Myocardial Perfusion Imaging After Severe COVID-19 Infection Demonstrates Regional Ischemia Rather Than Global Blood Flow Reduction

Abstract

Background: Acute myocardial damage is common in severe COVID-19. Post-mortem studies have implicated microvascular thrombosis, with cardiovascular magnetic resonance (CMR) demonstrating a high prevalence of myocardial infarction and myocarditis-like scar. The microcirculatory sequelae are incompletely characterized. Perfusion CMR can quantify the stress myocardial blood flow (MBF) and identify its association with infarction and myocarditis.Objectives: To determine the impact of the severe hospitalized COVID-19 on global and regional myocardial perfusion in recovered patients.Methods: A case-control study of previously hospitalized, troponin-positive COVID-19 patients was undertaken. The results were compared with a propensity-matched, pre-COVID chest pain cohort (referred for clinical CMR; angiography subsequently demonstrating unobstructed coronary arteries) and 27 healthy volunteers (HV). The analysis used visual assessment for the regional perfusion defects and AI-based segmentation to derive the global and regional stress and rest MBF.Results: Ninety recovered post-COVID patients {median age 64 [interquartile range (IQR) 54–71] years, 83% male, 44% requiring the intensive care unit (ICU)} underwent adenosine-stress perfusion CMR at a median of 61 (IQR 29–146) days post-discharge. The mean left ventricular ejection fraction (LVEF) was 67 ± 10%; 10 (11%) with impaired LVEF. Fifty patients (56%) had late gadolinium enhancement (LGE); 15 (17%) had infarct-pattern, 31 (34%) had non-ischemic, and 4 (4.4%) had mixed pattern LGE. Thirty-two patients (36%) had adenosine-induced regional perfusion defects, 26 out of 32 with at least one segment without prior infarction. The global stress MBF in post-COVID patients was similar to the age-, sex- and co-morbidities of the matched controls (2.53 ± 0.77 vs. 2.52 ± 0.79 ml/g/min, p = 0.10), though lower than HV (3.00 ± 0.76 ml/g/min, p< 0.01).Conclusions: After severe hospitalized COVID-19 infection, patients who attended clinical ischemia testing had little evidence of significant microvascular disease at 2 months post-discharge. The high prevalence of regional inducible ischemia and/or infarction (nearly 40%) may suggest that occult coronary disease is an important putative mechanism for troponin elevation in this cohort. This should be considered hypothesis-generating for future studies which combine ischemia and anatomical assessment.

Advanced cardiac imaging in the spectrum of COVID-19 related cardiovascular involvement

“…LGE has been reported less frequently. In a case control study on 90 hospitalized patients with troponin-positive COVID-19 infection [84], CMR performed 2 months after recovery showed post-myocarditis scar in 34% of cases and post-ischemic scar in 17% of cases. Notably, 36% of patients showed adenosine-induced regional perfusion defects.…”

CMR Findings in COVID-19 Recovered Patients: A Review on Parametric Mapping, Feature-Tracking, and LGE

“…In most studies, recovered patients also exhibited increased or raised T2 values [4,27,29,34,35,38,41]. Finally, ECV was reported in a few studies [4,25,27,[29][30][31][32][36][37][38]41], and their pooled effect suggests that patients who recovered from COVID-19 have similar values to controls.…”

“…Studies including patients who recovered from COVID-19 reported increased [4,27,28,33,35,36], slightly increased [29,32,38,39,41] or similar [31,34] T1 native mapping values compared to controls. In particular, Kotecha et al [28], Puntmann et al [35], and Thornton et al [37] found significantly higher T1 native mapping values in large groups of recovered subjects (148, 100 and 90, respectively) compared to different control groups, including patients without myocardial injury, healthy volunteers or controls, and risk factor-matched controls [26,28,35,37]. In addition, patients who recovered from COVID-19 and had MIS-myocarditis had higher T1 native values than those with non-MIS myocarditis [30].…”

“…We identified 648 records, from which 60 were retrieved for further analysis. Following the eligibility assessment, nineteen studies were finally included in this review [4,[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]; their characteristics are shown in Table 1 (Ref. [4,[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]).…”

Frontiers of COVID-19-related myocarditis as assessed by cardiovascular magnetic resonance

“…A return to normal of EGE within 1 month after acute myocardial inflammatory injury indicates that left ventricular function has recovered well. Myocardial perfusion imaging after severe COVID-19 also demonstrates regional ischaemia rather than global blood flow reduction[ 37 ]. Nevertheless, the biggest limitation of EGE is that it is unable to quantify SI accurately.…”