Cardiac complications of secondary hyperparathyroidism in chronic hemodialysis patients

Aim: To evaluate the effects of intact parathormone (iPTH) on left ventricular function using transthoracic echocardiography on chronic hemodialysis (HD) patients with secondary hyperparathyroidism. In HD patients, mortality is high and is frequently due to cardiac complications. Secondary hyperparathyroidism, high levels of phosphate (PO4), and high calcium phosphate product (Ca x PO4) are related to cardiac complications. Materials and methods: We examined 20 patients with normal iPTH levels (Group 1) and 20 patients with high iPTH levels (Group 2). Intact parathormone levels were measured in serum with a Coat-A-Count kit (Diagnostic Products Corporation, Los Angeles, CA, USA) using an immunoradiometric assay. The normal level of iPTH was 0.8-5.2 pmol/L. In patients with end-stage renal disease, iPTH levels should be 1.5 to 3 times higher than the normal range in order to maintain the bone mass; thus, patients with iPTH levels 4 or more times higher than the normal range (PTH >= 20.8 pmol/L) were defined as Group 2 while patients who had normal iPTH levels were defined as Group 1. Results: In both groups, Doppler parameters indicated diastolic dysfunction. However, mitral annular E velocity was lower in Group 2 than in Group 1 (6.1 +/- 1.1 cm/s and 7.5 +/- 1.6 cm/s, respectively; P = 0.034). It is well known that left ventricular hypertrophy (LVH) increases mortality rates. Left ventricle mass index and relative wall thickness are parameters reflecting LVH, and both were higher in Group 2 (294.4 +/- 103.0 g/m(2) and 53.5 +/- 11.7%) when compared with Group 1 (179.2 +/- 104.2 g/m(2) and 41.8 +/- 8.9%). These differences were found to be statistically significant (P < 0.001). Conclusion: This study demonstrates that high levels of iPTH contribute to diastolic dysfunction and LVH in hemodialysis patients.