Abstract WP161: Improvement in Cerebral Hemodynamic Parameters and outcomes after Superficial Temporal Artery- Middle Cerebral Artery Bypass in Patients with Severe Steno-occlusive Disease of Intracranial Carotid and Middle Cerebral Artery

Abstract

Background and Objective —Older as well as the recent extracranial-intracranial (EC/IC) bypass trial in patients with symptomatic carotid occlusion failed to demonstrate reduction in stroke recurrence. However, the role of superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery in patients with symptomatic intracranial steno-occlusive disease has been evaluated scarcely. We evaluated the changes in various hemodynamic parameters in patients with severe steno-occlusive disease of intracranial internal carotid (ICA) or middle cerebral artery (MCA) who underwent STA-MCA bypass surgery for impaired cerebral vasodilatory reserve (CVR). Methods —Patients with severe steno-occlusive disease of intracranial ICA or MCA underwent transcranial Doppler (TCD) ultrasonography and CVR assessment using breath-holding index (BHI). Patients with impaired BHI (<0.69) were further evaluated with acetazolamide-challenged hexamethylpropyleneamine oxime single-photon emission computed tomography (HMPAO-SPECT). STA-MCA bypass surgery was offered to patients with impaired CVR on SPECT. TCD and SPECT were repeated in all patients at 4±1 months and they were followed-up for cerebral ischemic events. Results —112 patients (73males, mean age 56yrs; range 23-78yrs) fulfilled our inclusion criteria. HMPAO-SPECT demonstrated impaired CVR in 77 (69%) patients. Forty-six of them underwent STA-MCA bypass while 31 received best medical treatment. TCD and acetazolamide-challenged HMPAO-SPECT repeated 4±1 months after surgery showed significant improvement in STA-MCA bypass group. During follow-up (mean 24 months; range 4 to 33months), only 6/46 (13%) patients in bypass group developed cerebral ischemic events as compared to14/31 (45%) cases on medical therapy (absolute risk reduction 32%, p=0.008). Conclusion —STA-MCA bypass surgery in carefully selected patients with symptomatic severe intracranial steno-occlusive disease results in significant improvement in hemodynamic parameters and reduction in stroke recurrence