Carotid plaque fissure: An underestimated source of intraplaque hemorrhage

Mat J Daemen,Marina S Ferguson,Frank J Gijsen,Daniel S Hippe,M Eline Kooi,Kevin Demarco,Allard C Van Der Wal,Chun Yuan,Thomas S Hatsukami

doi:10.1016/j.atherosclerosis.2016.09.069

Abstract

Background and aimsPlaque fissuring, a phenomenon morphologically distinct from the classical rupture of a thinned fibrous cap, has not been well characterized in carotid atherosclerosis. The aim of this study was to establish the prevalence of plaque fissures in advanced carotid plaques with an otherwise intact luminal surface, and to determine whether they might be a source of intraplaque hemorrhage (IPH). MethodsWe evaluated 244 surgically intact, ‘en bloc’ embedded, serially sectioned carotid endarterectomy specimens and included only those plaques with a grossly intact luminal surface. ResultsAmong the 67 plaques with grossly intact luminal surface, cap fissure was present in 39 (58%) plaques. A total of 60 individual fissures were present, and longitudinally mean fissure length was 1.3 mm. Most fissures were found distal to the bifurcation (63%), proximal to the stenosis (88%), and in the posterior (opposite the flow divider) or lateral quadrants (80%). 36% of the fissures remained in the superficial third of the plaque. 52% extended from the lumen surface to the middle third of the plaque and 12% reached the outer third of the plaque on cross section. Fissures often occurred between two tissue planes and were connected to IPH (fresh: 63%; any type: 92%) and calcifications (43%). No correlation was found with patient characteristics such as symptom status, carotid stenosis, hypertension, diabetes, smoking and medications (statins or antiplatelet agents). ConclusionsPlaque fissures are common in advanced carotid plaques with an otherwise grossly intact luminal surface and are associated with fresh intraplaque hemorrhage. As they occur on the interface between plaque components with different mechanical properties, further biomechanical studies are needed to unravel the underlying failure mechanisms.

Highlights

Fibrous cap rupture is one form of luminal surface disruption and is defined as a structural defect in the fibrous cap that separates the lipid-rich necrotic core of a plaque from the lumen of the artery [1]
We quantified the presence of plaque fissures in carotid artery plaques with an otherwise intact luminal surface and examined the relation of these fissures with intraplaque hemorrhage (IPH) and other plaque features in a consecutive series of 244 surgically intact, ‘en bloc’ embedded, and serially sectioned carotid endarterectomy specimens
Fissures in the shoulder regions were characterized by the presence of a luminal tear lifting a layer of the intima from the underlying fibrous tissue (Fig. 1B) and a hemorrhage tract extending into the necrotic core (Fig. 1C), a tract often lined by macrophages (60%) (Fig. 1D) or showed a hemorrhage dissecting the tissue planes and extending into the matrix around calcifications (Fig. 2A and B)

Summary

Introduction

Fibrous cap rupture is one form of luminal surface disruption and is defined as a structural defect (a gap) in the fibrous cap that separates the lipid-rich necrotic core of a plaque from the lumen of the artery [1]. We quantified the presence of plaque fissures in carotid artery plaques with an otherwise intact luminal surface and examined the relation of these fissures with IPH and other plaque features in a consecutive series of 244 surgically intact, ‘en bloc’ embedded, and serially sectioned carotid endarterectomy specimens. Methods: We evaluated 244 surgically intact, ‘en bloc’ embedded, serially sectioned carotid endarterectomy specimens and included only those plaques with a grossly intact luminal surface. Conclusions: Plaque fissures are common in advanced carotid plaques with an otherwise grossly intact luminal surface and are associated with fresh intraplaque hemorrhage. As they occur on the interface between plaque components with different mechanical properties, further biomechanical studies are needed to unravel the underlying failure mechanisms

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