Vascular changes in chronic renal disease patients with secondary hyperparathyroidism.
BACKGROUND
Secondary hyperparathyroidism (SHPT) and its metabolic consequences - high serum phosphate and calcium x phosphate (Ca x P) product - are associated with cardiovascular disease in chronic kidney disease (CKD). We evaluated the relationship between PTH, mineral metabolism, vascular reactivity and arterial stiffness in patients with CKD.


METHODS
The study included 31 CKD patients and 12 matched controls. Brachial artery diameter was recorded at baseline and after reactive hyperemia (flow-mediated vasodilation) and 0.45 mg of trinitrate, to analyze the flow-dependent and flow-independent responses. Large vessel stiffness was evaluated on the common carotid artery.


RESULTS
Compared with controls, both flow-mediated (5.8% +/- 4.3% vs. 11.6% +/- 5.4%; p<0.001) and flow-independent (11.7% +/- 7.6% versus 23% +/- 7.5%; p<0.001) vasodilation were reduced in CKD. Flow-mediated vasodilation was negatively correlated with PTH (r=-0.416, p<0.05) and age (r=-0.365, p<0.05) and positively with flow-independent vasodilation (r=0.483, p<0.01). Blood pressure, dialysis duration, hematocrit and serum levels of Ca, P, and Ca x P product, lipids, and medications did not influence flow-mediated function. Carotid distension correlated independently and negatively with age (r=-0.681, p<0.01) and Ca x P product (r=-0.496, p<0.01) but was not influenced by PTH.


CONCLUSIONS
In CKD, PTH adversely affects vascular reactivity, possibly by interfering with endothelial function, while large vessel distension is influenced by Ca x P product but not by PTH. This result suggests a dual mechanism of vascular aggression in SHPT: an endothelial effect mediated by PTH and a media/adventitial effect linked to alterations in mineral metabolism.
Bortotolotto
Luiz A
LA
Heart Institute (InCor), Hospital das Clinicas, University of Sao Paulo Medical School, Sao Paulo - Brazil.
Costa-Hong
Valeria
V
Jorgetti
Vanda
V
Consolim-Colombo
Fernanda
F
Rosa
Kaleizu
K
Silva
Bruno C
BC
Krieger
Eduardo M
EM
De Lima
José J G
JJ
D000328:Adult; D050197:Atherosclerosis / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D001794:Blood Pressure / Q000502:physiology; D001916:Brachial Artery / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D002118:Calcium / Q000378:metabolism; D016022:Case-Control Studies; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D004548:Elasticity; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000150:complications* / Q000209:etiology / Q000378:metabolism*; D007674:Kidney Diseases / Q000150:complications* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010281:Parathyroid Hormone / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D012039:Regional Blood Flow / Q000502:physiology; D017539:Tunica Intima / Q000473:pathology; D017540:Tunica Media / Q000473:pathology
D010281:Parathyroid Hormone; D010710:Phosphates; D002118:Calcium