Abstract 12022: Predictors of Mortality in Patients With Biopsy-Proven Cardiac AL Amyloidosis

Introduction: Cardiac involvement occurs in ~50% of patients with light-chain (AL) amyloidosis and conveys a poor prognosis. This study examined the role of histopathologic and echocardiographic parameters in predicting mortality. Methods: Patients with endomyocardial biopsy-proven cardiac AL amyloidosis treated at MD Anderson Cancer Center between 6/2011 and 6/2020 were identified. Stored echocardiographic images were processed for longitudinal strain (global [GLS], apical, mid, basal) as well as radial and circumferential strain of the left ventricle (LV), right ventricle (RV) free wall, left atrium (LA), and right atrium, using the Epsilon EchoInsight Software. A detailed histomorphologic characterization of stored endomyocardial biopsy samples was performed by a cardiac pathologist and scored as < or > 5% AL deposits. Results: We identified 43 patients; 44% were women and 63% white. Median age was 65 years (IQR 59-70). Twenty-two (51%) underwent stem cell transplantation (SCT). A total of 29 patients (67%) died during follow up period (median follow up: 4.2 years (95% CI, 2.8-8.6)). Median overall survival (OS) was 18 months (95% CI, 8.1-37). Lower LA GLS and absence of SCT as a time-varying covariate were significantly and independently associated with increased risk of death in the multivariable cox regression analysis (HR 3.8, 95% CI 1.4-10.2 for LA GLS < 13.5 vs >13.5, p=0.008 and 0.20, 0.06-0.65 for SCT vs no SCT, p<0.001, respectively). Higher LV mass and lower RV TAPSE were associated with increased odds of having >5% of interstitial amyloid deposition on biopsy in the multivariable logistic regression analysis (OR 5.5, 95% CI 1.1-26.8 for >195.6g vs ≤195.6g, p=0.036 and 8.1, 1.2-54.3 for RV TAPSE<1.6cm vs ≥1.6cm, p=0.032, respectively). Conclusions: LA GLS < 13.5 was an independent predictor of mortality in our cohort, and its performance in the routine assessment of AL amyloidosis may be justified. Furthermore, SCT for cardiac AL amyloidosis was associated with improved OS. This finding needs to be confirmed by larger studies in the era of contemporary systemic therapies. Although LV mass and RV TAPSE were associated with higher interstitial amyloid deposition, histopathologic parameters did not predict mortality in this cohort.