Dataset Information

Pulsatile microvascular cerebral blood flow waveforms change with intracranial compliance and age.

ABSTRACT:

Significance

Diffuse correlation spectroscopy (DCS) is an optical method to measure relative changes in cerebral blood flow (rCBF) in the microvasculature. Each heartbeat generates a pulsatile signal with distinct morphological features that we hypothesized to be related to intracranial compliance (ICC).

Aim

We aim to study how three features of the pulsatile rCBF waveforms: the augmentation index (AIx), the pulsatility index, and the area under the curve, change with respect to ICC. We describe ICC as a combination of vascular compliance and extravascular compliance.

Approach

Since patients with Chiari malformations (CM) (n=30) have been shown to have altered extravascular compliance, we compare the morphology of rCBF waveforms in CM patients with age-matched healthy control (n=30).

Results

AIx measured in the supine position was significantly less in patients with CM compared to healthy controls (p<0.05). Since physiologic aging also leads to changes in vessel stiffness and intravascular compliance, we evaluate how the rCBF waveform changes with respect to age and find that the AIx feature was strongly correlated with age (Rhealthy subjects=-0.63, Rpreoperative CM patient=-0.70, and Rpostoperative CM patients=-0.62, p<0.01).

Conclusions

These results suggest that the AIx measured in the cerebral microvasculature using DCS may be correlated to changes in ICC.

SUBMITTER: Kedia N

PROVIDER: S-EPMC10799239 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature

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Publications

Pulsatile microvascular cerebral blood flow waveforms change with intracranial compliance and age.

Kedia Nikita N McDowell Michael M MM Yang Jason J Wu Jingyi J Friedlander Robert M RM Kainerstorfer Jana M JM

Neurophotonics 20240120 1

<h4>Significance</h4>Diffuse correlation spectroscopy (DCS) is an optical method to measure relative changes in cerebral blood flow (rCBF) in the microvasculature. Each heartbeat generates a pulsatile signal with distinct morphological features that we hypothesized to be related to intracranial compliance (ICC).<h4>Aim</h4>We aim to study how three features of the pulsatile rCBF waveforms: the augmentation index (AIx), the pulsatility index, and the area under the curve, change with respect to I ...[more]

PMID: 38250664

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Project description:BACKGROUND:Systemic blood flow in patients on extracorporeal assist devices is frequently not or only minimally pulsatile. Loss of pulsatile brain perfusion, however, has been implicated in neurological complications. Furthermore, the adverse effects of absent pulsatility on the cerebral microcirculation are modulated similarly as CO2 vasoreactivity in resistance vessels. During support with an extracorporeal assist device swings in arterial carbon dioxide partial pressures (PaCO2) that determine cerebral oxygen delivery are not uncommon-especially when CO2 is eliminated by the respirator as well as via the gas exchanger of an extracorporeal membrane oxygenation machine. We, therefore, investigated whether non-pulsatile flow affects cerebrovascular CO2 reactivity (CVR) and regional brain oxygenation (rSO2). METHODS:In this prospective, single-centre case-control trial, we studied 32 patients undergoing elective cardiac surgery. Blood flow velocity in the middle cerebral artery (MCAv) as well as rSO2 was determined during step changes of PaCO2 between 30, 40, and 50 mmHg. Measurements were conducted on cardiopulmonary bypass during non-pulsatile and postoperatively under pulsatile blood flow at comparable test conditions. Corresponding changes of CVR and concomitant rSO2 alterations were determined for each flow mode. Each patient served as her own control. RESULTS:MCAv was generally lower during hypocapnia than during normocapnia and hypercapnia (p < 0.0001). However, the MCAv/PaCO2 slope during non-pulsatile flow was 14.4 cm/s/mmHg [CI 11.8-16.9] and 10.4 cm/s/mmHg [CI 7.9-13.0] after return of pulsatility (p = 0.03). During hypocapnia, non-pulsatile CVR (4.3 ± 1.7%/mmHg) was higher than pulsatile CVR (3.1 ± 1.3%/mmHg, p = 0.01). Independent of the flow mode, we observed a decline in rSO2 during hypocapnia and a corresponding rise during hypercapnia (p < 0.0001). However, the relationship between ΔrSO2 and ΔMCAv was less pronounced during non-pulsatile flow. CONCLUSIONS:Non-pulsatile perfusion is associated with enhanced cerebrovascular CVR resulting in greater relative decreases of cerebral blood flow during hypocapnia. Heterogenic microvascular perfusion may account for the attenuated ΔrSO2/ΔMCAv slope. Potential hazards related to this altered regulation of cerebral perfusion still need to be assessed. TRIAL REGISTRATION:The study was retrospectively registered on October 30, 2018, with Clinical Trial.gov (NCT03732651).

Dataset Information

Pulsatile microvascular cerebral blood flow waveforms change with intracranial compliance and age.

Significance

Aim

Approach

Results

Conclusions

Publications

Pulsatile microvascular cerebral blood flow waveforms change with intracranial compliance and age.

Similar Datasets

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