Myocardial extracellular volume fraction measured by EQ-CMR was significantly higher in patients with systemic AL amyloidosis than in healthy controls (0.40 vs 0.25, P<0.001).
Observational (n=142)
Does equilibrium contrast cardiovascular magnetic resonance (EQ-CMR) accurately quantify myocardial extracellular volume (ECV) fraction as a marker of cardiac amyloid burden in patients with systemic AL amyloidosis?
Myocardial ECV measurement by EQ-CMR provides a noninvasive method to quantify cardiac amyloid burden, correlating significantly with clinical, echocardiographic, and biomarker parameters in systemic AL amyloidosis.
Absolute Event Rate: 0.4% vs 0.25%
p-value: p=<0.001
BACKGROUND: Cardiac involvement predicts outcome in systemic AL amyloidosis and influences therapeutic options. Current methods of cardiac assessment do not quantify myocardial amyloid burden. We used equilibrium contrast cardiovascular magnetic resonance (EQ-CMR) to quantify the cardiac interstitial compartment, measured as myocardial extracellular volume (ECV) fraction, hypothesizing it would reflect amyloid burden. METHODS AND RESULTS: Sixty patients with systemic AL amyloidosis (65% men, median age 65 years) underwent conventional clinical cardiovascular magnetic resonance, including late enhancement, equilibrium contrast cardiovascular magnetic resonance, and clinical cardiac evaluation, including ECG, echocardiography, assays of N-terminal pro-brain natriuretic peptide and Troponin T, and functional assessment comprising the 6-minute walk test in ambulant individuals. Cardiac involvement in the amyloidosis patients was categorized as definite, probable, or none, suspected by conventional criteria. Findings were compared with 82 healthy controls. Mean ECV was significantly greater in patients than healthy controls (0.25 versus 0.40, P<0.001) and correlated with conventional criteria for characterizing the presence of cardiac involvement, the categories of none, probable, definite corresponding to ECV of 0.276 versus 0.342 versus 0.488, respectively (P<0.001). ECV was correlated with cardiac parameters by echocardiography (eg, Tissue Doppler Imaging TDI S-wave R=0.52, P<0.001) and conventional cardiovascular magnetic resonance (eg, indexed left ventricular mass R=0.56, P<0.001). There were also significant correlations with N-terminal pro-brain natriuretic peptide (R=0.69, P<0.001) and Troponin T (R=0.53, P=0.006). ECV was associated with smaller QRS voltages (R=0.57, P<0.001) and correlated with poorer performance in the 6-minute walk test (R=0.36, P=0.03). CONCLUSIONS: Myocardial ECV measurement has potential to become the first noninvasive test to quantify cardiac amyloid burden.
Banypersad et al. (2012) conducted an observational in Systemic AL amyloidosis (n=142). Systemic AL amyloidosis vs. Healthy controls was evaluated on Mean myocardial extracellular volume (ECV) fraction (p=<0.001). Myocardial extracellular volume fraction measured by EQ-CMR was significantly higher in patients with systemic AL amyloidosis than in healthy controls (0.40 vs 0.25, P<0.001).