Impact of plaque burden and composition on coronary slow flow in ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention: intravascular ultrasound and virtual histology analysis

Abstract

Aim Coronary slow flow (SF) is an important complication of percutaneous coronary intervention (PCI) associated with poor prognosis. The aim was to assess grey-scale intravascular ultrasound (IVUS) and virtual histology (VH-IVUS) characteristics of culprit lesion in ST-elevation myocardial infarction (STEMI). Methods A total of 295 consecutive patients with STEMI underwent coronary angiogram and IVUS. Following PCI, patients divided into two groups; SF (thrombolysis in myocardial infarction [TIMI] flow ≤ 2, n = 74) and normal flow (NF) (TIMI flow >2, n = 221). Coronary plaque burden and its composition in relation to SF were evaluated. Results On grey-scale IVUS, the plaque area (12.3 mm2 vs. 11.5 mm2, p = .01), plaque volume (110.7 mm3 vs. 99.8 mm3, p < .001), lesion external elastic membrane (EEM) cross-sectional area (14.9 mm2 vs. 14.0 mm2, p = .011) and remodelling index (1.3 vs. 1.2, p = .043) were significantly higher in SF group. On VH-IVUS, absolute fibrous volume (48.1 mm3 vs. 41.5 mm3, p ≤ .001), fibrofatty volume (23.8 mm3 vs. 18.6 mm3, p = .015), necrotic core volume (8.3 mm3 vs. 5.5 mm3, p < .001), dense calcium volume (1.2 mm3 vs. 0.6 mm3, p = .003) and thin cap fibroatheroma either single (30.1% vs. 16.1%, p < .001) or multiple (9.6% vs. 1.8%, p < .001) were higher in SF arm. In multivariable analysis, absolute necrotic core volume (odds ratio = 1.159; 95% CI 1.030–1.305, p = .015) was the only independent predictor of SF. Conclusions Higher necrotic core volume as detected by VH-IVUS may be a potential risk factor for the development of coronary SF phenomenon in patients with STEMI after PCI.