Myocardial Stunning During Hemodialysis: Role of Dialyste Calcium Concentration

Chronic kidney disease (CKD) is linked to elevated mortality rate, and cardiovascular disease is the main cause related to this outcome. The cardiovascular mortality among patients on conventional hemodialysis (CHD) is high, achieving up to 30 times more risk of death when comparing to individuals of same age on general population. Congestive heart failure can develop in 25% to 50% of patients, leading to a worse prognosis. CKD patients present anatomic and functional abnormalities on peripheral bed vases and also cardiovascular abnormalities that can cause myocardial ischemia. This last usually is transitory and lead to left ventricular dysfunction that can persist even after the end of dialysis session despite normal coronary perfusion. The prolonged dysfunction is called myocardial stunning (MS). Patients on CHD are subject to hemodynamic instability, myocardial ischemia and development of regional abnormalities of myocardial wall (ARPM´s). MS induced by intradialytic ischemia is a complication that can be minimized by applying techniques associated to more stability during the CHD, as cool dialysate or increasing the length of the therapy. The goal of the present study is to evaluate the behavior of cardiovascular system (trough hemodynamic performance during CHD, accessing MS by echocardiography technique, and biomarkers associated to MS). Finally, the investigators aimed to investigate the role of two different dialysate calcium concentration (2,5 and 3,5 mEq/l) in the genesis of MS during CHD. The elucidation of pathogenesis of MS during CHD might help us modified hemodialysis technique in order to prevent MS, and reduce the high cardiovascular mortality among CKD patients.

Patients on hemodialysis patients present anatomic and functional abnormalities on peripheral bed vases and also cardiovascular abnormalities that can cause myocardial ischemia. This last usually is transitory and lead to left ventricular dysfunction that can persist even after the end of dialysis session despite normal coronary perfusion. The prolonged dysfunction is called myocardial stunning (MS). Patients on dialysis are subject to hemodynamic instability, myocardial ischemia and development of regional abnormalities of myocardial wall (ARPM´s). Some authors have demonstrated that CHD cause segmental and global myocardial ischemia, and up to 65% of patients have recurrent myocardial ischemia. There are some associated factors: high ultrafiltration rates, intradialytic hypotension, reduced systolic blood pressure and high risk of cardiovascular events and death. MS induced by intradialytic ischemia is a complication that can be minimized by applying techniques associated to more stability during the CHD, as cool dialysate or increasing the length of the therapy. More specifically, MS can be the result of repair process, with oxygen free radicals generation and reduction of the synthesis of contractile proteins, in association with a reduced muscle responses to calcium which in turns lead to ventricular dysfunction (the calcium hypothesis). The goal of the present study is to evaluate the behavior of cardiovascular system (trough hemodynamic performance during CHD, accessing MS by echocardiography technique, and biomarkers associated to MS). Finally, the investigators aimed to investigate the role of two different dialysate calcium concentration (2,5 and 3,5 mEq/l) in the genesis of MS during CHD. The elucidation of pathogenesis of MS during CHD might help us modified hemodialysis technique in order to prevent MS, and reduce the high cardiovascular mortality among CKD patients.