Myocardial changes in incident haemodialysis patients over 6-months: an observational cardiac magnetic resonance imaging study

Abstract

Patients commencing on haemodialysis (HD) have an increased risk of cardiovascular events in the first year after starting HD compared to those patients established on HD longer. Left ventricular (LV) hypertrophy and abnormal myocardial strain predict mortality. There may be changes in the myocardium of incident HD patients over a 6-month period of HD which may explain changes in cardiovascular risk. We used CMR to consider changes in LV mass, myocardial strain and T1 mapping. We examined changes in pre-dialysis highly sensitive troponin T. 33 patients undergoing HD for <12 months were recruited. Participants underwent CMR at baseline and after 6-months of standard care. 6-months of HD was associated with reduction in LV mass index (Baseline: 78.8 g/m² follow up: 69.9 g/m², p = <0.001). LV global longitudinal strain also improved (Baseline: -17.9%, follow up: -21.6%, p = <0.001). Change in T1 time was not significant (Baseline septal T1 1277.4 ms, follow up 1271.5 p = 0.504). Highly sensitive troponin T was lower at follow up (Baseline 38.8 pg/L, follow up 30.8 pg/L p = 0.02). In incident HD patients, 6-months of HD was associated with improvements in LV mass, strain and troponin. These findings may reflect improvement in known cardiac tissue abnormalities found in patients over the first year of HD.

Figure 1

Box plot of Left Ventricular Mass Index at baseline and follow up.

Figure 2

Scatter plots of Left Ventricular Mass Index and Global longitudinal strain at baseline and follow-up.

Figure 3

Typical changes in a study participant whose cardiac parameters improved over the duration of the study. Panels A–C are baseline images, panels D–F are follow up images. Panel A shows a short axis view of the left ventricle on baseline imaging, the myocardial thickness measures 1.7 cm, by follow up (panel D) the diameter had reduced to 1.4 cm. Panel B shows a typical T1 map obtained during the study, an interventricular septal segment has been drawn on and shows a T1 time of 1294 ms, by follow up (panel E) the corresponding segment had a noticeable reduction in T1 time to 1211 ms. Panel C shows a representative graph of global longitudinal strain; the horizontal axis is time throughout the cardiac cycle and the vertical axis shows amount of myocardial displacement. On comparison of panel C with panel F the displacement is greater in panel F, representing an improvement in myocardial strain mechanics over the study follow up period.