Cerebrovascular Pressure Reactivity According to Long-Pressure Reactivity Index During Spreading Depolarizations in Aneurysmal Subarachnoid Hemorrhage

Abstract

Background Spreading depolarization (SD) has been linked to the impairment of neurovascular coupling. However, the association between SD occurrence and cerebrovascular pressure reactivity as a surrogate of cerebral autoregulation (CA) remains unclear. Therefore, we analyzed CA using the long-pressure reactivity index (L-PRx) during SDs in patients with aneurysmal subarachnoid hemorrhage (aSAH). Methods A retrospective study of patients with aSAH who were recruited at two centers, Heidelberg (HD) and Berlin (BE), was performed. Continuous monitoring of mean arterial pressure (MAP) and intracranial pressure (ICP) was recorded. ICP was measured using an intraparenchymal probe in HD patients and was measure in BE patients through external ventricular drainage. Electrocorticographic (ECoG) activity was continuously recorded between 3 and 13 days after hemorrhage. Autoregulation according to L-PRx was calculated as a moving linear Pearson’s correlation of 20-min averages of MAP and ICP. For every identified SD, 60-min intervals of L-PRx were averaged, plotted, and analyzed depending on SD occurrence. Random L-PRx recording periods without SDs served as the control. Results A total of 19 patients (HD n = 14, BE n = 5, mean age 50.4 years, 9 female patients) were monitored for a mean duration of 230.4 h (range 96–360, STD ± 69.6 h), during which ECoG recordings revealed a total number of 277 SDs. Of these, 184 represented a single SD, and 93 SDs presented in clusters. In HD patients, mean L-PRx values were 0.12 (95% confidence interval [CI] 0.11–0.13) during SDs and 0.07 (95% CI 0.06–0.08) during control periods (p < 0.001). Similarly, in BE patients, a higher L-PRx value of 0.11 (95% CI 0.11–0.12) was detected during SDs than that during control periods (0.08, 95% CI 0.07–0.09; p < 0.001). In a more detailed analysis, CA changes registered through an intraparenchymal probe (HD patients) revealed that clustered SD periods were characterized by signs of more severely impaired CA (L-PRx during SD in clusters: 0.23 [95% CI 0.20–0.25]; single SD: 0.09 [95% CI 0.08–0.10]; control periods: 0.07 [95% CI 0.06–0.08]; p < 0.001). This group also showed significant increases in ICP during SDs in clusters compared with single SD and control periods. Conclusions Neuromonitoring for simultaneous assessment of cerebrovascular pressure reactivity using 20-min averages of MAP and ICP measured by L-PRx during SD events is feasible. SD occurrence was associated with significant increases in L-PRx values indicative of CA disturbances. An impaired CA was found during SD in clusters when using an intraparenchymal probe. This preliminary study validates the use of cerebrovascular reactivity indices to evaluate CA disturbances during SDs. Our results warrant further investigation in larger prospective patient cohorts.

Oxygen-based autoregulation indices associated with clinical outcomes and spreading depolarization in aSAH

“…Both tended to decrease prior to SD and generally tended to increase after SD with significant positive slopes for both sources. These PRx trends indicate variability in relationship to SD however could be consistent with the previous associations of SD leading to worsening PRx 10 . Since PRx was not consistently associated with outcome, it seems that the association between ORx and OSRx with SD may be more clinically relevant.…”

“…Previous data on the relationship between SD and autoregulation was summarized in a recent comprehensive review 16 . In addition to the associations of ORx and OSRx that we previously reported 7 , another group found associations between SD and impaired autoregulation as measured by the PRx 10 , hypothesizing that SD may in fact be the source of impaired autoregulation. Interestingly, these findings were different depending on whether a parenchymal or ventricular source of ICP monitoring was used.…”

“…Evolving understanding of the mechanisms of DCI have opened new physiologically based therapeutic approaches to prevent and treat this problem. Two of the most relevant of these include the role of impaired autoregulation [2][3][4][5][6][7][8][9] and occurrence of spreading depolarization (SD) events 7,[10][11][12][13] .…”

Multimodal monitoring: practical recommendations (dos and don'ts) in challenging situations and uncertainty

“…Prx/L-Prx is a strong indicator of outcome in neurological injuries such as TBI, SAH, etc. ( 86 , 87 ). It can also be correlated with the non-invasive transcranial Doppler mean flow index ( 88 ) and the near-infrared spectroscopy hemoglobin volume index (HVx) ( 89 ).…”

Oxygen-based autoregulation indices associated with clinical outcomes and spreading depolarization in aSAH

“…Evolving understanding of the mechanisms of DCI have opened new physiologically based therapeutic approaches to prevent and treat this problem. Two of the most relevant of these include the role of impaired autoregulation [2][3][4][5][6][7][8][9] and occurrence of spreading depolarization (SD) events 7,[10][11][12][13] .…”