How do you medically manage acute basilar artery occlusion in patients with low NIHSS who are not candidates for EVT but at risk for deterioration?  

First, I would consider endovascular therapy even with a low NIHSS, if the patient is otherwise a good candidate. If this were not possible, I would angicoagulate with IV heparin initially, then a DOAC (direct oral anticoagulant).

Heparin without bolus followed by DOAC.