Association of chronic kidney disease with abnormal cardiac mechanics and adverse outcomes in patients with heart failure and preserved ejection fraction

Aims Chronic kidney disease (CKD) is associated with worse outcomes in heart failure with preserved ejection fraction (HFpEF). Whether this association is due the effect of CKD on intrinsic abnormalities in cardiac function is unknown. We hypothesized that CKD is independently associated with worse cardiac mechanics in HFpEF. Methods and Results We prospectively studied 299 patients enrolled in the Northwestern University HFpEF Program. Using the creatinine-based CKD-Epi equation to calculate estimated glomerular filtration rate (EGFR), study participants were analysed by CKD status (using EGFR <60 mL/min/1.73 m² to denote CKD). Indices of cardiac mechanics (longitudinal strain parameters) were measured using speckle-tracking echocardiography. Using multivariable-adjusted linear and Cox regression analyses, we determined the association between CKD and echocardiographic parameters and clinical outcomes (cardiovascular hospitalization or death). Of 299 study participants, 48% had CKD. CKD (dichotomous variable) and reduced EGFR (continuous variable) were both associated with worse cardiac mechanics indices including left atrial (LA) reservoir strain, LV longitudinal strain, and right ventricular free wall strain even after adjusting for potential confounders, including co-morbidities, EF, and volume status. For example, for each 1-SD decrease in EGFR, LA reservoir strain was 3.52% units lower (P < 0.0001) after multivariable adjustment. Reduced EGFR was also associated with worse outcomes [adjusted hazard ratio (HR) 1.28, 95% confidence interval (CI) 1.01-1.61 per 1-SD decrease in EGFR; P = 0.039]. The association was attenuated after adjustment for indices of cardiac mechanics (P = 0.064). Conclusion In HFpEF, CKD is independently associated with worse cardiac mechanics, which may explain why HFpEF patients with CKD have worse outcomes.