Extracranial & Intracranial
Ischemic stroke is the commonest type of stroke. Many of these patients have underlying stenosis of an extracranial vessel (commonly cervical internal carotid or the vertebral ostium), or stenosis of an intracranial vessel ( petrous/ cavernous/ supraclinoid internal carotid artery or the MCA or distal vertebral or basilar ). The stenosis may cause stroke either due to thromboembolism following plaque destabilization or due to poor flow (hemodynamic).
The indication for stenting the extracranial ICA is if the stenosis is > 50% & symptomatic or >70% and asymptomatic. Intracranial stenting is done if the stenosis is >50% & symptomatic inspite of adequate medical treatment (antiplatelets & statins). Both types of procedures are avoided in patients with a S. Creatinine >2.5 mg% and if the vessels are extremely tortuous.
Stenting of the cervical internal carotid artery is done under cover of a ‘Distal protection device’, which markedly reduces the risk of embolism from the plaque during stent deployement. It is much less invasive than its surgical counterpart (Carotid Endarterectomy), it is done under local anesthesia & there is no risk of infection or cranial nerve palsies as in surgery. In medically high risk patients & in those with contralateral total occlusion, there is no alternative to stenting.
As far as intracranial stenting is concerned, there is no surgical counterpart & Warfarin has been proven to be of no use (in fact riskier) in symptomatic intracranial atherosclerosis.
Both the procedures, although not free of risk are becoming safer & safer with the rapid advances taking place in stent & other hardware technology & increase in experience & expertise as more & more of these procedures are being done.
1) Severe stenosis of Rt. ICA origin stented under cover of a distal protection device. The patient presented with recurrent Rt. MCA territory TIAs inspite of medical treatment.
2) Severe stenosis of Lt. ICA origin stented under cover of a distal protection device. The patient presented with a minor Lt. MCA territory
3) stenting of critical stenosis of the Lt. VA ostium with a hypoplastic Rt. VA. The patient presented with recurrent vertebrobasilar TIAs inspite of medical treatment.
4) Stenting of critical stenosis of Rt. MCA. The patient presented with crescendo TIAs inspite of optimum medical treatment
5) Stenting of severe stenosis of Rt. Supraclinoid ICA. The patient presented with a minor Rt. MCA territory stroke.
6) Stenting of severe mid-Basilar stenosis. The patient presented with recurrent vertebrobasilat TIAs
7) Stenting of Rt. Vertebrobasilar junction. The Lt. vertebral artery was hypoplastic & the patient presented with recurrent vertebrobasilar TIAs