Carotid artery stenting utilizing self-expansion without post-stenting angioplasty in patients at high risk for reperfusion injury (a pilot study of a technical modification)

Carotid artery stenosis accounts for 15–20% of cerebrovascular ischemic strokes. Endovascular carotid artery stenting (CAS) has been recognized as an alternative treatment method for carotid artery stenosis with outcomes similar to carotid endarterectomy (CEA) [ 1 ]. One of the most serious complications after extracranial carotid artery revascularization is cerebral hyperperfusion syndrome (CHS). CHS is defined as an increase in cerebral perfusion of more than 100% compared to base-line values such as the middle cerebral artery (MCA) mean flow volume (MFV), peak systolic velocity (PSV) and velocity index using transcranial color- coded duplex [ 2 , 3 ]. Its incidence ranges from 0.5 to 6.8%. CHS typically presents with migraine like headaches, seizures, and focal deficits. Radiological findings can vary from negative findings to brain edema, subarachnoid hemorrhage and intracerebral hemorrhage. Hyper-perfusion induced cerebral hemorrhage (HICH) has a reported mortality rate of 75%. Several theories have been proposed to explain the pathophysiology of CHS, with the most widely accepted being the derangement of cerebral autoregulation mechanisms in hypo-perfused brains. Risk factors for CHS include hypertension, severe carotid artery stenosis of more than 90%, poor collaterals, presence of contralateral carotid disease and recent cerebrovascular events. Strict blood pressure control is the only proven method to prevent its occurrence [ 4 ]. However, some studies suggest that staged CAS and gentle carotid stenting with intentional residual stenosis can provide preventive benefits by allowing for a gradual restoration of cerebral blood flow [ 5 ]. In this pilot study we hypothesized that by omitting the post stenting angioplasty, the radial force of the stent would allow for gradual restoration of cerebral blood flow and controlled cerebral reperfusion. The Subsequent angiographic assessment after one month determined which candidates required a second-stage angioplasty.