Abstract 4037: Dynamic Cerebral Autoregulation in Patients with Subarachnoid Hemorrhage and Delayed Cerebral Ischemia

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Varun Reddy ◽  
Fadar Otite ◽  
Ajit Puri ◽  
Amir Zamani ◽  
Jorge Serrador ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebral Ischemia ◽  
Transfer Function ◽  
Flow Velocity ◽  
Cerebral Autoregulation ◽  
Delayed Cerebral Ischemia ◽  
Subsequent Development ◽  
Frequency Range ◽  
The Relationship ◽  
Dynamic Cerebral Autoregulation

Introduction: We have previously shown that early impairments in dynamic cerebral autoregulation are strongly associated with subsequent development of angiographic cerebral vasospasm. While angiographic cerebral vasospasm is associated with delayed cerebral ischemia (DCI), the relationship between cerebral autoregulation and DCI has not been previously investigated. Our study is designed to specifically test the relationship between early changes in dynamic cerebral autoregulation and subsequent development of DCI. Methods: Thirty-nine consecutive patients with acute non-traumatic subarachnoid hemorrhage (SAH) and adequate transcranial Doppler windows, presenting within 24 hours of symptom onset, have been prospectively studied so far. Daily 5-minute measures of continuous beat-to-beat bilateral middle cerebral artery (MCA) flow velocity and mean arterial blood pressure (MAP) recordings were obtained on days 1-10. Transfer function analysis of spontaneous MAP and MCA mean flow velocity (MFV) oscillations were performed in the very low (0.03-0.07 Hz), low (0.07-0.15 Hz), and high (0.15-0.3 Hz) frequency ranges. Non contrast head CTs were reviewed by a neurologist and neuroradiologist blinded to the autoregulatory and angiographic data. Infarctions present within 6 weeks after SAH, which could not be attributed to instrumentation or peri-op strokes, were identified as DCI. Results: Patients with DCI had significantly higher Hunt and Hess (H&H) scores (median=4 vs 3, p<0.0001) compared to those without DCI. There was no difference in MAP (p=0.746), right MCA (p=0.8327)) or left MCA MFV (p=0.4278) between patients with and without DCI across all time points. Patients with DCI had a lower transfer function phase in the very low frequency (autoregulatory frequency) range. Subgroup analysis of patients with H&H scores ≥3 (N=14) showed that those with DCI had significantly lower phases on day 3 compared to those without DCI (-13±80 vs. 63±26, p=0.048). Conclusion: Our preliminary data show that dynamic cerebral autoregulation, as measured by transfer function phase in the autoregulatory frequency range, is significantly impaired in the early days after SAH and that this early impairment is associated with the development of DCI. We are continuing to collect data on additional patients with SAH to confirm our findings in a larger cohort. Impairments in dynamic cerebral in the early days post SAH may be reliable predictors for identifying patients at higher risk of delayed cerebral ischemia.

Changes on Dynamic Cerebral Autoregulation Are Associated with Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage (P06.257)

Neurology ◽  
2012 ◽  
Vol 78 (Meeting Abstracts 1) ◽  
pp. P06.257-P06.257
Author(s):  
S. Ortega-Gutierrez ◽  
N. Petersen ◽  
A. Reccius ◽  
A. Huang ◽  
G. Linares-Tapia ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebral Ischemia ◽  
Cerebral Autoregulation ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Delayed Cerebral Ischemia ◽  
Dynamic Cerebral Autoregulation

scholarly journals Association of transcranial Doppler blood flow velocity slow waves with delayed cerebral ischemia in patients suffering from subarachnoid hemorrhage: a retrospective study

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Vasilios E. Papaioannou ◽  
Karol P. Budohoski ◽  
Michal M. Placek ◽  
Zofia Czosnyka ◽  
Peter Smielewski ◽  
...  
Keyword(s):  
Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Cerebral Ischemia ◽  
Flow Velocity ◽  
Transcranial Doppler ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Delayed Cerebral Ischemia ◽  
Area Under The Curve ◽  
Slow Waves

