CMR-derived myocardial strain analysis differentiates ischemic and dilated cardiomyopathy-a propensity score-matched study

Abstract

Left ventricular (LV) longitudinal, circumferential, and radial motion can be measured using feature tracking of cardiac magnetic resonance (CMR) images. The aim of our study was to detect differences in LV mechanics between patients with dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) who were matched using a propensity score-based model. Between April 2017 and October 2019, 1224 patients were included in our CMR registry, among them 141 with ICM and 77 with DCM. Propensity score matching was used to pair patients based on their indexed end-diastolic volume (EDVi), ejection fraction (EF), and septal T1 relaxation time (psmatch2 module L Feature tracking provided six parameters for global longitudinal, circumferential, and radial strain with corresponding strain rates in each group. Strain parameters were compared between matched pairs of ICM and DCM patients using paired t tests. Propensity score matching yielded 72 patients in each group (DCM mean age 58.6 ± 11.6 years, 15 females; ICM mean age 62.6 ± 13.2 years, 11 females, p = 0.084 and 0.44 respectively; LV-EF 32.2 ± 13.5% vs. 33.8 ± 12.1%, p = 0.356; EDVi 127.2 ± 30.7 ml/m² vs. 121.1 ± 41.8 ml/m², p = 0.251; native T1 values 1165 ± 58 ms vs. 1167 ± 70 ms, p = 0.862). There was no difference in global longitudinal strain between DCM and ICM patients (- 10.9 ± 5.5% vs. - 11.2 ± 4.7%, p = 0.72), whereas in DCM patients there was a significant reduction in global circumferential strain (- 10.0 ± 4.5% vs. - 12.2 ± 4.7%, p = 0.002) and radial strain (17.1 ± 8.51 vs. 21.2 ± 9.7%, p = 0.039). Our data suggest that ICM and DCM patients have inherently different myocardial mechanics, even if phenotypes are similar. Our data show that GCS is significantly more impaired in DCM patients. This feature may help in more thoroughly characterizing cardiomyopathy patients.

Keywords: CMR; Feature tracking; Heart failure; Strain.

Fig. 1

Example of the calculation of GCS in an ICM patient (a, b) and a matched DCM patient (c, d) by cvi42 software (circle cardiovascular imaging, Calgary, Canada). DCM dilated cardiomyopathy, GCS global circumferential strain, ICM ischemic heart disease

Fig. 2

Flow chart for patient selection. Out of our tertiary care centre registry with 1224 patients we identified 141 patients with ICM (defined by typical subendocardial or transmural LGE) and 77 patients with DCM (reduced EF, absence of LGE or midwall sign). After matching for EF, T1 mapping, and EDVi, 72 patients remained in each group. DCM dilated cardiomyopathy, EDVi indexed end-diastolic volume, EF ejection fraction ICM ischemic cardiomyopathy

Fig. 3

Box-and-whisker plots comparing DCM and ICM patients for a GCS, b GLS, and c GRS. DCM dilated cardiomyopathy, ICM ischemic cardiomyopathy, GCS global circumferential strain, GLS global longitudinal strain, GRS global radial strain