Time-dependent change of relative apical longitudinal strain index in patients with wild-type transthyretin amyloid cardiomyopathy.

Abstract

This study was conducted to investigate the meaning of left ventricular (LV) apical sparing in patients with wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM). 165 patients who were diagnosed with ATTRwt-CM at Kumamoto University Hospital from January 2002 to December 2020 and had sufficient data for two-dimensional speckle tracking echocardiography were enrolled. Of these, 86 patients (52%) had LV apical sparing (relative apical longitudinal strain index (RapLSI)>1.0). Multivariable logistic regression analysis revealed the following variables were significantly associated with LV apical sparing: interventricular septal thickness in diastole (odds ratio (OR), 1.19; 95% confidence interval (CI), 1.01-1.41; p<0.05); E/e' ratio (OR, 1.06; 95% CI, 1.00-1.11; p<0.05); and heart-to-contralateral ratio by 99mTc-labeled pyrophosphate scintigraphy (OR, 3.40; 95% CI, 1.07-10.83; p<0.05).Next, we compared RapLSI at the time of diagnosis with that during the follow-up period (396days (346-458) after diagnosis) in 92 patients. RapLSI increased significantly during the follow-up period compared with RapLSI at diagnosis in the non-LV apical sparing group (0.89±0.32 vs 0.74±0.18, p<0.01) but not in the LV apical sparing group (1.33±0.53 vs 1.39±0.45, p=0.46). A total of 12 patients (29%) in the non-LV apical sparing group developed LV apical sparing and 11 patients (22%) in LV apical sparing group diminished LV apical sparing during the follow-up period. Approximately half of ATTRwt-CM patients did not have LV apical sparing at diagnosis. Because RapLSI in ATTRwt-CM significantly changed over time, repeated two-dimensional speckle tracking analysis is important for suspected ATTR-CM patients.