Author/Editor		Žvan, B; Zaletel, M; Pogačnik, T; Bajrović, FF
Title		Effect of generalized sympathetic activation by cold pressor test on cerebral hemodynamics in diabetics with autonomic dysfunction
Type		članek
Source		Cerebrovasc Dis
Vol. and No.		Letnik 20
Publication year		2005
Volume		str. 449-55
Language		eng
Abstract		Background: We examined the effects of the cold pressor test on the cerebral circulation in diabetics with autonomic dysfunction without orthostatic hypotension using transcranial Doppler. Methods; Twenty diabetics with autonomic dysfunction and 19 age-matched healthy controls participated in the study. The mean arterial blood velocity was measured in the middle cerebral artery during the cold pressor test together with the mean arterial blood pressure. Results; The mean arterial blood velocity significantly (p < 0.01) increased during the 1 st, 2nd, and 3rd min of the cold pressor test by 10.6, 14.1, and 13.4%, respectively, in the control subjects and by 5.8, 7.2, and 6.8%, respectively, in the diabetics. Simultaneously, the mean arterial blood pressure significantly (p < 0.01) increased by 12, 26, and 23%, respectively, in the controls and by 9.4, 12.4 and 12.9%, respectively, in the diabetics. The increases in the mean arterial velocity as well as in the mean arterial blood pressure were significantly higher in the controls than in the diabetics (p < 0.01). The change in the mean arterial blood pressure related significantly to the change in the mean arterial blood velocity both in the controls (p<0.01, r=0.76) and in the diabetics (p<0.01; r=0.59). The slope of the regression line was significantly steeper in the controls (b=0.42, SE=0.05) as compared with the diabetics with autonomic dysfunction (b=0.27, SE=0.05; p=0.02). Moreover, also the relative increase in the cerebrovascular resistance index was higher in the controls than in the diabetics (p<0.05). Conclusion: These findings in the diabetics with autonomic neuropathy, but without orthostatic hypotension, suggest a failure in the cerebral autoregulation due to impaired cerebrovascular neurogenic control.
Descriptors		CEREBROVASCULAR CIRCULATION AUTONOMIC NERVOUS SYSTEM COLD DIABETIC NEUROPATHIES SYMPATHETIC NERVOUS SYSTEM MIDDLE AGE AGED SEX FACTORS BLOOD PRESSURE HEMODYNAMICS ULTRASONOGRAPHY, DOPPLER, TRANSCRANIAL VASCULAR RESISTANCE