Revascularization for Symptomatic Occlusion of the Anterior Cerebral Artery Using Superficial Temporal Artery
A 69-year-old man, with hypertension and past history as heavy smoker and chronic alcoholic for 40 years, presented with several episodes of transient weakness involving left lower extremity that lasted for 6 months. Each episode occurred once a week, and lasted approximately for 10-20 seconds. The initial magnetic resonance imaging (MRI) from another hospital revealed multifocal stenosis of cerebral artery including left proximal internal carotid artery (ICA), right proximal external carotid artery (ECA), right middle cerebral artery (MCA) at the M1 segment, and occlusion of right ACA at the A2 segment without any evidence of cerebral infarct in the diffusion weighted imaging. Despite the medical treatment with warfarin for one month, there was an increase in the frequency of transient ischemic attack (TIA) in the left leg. Follow-up MRI revealed acute focal infarct in the right frontal periventricular white matter corresponding to the territory of right ACA (). The rate of occurrence of TIA was once or twice a day despite combined medical treatment with warfarin and aspirin.\nThe patient visited our hospital one month after the first experience of infarct. On presentation, no apparent neurological deficit was found. Cardiac evaluation did not reveal any remarkable findings. Cerebral angiography revealed multifocal atherosclerotic luminal irregularity in both the ICA, especially moderate stenosis of the right supraclinoid ICA segment. Right ACA was occluded at the A2 segment, but collateral flow from right MCA and posterior cerebral artery (PCA) was minimal (). Basal and acetazolamide-stressed brain perfusion single photon emission computerized tomography (SPECT) with 99mTc-hexamethylpropyleneamin oxime was performed to evaluate the patient's hemodynamic status. Brain SPECT showed decreased perfusion and decreased vascular reserve in the right frontal lobe ().\nOral anticoagulant and antiplatelet agent were discontinued 1 week prior to surgery. After 2 months from experience of cerebral infarct, revascularization surgery was performed. After confirmation of sufficient length and integrity of parietal branch of the STA in preoperative ECA angiography, we planned end-to-side anastomosis between ipsilateral STA and distal ACA. Under general anesthesia, curvelinear skin incision was made along the parietal branch of the superficial temporal artery (STA), and then extended to the contralateral frontal just behind the hairline. The parietal branch of the STA were saved and prepared for anastomosis to the distal ACA. The frontal branch of the STA with galeal flap was saved as well during the preparation in case of adverse events, such as graft failure (). The length of parietal branch of the STA was 11 cm from the bifurcation of the STA. After right paramedian craniotomy and opening of the dura, the cortical branches of the right ACA were observed. We chose one of the cortical branches as a recipient artery, in which no flow was detected on the intraoperative Doppler. After confirmation of sufficient length and good pulsation of the parietal branch of the STA, end-to-side anastomosis between STA and ACA was performed (). Anterograde flow from the STA and flow diversion to the recipient artery was confirmed on the intraoperative Doppler.\nThe TIA of the left leg disappeared immediately after surgery. Oral antiplatelet agent (aspirin) was resumed on the first postoperative day with a dose of 100 mg/day. The patient was discharged with no apparent neurological deficit. Six months after the operation, follow-up cerebral angiography showed obvious flow through right STA to the territory of the right ACA and decreased leptomeningeal collateral flow from right PCA (). Brain SPECT revealed improved perfusion and vascular reserve when compared with preoperative imaging (). The patient received follow-up care for 30 months after surgery without occurrence of any remarkable events.