Abstract Background Cerebral vasospasm (VS) and delayed cerebral ischemia (DCI) constitute major complications following subarachnoid hemorrhage (SAH). A few studies have examined the relationship between different indices of cerebrovascular dynamics with the occurrence of VS. However, their potential association with the development of DCI remains elusive. In this study, we investigated the pattern of changes of different transcranial Doppler (TCD)-derived indices of cerebrovascular dynamics during vasospasm in patients suffering from subarachnoid hemorrhage, dichotomized by the presence of delayed cerebral ischemia. Methods A retrospective analysis was performed using recordings from 32 SAH patients, diagnosed with VS. Patients were divided in two groups, depending on development of DCI. Magnitude of slow waves (SWs) of cerebral blood flow velocity (CBFV) was measured. Cerebral autoregulation was estimated using the moving correlation coefficient Mxa. Cerebral arterial time constant (tau) was expressed as the product of resistance and compliance. Complexity of CBFV was estimated through measurement of sample entropy (SampEn). Results In the whole population (N = 32), magnitude of SWs of ipsilateral to VS side CBFV was higher during vasospasm (4.15 ± 1.55 vs before: 2.86 ± 1.21 cm/s, p < 0.001). Ipsilateral SWs of CBFV before VS had higher magnitude in DCI group (N = 19, p < 0.001) and were strongly predictive of DCI, with area under the curve (AUC) = 0.745 (p = 0.02). Vasospasm caused a non-significant shortening of ipsilateral values of tau and increase in SampEn in all patients related to pre-VS measurements, as well as an insignificant increase of Mxa in DCI related to non-DCI group (N = 13). Conclusions In patients suffering from subarachnoid hemorrhage, TCD-detected VS was associated with higher ipsilateral CBFV SWs, related to pre-VS measurements. Higher CBFV SWs before VS were significantly predictive of delayed cerebral ischemia.

scholarly journals Impairment of Cerebral Autoregulation Predicts Delayed Cerebral Ischemia After Subarachnoid Hemorrhage

Stroke ◽  
2012 ◽  
Vol 43 (12) ◽  
pp. 3230-3237 ◽  
Author(s):  
Karol P. Budohoski ◽  
Marek Czosnyka ◽  
Peter Smielewski ◽  
Magdalena Kasprowicz ◽  
Adel Helmy ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebral Ischemia ◽  
Cerebral Autoregulation ◽  
Delayed Cerebral Ischemia

scholarly journals Dynamic cerebral autoregulation during passive heat stress in humans

2009 ◽  
Vol 296 (5) ◽  
pp. R1598-R1605 ◽  
Author(s):  
David A. Low ◽  
Jonathan E. Wingo ◽  
David M. Keller ◽  
Scott L. Davis ◽  
Jian Cui ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heat Stress ◽  
Transfer Function ◽  
High Frequency ◽  
Cerebral Autoregulation ◽  
Low Frequency ◽  
Passive Heating ◽  
Frequency Range ◽  
Very Low Frequency ◽  
Dynamic Cerebral Autoregulation

