Detection of viral SARS-CoV-2 genomes and histopathological changes in endomyocardial biopsies

Abstract

Aims: Since December 2019, the novel coronavirus SARS-CoV-2 has spread rapidly throughout China and keeps the world in suspense. Cardiovascular complications with myocarditis and embolism due to COVID-19 have been reported. SARS-CoV-2 genome detection in the heart muscle has not been demonstrated so far, and the underlying pathophysiological mechanisms remain to be investigated.

Methods and results: Endomyocardial biopsies (EMBs) of 104 patients (mean age: 57.90 ± 16.37 years; left ventricular ejection fraction: 33.7 ± 14.6%, sex: n = 79 male/25 female) with suspected myocarditis or unexplained heart failure were analysed. EMB analysis included histology, immunohistochemistry, and detection of SARS-CoV-2 genomes by real-time reverse transcription polymerase chain reaction in the IKDT Berlin, Germany. Among 104 EMBs investigated, five were confirmed with SARS-CoV-2 infected by reverse real-time transcriptase polymerase chain reaction. We describe patients of different history of symptoms and time duration. Additionally, we investigated histopathological changes in myocardial tissue showing that the inflammatory process in EMBs seemed to permeate vascular wall leading to small arterial obliteration and damage.

Conclusions: This is the first report that established the evidence of SARS-CoV-2 genomes detection in EMBs. In these patients, myocardial injury ischaemia may play a role, which could explain the ubiquitous troponin increases. EMB-based identification of the cause of myocardial injury may contribute to explain the different evolution of complicated SARS-CoV-2-infection and to design future specific and personalized treatment strategies.

Keywords: COVID-19; Endomyocardial biopsy; Heart failure; Myocarditis; SARS-CoV-2-infection.

Figure 1

(A) Myocardium with recent necrosis (arrows) in the upper part, below granulation tissue with moderate infiltrates of inflammatory cells. At the bottom persisting myocytes. PAS. Bar 50 μm. (B) Immunohistochemical staining of CD11b + macrophages. Vessels are involved in the inflammation process. Bar 20 μm. (C) Perforin positive cells in the neighbourhood of an oblique cut blood vessel (arrow) within the myocardium. Staining by antibody against perforin, hemalum. Bar 20 μm. (D) Five to six myocyte layers below the endocardium ruptured capillary and bleeding (arrow). Azan staining. Bar 20 μm. (E) Increase of T‐lymphocytes stained by CD3 antibody. Bar 50 μm. (F) Increase of CD45R0 positive T memory cells. Bar 50 μm.