Impact of clinical and echocardiographic characteristics on occurrence of cardiac events in cardiac amyloidosis as proven by endomyocardial biopsy.

BACKGROUND: Although patients with immunoglobulin light chain (AL) cardiac amyloidosis exhibit worse outcomes than those with transthyretin (TTR) cardiac amyloidosis, few data exist regarding the occurrence of cardiac events and the echocardiographic indices in endomyocardial biopsy (EMBx) proven amyloidosis.

METHODS: From November 2007 to October 2012, we identified 33 patients with EMBx-proven amyloidosis. There were 12 patients (8 men; mean age: 66 years) with AL and 21 patients (20 men; mean age: 78 years) with TTR. We performed serial echocardiography and observed the patients during follow-up; defining all-cause mortality as the primary endpoint and hospitalization for heart failure as the secondary endpoint.

RESULTS: The survival rates at 12 months were 20.8% and 85.7% in AL and TTR, respectively (p<0.001). The cumulative incidences of the composite of death or readmission for heart failure at 12 months were 91.7% and 51.3% in AL and TTR, respectively (p<0.001). A multivariate analysis showed that the AL type amyloid was the powerful predictor of mortality (hazard ratio: 8.50, 95% confidence interval: 1.79 to 40.57, p<0.05). Under these conditions, the E/e' in AL tended to increase from 23±13 to 28±11 (p=0.06) with marked increases in B-type natriuretic peptide (779±456 pg/ml to 1576±895 pg/ml, p<0.05), although these remained unchanged in TTR, which exhibited significantly increased left ventricular end-diastolic dimensions from 40±4 mm to 42±4 mm (p<0.05).

CONCLUSIONS: The survival rate was generally worse in AL cardiac amyloidosis, although the readmission for heart failure remains high in TTR cardiac amyloidosis with the occurrence of left ventricular dilatation.