Reliability of cerebral autoregulation using different measures of perfusion pressure in patients with subarachnoid hemorrhage.
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SUBMITTER: Olsen MH
PROVIDER: S-EPMC8958499 | biostudies-literature | 2022 Mar
REPOSITORIES: biostudies-literature
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Reliability of cerebral autoregulation using different measures of perfusion pressure in patients with subarachnoid hemorrhage.
Olsen Markus Harboe MH Capion Tenna T Riberholt Christian Gunge CG Bache Søren S Berg Ronan M G RMG Møller Kirsten K
Physiological reports 20220301 6
Dynamic cerebral autoregulation to spontaneous fluctuations in cerebral perfusion pressure (CPP) is often assessed by transcranial Doppler (TCD) in the time domain, yielding primarily the mean flow index (Mx), or in the frequency domain using transfer function analysis (TFA), yielding gain and phase. For both domains, the measurement of blood pressure is critical. This study assessed the inter-method reliability of dynamic cerebral autoregulation using three different methods of pressure measure ...[more]
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Project description:Background and purposeDCI is a serious complication following aneurysmal SAH and remains a leading cause of morbidity and mortality. Our aim was to evaluate CTP in aneurysmal SAH by using outcome measures of DCI.Materials and methodsThis was a retrospective study of consecutive patients with SAH enrolled in a prospective institutional review board-approved clinical accuracy trial. Qualitative CTP deficits were determined by 2 neuroradiologists blinded to clinical and imaging data. Quantitative CTP was performed by using a standardized protocol with region-of-interest placement sampling of the cortex. Primary outcome measures were permanent neurologic deficits and infarction. The secondary outcome measure was DCI, defined as clinical deterioration. CTP test characteristics (95% CI) were determined for each outcome measure. Statistical significance was calculated by using the Fisher exact and Student t tests. ROC curves were generated to determine accuracy and threshold analysis.ResultsNinety-six patients were included. Permanent neurologic deficits developed in 33% (32/96). CTP deficits were seen in 78% (25/32) of those who developed permanent neurologic deficits and 34% (22/64) of those without (P < .0001). CTP deficits had 78% (61%-89%) sensitivity, 66% (53%-76%) specificity, and 53% (39%-67%) positive and 86% (73%-93%) negative predictive values. Infarction occurred in 18% (17/96). CTP deficits were seen in 88% (15/17) of those who developed infarction and 41% (32/79) of those without (P = .0004). CTP deficits had an 88% (66%-97%) sensitivity, 59% (48%-70%) specificity, and 32% (20%-46%) positive and 96% (86%-99%) negative predictive values. DCI was diagnosed in 50% (48/96). CTP deficits were seen in 81% (39/48) of patients with DCI and in 17% (8/48) of those without (P < .0001). CTP deficits had 81% (68%-90%) sensitivity, 83% (70%-91%) specificity, and 83% (70%-91%) positive and 82% (69%-90%) negative predictive values. Quantitative CTP revealed significantly reduced CBF and prolonged MTT for DCI, permanent neurologic deficits, and infarction. ROC analysis showed that CBF and MTT had the highest accuracy.ConclusionsCTP may add prognostic information regarding DCI and poor outcomes in aneurysmal SAH.
| S-EPMC4004022 | biostudies-literature
Project description:Background: Cerebral perfusion pressure (CPP) is an important target in aneurysmal subarachnoid hemorrhage (aSAH), but it does not take into account autoregulatory disturbances. The pressure reactivity index (PRx) and the CPP with the optimal PRx (CPPopt) are new variables that may capture these pathomechanisms. In this study, we investigated the effect on the outcome of certain combinations of CPP or ΔCPPopt (actual CPP-CPPopt) with the concurrent autoregulatory status (PRx) after aSAH. Methods: This observational study included 432 aSAH patients, treated in the neurointensive care unit, at Uppsala University Hospital, Sweden. Functional outcome (GOS-E) was assessed 1-year postictus. Heatmaps of the percentage of good monitoring time (%GMT) of PRx/CPP and PRx/ΔCPPopt combinations in relation to GOS-E were created to visualize the association between these variables and outcome. Results: In the heatmap of the %GMT of PRx/CPP, the combination of lower CPP with higher PRx values was more strongly associated with lower GOS-E. The tolerance for lower CPP values increased with lower PRx values until a threshold of -0.50. However, for decreasing PRx below -0.50, there was a gradual reduction in the tolerance for lower CPP. In the heatmap of the %GMT of PRx/ΔCPPopt, the combination of negative ΔCPPopt with higher PRx values was strongly associated with lower GOS-E. In particular, negative ΔCPPopt together with PRx above +0.50 correlated with worse outcomes. In addition, there was a transition toward an unfavorable outcome when PRx went below -0.50, particularly if ΔCPPopt was negative. Conclusions: The PRx levels influenced the association between CPP/ΔCPPopt and outcome. Thus, this variable could be used to individualize a safe CPP-/ΔCPPopt-range.
