Plaque characteristics and arterial remodeling in coronary and peripheral arterial systems

Abstract

Background: Few studies have examined plaque characteristics among multiple arterial beds in vivo. The purpose of this study was to compare the plaque morphology and arterial remodeling between coronary and peripheral arteries using gray-scale and radiofrequency intravascular ultrasound (IVUS) at clinical presentation.

Methods and results: IVUS imaging was performed in 68 patients with coronary and 93 with peripheral artery lesions (29 carotid, 50 renal, and 14 iliac arteries). Plaques were classified as fibroatheroma (VH-FA) (further subclassified as thin-capped [VH-TCFA] and thick-capped [VH-ThCFA]), fibrocalcific plaque (VH-FC) and pathological intimal thickening (VH-PIT). Plaque rupture (13% of coronary, 7% of carotid, 6% of renal, and 7% of iliac arteries; P = NS) and VH-TCFA (37% of coronary, 24% of carotid, 16% of renal, and 7% of iliac arteries; P = 0.02) were observed in all arteries. Compared with coronary arteries, VH-FA was less frequently observed in renal (P < 0.001) and iliac arteries (P < 0.006). Lesions with positive remodeling demonstrated more characteristics of VH-FA in coronary (84% vs. 25%, P < 0.001), carotid (72% vs. 20%, P = 0.001), and renal arteries (42% vs. 4%, P = 0.001) compared with those with intermediate/negative remodeling. There was positive relationship between remodeling index and percent necrotic area in all four arteries.

Conclusions: Atherosclerotic plaque phenotypes were heterogeneous among four different arteries; renal and iliac arteries had more stable phenotypes compared with coronary artery. In contrast, the associations of remodeling pattern with plaque phenotype and composition were similar among the various arterial beds.

Figure 1

The frequencies of plaque phenotypes in each vascularture. The distribution of plaque phenotypes was different among four vascular beds (P<0.001). Plaques demonstrated less characteristics of VH-FA (both VH-TCFA and VH-ThCFA) in renal (p<0.001 vs. coronary) and iliac arteries (p=0.006 vs. coronary). VH-FA= fibroatheroma; VH-TCFA=thin-capped fibroatheroma; VHThCFA= thick-capped fibroatheroma; PIT=pathological intimal thickening; and VH-FC=fibrocalcific plaque.

Figure 2

Plaque composition at the smallest lumen site in four arteries. Box-whisker plots displayed the percent area of (A) fibrous plaque, (B) fibro-fatty plaque, (C) necrotic core, and (D) dense calcium of the whole plaque area. Renal arteries had less percentage of necrotic core (**p<0.001 vs. coronary). Carotid (*p=0.04 vs. coronary) and renal arteries (*p=0.01 vs. coronary) had less percentage of dense calcium.

Figure 3

The distributions of plaque phenotypes stratified by remodeling mode in four arteries. The distributions of plaque phenotypes were different between positive and intermediate/negative remodeled lesions in coronary (p<0.001), carotid (p=0.01), renal (p=0.01), and iliac arteries (p=0.04). Compared to intermediate/negative remodeled lesions, positive remodeled lesions demonstrated more characteristics of VH-FA (VH-TCFA and VH-ThCFA) in coronary (84% vs. 25%, p<0.001), carotid (72% vs. 20%, p=0.001), and renal arteries (42% vs. 4%, p=0.001). VH-FA= fibroatheroma; VH-TCFA= thin-capped fibroatheroma; VH-ThCFA= thick-capped fibroatheroma; VH-PIT=pathological intimal thickening; and VH-FC=fibrocalcific plaque.