Bilateral brachial artery occlusion decreases internal carotid artery volume flow: a simple adjunct for cerebral protection?

Cerebral protection during retrograde brachiocephalic artery stenting using a single filter and increased subclavian steal phenomenon: illustrative case

BACKGROUND

Cerebral protection during brachiocephalic artery (BCA) stenting is important. However, the maneuver is sometimes challenging because both the internal carotid artery (ICA) and vertebral artery (VA) should be protected. Herein, the authors present an alternative cerebral protection technique involving filter protection for the ICA and hemodynamic protection for the VA during retrograde BCA stenting.

OBSERVATIONS

A 64-year-old man with a thoracic aortic aneurysm presented with cold sensation and numbness in his right arm due to BCA stenosis. Endovascular stenting under cerebral protection was planned. Cerebral protection was attempted through the brachial access. Despite the successful placement of the filter in the ICA, selective catheterization of the VA failed. Furthermore, repeated transfemoral catheterization of the BCA was unsuccessful. Concerning a thoracic aortic aneurysm injury, the authors performed retrograde BCA stenting using a transbrachial approach. Hemodynamic protection of the VA was provided by increasing the subclavian steal phenomenon that resulted in successful recanalization of the BCA.

LESSONS

Retrograde BCA stenting performed while protecting the ICA with a filter and the right VA by increasing the subclavian steal phenomenon was successful. This simple technique is feasible, especially in patients with steno-occlusive lesions of the BCA concurrent with the dominant vertebra/vertebral collateral pathway.

Cerebral venous steal equation for intracranial segmental perfusion pressure predicts and quantifies reversible intracranial to extracranial flow diversion

Cerebral perfusion is determined by segmental perfusion pressure for the intracranial compartment (SPP), which is lower than cerebral perfusion pressure (CPP) because of extracranial stenosis. We used the Thevenin model of Starling resistors to represent the intra-extra-cranial compartments, with outflow pressures ICP and Pe, to express SPP = Pd–ICP = FFR*CPP–Ge(1 − FFR)(ICP–Pe). Here Pd is intracranial inflow pressure in the circle of Willis, ICP—intracranial pressure; FFR = Pd/Pa is fractional flow reserve (Pd scaled to the systemic pressure Pa), Ge—relative extracranial conductance. The second term (cerebral venous steal) decreases SPP when FFR < 1 and ICP > Pe. We verified the SPP equation in a bench of fluid flow through the collapsible tubes. We estimated Pd, measuring pressure in the intra-extracranial collateral (supraorbital artery) in a volunteer. To manipulate extracranial outflow pressure Pe, we inflated the infraorbital cuff, which led to the Pd increase and directional Doppler flow signal reversal in the supraorbital artery. SPP equation accounts for the hemodynamic effect of inflow stenosis and intra-extracranial flow diversion, and is a more precise perfusion pressure target than CPP for the intracranial compartment. Manipulation of intra-extracranial pressure gradient ICP–Pe can augment intracranial inflow pressure (Pd) and reverse intra-extracranial steal.

Percutaneous and open retrograde endovascular stenting of symptomatic high-grade innominate artery stenosis: technique and follow-up

BACKGROUND AND PURPOSE

Angioplasty and stenting of the IA have been reported with high technical and clinical success rates, low complication rates and good mid-term patency rates. Different antegrade or retrograde endovascular catheter-based approaches and combinations with surgical exposure of the CCA are used. The purpose of this study was to determine safety, efficacy and mid-term clinical and radiological outcome of the stent-assisted treatment of atherosclerotic stenotic disease of the IA with special focus on the different technical approaches.

MATERIALS AND METHODS

Between 1996 and 2008, 18 patients (12 men, 6 women) with symptomatic high-grade stenosis (>80%) of the IA were treated with endovascular stent placement. Their mean age was 60.4 years (range, 48-78 years). Mean angiographic and clinical follow-up was 2.7 years (range, 0.3-9.1 years). Clinical follow-up was performed by using the mRS at hospital discharge, routine follow-up controls, and a questionnaire. In 11 patients, a percutaneous approach was used. In 7 patients, the lesions were accessed retrogradely through a cervical cut-down with common carotid arteriotomy. In 2 patients, a simultaneous ipsilateral carotid endarterectomy was performed.

RESULTS

In all patients, primary stent placement was performed. There were 2 procedure-related transient complications (11.1%) due to cerebral embolism without permanent morbidity or mortality. During the follow-up, all patients showed improvement of the preprocedural symptoms. At the latest clinical follow-up (mean, 2.7 years), all patients showed an excellent or good outcome (mRS, 0 or 1). In 2 patients (11.1%), a secondary stent placement was needed due to a significant symptomatic in-stent stenosis.

CONCLUSIONS

Percutaneous and open retrograde stenting of high-grade stenosis of the IA is a viable less invasive alternatives to open bypass surgery with good midterm clinical results and patency rates.