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| S-EPMC3587818 | biostudies-other
Project description:Background and purposeCerebral autoregulation may be impaired in the early days after subarachnoid hemorrhage (SAH). The purpose of this study was to examine the relationship between cerebral autoregulation and angiographic vasospasm (aVSP) and radiographic delayed cerebral ischemia (DCI) in patients with SAH.MethodsSixty-eight patients (54±13 years) with a diagnosis of nontraumatic SAH were studied. Dynamic cerebral autoregulation was assessed using transfer function analysis (phase and gain) of the spontaneous blood pressure and blood flow velocity oscillations on days 2 to 4 post-SAH. aVSP was diagnosed using a 4-vessel conventional angiogram. DCI was diagnosed from CT. Decision tree models were used to identify optimal cut-off points for clinical and physiological predictors of aVSP and DCI. Multivariate logistic regression models were used to develop and validate a risk scoring tool for each outcome.ResultsSixty-two percent of patients developed aVSP, and 19% developed DCI. Patients with aVSP had higher transfer function gain (1.06±0.33 versus 0.89±0.30; P=0.04) and patients with DCI had lower transfer function phase (17.5±39.6 versus 38.3±18.2; P=0.03) compared with those who did not develop either. Multivariable scoring tools using transfer function gain>0.98 and phase<12.5 were strongly predictive of aVSP (92% positive predictive value; 77% negative predictive value; area under the receiver operating characteristic curve, 0.92) and DCI (80% positive predictive value; 91% negative predictive value; area under the curve, 0.94), respectively.ConclusionsDynamic cerebral autoregulation is impaired in the early days after SAH. Including autoregulation as part of the initial clinical and radiographic assessment may enhance our ability to identify patients at a high risk for developing secondary complications after SAH.
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Project description:BackgroundDelayed cerebral ischemia remains one of the principal therapeutic targets after aneurysmal subarachnoid hemorrhage. While large vessel vasospasm may contribute to ischemia, increasing evidence suggests that physiological impairment through disrupted impaired cerebral autoregulation (CA) and spreading depolarizations (SDs) also contribute to delayed cerebral ischemia and poor neurological outcome. This study seeks to explore the intermeasure correlation of different measures of CA, as well as correlation with SD and neurological outcome.MethodsSimultaneous measurement of 7 continuous indices of CA was calculated in 19 subjects entered in a prospective study of SD in aneurysmal subarachnoid hemorrhage undergoing surgical aneurysm clipping. Intermeasure agreement was assessed, and the association of each index with modified Rankin Scale score at 90 days and occurrence of SD was assessed.ResultsThere were 4102 hours of total monitoring time across the 19 subjects. In time-resolved assessment, no CA measures demonstrated significant correlation; however, most demonstrate significant correlation averaged over 1 hour. Pressure reactivity (PRx), oxygen reactivity, and oxygen saturation reactivity were significantly correlated with modified Rankin Scale score at 90 days. PRx and oxygen reactivity also were correlated with the occurrence of SD events. Across multiple CA measure reactivity indices, a threshold between 0.3 and 0.5 was most associated with intervals containing SD.ConclusionsDifferent continuous CA indices do not correlate well with each other on a highly time-resolved basis, so should not be viewed as interchangeable. PRx and oxygen reactivity are the most reliable indices in identifying risk of worse outcome in patients with aneurysmal subarachnoid hemorrhage undergoing surgical treatment. SD occurrence is correlated with impaired CA across multiple CA measurement techniques and may represent the pathological mechanism of delayed cerebral ischemia in patients with impaired CA. Optimization of CA in patients with aneurysmal subarachnoid hemorrhage may lead to decreased incidence of SD and improved neurological outcomes. Future studies are needed to evaluate these hypotheses and approaches.
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