This study tested the hypothesis that passive heating impairs cerebral autoregulation. Transfer function analyses of resting arterial blood pressure and middle cerebral artery blood velocity (MCA Vmean), as well as MCA Vmean and blood pressure responses to rapid deflation of previously inflated thigh cuffs, were examined in nine healthy subjects under normothermic and passive heat stress (increase core temperature 1.1 ± 0.2°C, P < 0.001) conditions. Passive heating reduced MCA Vmean [change (Δ) of 8 ± 8 cm/s, P = 0.01], while blood pressure was maintained (Δ −1 ± 4 mmHg, P = 0.36). Coherence was decreased in the very-low-frequency range during heat stress (0.57 ± 0.13 to 0.26 ± 0.10, P = 0.001), but was >0.5 and similar between normothermia and heat stress in the low- (0.07–0.20 Hz, P = 0.40) and high-frequency (0.20–0.35 Hz, P = 0.12) ranges. Transfer gain was reduced during heat stress in the very-low-frequency (0.88 ± 0.38 to 0.59 ± 0.19 cm·s−1·mmHg−1, P = 0.02) range, but was unaffected in the low- and high-frequency ranges. The magnitude of the decrease in blood pressure (normothermia: 20 ± 4 mmHg, heat stress: 19 ± 6 mmHg, P = 0.88) and MCA Vmean (13 ± 4 to 12 ± 6 cm/s, P = 0.59) in response to cuff deflation was not affected by the thermal condition. Similarly, the rate of regulation of cerebrovascular conductance (CBVC) after cuff release (0.44 ± 0.22 to 0.38 ± 0.13 ΔCBVC units/s, P = 0.16) and the time for MCA Vmean to recover to precuff deflation baseline (10.0 ± 7.9 to 8.7 ± 4.9 s, P = 0.77) were not affected by heat stress. Counter to the proposed hypothesis, similar rate of regulation responses suggests that heat stress does not impair the ability to control cerebral perfusion after a rapid reduction in perfusion pressure, while reduced transfer function gain and coherence in the very-low-frequency range during heat stress suggest that dynamic cerebral autoregulation is improved during spontaneous oscillations in blood pressure within this frequency range.

Differential effects of acute hypoxia and high altitude on cerebral blood flow velocity and dynamic cerebral autoregulation: alterations with hyperoxia

2008 ◽  
Vol 104 (2) ◽  
pp. 490-498 ◽  
Author(s):  
Philip N. Ainslie ◽  
Shigehiko Ogoh ◽  
Katie Burgess ◽  
Leo Celi ◽  
Ken McGrattan ◽  
...  
Keyword(s):  
Blood Flow ◽  
Transfer Function ◽  
High Altitude ◽  
Blood Flow Velocity ◽  
Cerebral Autoregulation ◽  
Acute Hypoxia ◽  
Low Frequency ◽  
Frequency Range ◽  
Transfer Function Gain ◽  
Dynamic Cerebral Autoregulation

We hypothesized that 1) acute severe hypoxia, but not hyperoxia, at sea level would impair dynamic cerebral autoregulation (CA); 2) impairment in CA at high altitude (HA) would be partly restored with hyperoxia; and 3) hyperoxia at HA and would have more influence on blood pressure (BP) and less influence on middle cerebral artery blood flow velocity (MCAv). In healthy volunteers, BP and MCAv were measured continuously during normoxia and in acute hypoxia (inspired O2 fraction = 0.12 and 0.10, respectively; n = 10) or hyperoxia (inspired O2 fraction, 1.0; n = 12). Dynamic CA was assessed using transfer-function gain, phase, and coherence between mean BP and MCAv. Arterial blood gases were also obtained. In matched volunteers, the same variables were measured during air breathing and hyperoxia at low altitude (LA; 1,400 m) and after 1–2 days after arrival at HA (∼5,400 m, n = 10). In acute hypoxia and hyperoxia, BP was unchanged whereas it was decreased during hyperoxia at HA (−11 ± 4%; P < 0.05 vs. LA). MCAv was unchanged during acute hypoxia and at HA; however, acute hyperoxia caused MCAv to fall to a greater extent than at HA (−12 ± 3 vs. −5 ± 4%, respectively; P < 0.05). Whereas CA was unchanged in hyperoxia, gain in the low-frequency range was reduced during acute hypoxia, indicating improvement in CA. In contrast, HA was associated with elevations in transfer-function gain in the very low- and low-frequency range, indicating CA impairment; hyperoxia lowered these elevations by ∼50% ( P < 0.05). Findings indicate that hyperoxia at HA can partially improve CA and lower BP, with little effect on MCAv.

