The incremental value of left ventricular energy loss in predicting adverse events in chronic kidney disease patients with preserved ejection fraction.

ABSTRACT

BACKGROUND: Vector flow mapping (VFM) is a new echocardiographic technology that can effectively evaluate systolic and diastolic hemodynamic function. However, little is known about the prognostic value of VFM-related parameters. In this paper we aimed to investigate whether left ventricular energy loss (EL) parameters as assessed by VFM enhance prediction of adverse events in patients with chronic kidney disease with preserved ejection fraction. METHODS: One hundred thirty-nine prospectively recruited patients (66% male, 58% on dialysis) with CKD stage 3-5 with normal left ventricular ejection fraction (LVEF) made up the study cohort. Global longitudinal strain (GLS) was calculated using 2-dimensional speckle tracking, and the LV EL during one cardiac cycle for each period was measured using VFM technology. Participants were followed for 4.17 ± 1.58 years for the primary end point of overall mortality and major adverse cardiovascular events (MACE). RESULTS: Forty-five (32%) patients had a primary endpoint event. The EL during each period especially during the ejection stage (Ej-EL) was significantly higher in patients with adverse events than in those without, meanwhile the LV GLS were lower. The Ej-EL (HR 1.11; 95% CI 1.06-1.15) and LV GLS (HR 0.87; 95% CI 0.81-0.94) (all P < .001) were independent predictors for the primary end point. Increased Ej-EL (≥6.13, 10-3 J/m s) and impaired GLS (<15.52, %) were associated with a higher risk of overall mortality death and MACE (log rank χ2 = 26.94, 7.19; P < .001, =0.007), and DeLong tests showed that Ej-EL (AUC = 0.823) has a slight advantage in predicting adverse events compared to GLS (AUC = 0.681). Furthermore, the addition of Ej-EL to a model with conventional parameters did more to improve the model's discrimination compared to GLS. CONCLUSIONS: Increased Ej-EL as determined by VFM is associated with a higher risk of overall death and MACE in CKD patients with preserved EF.