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Introduction: Patients with acute ischemic stroke (AIS) have elevated blood pressure (BP) variability (BPV) and reduced baroreflex sensitivity (BRS) at rest for several days after initial stroke symptoms. We aimed to assess BPV and BRS in AIS patients during pressor challenge maneuvers in the acute and subacute phases of stroke. Pressor challenge maneuvers simulate day-to-day activities and can predict the quality of life., Methods: Continuous beat-to-beat BP and ECG in 15 AIS patients (mean age 69 ± 7.5 years) and 15 healthy controls (57 ± 16 years) were recorded at rest and during a 5-min rapid head positioning (RHP) paradigm. Patients were assessed within 24 h (acute phase) and 7 days (subacute phase) of stroke onset. Low frequency (LF) SBP power (measure of BPV), LF-α, and combined α-index (measure of BRS) were calculated from the recordings., Results: In the acute phase, at rest, LF-SBP power was higher ( P  = 0.024) and α-index was lower ( P  = 0.006) in AIS patients than in healthy controls. There was no change in LF-SBP during RHP in the patients but in healthy controls, it increased significantly ( P  = 0.018). In the subacute phase, at rest, the alpha-index increased ( P  = 0.037) and LF-SBP decreased ( P  = 0.029) significantly in the AIS patients, however, there was still no rise in the LF-SBP power during RHP ( P  = 0.240)., Conclusion: AIS patients have a high resting BPV. High resting BPV may be responsible for blunted BPV responses during pressor challenge maneuvers such as RHP, suggesting ongoing autonomic dysfunction and compromised quality of life., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

(1) Background: Larger blood pressure variability (BPv) in the first 3 h post-stroke onset increases pathophysiological effects such as infarct size, and leads to greater risk of disability, comorbidities and mortality at 90 days. However, there is limited information on the relationship between systemic and cerebral haemodynamic and variability parameters. (2) Objectives: This study determined the effect of a gradual change in head position (GHP) on cerebral blood flow velocity variability (CBFVv) and mean arterial blood pressure variability (MABPv), in healthy controls and acute ischaemic stroke (AIS) patients. Methods: CBFVv and MABPv were expressed as standard deviation (SD) and coefficient of variation. A total of 16 healthy controls (mean age 57 ± 16 years) were assessed over two visits, 12 ± 8 days apart, and 15 AIS patients (mean age 69 ± 8.5 years) were assessed over three visits (V1: 13.3 ± 6.9 h, V2: 4.9 ± 3.2 days and V3: 93.9 ± 11.5 days post-stroke). (3) Results: In response to GHP, MABPv does not initially increase, but over time MABPv showed a significant increase in response to GHP in AIS (visits 2 and 3) and controls (visit 2). Additionally, in response to GHP in AIS, CBFVv increased in the affected hemisphere. Lastly, in AIS, a significant correlation between CBFVv and MABPv, assessed by SD, was seen in the unaffected hemisphere, whereas this relationship was not demonstrated in the affected hemisphere. (4) Conclusions: To our knowledge, this is the first study to analyse the relationship between CBFVv and MABPv. Shedding light on the effect of head position on the relationship between cerebral blood flow and blood pressure is important to improve our understanding of the underlying effects of cerebral autoregulation impairment. This early mechanistic study provides evidence supporting supine head positioning in healthy controls and stroke patients, through demonstration of a reduction of MABPv and increase in CBFVv.

Despite careful patient selection, successful recanalization in intravenous thrombolysis is only achieved in approximately 50% of cases. Understanding changes in cerebral autoregulation during and following successful recanalization in acute ischemic stroke patients who receive intravenous thrombolysis, may inform the management of common physiological perturbations, including blood pressure, in turn reducing the risk of reperfusion injury. Cerebral blood velocity (Transcranial Doppler), blood pressure (Finometer) and end-tidal carbon dioxide (capnography) were continuously recorded in 11 acute ischemic stroke patients who received intravenous thrombolysis (5 female, mean ± SD age 68±12 years) over 4-time points, during and at the following time intervals after intravenous thrombolysis: 23.9±2.6 hrs, 18.1±7.0 days and 89.6±4.2 days. Reductions in blood pressure (p = 0.04) were observed during intravenous thrombolysis. Reductions in heart rate (p<0.005) and critical closing pressure [Affected hemisphere (p = 0.02) and non-affected hemisphere (p<0.005)] were observed post intravenous thrombolysis. End-tidal CO2 increased during the sub-acute and chronic stages (p = 0.028). Reduction in affected hemisphere phase at low frequency was observed during intravenous thrombolysis (p = 0.021) and at subsequent visits (p = 0.048). No changes were observed in cerebral blood velocity, coherence, gain and Autoregulation Index during the follow-up period. Intravenous thrombolysis in acute ischemic stroke patients induced changes in affected hemisphere phase and other key hemodynamic parameters, but not Autoregulation Index. Further investigation of cerebral autoregulation is warranted in a larger acute ischemic stroke cohort to inform its potential role in individualized management plans. [ABSTRACT FROM AUTHOR]

