Regional amyloid distribution and impact on mortality in light-chain amyloidosis: a T1 mapping cardiac magnetic resonance study.

BACKGROUND

T1 mapping allows quantitative assessment of "diffuse" deposition of amyloid protein in the myocardium. Early detection of cardiac involvement and potential prognostic improvement could benefit patients with AL amyloidosis.

OBJECTIVES

This study aims to evaluate the regional variation of amyloid infiltration in the left ventricle and the prognostic value of T1 mapping in patients with AL amyloidosis.

METHODS

We prospectively enrolled 77 patients with AL amyloidosis who underwent cardiac magnetic resonance on a 3.0-T scanner. Native T1 and extracellular volume (ECV) were quantitated on the basal, mid, and apical levels of the left ventricle. Late gadolinium enhancement (LGE) pattern (no or non-specific LGE, sub-endocardial LGE, and transmural LGE) was also assessed. Forty healthy subjects served as controls. The primary end point was all-cause mortality.

RESULTS

Basal ECV (26.9 ± 2.8% versus 31.1 ± 4.9%, p < .001) were lower than apical ECV in the healthy controls; however, basal ECV (60.6 ± 11.5% versus 53.0 ± 9.6%, p = .003) were significantly higher than apical ECV in patients with transmural LGE. During the follow-up period (median duration, 28 months; 25th-75th percentile, 13.5-38.0 months), 46 patients died. Basal ECV has the largest area under the curve of 0.845 (95% CI, 0.747-0.917) to predict all-cause mortality. Multivariable Cox analysis indicated that basal ECV was an independent prognostic factor and showed incremental prognostic value beyond NYHA class, Mayo stage, and LGE pattern.

CONCLUSION

We demonstrated that T1 mapping may have the potential to detect a characteristic amyloid deposition with a decreasing gradient from base to apex. Furthermore, myocardial ECV indicated that basal amyloid infiltration provided robust and incremental prognostic value in patients with AL amyloidosis.