Early and asymptomatic cardiac dysfunction in chronic kidney disease
Nephrology, Dialysis and Transplantation
Heart failure is highly prevalent and associated with high mortality in chronic kidney disease (CKD). However, the pathophysiology of cardiac dysfunction in CKD, especially in the early asymptomatic stage, is not well understood. We studied sub"clinical cardiac dysfunction in asymptomatic CKD patients without co" morbid cardiac disease or diabetes mellitus by evaluating peak cardiac performance. Methods: In a cross"sectional study (n=130) we investigated 70 male non"diabetic CKD patients (21
... CKD patients (21 CKD 2"3a, 27 CKD 3b"4 and 22 CKD 5) employing specialised cardiopulmonary exercise testing to measure peak cardiac output and cardiac power output non"invasively. Data from 35 age"matched healthy male volunteers were obtained for comparison. In addition, as a positive control, data from 25 age"matched male heart failure patients in NYHA class II & III were also obtained. Results: The study subjects showed a graded reduction in peak cardiac power with 6.13±1.11 W in control, 5.02±0.78 W in CKD 2"3a, 4.59±0.53 W in CKD 3b"4 and 4.02±0.73 W in CKD 5 although not as impaired as in heart failure with 2.34±0.63 W (all P<0.005 vs control). The central haemodynamic characteristics of the cardiac impairment in CKD mirrored that of heart failure with reduced flow and pressure generating capacities, reduced chronotropic reserve and impaired contractility. Conclusion: The study demonstrates for the first time, impaired peak cardiac performance and cardiac functional reserve in asymptomatic CKD patients. The evidence of myocardial dysfunction in the absence of co"morbid cardiac disease and diabetes warrants further evaluation of current pathophysiological concepts of cardiovascular disease in CKD.