Prognostic value of depressed midwall systolic function in cardiac light-chain amyloidosis.

BACKGROUND: Cardiac amyloidosis represents an archetypal form of restrictive heart disease, characterized by profound diastolic dysfunction. As ejection fraction is preserved until the late stage of the disease, the majority of patients do fulfill the definition of diastolic heart failure, that is, heart failure with preserved ejection fraction (HFpEF). In another clinical model of HFpEF, that is, pressure-overload hypertrophy, depressed midwall fractional shortening (mFS) has been shown to be a powerful prognostic factor.

OBJECTIVE AND METHODS: To assess the potential prognostic role of mFS in cardiac light-chain amyloidosis with preserved ejection fraction, we enrolled 221 consecutive untreated patients, in whom a first diagnosis of cardiac light-chain amyloidosis was concluded between 2008 and 2010. HFpEF was present in 181 patients. Patients in whom cardiac involvement was excluded served as controls (n = 121). Prognosis was assessed after a median follow-up of 561 days.

RESULTS: When compared with light-chain amyloidosis patients without myocardial involvement, cardiac light-chain amyloidosis was characterized by increased wall thickness (P <0.001), reduced end-diastolic left ventricular volumes (P <0.001), and diastolic dysfunction (P <0.001). In patients with preserved ejection fraction, mFS was markedly depressed [10.6% (8.7-13.5) vs. 17.8% (15.9-19.5) P <0.001]. At multivariable analysis, mFS, troponin I, and NT-pro-brain natriuretic peptide were the only significant prognostic determinants (P <0.001), whereas other indices of diastolic (E/E' ratio, transmitral and pulmonary vein flow velocities) and systolic function (tissue Doppler systolic indices, ejection fraction), or the presence/absence of congestive heart failure did not enter the model.

CONCLUSION: In cardiac light-chain amyloidosis with normal ejection fraction, depressed circumferential mFS, a marker of myocardial contractile dysfunction, is a powerful predictor of survival.