Global and segmental left ventricular strain, contraction time parameters, and strain rate in patients with amyloid cardiomyopathy based on feature tracking magnetic resonance imaging data
TL;DR
In patients with ACM, FT-CMR reveals a characteristic peak strain gradient with relative preservation of apical segments in the longitudinal direction, TTP prolongation in the apical segments in all directions, and directionally variable PSSR values.
Abstract
Aim . To describe the characteristics of peak myocardial strain, time-to-peak strain, and peak systolic strain rate (PSSR) at the basal, mid, and apical left ventricular (LV) levels in the longitudinal, circumferential, and radial directions in patients with amyloid cardiomyopathy (ACM) using feature-tracking cardiac magnetic resonance (FT-CMR) imaging. Material and methods. This single-center observational study included 25 patients with verified ACM. Cardiac MRI was performed on 1,5 and 3,0 T scanners, acquiring shortand long-axis cine steady-state free precession (SSFP) images. Postprocessing analysis of LV strain was performed on cine SSFP images using feature tracking (CVI42, Circle Cardiovascular Imaging Inc.). Peak strain, TTP, and PSSR were assessed in the radial, circumferential, and longitudinal directions at the basal, mid, and apical LV levels. Quantitative values are presented as M±SD. R e sults . Peak longitudinal strain progressively increased in absolute value from basal to apical segments as follows: -1,02±9,55% (basal) ® -8,47±5,69% (mid) ® -12,18±3,01% (apical), consistent with a pattern of comparatively preserved apical longitudinal strain. The peak circumferential strain also increased from basal to apical segments as follows: -14,47±2,89% ® -15,73±3,50% ®-18,42±4,69%. The peak radial strain was highly variable as follows: 60,00±33,11% (basal), 25,69±13,37% (mid), and 50,86±37,97% (apical). The mean TTP was highest at the apical level for all following directions: radial 357,11±114,83 ms; circumferential 391,97±62,42 ms; longitudinal 394,52±63,25 ms. Longitudinal PSSR was -0,86±2,18; -0,96±0,95 and -0,85±0,40 1/s (basal, mid, apical), while circumferential PSSR — -0,91±0,28; -0,94±0,18 and –1,18±0,88 1/s, and radial PSSR — 7,48±10,30; 2,19±1,72 and 6,74±7,86 1/s. Conclusion . In patients with ACM, FT-CMR reveals a characteristic peak strain gradient with relative preservation of apical segments in the longitudinal direction, TTP prolongation in the apical segments in all directions, and directionally variable PSSR values. Comprehensive segmental FT-CMR assessment of strain, TTP, and PSSR can serve as an additional noninvasive tool for characterizing LV mechanics in amyloid lesions.