Diagnostic and Prognostic Utility of Cardiovascular Magnetic Resonance Imaging in Light-Chain Cardiac Amyloidosis

Abstract

While the presence of abnormal late gadolinium enhancement (LGE) in cardiac amyloidosis has been well established, its prognostic implication and utility to identify cardiac involvement in patients with systemic amyloidosis is unknown. We sought to assess the diagnostic and prognostic significance of cardiovascular magnetic resonance (CMR) imaging in patients with light chain (AL) amyloidosis but unknown cardiac involvement. CMR with LGE was performed in 28 patients with systemic amyloidosis. The presence of cardiac amyloidosis was determined by a separate clinical evaluation. The performance of LGE for the prediction of cardiac amyloidosis and prognostic implications of LGE were determined. LGE was observed in 19 (68%) patients. The sensitivity, specificity, positive predictive value and negative predictive value of LGE for the identification of clinical cardiac involvement was 86%, 86%, 95%, and 67% respectively. During a median follow-up of 29 months, there were 5 deaths (82% survival). LGE itself did not predict survival (p=0.62). LGE volume positively correlated to serum level of B-type natriuretic peptide (BNP) (R=0.64, p≤0.001) and in multivariable analysis, LGE volume proved the strongest independent predictor of BNP. BNP was correlated to New York Heart Association class (p=0.03). Reduced right ventricular end-diastolic volume (p < 0.01) and stroke volume (p = 0.02) were associated with mortality. In conclusion, in patients with systemic amyloidosis, LGE is highly sensitive and specific for the identification of cardiac involvement, but does not predict survival. LGE does correlate strongly to heart failure severity as assessed by BNP.

Role of imaging in the diagnosis and management of patients with cardiac amyloidosis: State of the art review and focus on emerging nuclear techniques

“…There have been conflicting data regarding prognostic value of LGE CMR in cardiac amyloidosis. 23,39,46,47 While some studies failed to establish prognostic value of LGE, other studies have shown that LGE was the only predictor of 1-year mortality (P = .03) beyond ECG and diastology. 23 T1 mapping, on the other hand, seems more robust and a better predictor of outcomes with 90% accuracy, in part due to its superior discriminatory power.…”

The role of cardiac magnetic resonance imaging in differentiating the underlying causes of left ventricular hypertrophy

“…36 In addition, cardiac involvement of amyloidosis displays a characteristic pattern of LGE on LGE imaging if the images are acquired four minutes after injection of contrast agent ( figure 4). LGE is found in approximately 70% of patients. 37,38 This ill-defined, generally subendocardial pattern of LGE matches the distribution of the amyloid deposition. 39 Although most profound in the subendocardial layer of the myocardium, amyloid deposition occurs throughout the entire myocardium, and therefore has a higher T1 signal than normal myocardium.…”

“…However, to additionally perform LGE imaging in these patients has shown to be clinically relevant, since the presence of LGE helps to confirm the diagnosis and also the difference in T1 signal between epicardial and subendocardium is of prognostic importance in cardiac amyloidosis. 37,38 A higher T1 signal in LGE imaging indicates higher amyloid deposition. When amyloid deposition is mainly present subendocardially, than T1 difference between subendocardium and subepicardium is high.…”

Magnetic Resonance Imaging of the Myocardium, Coronary Arteries, and Anomalous Origin of Coronary Arteries

“…In a study by Ruberg and colleagues [ 206 ], which involved 28 patients with systemic AL amyloidosis, 19 patients were found to have DE. Although the presence of DE did not predict mortality (during the median follow-up time of 29 months), the amount of DE, expressed as a percentage of the LV mass, was the strongest independent predictor of the B-type natriuretic peptide level when compared to other LV quantitative factors.…”