Speckle tracking echocardiography detects uremic cardiomyopathy early and predicts cardiovascular mortality in ESRD.

Cardiovascular mortality is high in ESRD, partly driven by sudden cardiac death and recurrent heart failure due to uremic cardiomyopathy. We investigated whether speckle-tracking echocardiography is superior to routine echocardiography in early detection of uremic cardiomyopathy in animal models and whether it predicts cardiovascular mortality in patients undergoing dialysis. Using speckle-tracking echocardiography in two rat models of uremic cardiomyopathy soon (4-6 weeks) after induction of kidney disease, we observed that global radial and circumferential strain parameters decreased significantly in both models compared with controls, whereas standard echocardiographic readouts, including fractional shortening and cardiac output, remained unchanged. Furthermore, strain parameters showed better correlations with histologic hallmarks of uremic cardiomyopathy. We then assessed echocardiographic and clinical characteristics in 171 dialysis patients. During the 2.5-year follow-up period, ejection fraction and various strain parameters were significant risk factors for cardiovascular mortality (primary end point) in a multivariate Cox model (ejection fraction hazard ratio [HR], 0.97 [95% confidence interval (95% CI), 0.95 to 0.99; P=0.012]; peak global longitudinal strain HR, 1.17 [95% CI, 1.07 to 1.28; P<0.001]; peak systolic and late diastolic longitudinal strain rates HRs, 4.7 [95% CI, 1.23 to 17.64; P=0.023] and 0.25 [95% CI, 0.08 to 0.79; P=0.02], respectively). Multivariate Cox regression analysis revealed circumferential early diastolic strain rate, among others, as an independent risk factor for all-cause mortality (secondary end point; HR, 0.43; 95% CI, 0.25 to 0.74; P=0.002). Together, these data support speckle tracking as a postprocessing echocardiographic technique to detect uremic cardiomyopathy and predict cardiovascular mortality in ESRD.

Speckle-tracking echocardiography in comparison with ejection fraction for prediction of cardiovascular mortality in patients with end-stage renal disease.

BACKGROUND: Cardiovascular disease is the major cause of death in end-stage renal disease (ESRD). To develop better means to assess cardiovascular risk in these patients, we compared conventional echocardiography-derived left ventricular ejection fraction (EF) with the novel method of 2D speckle-tracking echocardiography to determine cardiac strain. METHODS: Predictive performances of conventional EF and speckle-tracking echocardiography-derived global longitudinal strain (GLS) were compared using receiver-operator curve (ROC) analyses and calibration by calibration plots. We also took into account other known cardiovascular risk factors through multivariable logistic regression analysis. RESULTS: The study comprised 171 ESRD patients (mean age 64 years, 64% male) on maintenance dialysis therapy (93% haemodialysis, 7% peritoneal dialysis) for an average period of 39 months. During 2.1 years of follow-up, 42 patients (25%) died from cardiovascular disease. ROC analysis of GLS resulted in an area under the curve of 0.700 [95% confidence interval (CI) 0.603-0.797] compared with an area under the curve of EF of 0.615 (95% CI 0.514-0.716) (P = 0.059 for difference). The total absolute deviation between predicted and observed outcome frequencies obtained by calibration plots were 13.8% for EF compared with only 6.4% for GLS. Best results of ROC analysis (area under the curve = 0.759; P = 0.06), calibration and goodness-of-fit (χ2 = 28.34, P ≤ 0.0001, R 2 = 0.25) were achieved for GLS added to a baseline model consisting of known cardiovascular risk factors in a multivariate regression analysis. CONCLUSIONS: In summary, in chronic dialysis patients, GLS is a more precise predictor of cardiovascular mortality than conventional echocardiography-derived EF.