Dynamic cerebral autoregulation assessed by respiratory manoeuvres in non‐insulin‐treated Type 2 diabetes mellitus

Huq, Raqib; Philbey, Charlotte; Mistri, Amit; Panerai, Ronney B.; Robinson, Thompson G.

doi:10.1111/j.1464-5491.2011.03497.x

Cited by 12 publications

(8 citation statements)

References 21 publications

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“…Possible subject classification confounds include the presence of diabetes in four (likely five) OSA patients, as well as the potential for undiagnosed hypertension, with both conditions associated with neural deficits [76], [77] and altered cerebral blood flow regulation in hypertension especially [78]–[80], and to some stimuli in diabetes mellitus type 2 [81]–[83]. The OSA and control groups were not matched for BMI, although the extent to which obesity influences cerebral perfusion is unclear [84].…”

Section: Discussionmentioning

confidence: 99%

Global Brain Blood-Oxygen Level Responses to Autonomic Challenges in Obstructive Sleep Apnea

et al. 2014

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Obstructive sleep apnea (OSA) is accompanied by brain injury, perhaps resulting from apnea-related hypoxia or periods of impaired cerebral perfusion. Perfusion changes can be determined indirectly by evaluation of cerebral blood volume and oxygenation alterations, which can be measured rapidly and non-invasively with the global blood oxygen level dependent (BOLD) signal, a magnetic resonance imaging procedure. We assessed acute BOLD responses in OSA subjects to pressor challenges that elicit cerebral blood flow changes, using a two-group comparative design with healthy subjects as a reference. We separately assessed female and male patterns, since OSA characteristics and brain injury differ between sexes. We studied 94 subjects, 37 with newly-diagnosed, untreated OSA (6 female (age mean ± std: 52.1±8.1 yrs; apnea/hypopnea index [AHI]: 27.7±15.6 events/hr and 31 male 54.3±8.4 yrs; AHI: 37.4±19.6 events/hr), and 20 female (age 50.5±8.1 yrs) and 37 male (age 45.6±9.2 yrs) healthy control subjects. We measured brain BOLD responses every 2 s while subjects underwent cold pressor, hand grip, and Valsalva maneuver challenges. The global BOLD signal rapidly changed after the first 2 s of each challenge, and differed in magnitude between groups to two challenges (cold pressor, hand grip), but not to the Valsalva maneuver (repeated measures ANOVA, p<0.05). OSA females showed greater differences from males in response magnitude and pattern, relative to healthy counterparts. Cold pressor BOLD signal increases (mean ± adjusted standard error) at the 8 s peak were: OSA 0.14±0.08% vs. Control 0.31±0.06%, and hand grip at 6 s were: OSA 0.08±0.03% vs. Control at 0.30±0.02%. These findings, indicative of reduced cerebral blood flow changes to autonomic challenges in OSA, complement earlier reports of altered resting blood flow and reduced cerebral artery responsiveness. Females are more affected than males, an outcome which may contribute to the sex-specific brain injury in the syndrome.

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Section: Discussionmentioning

confidence: 99%

Global Brain Blood-Oxygen Level Responses to Autonomic Challenges in Obstructive Sleep Apnea

et al. 2014

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“…Loss of blood flow regulation occurs in a variety of cerebrovascular conditions, both in acute stroke(25-27), and in chronic cerebrovascular conditions such as small vessel disease(28, 29), metabolic syndrome(30, 31), and high grade carotid artery stenosis(32-34). Poor blood flow is an important predictor of stroke risk.…”

Section: Discussionmentioning

confidence: 99%

Dissociation among hemodynamic measures in asymptomatic high grade carotid artery stenosis

