Flow-mediated dilatation and intima-media thickness in patients with lacunar infarctions.

OBJECTIVES: To evaluate systemic endothelial function and atherosclerotic changes in patients with lacunar infarctions (LI) we examined flow-mediated dilatation (FMD) and intima-media thickness (IMT) and compared them to patients with similar risk factors (SR) and healthy controls. METHODS: FMD and IMT were investigated in patients with LI (20 patients, aged 60.9 +/- 7.3 years), 21 age- and gender-matched patients with SR and 21 healthy controls. RESULTS: FMD was more impaired in patients with LI (0.4% +/- 5.0%) compared to patients with SR (3.8% +/- 4.8%) and healthy controls (7.9% +/- 6.0%) (P < or = 0.01), whereas IMT was similarly thickened in both groups of patients. CONCLUSIONS: We found that patients with LI have a diminished FMD, but a similar IMT, compared to patients with SR. Our results reveal that for a given level of atherosclerosis patients with LI have additional endothelial impairment.

Effect of generalized sympathetic activation by cold pressor test on cerebral hemodynamics in diabetics with autonomic dysfunction.

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 1st, 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.

Coupling between visual evoked cerebral blood flow velocity responses and visual evoked potentials in migraneurs.

Neurovascular coupling may be altered in migraneurs. Therefore, visual evoked potentials (VEP) and visually evoked cerebral blood flow velocity responses (VEFR) were simultaneously recorded in 30 healthy controls and 30 migraneurs interictally using a checkerboard stimulus with visual contrasts of 1%, 10% and 100%. The VEFR were measured in the posterior cerebral artery using transcranial Doppler and VEP were recorded from occipital leads. We found an increase in VEFR and VEP in both the healthy and migraneur groups (P < 0.01). VEFR were significantly higher in migraneurs (P < 0.01), while VEP did not significantly differ between the groups (P > 0.05). Regression showed a significant association between VEP and VEFR in both healthy controls (r = 0.66, P < 0.01) and migraneurs (r = 0.63, P < 0.01). The regression coefficient of migraneurs (b = 0.88, SE = 0.08) was significantly higher than that of healthy controls (b = 0.55, SE = 0.07) (P = 0.04). We conclude that neurovascular coupling is increased in migraneurs interictally.

Testing of cerebral endothelium function with L-arginine after stroke.

BACKGROUND: Endothelium-dependent vasodilatation could be impaired during hypoperfusion. L-arginine (L-A), a precursor of nitric oxide, is able to elicit endothelium-dependent vasodilatation. To determine cerebral vascular endothelial function in the early stages after ischemic stroke, we studied cerebrovascular reactivity to L-A with transcranial Doppler (TCD). METHODS: The study group consisted of 15 patients with the middle cerebral artery syndrome, aged 57.6+/-9.8 years. They were investigated on days 7 to 10 after ischemic stroke. The control group consisted of 15 healthy volunteers, aged 58+/-10.7 years. All subjects received an intravenous infusion of L-A over 20 min at a rate of 1.5 g/min. The mean arterial velocity (vm) was measured in both middle cerebral arteries by using a bitemporal monitoring system (Multi-Dop X4, DWL). At the same time, the mean arterial pressure (MAP) and heart rate (HR) were measured by Finapres and ECG. The end-tidal CO2 (Et-Co2) was monitored by capnograph. The Vm over 5-min intervals at rest and during the infusion of L-A was determined by using the DWL TCD8 software. RESULTS: The Vm significantly increased in both hemispheres of both groups (p=0.00). Vm differences between rest and L-A stimulation were lower in the ischemic hemispheres compared to the healthy ones (p=0.00), but did not differ between the ischemic hemispheres and hemispheres of the healthy group (p>0.05). MAP, HR and Et-Co2 did not change during the infusion (p>0.05). CONCLUSIONS: Cerebrovascular reactivity to L-A is impaired in patients with recent stroke. The amino acid could thus be useful in testing endothelium function both in healthy persons and in stroke patients since endothelium dysfunction seems to be an important factor in reperfusion injury.

The effect of age on cerebrovascular reactivity to cold pressor test and head-up tilt.

OBJECTIVE: To compare the cold pressor test (CPT) and head-up tilt (HUT) responses of the older and younger healthy individuals by transcranial Doppler. SUBJECTS AND METHODS: Forty healthy volunteers were divided into two age groups (18-39 years, 40-69 years). Mean blood velocity (v(m)) in both middle cerebral arteries was monitored during CPT and HUT. Mean arterial blood pressure, heart rate and end-tidal CO(2) (Et-CO(2)) were measured simultaneously. RESULTS: The v(m) increased by 7.1% during CPT and decreased by 10.1% during HUT. The v(m) responses were significantly lower in the older group (P < 0.01). Linear regression analysis showed a significant effect of age on dv(m) during both CPT (P < 0.01) as well as HUT (P < 0.01). CONCLUSION: The age affected the v(m) responses to CPT and HUT in the group of older subjects.

