Cardiac abnormalities in patients with chronic renal failure on haemodialysis: role of parathormone

ABSTRACT

The study was conducted at Kasr Al-Aini University Hospital between December 2001-December 2003 on 42 patients [19 males and 23 females] with a mean age of 43 +/- 10 years. All patients have established end stage renal disease and on regular haemodialysis at the dialysis unit at Kasr El Aini Teaching Hospital. Patients were divided into three groups according to their serum parathormone [PTH] Group A includes 11 patients with normal serum PTH ranging between [12-71Pg/dl], group B includes 15 patients with target PTH range [3-4 folds the upper limit of normal 210-280 Pg/dI]. Group C includes 16 patients with high serum PTH [higher than target range >280Pg/dl]. All patients have a target urea reduction ratio [URR] >65% i.e. >1.3 Kt/v indicating efficient dialysis. The mean age of patients in the different groups showed no significant difference. Assessment of the traditional risk factors for atherosclerosis regarding arterial blood pressure, serum lipid profiles showed that the mean arterial blood pressure was significantly higher [p<0.05] in group C when compared to group B and highly significant when compared to group A [p<0.01]. Serum LDL cholesterol was significantly higher in group C patients compared to group A [p<0.01] with no significant difference in relation to group B. Serum HDL was significantly lower in group C compared to group A and B [p<0.01]. Also group B showed highly significant decrease in serum HDL compared to group A [p<0.01]. Serum triglycerides was significantly higher in-group C compared to group B, A with a p value [0.05, 0.01] respectively. The principal serum correlates with parathormone that are calcium and phosphorus were compared between the three groups. Serum calcium was found to be highly significantly lower in group C compared to group B and A and also in group B compared to group A with a p value <0.01]. Also serum phosphorus was highly significant higher in-group C compared to group B and A and also in-group B compared to group A with a p value [<0.01]. Resting ECG ischaemic changes was observed in 6/16 patients in group C compared to 2/15 patients in group B, while no resting ECG changes was observed in group A. Assessment of the systolic functions of the heart by echocardiography showed that the ejection fraction [EF] was significantly higher in group B compared to group A, while in group C the EF was significantly lower compared to group A and B [p<0.01]. As for diastolic functions [E/A] ratio, the only significant difference was found between group C and A [p<0.05]. Structural alteration was studied by assessment of the interventricular system thickness [IVS] and left ventricular mass. Patients with group C showed a highly significant difference compared to group A and B [p<0.01] being higher in group C. Left ventricular mass was also significantly higher in group C compared to group A and B [p<0.01] with no significant difference between group A and B. As regards valvular and soft tissue calcifications patients with group C showed significantly higher calcific valvular lesions compared to group A and B [p<0.01]. Correlation between PTH, calcium and phosphorus and different variables showed that PTH and serum phosphorus was significantly positively correlated with mean arterial blood pressure, triglycerides Total cholesterol, left ventricular mass and interventricular septum thickness while calcium showed significant negative correlation with the same variables [p<0.01]. As for cardiac ejection fraction, serum PTH and phosphorus showed significant negative correlation while serum calcium showed significant positive correlation with the same variables [p<0.01]. In conclusion alteration of serum PTH level with calcium, phosphorus homeostasis in patients with renal failure may play an important role in potentiation of the classic risk factors for cardiovascular morbidity in addition to its direct effect on structural and functional alteration of the myocardium in these patients making control of such metabolic derangement an essential target for the prevention of cardiovascular morbidity in these patients