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Decrease in pulsatile flow in the anterior cerebral arteries in infantile hydrocephalus
Insights
Ventriculomegaly, not just intracranial pressure, significantly impairs cerebral artery blood flow in infants with hydrocephalus. This pulsatility index (PI) can help monitor brain injury risk.
Area of Science:
- Pediatric Neurology
- Neurocritical Care
- Cerebrovascular Physiology
Background:
- Hydrocephalus in infants, often caused by intraventricular hemorrhage, can lead to increased intracranial pressure (ICP) and affect cerebral blood flow.
- Ventriculomegaly, the enlargement of brain ventricles, is a key feature of hydrocephalus and its impact on cerebral hemodynamics requires further investigation.
Purpose of the Study:
- To investigate the effect of ventriculomegaly and elevated intracranial pressure (ICP) on pulsatile flow in the anterior cerebral artery (ACA) in infants with hydrocephalus.
- To determine if the pulsatility index (PI) can serve as a sensitive indicator of compromised cerebral blood flow and potential brain injury.
Main Methods:
- A noninvasive Doppler technique was used to assess pulsatile flow in the ACA of 11 infants diagnosed with hydrocephalus.
- The pulsatility index (PI), calculated from systolic and diastolic flow amplitudes, was measured and correlated with the degree of ventriculomegaly and ICP levels.
Main Results:
- All 11 infants exhibited elevated PI, indicating impaired pulsatile flow, and all had significant ventriculomegaly.
- Elevated ICP was present in most patients, but two with ventriculomegaly and normal ICP also showed elevated PI, suggesting ventriculomegaly is a critical factor.
- Treatment of ventriculomegaly led to a decrease in PI, while untreated patients had poor outcomes, including mortality.
Conclusions:
- Ventriculomegaly, more so than elevated ICP, appears to be a critical determinant of impaired pulsatile flow in the ACA in infants with hydrocephalus.
- The pulsatility index (PI) may be a valuable, noninvasive parameter for monitoring cerebral hemodynamic changes, predicting ischemic injury, and guiding intervention timing in pediatric hydrocephalus.
Abstract:
The effect of ventriculomegaly with or without elevated intracranial pressure (ICP) on pulsatile flow in the anterior cerebral artery has been studied by a noninvasive Doppler technique in 11 infants with hydrocephalus. The cause of hydrocephalus was intraventricular hemorrhage in nine infants, Arnold-Chiari malformation in one, and bacterial meningitis in one. The pulsatility index (PI) (inversely related to pulsatile flow) was calculated from the systolic and diastolic amplitudes of flow in the anterior cerebral artery. All 11 patients with elevated PI had marked ventriculomegaly, and all but two had raised ICP. Four patients with massive ventriculomegaly and elevated ICP had maximal PI (ie, 1.00). The finding of elevated PI with ventriculomegaly and normal ICP, observed in two patients, suggested that ventriculomegaly is a more critical factor than ICP in the pathogenesis of the impaired flow. Treatment of ventriculomegaly in seven patients resulted in a decrease in PI. Of the four untreated patients, three died and one was not available for further study. Compromised flow in the anterior cerebral artery may be a sensitive barometer of impending ischemic injury with evolving ventriculomegaly, particularly following intraventricular hemorrhage. The PI may be a valuable parameter for the study of the mechanism of brain injury and for determination of optimal timing of corrective intervention.