What pre-operative work-up do you follow in your institution prior to EC-IC bypass in patients with a focal intracranial stenosis and patients with MMD?

Great question. There is no standardized workup. You would want to make sure there is impaired flow with poor reserve and signs and symptoms suggestive of ischemia (ischemic stroke or TIA). My practice is to do perfusion pre and post-diamox. The success of revascularization is dependent on demand and thus you would need to make sure the patient has very limited if any cerebrovascular demand. An adjunctive test that can be done is a TCD with CO2 challenge or breath holding if the perfusion results are equivocal. Hope this helps.