LEFT VENTRICULAR STRAIN BY CARDIAC MRI IN END-STAGE RENAL DISEASE PATIENTS AFTER KIDNEY TRANSPLANTATION

Abstract

Cardiovascular disease is a significant cause of morbidity and mortality in patients with end-stage renal disease (ESRD) and kidney transplant (KT) patients. Compared with left ventricular ejection fraction (LVEF), left ventricular (LV) strain has emerged as an important marker of LV function as it is less load dependent. We sought to evaluate changes in LV strain using cardiac magnetic resonance imaging (CMR) in ESRD patients who received KT, to determine whether KT may improve LV function. We conducted a prospective multi-centre longitudinal study of 79 ESRD patients (22 peritoneal dialysis, 57 hemodialysis), of whom 40 continued dialysis (control group) and 39 underwent living-donor KT. CMR was performed at baseline and 12 months post-transplant. A single, blinded reader measured peak systolic strain parameters (global longitudinal strain [GLS], global circumferential strain [GCS], and global radial strain [GRS]) by feature tracking using a commercially available software cvi42. LVEF, indexed LV end-diastolic volume (LVEDVi) and LV end-systolic volume (LVESVi) were independently measured. Among 79 participants (mean age 55; 30% women), KT patients were taking significantly fewer antihypertensive medications at 12 months (baseline 2.4±1.7 versus 12-month 1.5±1.0, p=0.001), while no difference was observed for dialysis patients (baseline 2.1±1.6 versus 12-month 2.1±1.6, p=0.54). KT patients had significant improvement in GCS (p=0.007) and GRS (p=0.003), but a decline in GLS over 12 months (p=0.026), while no significant change in any LV strain was observed in the dialysis group (Table). When LV strain changes were compared between the two groups, improvement in GCS (p=0.048) and GRS (p=0.031) remained significant, while the decline in GLS did not (p=0.52) (Table). LVEF significantly improved at 12 months for KT patients, but not for dialysis patients (Table). Over 12 months, change in LVEF was significantly correlated with changes in GCS (Spearman's r=-0.42, p<0.001), GRS (Spearman's r=0.64, p<0.001), and GLS (Spearman's r=-0.34, p=0.003). Improvements in GCS and GRS over 12 months were significantly correlated with reductions in LVEDVi and LVESVi (all p<0.05). There was no significant correlation between changes in LV strain and change in blood pressure (BP) (all p>0.10). Compared with continuation of dialysis, KT was associated with significant improvements in GCS and GRS after 12 months, which did not correlate with BP change. The observed improvements in LV strain support the notion that KT has favorable effects on LV function beyond volume and BP control. Larger studies with longer follow-up will be needed to confirm these findings.