Hyperperfusion syndrome after carotid endarterectomy
Hyperperfusion syndrome after carotid endarterectomy (CEA) or carotid artery stenting (CAS) is a rare complication.
Hyperperfusion occurs in ~7.5% (range 1-14%) of patients but only a minority (~1.5%) of patients are symptomatic 1,2, with incidence being reported slightly more after CEA (~2%) than after CAS (~1%) 3.
Presentation is usually within the first week of surgery but has been reported up to a month after surgery 1. Although there is a varied clinical spectrum, common features include 1,4:
- ipsilateral headache
- ipsilateral intracranial hemorrhage and associated focal neurological deficits
The pathophysiological mechanism is unknown but thought to be secondary to increased cerebral blood flow (CBF) from a loss of cerebral autoregulation 1,2. Hyperperfusion is defined as CBF >100% above preoperative baseline but patients have been reported to be symptomatic with increases of 20-40% 1,4.
Features are consistent with cerebral edema and/or intracerebral hemorrhage ipsilateral to the side of the carotid artery procedure 4,7. The cerebral edema is classically of the white matter and is hypodense, diffuse, and may or may not have associated mass effect 4,7. The intracerebral hemorrhages are hyperdense and may either be petechial or large in morphology 4,7.
Characteristic ipsilateral features:
- increased CBF, by definition >100% increase compared with preoperative values 4,8
- increased CBV 8
- shortened MTT 8
- shortened TTP/Tmax 8
MRI demonstrates the same ipsilateral features as CT and often closely resembles PRES 4:
- T1: diffusely hypointense in affected regions 3,4
- T1 C+ (Gd): often no enhancement seen 4, although leptomeningeal enhancement has been reported 3
- T2 / FLAIR: diffusely hyperintense in affected regions 3,4
- DWI: usually normal 4
Regions of hemorrhage have varying MRI signal characteristics depending on age (see aging blood on MRI).
Treatment and prognosis
Management should focus on prevention, with particular attention to blood pressure management 7,9. However, if hyperfusion syndrome does manifest, antihypertensive medications such as labetalol and clonidine have been useful, and anti-epileptic medications may provide symptomatic relief to those with seizures 9.
- 1. Adhiyaman V, Alexander S. Cerebral hyperperfusion syndrome following carotid endarterectomy. QJM. 2007;100 (4): 239-44. doi:10.1093/qjmed/hcm009 - Pubmed citation
- 2. Lieb M, Shah U, Hines GL. Cerebral hyperperfusion syndrome after carotid intervention: a review. Cardiol Rev. 2012;20 (2): 84-9. doi:10.1097/CRD.0b013e318237eef8 - Pubmed citation
- 3. Cho HJ, Kim YJ, Lee JH et-al. Post-carotid stenting reperfusion injury with blood-brain barrier disruption on gadolinium-enhanced FLAIR MRI. BMC Neurol. 2014;14 (1): 178. doi:10.1186/s12883-014-0178-z - Free text at pubmed - Pubmed citation
- 4. Karapanayiotides T, Meuli R, Devuyst G et-al. Postcarotid endarterectomy hyperperfusion or reperfusion syndrome. Stroke. 2004;36 (1): 21-6. doi:10.1161/01.STR.0000149946.86087.e5 - Pubmed citation
- 5. Amon Y. Liu, Huy M. Do, Gregory W. Albers, Jaime R. Lopez, Gary K. Steinberg, Michael P. Marks. Hyperperfusion Syndrome with Hemorrhage after Angioplasty for Middle Cerebral Artery Stenosis. American Journal of Neuroradiology. 22 (8): 1597. Pubmed
- 6. Lin TW, Wang JN, Kan CD. Cerebral Hyperperfusion Syndrome After Surgical Repair of Congenital Supravalvular Aortic Stenosis. The Annals of thoracic surgery. 100 (3): e51-4. doi:10.1016/j.athoracsur.2015.05.046 - Pubmed
- 7. Moulakakis KG, Mylonas SN, Sfyroeras GS, Andrikopoulos V. Hyperperfusion syndrome after carotid revascularization. Journal of vascular surgery. 49 (4): 1060-8. doi:10.1016/j.jvs.2008.11.026 - Pubmed
- 8. Defeng Wang, Fengping Zhu, Ka Ming Fung, Wei Zhu, Yishan Luo, Winnie Chiu Wing Chu, Vincent Chung Tong Mok, Jinsong Wu, Lin Shi, Anil T. Ahuja, Ying Mao. Predicting Cerebral Hyperperfusion Syndrome Following Superficial Temporal Artery to Middle Cerebral Artery Bypass based on Intraoperative Perfusion-Weighted Magnetic Resonance Imaging. Scientific Reports. 5: srep14140. doi:doi:10.1038/srep14140
- 9. Farooq MU, Goshgarian C, Min J, Gorelick PB. Pathophysiology and management of reperfusion injury and hyperperfusion syndrome after carotid endarterectomy and carotid artery stenting. Experimental & translational stroke medicine. 8 (1): 7. doi:10.1186/s13231-016-0021-2 - Pubmed