scholarly journals Dexmedetomidine Weakens Dynamic Cerebral Autoregulation as Assessed by Transfer Function Analysis and the Thigh Cuff Method

2008 ◽  
Vol 109 (4) ◽  
pp. 642-650 ◽  
Author(s):  
Yojiro Ogawa ◽  
Ken-ichi Iwasaki ◽  
Ken Aoki ◽  
Wakako Kojima ◽  
Jitsu Kato ◽  
...  
Keyword(s):  
Steady State ◽  
Transfer Function ◽  
Arterial Pressure ◽  
Cerebral Autoregulation ◽  
Function Analysis ◽  
Low Frequency ◽  
High Dose ◽  
Frequency Range ◽  
Transfer Function Analysis ◽  
Dynamic Cerebral Autoregulation

Background Dexmedetomidine, which is often used in intensive care units in patients with compromised circulation, might induce further severe decreases in cerebral blood flow (CBF) with temporal decreases in arterial pressure induced by various stimuli if dynamic cerebral autoregulation is not improved. Therefore, the authors hypothesized that dexmedetomidine strengthens dynamic cerebral autoregulation. Methods Fourteen healthy male subjects received placebo, low-dose dexmedetomidine (loading, 3 microg x kg(-1) x h(-1) for 10 min; maintenance, 0.2 microg x kg(-1) x h(-1) for 60 min), and high-dose dexmedetomidine (loading, 6 microg x kg(-1) x h(-1) for 10 min; maintenance, 0.4 microg x kg(-1) x h(-1) for 60 min) infusions in a randomized, double-blind, crossover study. After 70 min of drug administration, dynamic cerebral autoregulation was estimated by transfer function analysis between arterial pressure variability and CBF velocity variability, and the thigh cuff method. Results Compared with placebo, steady state CBF velocity and mean blood pressure significantly decreased during administration of dexmedetomidine. Transfer function gain in the very-low-frequency range increased and phase in the low-frequency range decreased significantly, suggesting alterations in dynamic cerebral autoregulation in lower frequency ranges. Moreover, the dynamic rate of regulation and percentage restoration in CBF velocity significantly decreased when a temporal decrease in arterial pressure was induced by thigh cuff release. Conclusion Contrary to the authors' hypothesis, the current results of two experimental analyses suggest together that dexmedetomidine weakens dynamic cerebral autoregulation and delays restoration in CBF velocity during conditions of decreased steady state CBF velocity. Therefore, dexmedetomidine may lead to further sustained reductions in CBF during temporal decreases in arterial pressure.

scholarly journals Lack of correlation between cerebral vasomotor reactivity and dynamic cerebral autoregulation during stepwise increases in inspired CO2 concentration

2016 ◽  
Vol 120 (12) ◽  
pp. 1434-1441 ◽  
Author(s):  
Sung-Moon Jeong ◽  
Seon-Ok Kim ◽  
Darren S. DeLorey ◽  
Tony G. Babb ◽  
Benjamin D. Levine ◽  
...  
Keyword(s):  
Transfer Function ◽  
Cerebral Autoregulation ◽  
Function Analysis ◽  
Low Frequency ◽  
Frequency Range ◽  
Vasomotor Reactivity ◽  
Arterial Blood ◽  
Transfer Function Analysis ◽  
Cerebral Vasomotor Reactivity ◽  
Dynamic Cerebral Autoregulation

