Relationship between haemodynamic impairment and collateral blood flow in carotid artery disease
Nolan S Hartkamp1, Esben T Petersen2,3, Michael A Chappell4,5
11 Department of Radiology, University Medical Center Utrecht, Utrecht, the Netherlands.
Insights
Collateral blood flow in internal carotid artery (ICA) disease impacts brain perfusion. Reduced cerebral blood flow and reactivity occur in symptomatic patients, with collateral flow worsening impairment.
Area of Science:
- Neurology
- Vascular Medicine
- Medical Imaging
Background:
- Collateral blood flow is crucial in steno-occlusive internal carotid artery (ICA) disease to prevent ischemic damage.
- Understanding the impact of collateral circulation on cerebral hemodynamics in ICA disease is essential.
Purpose of the Study:
- To investigate the effect of carotid artery disease on cerebral perfusion and reactivity.
- To determine if collateral blood supply influences hemodynamic impairment at the brain tissue level.
Main Methods:
- MR imaging including time-of-flight, 2D phase contrast MRA, and arterial spin labeling (ASL).
- ASL was used to assess cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) before and after acetazolamide.
- Study included 88 patients with steno-occlusive ICA disease and 29 healthy controls.
Main Results:
- Asymptomatic ICA stenosis patients had normal cerebral hemodynamics.
- ICA occlusion patients showed compromised hemodynamics in both hemispheres.
- Symptomatic patients consistently exhibited hemodynamic impairment.
- Greater collateral blood flow correlated with increased hemodynamic impairment.
- Secondary collateral recruitment occurred only in symptomatic ICA occlusion patients.
Conclusions:
- Symptomatic steno-occlusive ICA disease is associated with reduced CBF and CVR.
- The presence of collateral flow exacerbates hemodynamic impairment.
- Recruitment of secondary collaterals indicates severe hemodynamic compromise.
Abstract:
Collateral blood flow plays a pivotal role in steno-occlusive internal carotid artery (ICA) disease to prevent irreversible ischaemic damage. Our aim was to investigate the effect of carotid artery disease upon cerebral perfusion and cerebrovascular reactivity and whether haemodynamic impairment is influenced at brain tissue level by the existence of primary and/or secondary collateral. Eighty-eight patients with steno-occlusive ICA disease and 29 healthy controls underwent MR examination. The presence of collaterals was determined with time-of-flight, two-dimensional phase contrast MRA and territorial arterial spin labeling (ASL) imaging. Cerebral blood flow and cerebrovascular reactivity were assessed with ASL before and after acetazolamide. Cerebral haemodynamics were normal in asymptomatic ICA stenosis patients, as opposed to patients with ICA occlusion, in whom the haemodynamics in both hemispheres were compromised. Haemodynamic impairment in the affected brain region was always present in symptomatic patients. The degree of collateral blood flow was inversely correlated with haemodynamic impairment. Recruitment of secondary collaterals only occurred in symptomatic ICA occlusion patients. In conclusion, both CBF and cerebrovascular reactivity were found to be reduced in symptomatic patients with steno-occlusive ICA disease. The presence of collateral flow is associated with further haemodynamic impairment. Recruitment of secondary collaterals is associated with severe haemodynamic impairment.