It is unclear whether physiological recordings containing high numbers of ectopic heartbeats can be used to measure the cerebral autoregulation (CA) of blood flow. This study evaluated the utility of such data for assessing dynamic CA capacity. Physiological recordings of cerebral blood flow velocity, heart rate, end-tidal CO2 and beat-to-beat blood pressure from acute ischaemic stroke (AIS) patients (n = 46) containing ectopic heartbeats of varying number (0.2 to 25 occurrences per minute) were analysed. Dynamic CA was determined using the autoregulation index (ARI) and the normalised mean square error (NMSE) was used to evaluate the fitting of the step response between BP and CBFV to Tiecks' model. We fitted linear mixed models on the CA variables incorporating ectopic burden, age, sex and hemisphere as predictor variables. Ectopic activity demonstrated an association with mean coherence (p = 0.006) but not with ARI (p = 0.162), impaired CA based on dichotomised ARI (p = 0.859) or NMSE (p = 0.671). Dynamic CA could be reliably assessed in AIS patients using physiological recordings with high rates of cardiac ectopic activity. This provides supportive data for future studies evaluating CA capability in AIS patients, with the potential to develop more individualised treatment strategies. Graphical Abstract. [ABSTRACT FROM AUTHOR]

The ideal technique for dynamic cerebral autoregulation (dCA) assessment in critically ill patients should provide considerable variability in blood pressure (BP) but without the need for patient cooperation. We proposed using rapid head positioning (RHP) over spontaneous BP fluctuations for dCA assessment in patients with acute ischemic stroke (AIS). Cerebral blood velocity (transcranial Doppler), beat-to-beat BP (Finometer), and end-tidal CO2 (capnography) were recorded during 5-min baseline and RHP in 16 controls (8 women and 8 men, mean age: 57 ± 16 yr) and 15 patients with AIS (7 women and 8 men, mean age: 69 ± 8 yr) at two (12 ± 8 days) and three visits (13.3 ± 6.9 h, 4.8 ± 3.2 days, and 93.9 ± 11.5 days from the symptom onset), respectively. All participants were able to complete the RHP protocol without difficulty. Compared with controls, patients with AIS were hypocapnic (all visits, P < 0.0024) and hypertensive (visit 1, P = 0.011), although BP gradually reduced after the acute phase. RHP demonstrated greater beat-to-beat BP variability (BPV) in controls (visits 1 and 2, P < 0.001) but not in patients with AIS at any visit. Compared with controls, a reduced autoregulation index (ARI) was demonstrated in patients with AIS, at visit 2 for the baseline recording but not at other visits or during RHP. The area under the receiver-operating curve was 0.53 and 0.54 for baseline and RHP, respectively. The RHP paradigm required minimal patient cooperation and could be considered a feasible alternative for assessing dCA, mainly in conditions leading to increased BPV. The lack of BPV increase in AIS with RHP deserves further investigation. [ABSTRACT FROM AUTHOR]

Genome scan in Chinese revealed an association of blood pressure with the microsatellite marker D17S1303, which lies in a quantitative trait locus for the abdominal obesity-metabolic syndrome (AOMS2) at 17p12 on chromosome 17. We previously reported that D17S1303 was associated with hypertension and obesity. Therefore, we studied 10 single nucleotide polymorphisms (SNP) within 3 kb of D17S1303. One hundred and eighty hypertensive subjects (91 men, 89 women, age 53±12 years) and 180 normotensive matched controls (91 men, 89 women, age 52±11) were genotyped using the Sequenom genotyping platform. Allelic frequencies in these Chinese subjects differed from those reported for Caucasians. Three SNPs (rs11656507, rs1357926, rs852319) were homozygous in our subjects. The genotype frequencies of rs852320, rs852321 and rs852322 did not differ between hypertensive and normotensive subjects. However, there were significant differences for rs1525402 (P=0.048), rs2692343 (P=0.022), rs2692344 (P=0.017) and rs2321313 (P=0.028). A four-locus haplotype comprising G at rs1525402, C at rs2692343, C at rs2692344 and G at rs2321313 was associated with lower systolic blood pressure (P=0.023) and normotension (P=0.048). Our results provide further evidence that there is a gene, as yet unidentified, influencing blood pressure in the vicinity of D17S1303 in a quantitative trait locus for abdominal obesity-metabolic syndrome at 17p12.Journal of Human Hypertension (2006) 20, 419–425. doi:10.1038/sj.jhh.1002003; published online 2 March 2006 [ABSTRACT FROM AUTHOR]

