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Surgical modulation of the natural course of collateral circulation in chronic ischemic patients
T Yamashita1, S Nakano, H Ishihara
1Department of Neurosurgery, Yamaguchi University School of Medicine, Japan.
Insights
Superficial temporal artery to middle cerebral artery (STA-MCA) bypass effectively improves cerebral hemodynamics in patients with chronic ischemic conditions. This surgical intervention is recommended for individuals with reduced cerebrovascular reactivity (CRC), enhancing blood flow and aiding treatment decisions for cerebral ischemia.
Area of Science:
- Neurology
- Neurosurgery
- Vascular Surgery
Background:
- Chronic cerebral occlusive lesions, such as internal carotid artery (ICA) or middle cerebral artery (MCA) stenosis/occlusion, can lead to significant hemodynamic compromise.
- Assessing baseline cerebral blood flow (CBF) and cerebrovascular reactivity (CRC) is crucial for understanding the severity of ischemic conditions.
- The natural course of compromised hemodynamics in these patients often shows no improvement without intervention.
Purpose of the Study:
- To evaluate hemodynamic compromise, specifically baseline CBF and CRC, in patients with chronic cerebral occlusive lesions.
- To determine the modulatory effect of superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis on these hemodynamic parameters.
- To establish the utility of hemodynamic classification for guiding treatment strategies in cerebral ischemia.
Main Methods:
- Utilized stable xenon-enhanced computed tomographic (CT) CBF measurement combined with an acetazolamide challenge to assess hemodynamics.
- Included 10 healthy volunteers and 49 patients with chronic ischemic conditions affecting the ICA or MCA.
- Monitored hemodynamic parameters in patients before and after a two-month follow-up period, as well as post-STA-MCA bypass.
Main Results:
- Compromised hemodynamics in patients with chronic steno-occlusive lesions did not spontaneously improve within two months.
- STA-MCA bypass significantly modulated hemodynamic compromise in ischemic patients.
- Patients with reduced CRC demonstrated improvement after STA-MCA bypass, irrespective of their baseline CBF levels.
Conclusions:
- STA-MCA bypass is a recommended intervention for patients experiencing reduced CRC, offering a therapeutic option for cerebral ischemia.
- Hemodynamic classification based on combined baseline CBF and CRC values provides a valuable tool for evaluating cerebral hemodynamics.
- This classification aids in selecting the optimal treatment for cerebral ischemia resulting from occlusive lesions.
Abstract:
The purpose of this study was to evaluate hemodynamic compromise in terms of baseline CBF and CRC in patients with chronic cerebral occlusive lesions and its modulation by a superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis. The study subjects were 10 healthy volunteers and 49 chronic ischemic patients with stenosis or occlusion of the internal carotid artery (ICA) or middle cerebral artery (MCA). The hemodynamics were measured using stable xenon enhanced computed tomographic CBF measurement with the acetazolamide challenge. The compromised hemodynamics in patients with chronic steno-occlusive lesions did not improve during their natural course after two months. STA-MCA bypass modulated hemodynamic compromise in the ischemic patients. We recommend STA-MCA bypass for patients with reduced CRC, regardless of whether baseline CBF is reduced or normal. Hemodynamic classification using a combination of baseline CBF values and CRC values is useful for evaluating cerebral hemodynamics and for choosing the best treatment for cerebral ischemia with occlusive lesions.