Increased intracranial arterial resistance in patients with type 2 diabetes mellitus.

BACKGROUND: The majority of the studies investigating risk factors for stroke have focused on the atherosclerosis of extracranial carotid arteries. Risk factors for the involvement of intracranial arteries in patients with stroke have not been widely investigated so far. The pulsatility index reflects the vascular resistance of intracranial arteries and could therefore be used as an estimate of the severity of vascular damage. MAIN PURPOSE: The present study aimed to examine the influence of type 2 diabetes mellitus and some other atherosclerosis risk factors on intracranial vascular resistance in patients with a previous stroke or transient ischemic attack. METHODS: Transcranial doppler investigations were performed in 103 patients with previous stroke (31 with diagnosis of type 2 diabetes, 72 without diabetes), at least 3 months after stroke occurred. Blood flow velocities of anterior cerebral arteries, middle cerebral arteries, the intracranial part of vertebral arteries and the basilar artery, as well as of the extracranial part of the internal carotid artery were measured, and Gosling's pulsatility index was calculated. The maximal pulsatility index of intracranial arteries was defined to express the most pronounced damage. RESULTS: Diabetic patients had a significantly higher pulsatility index than non-diabetic patients in all examined intracranial arteries. The maximal pulsatility index was also significantly higher in diabetic patients than in non-diabetic patients (1.24 +/- 0.25 vs. 1.00 +/- 0.23; p < 0.0001). There was no significant difference in the pulsatility index between men and women and between groups of patients with or without hypertension. In the multivariate analysis, the presence of diabetes (p < 0.0001) and the age of patients (p < 0.0001) were the only factors significantly predicting maximal pulsatility index, and this relationship was independent on the presence of hypertension. CONCLUSIONS: Diabetic patients with previous stroke have a higher pulsatility index than non-diabetic patients with previous strokes, which indicates a higher increase in intracranial arterial resistance and more severe damage to cerebral blood flow in diabetes mellitus.

[Changes in circulation of the blood in cerebral arteries in relation to age]. / Zmeny krvného prietoku v mozgových artériách v závislosti od veku.

The authors examined 12 people under 40 years and 12 above 40 years, mostly healthy volunteers. They investigated the rate of blood flow in the median cerebral artery after compression of the homolateral and contralateral internal carotid. They found that in more advanced age the rate of flow in the mentioned arteries is significantly reduced. During compression tests in more advanced age the decline in the flow rate is more marked in the median cerebral artery on the side of compression. In the other arteries the flow is promoted but the age dependence is not marked. The authors conclude from these findings that with advancing age the possibilities of autoregulation deteriorate more than those of the collateral circulation via Willis' circle.

[Cerebral circulation using transcranial and extracranial doppler ultrasonography in a patient with vertigo and ischemia in the area of the brain stem]. / Vysetrenie mozgovej cirkulácie pomocou transkraniálnej a extrakraniálnej dopplerovskej ultrasonografie u pacientov s vertigom a ischémiou v oblasti mozgového kmena.

The authors examined 32 patients with vertigo, 17 patients with focal ischaemia of the brain stem and 24 patients without signs of affections of the central nervous system by transcranial and extracranial Doppler ultrasonography. They measured the flow velocity in the basilar artery (BA), in the intracranial portion of the vertebral artery (VA) and in the extracranial portion of the internal carotid artery (ICA). In patients with vertigo they investigated functional and organic changes in the area of the cervical spine. They found significant differences in the flow velocities between groups as well as in different indices calculated from the assessed values. The lowest flow velocities were recorded in patients with focal ischaemia of the brain stem. The authors evaluate the influence of haemodynamics and disease of the cervical spine on the development of vertigo.

[Glucose-6-phosphate dehydrogenase and catalase in the erythrocytes of patients with cerebral ischemia attacks]. / Glukóza-6-fosfátdehydrogenáza a kataláza v erytrocytoch chorých s ischemickou mozgovou príhodou.

The authors assessed the activity of glucose-6-phosphate dehydrogenase and catalase in 73 patients with ischaemic cerebral attacks. They compared the results with a control group of 23 patients with vertebrogenic diseases. They recorded a mild decrease of activity of the above enzymes and draw attention to possible oxidation damage under conditions of cerebral hypoxia.