Marshall

Pavol

Cheung

et al. 2016

Journal of the Neurological Sciences

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Background Cerebral blood flow (CBF) regulation is a critical element in cerebrovascular pathophysiology, particularly in large vessel disease, but the best method to use for hemodynamic assessment is not clear. We examined 4 different blood-flow related measures in patients with unilateral high-grade carotid artery disease, assessing asymmetry between the occluded vs non-occluded side, and the correlations among the measures. Methods Thirty-three patients (age 50-93, 19M) with unilateral 80-100% ICA occlusion but no stroke underwent: 1) mean flow velocity (MFV) in both middle cerebral arteries by transcranial Doppler (TCD), 2) quantitative resting CBF using pseudo-continuous arterial spin labeling (pCASL) MRI, 3) Vasomotor reactivity (VMR) in response to 5% CO2 inhalation, and 4) Dynamic cerebral autoregulation (DCA) assessing the counter-regulation of blood flow to spontaneous changes in blood pressure using TCD monitoring and finger photoplethysmography. Paired T-tests and Pearson correlations assessed side-to-side differences within each measure, and correlations between measures. Results CBF (p=.001), MFV (p<.001), VMR (p=.008), and DCA (p=.047) all showed significantly lower values on the occluded side. The 4 measures were independent of each other on correlation analysis, even when controlling for age and anterior circle of Willis collateral (all partial correlations <.233 and p-values >.468). Conclusions These 4 measures showed high sensitivity to the occluded carotid artery, but their dissociation suggests that any given measure only partially characterizes the hemodynamic state. Additional research is needed to explore the multifaceted biology of cerebral blood flow regulation.

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“…Non-pregnant DM2 patients with good glycaemic control and no major complications showed normal autoregulation. 7 Others found affected dynamic autoregulation in DM2 with 6 and without microvascular disease. 5 We did not find evidence suggesting affected dynamic cerebral autoregulation in our group of pregnant women with DM2, but comparison with the aforementioned studies is difficult due to differences in age, disease duration and severity, and gender.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, we cannot exclude the possibility of cerebral blood flow (CBF) changes induced by metabolic activity such as might be present in patients with impaired CO 2 cerebrovascular reactivity. 7 Finally, the women were studied at a wide range of gestational age, but with a comparable median gestational age. The effect of advancing gestational age on ARI is not known; however, we did not find a correlation between gestational age and ARI (data not shown).…”

Section: Discussionmentioning

confidence: 99%

Cerebral autoregulation in pregnancies complicated by diabetes and overweight

Veen

Panerai

Haeri

et al. 2015

Diabetes and Vascular Disease Research

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Aim: The aim of this study was to estimate the impact of diabetes and obesity on cerebral autoregulation in pregnancy. Methods: Cerebral autoregulation was evaluated in women with gestational diabetes, type 2 diabetes mellitus and/or overweight (body mass index ⩾ 25 kg m −2 ) and compared to a cohort of euglycaemic pregnant women. The autoregulation index was calculated using simultaneously recorded cerebral blood flow velocity in the middle cerebral artery and blood pressure. Autoregulation index values of 0 and 9 indicate absent and perfect autoregulation, respectively. Results: Autoregulation index in women with either diabetes (n = 33, 6.6 ± 1.1) or overweight (n = 21, 6.7 ± 0.6) was not significantly different to that in control patients (n = 23, 6.6 ± 0.8, p = 0.96). Conclusion: Cerebral autoregulation is not impaired in pregnant women who have non-vasculopathic diabetes or overweight. This suggests that the increased risk of pre-eclampsia in diabetic and overweight women is not associated with early impaired cerebral autoregulation.

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Dynamic cerebral autoregulation assessed by respiratory manoeuvres in non‐insulin‐treated Type 2 diabetes mellitus

Cited by 12 publications

References 21 publications

Global Brain Blood-Oxygen Level Responses to Autonomic Challenges in Obstructive Sleep Apnea

Global Brain Blood-Oxygen Level Responses to Autonomic Challenges in Obstructive Sleep Apnea

Dissociation among hemodynamic measures in asymptomatic high grade carotid artery stenosis

Cerebral autoregulation in pregnancies complicated by diabetes and overweight

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