Reduced baroreflex sensitivity is associated with increased vascular calcification and arterial stiffness.
BACKGROUND
Vascular calcification is a critical determinant of cardiovascular morbidity and mortality in chronic haemodialysis (HD) patients. The pathophysiology underlying this observation remains obscure. Baroreceptor sensitivity (BRS) is important in the maintenance of an appropriate cardiovascular status both at rest and under the physiological stress of HD. BRS is determined by both the mechanical properties of the vascular wall, mediating the transfer of transmural pressure, and afferent and efferent autonomic function. We aimed to study the association between arterial structure, function and BRS in chronic HD patients.


METHODS
We studied 40 chronic HD patients mean age 62+/-2 (26-86) years who had received HD for a mean 40+/-4 (9-101) months. Spontaneous BRS was assessed using software studying the relationship between inter-beat variability and beat to beat changes in systolic blood pressure. Functional characteristics of conduit arteries (pulse wave analysis) were studied with applanation tonometry at the radial artery. Arterial calcification was assessed in lower limbs using reconstructed multi-slice computed tomography and quantified with volume-corrected calcification scores within the superficial femoral artery.


RESULTS
Mean BRS was 4.43+/-0.44 ms/mmHg, with a wide range from 1.0 to 11.5 ms/mmHg. This correlated with arterial stiffness as measured by time to shoulder calculated from the central pulse wave analysis (r = 0.4, P = 0.01). BRS was also associated with vascular calcification (P = 0.01) but not by other factors such as dialysis vintage, age or pre-dialysis systolic/diastolic blood pressure.


CONCLUSIONS
The reduction in BRS and the resulting aberrant blood pressure response to the physiological stress and volume changes of HD may be important in the further understanding of the pathophysiology of the increased mortality in HD patients with vascular calcification.
Chesterton
Lindsay J
LJ
Department of Renal Medicine, Derby City General Hospital, Uttoxeter Road, Derby DE22 3NE, UK.
Sigrist
Mhairi K
MK
Bennett
Terence
T
Taal
Maarten W
MW
McIntyre
Christopher W
CW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017704:Baroreflex / Q000502:physiology*; D001808:Blood Vessels / Q000473:pathology*; D002114:Calcinosis; D004548:Elasticity; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000209:etiology / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D017534:Radial Artery / Q000503:physiopathology