It is generally agreed that optimal head positioning is an important consideration in acute stroke management regime. However, there is limited literature investigating the effect of head positioning changes on cerebrovascular physiology in acute ischemic stroke (AIS). We aim to assess cerebral autoregulation (CA) and associated hemodynamic responses during gradual head positioning (GHP) changes, between AIS and controls. Cerebral blood flow velocity (CBFV, transcranial Doppler), blood pressure (BP, Finometer) and end-tidal CO 2 (capnography) were recorded between lying flat (0°) and sitting up (30°) head position, in 16 controls (8 women, mean age 57 ± 16 yrs) and 15 AIS patients (7 women, 69 ± 8 yrs). AIS patients carried out three visits at 13.3 ± 6.9 h, 4.8 ± 3.2 days and 93.9 ± 11.5 days from symptom onset, respectively. AIS patients were significantly hypertensive (p = 0.005), hypocapnic (p < 0.001), and had lower CBFV (p = 0.02) compared to controls, in both head positions. When comparing 5-min FLAT to SIT head position, reductions in BP (both AIS and controls, p < 0.001) and CBFV (controls only: dominant hemisphere p = 0.001 and non-dominant hemisphere p = 0.05) were demonstrated. Of note, a reduction in autoregulation index was observed in AIS, after 5-min SIT head positioning, at all 3 visits (p = 0.018). Conclusion: Key hemodynamic changes were demonstrated when the head position changes from 5-min FLAT to SIT head position (GHP) in mildly affected stroke patients. Importantly, these were associated with non-significant changes in CBFV but reduced measures of CA following AIS, which may be relevant in determining the optimal head position and the ideal timing of mobilisation. Clinical Trial Registration – URL: http://www.clinicaltrials.gov. Unique Identifier: NCT02932540 • There is an ongoing debate regarding the optimal head positioning in ischemic stroke patients • Cerebral hemodynamic was studied in ischemic stroke patients, between lying flat (0°) and sitting up (30°) head position • Reduction in autoregulation index were observed when head position changes from (0°) to (30°) in ischemic stroke patients • Understand cerebral hemodynamics in head positionings may provide optimal mobilisation timing in ischemic stroke patients [ABSTRACT FROM AUTHOR]

(1) Background: Larger blood pressure variability (BPv) in the first 3 h post-stroke onset increases pathophysiological effects such as infarct size, and leads to greater risk of disability, comorbidities and mortality at 90 days. However, there is limited information on the relationship between systemic and cerebral haemodynamic and variability parameters. (2) Objectives: This study determined the effect of a gradual change in head position (GHP) on cerebral blood flow velocity variability (CBFVv) and mean arterial blood pressure variability (MABPv), in healthy controls and acute ischaemic stroke (AIS) patients. Methods: CBFVv and MABPv were expressed as standard deviation (SD) and coefficient of variation. A total of 16 healthy controls (mean age 57 ± 16 years) were assessed over two visits, 12 ± 8 days apart, and 15 AIS patients (mean age 69 ± 8.5 years) were assessed over three visits (V1: 13.3 ± 6.9 h, V2: 4.9 ± 3.2 days and V3: 93.9 ± 11.5 days post-stroke). (3) Results: In response to GHP, MABPv does not initially increase, but over time MABPv showed a significant increase in response to GHP in AIS (visits 2 and 3) and controls (visit 2). Additionally, in response to GHP in AIS, CBFVv increased in the affected hemisphere. Lastly, in AIS, a significant correlation between CBFVv and MABPv, assessed by SD, was seen in the unaffected hemisphere, whereas this relationship was not demonstrated in the affected hemisphere. (4) Conclusions: To our knowledge, this is the first study to analyse the relationship between CBFVv and MABPv. Shedding light on the effect of head position on the relationship between cerebral blood flow and blood pressure is important to improve our understanding of the underlying effects of cerebral autoregulation impairment. This early mechanistic study provides evidence supporting supine head positioning in healthy controls and stroke patients, through demonstration of a reduction of MABPv and increase in CBFVv. [ABSTRACT FROM AUTHOR]