Risk Factors Associated with One Year Mortality from the Time of Cardiac Amyloid Diagnosis

Abstract

<h3>Purpose</h3> Cardiac amyloidosis (CA) is a form of restrictive cardiomyopathy caused by deposition of immunoglobulin light chains (AL) or misfolded transthyretin (ATTR) in the myocardial interstitium. When diagnosed late, it is associated with increased morbidity and mortality and traditional care pathways when applied to CA patients can be potentially harmful. We thus sought to identify risk factors that predict ≤ 1 year survival after initial diagnosis of CA. <h3>Methods</h3> We performed a single-center, retrospective analysis on patients with CA proven by biopsy or grade 2-3 technetium pyrophosphate scan. Demographic information, clinical parameters, lab results, right heart catheterization numbers, EKG tracings, cardiac imaging parameters (cardiac MRI and echocardiography), and medications were collected. Univariate analysis was performed using the Chi-square test to assess differences in discrete variables and the T-test for continuous variables. The results were analyzed by using SAS JMP pro15. <h3>Results</h3> The 62 CA patients in our cohort were predominantly Caucasian (51.2%) males (87.1%) with a mean age of 72.4 years. Most had ATTR CA (n=48, 77.4% ). Twenty-two (37.4%) patients had at least NYHA class III symptoms at the time of presentation. Overall, 19 (30.6%) died within a year after being diagnosed. Hyponatremia (Na<135, HR 4.21; 95% CI 1.53-11.65), higher brain natriuretic peptide (BNP) levels (≥ 400, HR 4.12; 95% CI 1.17-14.47), higher blood urea nitrogen (BUN) levels (>24, HR 3.45; 95% CI 1.11-10.71), no tafamidis treatment (HR 5.98; 95% CI 1.38-25.91) and impaired left ventricular global longitudinal strain (GLS) on echocardiogram (>-10%, HR 5.24; 95% CI 1.12-24.52) were significant predictors for increased 1-year mortality on univariate analysis. <h3>Conclusion</h3> In our cohort of patients, hyponatremia, elevated BNP, BUN, marked impairment LV GLS (but not LVEF), and not being on tafamidis (for ATTR patients) are risk factors associated with ≤ 1 year survival from the time of cardiac amyloidosis diagnosis.