Increased basal myocardial perfusion in patients with chronic kidney disease without symptomatic coronary artery disease.

BACKGROUND: Even minor renal dysfunction is a powerful cardiovascular risk factor. The abnormalities in coronary and peripheral artery function in different stages of chronic kidney disease (CKD) remain poorly understood. Our aim was to test by a positron emission tomography (PET)-based method whether microvascular dysfunction, an early marker of coronary dysfunction, exists already in early stages of CKD.
METHODS: Myocardial blood flow was measured at baseline and during dipyridamole-induced hyperaemia by PET. Peripheral artery endothelial function was examined by measuring flow-mediated dilatation (FMD) of the brachial artery at rest and during reactive hyperaemia. Twenty-two patients with moderate to severe kidney failure and 10 healthy controls were investigated. Diabetic patients were excluded. Baseline characteristics were similar between the groups with the exception of antihypertensive medication in all CKD patients.
RESULTS: The basal myocardial perfusion was statistically significantly higher in CKD patients than observed values in similarly aged controls. There was a statistically significant negative correlation between the baseline myocardial perfusion and the estimated glomerular filtration rate. Coronary flow reserve was comparable to healthy controls in all patients. FMD was significantly reduced in all patients with CKD regardless of the stage of kidney failure.
CONCLUSIONS: Coronary flow reserve was normal although baseline myocardial blood flow was increased in all CKD patients as compared to healthy controls. Peripheral endothelial dysfunction was detected in all patients. Our findings suggest that coronary perfusion and peripheral vascular function are disturbed by different mechanisms in patients with CKD.