Autonomic nervous system function in patients with acute brainstem stroke.

Dysfunction of the autonomic nervous system (ANS) often complicates the clinical course in patients with acute stroke. The studies of the function of ANS in patients with brainstem stroke are scarce. The purpose of our study was to evaluate the function of ANS in the early period after acute brainstem stroke and to find out whether the location of stroke in brainstem influences the function of ANS. We studied heart rate variability (HRV) and plasma levels of catecholamines in 14 eligible patients with medullary (6 patients) and non-medullary (8 patients) brainstem stroke during the first 6 weeks after stroke. Integrals over the low- (LFB; 0.04-0.15 Hz) and high-frequency bands (HFB; 0.15-0.40 Hz) of power spectra were calculated. When compared to controls, the integrals over HFB in the hyperacute (p < 0.001) and over LFB in the hyperacute (p < 0.005) and in the acute (p < 0.05) phases were significantly smaller in patients with medullary strokes. Integrals over LFB and HFB in patients with non-medullary strokes did not differ significantly from controls, regardless of the phase of the disease. Plasma levels of epinephrine in patients with non-medullary stroke in the hyperacute and in the acute phases were significantly higher than in controls (p < 0.005). We conclude that there is transient dysfunction of ANS in patients with acute medullary stroke, in contrast to those with non-medullary brainstem stroke.

DD genotype of the angiotensin-converting enzyme gene and stroke in Slovenian population.

The angiotensin-converting enzyme (ACE) is a rate-limiting enzyme in the renin angiotensin system, the enzyme is involved in the vascular remodelling and atherosclerosis. Its significance in pathogenesis of ischemic cerebrovascular insults (CVI) is not known. We analysed 124 Slovenian patients with CVI and compared them with 161 healthy controls for I/D polymorphism. Under a recessive model (chi2 = 1.76, p = 0.1, OR = 1.40, 95% CI: 0.85-2.34) we found no significant difference in I/D genotypes between patients with CVI and controls. This study shows that in a group of Slovenian CVI patients the DD genotype is not an important risk factor for the development of stroke.

The deterioration of cardiovascular reflexes in Parkinson's disease.

OBJECTIVES: We have investigated the deterioration of cardiovascular reflexes in Parkinson's disease. PATIENTS AND METHODS: In a group of 20 patients with Parkinson's disease (PD) and in a group of 10 age-matched control subjects a battery of cardiovascular reflex (CVR) tests (Valsalva manoeuvre, deep breathing test, handgrip test, orthostatic test) was repeated after 3 years. RESULTS: In PD patients at deep breathing test, at Valsalva manoeuvre and at orthostatic test the heart rate response decreased significantly (P<0.05). The impairment of systolic and diastolic blood pressure response at orthostatic test was significant as well (P < 0.005). At hand grip test no significant changes in heart rate and blood pressure response were found. In control subjects only heart rate response at orthostatic test decreased significantly after 3 years. CONCLUSION: Our results show progression of an impairment of sympathetic and parasympathetic control of the cardiovascular functions in patients with PD over a period of 3 years.

Influence of the cold pressor test on the middle cerebral artery circulation.

Cold pressor test (CPT) evokes generalized activation of the sympathetic nervous system (SNS). The activity of SNS may be estimated by monitoring the mean blood velocity (v(m)) in the middle cerebral artery (MCA) by using a transcranial Doppler monitoring system (TCD). To determine the response of SNS, we studied the v(m) during CPT. Thirty-four healthy volunteers, 13 female and 21 male (mean age 34 +/- 9.5 years, range 18 to 55 years) participated in our study. The experiment consisted of a 5-min baseline period followed by a 3-min immersion of the right hand in ice water. Blood velocity in both MCA's was monitored by bitemporal 2 MHz probes by using a Multi-Dop X4. MAP and heart rate (HR) were measured simultaneously by a Finapres non-invasive blood pressure monitor and a computerized ECG system. End-tidal CO2 (Et-CO2) was measured with an infrared capnograph. To determine v(m) over a chosen time interval the TCD-8 software was utilized. The results showed that during CPT v(m), MAP, and HR increased significantly (P < 0.01) for 9.8%, 18.5%, and 3.6%, respectively. Et-CO2 did not change significantly (P > 0.05). The increase of v(m) was also significantly higher in the stimulated hemispheres (P = 0.005) regarding to unstimulated ones. The increase of v(m) during CPT was not gender dependent. To establish the association between variables the models of multivariate regression were used. Multiple regression CPT model was significant (P < 0.01) and fitted data moderately well (R2 = 0.28). MAP and Et-CO2 were significant in the model (P < 0.01). It seems that the reactivity of the SNS can be estimated by measuring v(m) with TCD during CPT.

