Coronary atheroma composition and its association with segmental endothelial dysfunction in non-ST segment elevation myocardial infarction: novel insights with radiofrequency (iMAP) intravascular ultrasonography

Abstract

Little is known of the relationship between coronary atheroma composition and corresponding endothelial dysfunction. We tested the hypothesis that segmental epicardial vasoreactivity relates to atheroma composition in patients with non-ST segment elevation myocardial infarction (NSTEMI) in vivo. In 23 NSTEMI patients referred for coronary angiography, a non-culprit vessel underwent intracoronary salbutamol (0.30 μg/min) provocation during automated IVUS pullback. A 40 MHz rotational IVUS catheter delivered radiofrequency signals at constant 67 μm intervals via a custom-built IVUS console (iMAP, iLAB, Boston Scientific). Macrovascular response [change in segmental lumen volume (SLV) at baseline and following salbutamol], percent atheroma volume (PAV) and tissue composition was evaluated in 187 contiguous non-overlapping 5 mm coronary segments. Compared with segments that dilated, constrictive segments showed similar SLV, but greater vessel volumes and PAV at baseline. The extent of necrotic and lipidic plaque was significantly greater in constrictive segments, whereas fibrotic plaque content was significantly greater in segments that dilated. Calcific plaque content did not relate to endothelium-dependent vasoreactivity. The change in SLV correlated inversely with the amount of lipidic and necrotic plaque (both r = -0.23, p = 0.002), and directly with fibrotic plaque content (r = 0.23, p = 0.002). In a multivariable model, the extent of both lipidic and necrotic plaque independently associated with segmental vasoconstriction (β = 1.2, p = 0.023; β = 0.66, p = 0.027). Following NSTEMI, both lipidic and necrotic plaque content each associate with segmental endothelial dysfunction. The link between plaque composition and vessel reactivity provides a mechanistic basis of the pathogenesis associated with vulnerable plaque in humans in vivo.

Local coronary wall eccentricity and endothelial function are closely related in patients with atherosclerotic coronary artery disease

“…multitransmit radiofrequency) and software allow improved visualization of the coronary vessel wall, permitting a more detailed analysis of wall remodeling than was previously possible. The type of coronary wall remodeling (concentric vs. eccentric) may play an important role in local plaque progression or acute coronary syndrome [36]. Prior studies report that acute coronary syndromes tend to occur in vessels with angiographically mild disease [6].…”

The association between the extent of lipidic burden and delta-fractional flow reserve: analysis from coronary physiological and near-infrared spectroscopic measures

“…In general, lipid plaque is formulated through the influx of atherogenic inflammatory cytokines and oxidative stress, causing endothelial dysfunction (21). This mechanism is supported by another study which demonstrated severer endothelial dysfunction at target lesion harboring a great amount of necrotic core materials (20,22). Since the endothelium regulates vascular tone (8), lipidic atheroma with endothelial dysfunction may cause insufficient vascular response during hyperemic status, potentially leading to a greater delta-FFR.…”

“…Recent studies have reported a potential role of plaque vulnerability in reduced FFR (4,20). However, the mechanism behind this observation remains to be fully determined yet.…”

Tissue characterization and phenotype classification in patients presenting with acute myocardial infarction: Insights from the iWonder study

“…Previous studies have used radiofrequency IVUS derived from a 20 MHz IVUS catheter and applying the proprietary analysis software called VH‐IVUS . Available data with iMAP‐IVUS were limited to describing plaque composition, without the proposition of an algorithm for phenotype classification .…”