Abnormal cerebrovascular regulation in hypertensive patients.

Griffith, D N; Im, James

doi:10.1136/bmj.2.6150.1494-c

Cited by 6 publications

(4 citation statements)

References 3 publications

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“…4 -7 However, these reports lack evidence of a physiological substrate for the cognitive changes that are found with modest blood pressure elevation. In adults, findings support a relationship between long-standing hypertension with the presence of altered cerebral autoregulation, 8,9 decreased cerebral microvascular reactivity, 10,11 and white matter lesions. 12,13 Similar changes in hypertensive children have not been described.…”

supporting

confidence: 52%

“…Several analyses in adults using different hypercapnic reactivity stimuli and different measures of cerebral blood flow have attempted to characterize the physiological association between hypertension and cerebral reactivity with conflicting results. 10,11,24,25 However, an important distinction is that children do not typically have similar effects of age, atherosclerosis, and cerebrovascular disease to confound this relationship.…”

Section: Discussionmentioning

confidence: 99%

“…8,9 Both hypertrophy and remodeling of the cerebral artery walls have been proposed as the mechanisms behind this adjustment, resulting in wall thickening, luminal narrowing, and decreased compliance of the vessels. 19,20 Furthermore, in both adult and adolescent hypertensive patients, studies have demonstrated abnormal responses of the cerebral vessels to hypercapnia 10,11,21 and hypocapnia, 22,23 presumably as a result of increased arteriolar vascular resistance. We hypothesize that hypertension has similar effects on the small vessels in children, resulting in increased cerebrovascular resistance and decreased compliance, thereby explaining the decreased hypercapnic reactivity.…”

Section: Discussionmentioning

confidence: 99%

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Hypertension Impairs Vascular Reactivity in the Pediatric Brain

Wong

Kupferman

Prohovnik

et al. 2011

Stroke

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Background and Purpose-Chronic hypertension impairs cerebrovascular regulation in adults, but its effects on the pediatric population are unknown. The objective of this study was to investigate cerebrovascular abnormalities in hypertensive children and adolescents. Methods-Sixty-four children and adolescents aged 7 to 20 years underwent transcranial Doppler examinations of the middle cerebral artery at the time of rebreathing CO 2 . Time-averaged maximum mean cerebral blood flow velocity and end-tidal CO 2 were used to quantify cerebrovascular reactivity during hypercapnia. Patients were clinically categorized as hypertensive, prehypertensive, or white coat hypertensive based on 24-hour ambulatory blood pressure measurements. Their reactivities were compared with 9 normotensive control subjects and evaluated against baseline mean blood pressure z-scores and loads. Results-Untreated hypertensive children had significantly lower hypercapnic reactivity than normotensive children (2.556Ϯ1.832 cm/s ⅐ mm Hg versus 4.256Ϯ1.334 cm/s ⅐ mm Hg, PϽ0.05). Baseline mean diastolic blood pressure z-scores (rϭϪ0.331, Pϭ0.037) and diastolic blood pressure loads (rϭϪ0.351, Pϭ0.026) were inversely related to reactivity. Conclusions-Untreated hypertensive children and adolescents have blunted reactivity to hypercapnia, indicating deranged vasodilatory reactivity. The inverse relationship between diastolic blood pressure indices and reactivity suggests that diastolic blood pressure may be a better predictor of cerebral end organ damage than systolic blood pressure. (Stroke.

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supporting

confidence: 52%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Hypertension Impairs Vascular Reactivity in the Pediatric Brain

Wong

Kupferman

Prohovnik

et al. 2011

Stroke

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“…17 Another reported complication of hypertension is aberrant autoregulation. Griffith et al 18 studied cerebral blood flow in 10 hypertensive patients during inhalation of 5% carbon dioxide and noted that in five patients blood flow was decreased rather than increased. Meyer et al 19 noted that hypertensive patients with strokes were more likely to show decreased cerebral blood flow on a tilt table than normotensive individuals.…”

Section: Discussionmentioning

confidence: 99%

Occurrence of stroke in a nonhuman primate model of cerebrovascular disease.

Prusty

Kemper

Moss

et al. 1988

Stroke

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A relation between hypertension, atherosclerosis, and stroke is well documented in humans. We report a similar relation in two hypertensive cynomolgus monkeys with severe cerebral atherosclerosis. In our primate model hypertension is induced by surgical coarctation of the aorta. These monkeys, when fed an atherogenic diet, develop severe cerebrovascular atherosclerosis. In this setting two monkeys developed spontaneous cerebral hemispheric strokes that occurred during treatment of hypertension. Since the strokes were topographically related to severe atherosclerotic narrowing of cerebral arteries and occurred without evidence of either thrombosis or embolization, they are presumed to be related to disturbances of blood flow. In both humans and animals cerebral perfusion is autoregulated to a constant flow over a wide range of mean arterial blood pressures. In hypertension both the upper and lower limits of autoregulation are increased. With treatment of hypertension readaptation to more normal levels is reported to be inconsistent and slow to develop. It is therefore postulated that the strokes in these two monkeys were due to hypoperfusion as a result of the combination of pharmacologic reduction in blood pressure and severe occlusive atherosclerosis. 4 reported severe cerebrovascular atherosclerosis when the monkeys were fed an atherogenic diet. We report two cases of spontaneous stroke in this monkey model of cerebrovascular atherosclerosis. These monkeys were part of a group of 16 similarly treated animals on a pharmacologic regimen to reduce elevated blood pressure. Within this group, these two monkeys showed severe cerebrovascular atherosclerosis and the most marked reduction in blood pressure, suggesting that antihypertensive medication played a role in their pathogenesis. Materials and MethodsBoth brains were embedded whole in celloidin and cut in gapless serial sections at a thickness of 35 /im. Every twentieth section was stained with Nissl's stain for tissue reactions and vascular pathology, and the adjacent section was stained with Loyez stain for myelinated fibers. The large arteries at the base of the brain and the extracranial internal carotid arteries were removed at the time of autopsy and visually inspected at a magnification of 2 x for atherosclerotic plaques, thrombi, and emboli. Representative sections from predetermined sites (all areas labeled in Figure 4) and Received January 23, 1987; accepted August 3, 1987. all grossly visible atherosclerotic plaques were embedded in polyethylene glycol with 4-/u.m-thick sections stained with oil red O, Verhoeff-van Gieson's stain, and toluidine blue. Morphometric measurements were performed on the histologic cross sections with a Zeiss MOP III Image Analyzer (Thornwood, New York). Lesion size or intimal area was determined by digitizing the area between the internal elastic membrane and the luminal surface of the artery. The percent stenosis (shown in Figure 4) is the maximum narrowing observed in all arteries showing atherosclerosis and was calcul...

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Management of Hypertension in Patients With Acute Stroke

Lavin¹

1986

Arch Intern Med

100

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Abnormal cerebrovascular regulation in hypertensive patients.

Cited by 6 publications

References 3 publications

Hypertension Impairs Vascular Reactivity in the Pediatric Brain

Hypertension Impairs Vascular Reactivity in the Pediatric Brain

Occurrence of stroke in a nonhuman primate model of cerebrovascular disease.

Management of Hypertension in Patients With Acute Stroke

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