiographic findings of edge dissections and intramural hematomas after drug-eluting stent (DES) implantation. Methods We studied 887 patients with 1 045 non-in-stent restenosis lesions in 977 native arteries undergoing DES implantation with IVUS imaging, and compared the dissected stent end to the non-dissected stent end. Results Eighty-two dissections were detected; 51.2% (42/82) involved the proximal and 48.8% (40/82) the distal stent edge. When compared to the non-dissected stent end, residual plaque area [(8.0±4.3) mm2 vs (5.2±3.0) mm2, P【0.01], plaque burden [(52±12)% vs (36±15)%, P【0.01], plaque eccentricity (8.4±5.5 vs 4.0±3.4, P【0.01), and stent edge symmetry (1.17±0.11 vs 1.14±0.08, P=0.02) were larger; plaque burden≥50% was more frequent (62% vs 17%, P【0.01) and calcium deposits (52.5% vs 35.6%, P=0.03) more common; and the lumen/stent area (0.86±0.16 vs 1.02±0.18, P【0.01) was smaller in the stent dissected end. Independent predictors of stent edge dissection were residual plaque eccentricity (OR=1.3, P【0.01) and residual plaque burden≥50% (OR=7.3, P【0.01). Intramural hematomas occurred in 34.1% (28/82) of dissections.Independent predictors of intramural hematomas were plaque eccentricity (OR=1.4, P=0.005), plaque burden≥50% (OR=7.1, P=0.02), and mean lumen diameter to stent diameter ratio (OR=0.37, P=0.04).Concluslon IVUS identified edge dissections after 9.4% of DES implantations. Residual plaque eccentricity and significant plaque burden predicted coronary stent edge dissections. Dissections in less diseased reference segments with an arc of normal vessel wall (greater plaque eccentricity) more often evolved into an intramural hematoma.

Assessment of inconclusive left main coronary lesions: lessons from an intravascular ultrasound study

Objective Angiographic assessment of a left main coronary artery (LMCA) stenosis is often difficult and unreliable. Intravascular ultrasound (IVUS) assessment of absolute lumen dimensions has been shown to correlate with fractional flow reserve (FFR) and to predict clinical outcome in patients with a LMCA stenosis. Methods During 21 months period (October, 2004 to July, 2006), 153 patients (Ostial lesions, n=47; Non-ostial lesion, n=106) underwent IVUS evaluation specifically to assess the severity of an angiographically inconclusive LMCA narrowing. IVUS analysis included plaque morphology; external elastic membrane (EEM), lumen, plaque cross-sectional areas (CSA), plaque burden (plaque CSA/ EEM) and remodeling index (lesion EEM CSA/reference EEM CSA). Results Overall, minimum lumen area (MLA) and diameter (MLD) and plaque burden measured 8.2 mm2, 2.6 mm, and 59.3 %, respectively. An MLA【6.0 mm2 (which has been shown to correlate with a FFR 【0.75) was seen 41.5% in ostial lesions and 44.5% in non-ostial lesions. In particular, ostial LMCA lesions had a larger MLA and a smaller plaque burden than non-ostial lesions (Table). Conclusions Patients referred for LMCA evaluation commonly have insignificant narrowing. Negative remodeling was prominent at the LMCA ostium. These patients deserve IVUS assessment before revascularization.

Volumetric intravascular ultrasound comparisons of drug-eluting stent thrombosis and in-stent restenosis

Objectives We compared intravascular ultrasound (IVUS) findings of drug-eluting stent (DES)-treated lesions that developed stent thrombosis versus in-stent restenosis (ISR) to identify underlying mechanical differences. Methods IVUS findings in 15 post-DES thrombosis patients were compared with 45 matched ISR patients who had no evidence of stent thrombosis. Results Minimum stent area [MSA, (3.7±0.8) mm2 vs (4.9±1.8) mm2, P=0.01], minimum stent diameter [(1.9±0.3) mm vs (2.3±0.4) mm, P=0.005], mean stent area [(5.2±0.8) mm2 vs (7.2±2.1) mm2, P【0.01], and both focal [MSA/reference lumen area, (54.7±15.9)% vs (75.0±20.1)%, P=0.001] and diffuse stent expansion [mean stent area/reference lumen area, (76.6±23.0)% vs (110.3±23.3)%, P【0.01] were significantly smaller in the stent thrombosis group (vs the ISR group). An MSA 【4.0 mm2 (73.3% vs 35.6%, P=0.01) or 【5.0 mm2 (86.7% vs 53.3%, P=0.02) was more often found in the stent thrombosis group (vs the ISR group). The MSA site occurred more frequently in the proximal stent segment within the stent thrombosis group compared to the ISR group (60% vs 24.4%, P=0.01). There were no differences in edge dissection, stent fracture, or stent-vessel wall malapposition between the two groups. Independent predictors of stent thrombosis were diffuse stent expansion (OR=1.5, P=0.03) and proximal location of the MSA site (OR=12.7, P=0.04). Conclusion DES-treated lesions that develop thrombosis or restenosis are often underexpanded. Underexpansion appears to be more severe in DES-thrombosis lesions. Lesions with diffuse underexpansion and a proximal (vs distal) underexpanded MSA site are more predisposed to thrombus formation than ISR.