Effect of hyperparathyroidism on arterial distensibility in renal transplant recipients.
BACKGROUND
The cushioning function of the arterial system is altered in patients with end-stage renal failure. The role of hyperparathyroidism for the altered vessel wall properties of large arteries not known.


METHODS
To exclude the confounding effects of fluid volume changes and hypercirculation as well as uremic toxicity on vessel wall properties from those of hyperparathyroidism, the present study was conducted in 54 normotensive renal transplant recipients with good graft function, three to six months after transplantation. The vessel wall properties of the common carotid artery were investigated in 32 of them, who had increased plasma intact parathyroid hormone (iPTH) levels (136 +/- 12 ng/liter, SEM), and compared to those of 22 control recipients of same age with normal plasma iPTH levels (34 +/- 4 ng/liter). Arterial distension was measured by Doppler analysis of the vessel wall movements, blood pressure was determined by sphygmomanometry.


RESULTS
Blood pressure was 140 +/- 3/85 +/- 2 mm Hg in renal transplant recipients with hyperparathyroidism, 135 +/- 3/83 +/- 1 mm Hg in patients with normal plasma iPTH levels (NS). There was no difference in enddiastolic diameter of the common carotid artery (7.4 +/- 0.2 mm) in renal transplant recipients with hyperparathyroidism as compared with the control patients (7.3 +/- 0.2 mm; NS). Renal transplant recipients with hyperparathyroidism had a lower distension (389 +/- 27 microns vs. 486 +/- 28 microns, P < 0.05) and distensibility coefficient of the common carotid artery (15.1 +/- 1.1 10(-3)/kPa vs. DC 19.0 +/- 1.0 10(-3)/kPa, P < 0.001) when compared with the control patients. Multiple regression analysis showed that the distensibility coefficient of the common carotid artery was negatively correlated with age (P < 0.001), mean arterial blood pressure (P < 0.05) and plasma iPTH levels (P < 0.05). The effects of plasma iPTH levels were not related to serum calcium concentrations or to differences in the enddiastolic diameter of the common carotid artery.


CONCLUSIONS
The data suggest that secondary hyperparathyroidism can affect the cushioning function of larger arteries in patients with end-stage renal failure independently of high blood pressure.
Barenbrock
M
M
Department of Medicine D, University of Münster, Germany.
Hausberg
M
M
Kosch
M
M
Kisters
K
K
Hoeks
A P
AP
Rahn
K H
KH
D000328:Adult; D000367:Age Factors; D001794:Blood Pressure; D015992:Body Mass Index; D002118:Calcium / Q000097:blood; D017536:Carotid Artery, Common / Q000502:physiology; D005260:Female; D006454:Hemoglobins; D006801:Humans; D006961:Hyperparathyroidism / Q000209:etiology / Q000503:physiopathology*; D007668:Kidney / Q000098:blood supply*; D007676:Kidney Failure, Chronic / Q000150:complications / Q000503:physiopathology* / Q000601:surgery; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D012044:Regression Analysis; D014664:Vasodilation / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000502:physiology
D006454:Hemoglobins; D010281:Parathyroid Hormone; D002118:Calcium