Emergency Superficial Temporal Artery to Middle Cerebral Artery Bypass after Intravenous Recombinant Tissue Plasminogen Activator Administration for Acute Cerebral Ischemia in a Patient with Moyamoya Disease
A 33-year-old healthy male with no known previous medical history developed right hemiparesis and motor aphasia and was referred to our hospital. The patient's National Institutes of Health Stroke Scale (NIHSS) score was 20 points at the time of admission. A computed tomography (CT) scan was performed immediately and showed no acute lesion. According to the treatment protocol for acute cerebral ischemia, the patient received emergency intravenous rt-PA administration (0.6 mg/kg) by a neurologist at our hospital 2 h and 50 min after the onset of the event. After completion of rt-PA administration, symptoms progressed to complete right hemiplegia. During this treatment, the mean blood pressure was stable at 120–130 mm Hg, oxygen saturation was maintained at >99% by oxygen inhalation (2 l/min), and blood glucose level was stable (109–113 mg/dl). Emergency magnetic resonance imaging (MRI) showed an acute ischemic lesion in the left basal ganglia to corona radiata (fig. ). MR angiography (MRA) showed severe stenosis of the bilateral terminal portion of the internal carotid artery (ICA) and occlusion at the origin of the left MCA (fig. ). Perfusion MRI showed marked prolongation of the mean transit time (MTT) in a broad area of the left MCA territory, including Broca's area, indicating the existence of a large area of hypoperfusion (fig. ). Obvious diffusion-perfusion mismatch was detected. Blood pressure values measured just before and after MRI were 129 and 144 mm Hg, respectively.\nThe patient was referred to our department for consideration of endovascular revascularization. We performed digital subtraction angiography, which showed mild stenosis of the terminal portion of the right ICA, severe stenosis of the A1 portion of the right anterior cerebral artery, and severe stenosis of the terminal portion of the left ICA and M1 portion of the left MCA, with poor peripheral circulation when compared with the right (fig. ). Based on these data, acute cerebral ischemia induced by moyamoya disease or moyamoya-like angiopathy was diagnosed, because the patient had no remarkable past medical history or risk factors for arteriosclerosis. We first considered emergency endovascular revascularization because of clinical progression despite best medical treatment, but in a second stage, we considered the STA-MCA bypass was a better option than endovascular ballooning or stenting for this case on the premise of underlying moyamoya disease and progressive angiopathy. Since the patient showed no significant improvement during the examination, we finally decided to perform emergency STA-MCA bypass to prevent further progression of cerebral ischemia.\nDetailed informed consent was obtained from the patient's family, and the operation began 7 h after the administration of rt-PA. A successful single bypass using the parietal branch of the STA with a small craniotomy was achieved, as demonstrated by intraoperative indocyanine green videoangiography (data not shown). Revascularization was accomplished 9.5 h after the administration of rt-PA. Symptoms stabilized and subsequently improved postoperatively. The free radical scavenger edaravone (60 mg/day) [] was given postoperatively to minimize ischemic damage. Follow-up CT was performed on postoperative day 2 and confirmed the patency of the bypass, absence of postoperative hemorrhage, and no apparent progression of infarction. The phosphodiesterase inhibitor and antiplatelet and vasodilating agent cilostazol (200 mg/day) [] was started by oral administration on postoperative day 2 to improve peripheral cerebral blood flow and to reduce edema formation. MRI was performed on postoperative day 4 and confirmed the patency of the bypass with persistent stenosis of the terminal portion of bilateral ICA (fig. ) and new small lesions when compared with those seen on preoperative diffusion-weighted imaging (DWI) (fig. ). Perfusion MRI showed complete recovery of MTT in the left cerebral hemisphere (fig. ). Most areas of preoperative hypoperfusion seen after rt-PA administration were rescued by the emergency operation and additional medical treatment. Blood pressure values measured just before and after MRI were 113 and 108 mm Hg, respectively.\nHyperperfusion syndrome and hemorrhage into an area of ischemia did not occur. Four months after surgery, the patient resumed his previous full-time employment (Department of Statistical Analysis) and continued to take cilostazol (200 mg/day). He remains well at the 1.5-year follow-up visit.