Cardiac amyloidosis was associated with severely reduced stress myocardial blood flow (1.04 ± 0.51 ml/min/g) compared to healthy volunteers (2.91 ± 0.73 ml/min/g, p<0.001).
Observational (n=190)
Is cardiac amyloidosis associated with myocardial ischemia as assessed by CMR stress perfusion mapping and histopathology compared to patients without amyloidosis?
Cardiac amyloidosis causes severe inducible myocardial ischemia, demonstrable by CMR stress perfusion mapping and driven by microvascular and epicardial amyloid infiltration.
Absolute Event Rate: 1.04% vs 2.91%
p-value: p=<0.001
AIMS: Cardiac involvement is the main driver of clinical outcomes in systemic amyloidosis and preliminary studies support the hypothesis that myocardial ischaemia contributes to cellular damage. The aims of this study were to assess the presence and mechanisms of myocardial ischaemia using cardiovascular magnetic resonance (CMR) with multiparametric mapping and histopathological assessment. METHODS AND RESULTS: Ninety-three patients with cardiac amyloidosis (CA) (light-chain amyloidosis n = 42, transthyretin amyloidosis n = 51) and 97 without CA (three-vessel coronary disease 3VD n = 47, unobstructed coronary arteries n = 26, healthy volunteers HV n = 24) underwent quantitative stress perfusion CMR with myocardial blood flow (MBF) mapping. Twenty-four myocardial biopsies and three explanted hearts with CA were analysed histopathologically. Stress MBF was severely reduced in patients with CA with lower values than patients with 3VD, unobstructed coronary arteries and HV (CA: 1.04 ± 0.51 ml/min/g, 3VD: 1.35 ± 0.50 ml/min/g, unobstructed coronary arteries: 2.92 ± 0.52 ml/min/g, HV: 2.91 ± 0.73 ml/min/g; CA vs. 3VD p = 0.011, CA vs. unobstructed coronary arteries p < 0.001, CA vs. HV p < 0.001). Myocardial perfusion abnormalities correlated with amyloid burden, systolic and diastolic function, structural parameters and blood biomarkers (p < 0.05). Biopsies demonstrated abnormal vascular endothelial growth factor staining in cardiomyocytes and endothelial cells, which may be related to hypoxia conditions. Amyloid infiltration in intramural arteries was associated with severe lumen reduction and severe reduction in capillary density. CONCLUSION: Cardiac amyloidosis is associated with severe inducible myocardial ischaemia demonstrable by histology and CMR stress perfusion mapping. Histological evaluation indicates a complex pathophysiology, where in addition to systolic and diastolic dysfunction, amyloid infiltration of the epicardial arteries and disruption and rarefaction of the capillaries play a role in contributing to myocardial ischaemia.
Chacko et al. (Sun,) conducted a observational in Cardiac amyloidosis (n=190). Cardiac amyloidosis vs. Patients without cardiac amyloidosis (three-vessel coronary disease, unobstructed coronary arteries, or healthy volunteers) was evaluated on Stress myocardial blood flow (MBF) (p=<0.001). Cardiac amyloidosis was associated with severely reduced stress myocardial blood flow (1.04 ± 0.51 ml/min/g) compared to healthy volunteers (2.91 ± 0.73 ml/min/g, p<0.001).