Transient ischemic attacks, risk factors, and precerebral color doppler angiosonography.

The aim of this study was to ascertain the importance of color-coded Doppler sonography (CCDS), a noninvasive examination technique, in early detection of atherosclerotic lesions in precerebral arteries. CCDS was utilized in a group of patients with one or several transient ischemic attacks (TIA) and in a group of non-TIA (NTIA) cases, so that the degree of atherosclerotic lesions of precerebral vessies in TIA and NTIA patients might be compared. The presence of risk factors for cerebrovascular disease (CVD) was compared in both groups as well. We examined 87 patients with TIA (38 women and 49 men), aged 19-86 years (mean, 60.97 ± 11.97 years) and 48 NTIA patients (22 women and 26 men), aged 35-85 years (mean,60.04 ± 9.37years). No statistically significant differences in age and gender were found between the groups. A significant difference was found between the common carotid artery intimal-medial thickness (CCA IMT) in TIA patients (CCA IMT right + left = 1.12 ± 0.44 mm) and NTIA patients (CCA IMT right + left = 0.91 ± 0.32 mm) (p < 0.0001). A positive significant association was found between both groups in the number of different plaques (p < 0.0001) and the number of stenoses (p < 0.0001). When risk factors were compared, the difference between TIA and NTIA groups was statistically significant in regard to high-density lipoproteins (p < 0.002), total cholesterol (p < 0.004), and blood glucose concentrations (p < 0.013), as well as systolic blood pressure (p < 0.011). In conclusion, Doppler sonographic changes in precerebral arteries were present in the TIA group in spite of the fact that both groups had identical risk factors for CVD. CCDS is a valuable aid for early detection of TIA patients who have a significant risk of developing brain infarction.

Autonomic function testing in patients with migraine.

Autonomic nervous system function was studied in 62 patients with migraine. The Valsalva maneuver, deep breathing test, sustained handgrip test, orthostatic test and spectral analysis of heart rate variability in the supine and standing positions were performed in a group of 62 patients of both sexes, aged 21 to 50 years, and in an age-matched control group of 45 healthy volunteers. Heart rate increases during sustained handgrip was significantly reduced in the headache group, when compared to the control group, while the results of the remaining cardiovascular tests did not significantly differ between the control and headache groups. In standing patients, the integrals of middle frequency bands of amplitude spectra were smaller in patients than in controls because the increase induced by standing was smaller in migraine patients. The results in patients with migraine with aura (21 patients) and migraine without aura (41 patients) did not differ significantly from each other. The same was true for the results of the female and male patients. It is concluded that sympathetic function is impaired in migraine patients.

Autonomic function testing in patients with tension-type headache.

Autonomic nervous system function was studied in 51 patients with tension-type headache. The Valsalva manoeuvre, deep breathing test, sustained handgrip test, orthostatic test and spectral analysis of heart rate variability in the supine and standing positions were performed in a group of 51 patients of both sexes aged 21 to 50 years and in an age-matched control group of 45 healthy volunteers. Diastolic blood pressure increase and particularly heart rate increase during sustained handgrip were significantly reduced in the headache group, when compared to the control group, while the results of the remaining tests did not significantly differ between the control and headache groups. No significant differences were found between the episodic (19 patients) and chronic (32 patients) tension-type headache subgroups. It is concluded that sympathetic function is impaired in tension-type headache patients.

Calcification of basal ganglia, postoperative hypoparathyroidism and extrapyramidal, cerebellar, pyramidal motor manifestations.

A patient is described who 32 years after thyroidectomy developed a chronic progressive syndrome due to hypoparathyroidism, with multiple extrapyramidal signs (faciobuccolingual dyskinesias, choreiform and athetotic movements of upper extremities, tremor of hands, cogwheel phenomenon), cerebellar manifestations (dysarthria, dysgraphia, mild gait ataxia), and pyramidal signs as well as an organic psychosis and epilepsy. A CT scan showed calcification of the basal ganglia. Therapy for hypoparathyroidism produced partial regression of the disorder. To explain the physiopathologic mechanism of the syndrome, Selye et al. advanced an attractive hypothesis of calciphylaxis, which assumes that a sensitizer and a challenger together induce development of calcification. In the case reported calcification involved the periventricular region and was not limited to the basal ganglia. It is suggested that either a sensitizer or a challenger may enter the periventricular tissue via the ependyma.