125 - Defining the Echocardiographic Phenotype of TTR Amyloid Utilizing Speckle Based Strain Imaging

Background: Cardiac involvement confers high morbidity and mortality in systemic amyloidosis, and is a dominant feature in this frequently underdiagnosed disease. Few studies have clearly defined the echocardiographic phenotype of TTR amyloid cardiomyopathy. In the present study, we sought to utilize novel speckle based strain imaging in biopsy-proven TTR amyloid patients to determine if there were differences between TTR subtypes (wild-type, familial), and whether these parameters associate with clinical outcomes. Methods: 81 patients with an endomyocardial biopsy positive for TTR amyloidosis and in whom a technically adequate 2D echocardiogram was available within 1 year of diagnosis were included. Conventional 2D echocardiographic analysis was performed in addition to novel speckle-derived strain of the left ventricle (LV) to construct the 18-segment model, and right ventricular (RV) basal, midventricular, and apical free wall segments. Results: Mean age at diagnosis was 72.5 years, 84% men, 42% African American. 56% had wild type TTR, while 44% had the familial form. There was a high incidence of comorbidities including diabetes (19%), hypertension (56.8%) and atrial fibrillation (42%). We observed reduced global LV longitudinal strain with a mean of -11.25 ± 2.85%, largely due to decrease in LV strain in the basal and mid-ventricular segments with relative sparing of the apical segments. There was no statistically significant difference in global LV longitudinal strain between WT and familial TTR (P = .35). Global right ventricular strain was reduced overall and to a similar extent in both WT and familial TTR forms (P = .06). Multi-regression analysis, performed to determine whether strain predicts hospitalization for heart failure or all hospitalizations showed that global LV and RV strain were both strongly predictive of hospitalization for heart failure (P = .005 and P = .003 respectively). Additionally, apical left ventricular strain was predictive of hospitalization for heart failure (P = .017). Regarding hospitalization for any reason, global right ventricular strain was found to be predictive with P-value of .01. Conclusion: Among those with endomyocardial biopsy-proven TTR cardiac amyloidosis a similar apical sparing pattern to what has been reported in AL amyloidosis is observed and no statistically significant difference exists in global LV longitudinal strain between those with WT or familial TTR. Global left ventricular and right ventricular strain in addition to mean apical strain are all predictive of hospitalization for heart failure which is a novel finding.