Hypocalcemia is related to left ventricular diastolic dysfunction in patients with chronic kidney disease

Abstract

Background: Left ventricular (LV) diastolic dysfunction in patients with chronic kidney disease (CKD) is of a complex nature and is the predominant cause of congestive heart failure in this group of patients. This work aimed to evaluate the potential effect of disturbances in calcium-phosphorus (Ca-P) metabolism in patients with CKD on LV diastolic function as assessed by echocardiography.

Materials and methods: The study group consisted of 81 ambulatory patients with CKD, stages 2-5, with preserved LV systolic function-LV ejection fraction >50% and with sinus rhythm. Standard echocardiography was performed in all patients with tissue Doppler echocardiography for the evaluation of the systolic velocity and both diastolic velocities of LV (EmLV and AmLV). The following laboratory parameters were measured: serum creatinine concentration, estimated glomerular filtration rate, and the levels of urea, P, Ca, parathormone, platelet count, hemoglobin level, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. Patients were divided into two groups according to the results of EmLV: group with LV diastolic dysfunction (EmLV<8cm/s) DF (+) and group with normal LV diastolic function DF (-), when EmLV was ≥8cm/s.

Results: Patients in DF (+) group, as compared to DF (-) patients, manifested a lower serum Ca level and an elevated NT-proBNP level [9.03±0.76mg/dL vs 9.44±0.78mg/dL, p=0.02, and 257.9 (32.6-12,633)pg/ml vs 149 (11.7-966)pg/ml, p=0.035, respectively]. The area under the receiver operating characteristics (ROC) curve of Ca for diastolic dysfunction was 0.627, 95% CI (0.511-0.734), p=0.04, whereas ROC derived Ca value of ≤9.82mg/dL was characterized by a sensitivity of 91.8% and specificity of 38.1% for diagnosing LV diastolic dysfunction. The only independent variable predicting LV diastolic dysfunction as measured by a multivariate logistic regression analysis was Ca level≤9.82mg/dL with odds ratio=8.81 (95% CI 1.49-51.82), p=0.014.

Conclusions: Hypocalcemia is an independent predictive factor for LV diastolic dysfunction in patients with CKD.

Keywords: Calcium; Diastolic dysfunction; Doppler ultrasound; Kidney.