[Evidence of Efficacy of Superficial Temporal Artery-Middle Cerebral Artery Bypass in Japan].

The Japanese EC-IC Bypass Trial(JET)Study demonstrated that a superficial temporal artery-middle cerebral artery(STA-MCA)bypass is effective in preventing the recurrence of ischemic stroke in cases of atherosclerotic internal carotid artery or MCA steno-occlusive lesions with symptoms. The JET-2 Study revealed that the hemodynamic criteria for STA-MCA bypass in the JET Study(rest cerebral blood flow < 80% and cerebrovascular reactivity < 10%)were adequate. An STA-MCA bypass was ranked as recommendation B; the level of evidence was moderate under the conditions of quantitative evaluation of cerebral hemodynamics and low frequency of perioperative complications, as described in the Japanese Guidelines for the Management of Stroke 2021. An education system for the accurate assessment of cerebral hemodynamics, meticulous surgical procedures, and perioperative management for STA-MCA bypass is necessary to hand over evidence of STA-MCA bypass efficacy in Japan to future generations. Simultaneously, new evidence of STA-MCA bypass efficacy should be explored with the advancement of medicine and should be disseminated worldwide.