Cerebral vasomotor reactivity (CVMR) and dynamic cerebral autoregulation (CA) are measured extensively in clinical and research studies. However, the relationship between these measurements of cerebrovascular function is not well understood. In this study, we measured changes in cerebral blood flow velocity (CBFV) and arterial blood pressure (BP) in response to stepwise increases in inspired CO2 concentrations of 3 and 6% to assess CVMR and dynamic CA in 13 healthy young adults [2 women, 32 ± 9 (SD) yr]. CVMR was assessed as percentage changes in CBFV (CVMRCBFV) or cerebrovascular conductance index (CVCi, CVMRCVCi) in response to hypercapnia. Dynamic CA was estimated by performing transfer function analysis between spontaneous oscillations in BP and CBFV. Steady-state CBFV and CVCi both increased exponentially during hypercapnia; CVMRCBFV and CVMRCVCi were greater at 6% (3.85 ± 0.90 and 2.45 ± 0.79%/mmHg) than at 3% CO2 (2.09 ± 1.47 and 0.21 ± 1.56%/mmHg, P = 0.009 and 0.005, respectively). Furthermore, CVMRCBFV was greater than CVMRCVCi during either 3 or 6% CO2 ( P = 0.017 and P < 0.001, respectively). Transfer function gain and coherence increased in the very low frequency range (0.02-0.07 Hz), and phase decreased in the low-frequency range (0.07–0.20 Hz) when breathing 6%, but not 3% CO2. There were no correlations between the measurements of CVMR and dynamic CA. These findings demonstrated influences of inspired CO2 concentrations on assessment of CVMR and dynamic CA. The lack of correlation between CVMR and dynamic CA suggests that cerebrovascular responses to changes in arterial CO2 and BP are mediated by distinct regulatory mechanisms.

Abstract TP461: Screening CT Angiography to Identify Patients at Low Risk for Delayed Cerebral Ischemia Following Subarachnoid Hemorrhage

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Andrew Nguyen ◽  
Craig A Williamson ◽  
Aditya S Pandey ◽  
Kyle M Sheehan ◽  
Venkatakrishna Rajajee
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebral Ischemia ◽  
Ct Angiography ◽  
Predictive Value ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Delayed Cerebral Ischemia ◽  
Subsequent Development ◽  
Low Risk ◽  
Eligibility Criteria ◽  
Risk Period

Introduction: Delayed Cerebral Ischemia (DCI) occurs during a risk period of 3-21 days following aneurysmal subarachnoid hemorrhage (aSAH) and is associated with worse outcomes. The identification of patients at low risk for DCI might permit triage to less intense monitoring and management. While large-vessel vasospasm (LVV) is a distinct clinical entity from DCI, the presence of moderate-severe LVV is associated with a higher risk of DCI. Hypothesis: The absence of moderate-severe LVV on screening CT angiography (CTA) performed within the first few days of the DCI risk period will accurately identify patients at low risk for subsequent DCI. Methods: Our institutional SAH outcomes registry was queried for all aSAH patients admitted 2016 - 2019 who underwent CTA brain between days 4-8 following ictus. We excluded patients who suffered DCI prior to this CTA study. All variables are prospectively entered into the registry, and outcomes including DCI and LVV are prospectively adjudicated. We evaluated the accuracy of moderate-severe LVV on CTA performed 4-8 days from ictus for the prediction of subsequent DCI, with a focus on the Negative Predictive Value (NPV). Results: A total of 243 aSAH patients were admitted during the study timeframe and 76 (31%) underwent CTA during the 4-8 day window following ictus. Of these, 22 were excluded for occurrence of DCI prior to the CTA study. Of 54 patients meeting eligibility criteria, 11 (20%) had moderate-severe LVV on the screening CTA study performed during the risk period. Seven of 11 (64%) patients with moderate-severe LVV on the day 4-8 screening CTA, vs 6 of 43 (14%) patients without, subsequently developed DCI. The NPV of CTA performed during days 4-8 for the subsequent development of DCI was 86% (95%CI 77-92%). Sensitivity was 54% (25-81%), Specificity 90% (77-97%) and Positive Predictive Value 64% (38-83%). Conclusions: The NPV of screening CTA performed between days 4-8 following SAH for the subsequent development of DCI was moderate, at 86%. The population studied likely represents a high-risk cohort, however, prospective studies of alternate risk-stratification strategies are necessary.

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