Histopathological comparison of intramural coronary artery remodeling and myocardial fibrosis in obstructive versus end-stage hypertrophic cardiomyopathy. (15th September 2019)

• Record Type: Journal Article
• Authors: Foà, Alberto; Agostini, Valentina; Rapezzi, Claudio; Olivotto, Iacopo; Corti, Barbara; Potena, Luciano; Biagini, Elena; Martin Suarez, Sofia; Rotellini, Matteo; Cecchi, Franco; Stefano, Pierluigi; Coppini, Raffaele; Ferrantini, Cecilia; Bacchi Reggiani, Maria L.; Leone, Ornella
• Is Part Of: International journal of cardiology. Volume 291(2019)
• Page Start: 77
• Page End: 82
• Publication Date: 2019-09-15
• Subjects: Hypertrophic cardiomyopathy -- Histopathology -- Myocardial fibrosis -- Vascular remodeling; Cardiology -- Periodicals; Electronic journals; 616.12
• DOI: 10.1016/j.ijcard.2019.03.060
• Languages: English
• ISSNs: 0167-5273

Abstract

Abstract: Background: Although imaging techniques have demonstrated the existence of microvascular abnormalities in hypertrophic cardiomyopathy (HCM), a detailed histopathological assessment is lacking as well as a comparison between different phases of the disease. We aimed to compare microvasculopathy and myocardial fibrosis in hypertrophic obstructive cardiomyopathy (HOCM) versus end-stage (ES) HCM. Methods: 27 myectomy specimens of HOCM patients and 30 ES-HCM explanted hearts were analyzed. Myocardial fibrosis was quantitatively determined with dedicated software and qualitatively classified as scar-like or interstitial. Intramural coronary arteries were evaluated separately according to lumen diameter: 100–500 μ versus <100 μ. Microvasculopathy assessment included the description of medial and intimal abnormalities and stenosis grading. The two subgroups were compared considering only the anterobasal septum of ES explanted hearts. Results: Median value of fibrosis in the anterobasal septum of explanted hearts was 34.6% as opposed to 10.3% of myectomy specimens ( p < 0.001). Scar-like fibrosis was widely found in ES hearts while interstitial fibrosis was distinctive of HOCM ( p < 0.001). All slides showed 100–500 μ microvasculopathy without any differences between subgroups in terms of lumen narrowing, extent of the disease and type of parietal involvement. Among ES hearts these lesions were associated with scar-like fibrosis ( p = 0.034). <100-μ microvasculopathy was also frequent with no differences between subgroups. Conclusions: Microvasculopathy is an intrinsic feature of HCM with similar characteristics across the natural phases of the disease. Conversely, myocardial fibrosis changes over time with ES hearts showing a three-fold greater amount, mainly scar-like. ES showed a closer association between microvasculopathy and replacement fibrosis. Highlights: Vascular remodeling is an early and intrinsic feature of HCM. Vessels are equally altered in spite of the phenotypic expression of the disease. Interstitial fibrosis prevails in HOCM, replacement fibrosis is distinctive of ES-HCM. In ES-HCM, vasculopathy shows a more stringent association with scar-like fibrosis. Microvascular ischemia may cause myocardial scarring and promote ES progression.