Subarachnoid hemorrhage with hyperdensity in basal cisterns

A 46-year-old woman with a history of smoking, poorly controlled hypertension, and family history of intracranial aneurysm presents to the emergency department with sudden-onset severe occipital headache described as "the worst headache of her life," accompanied by brief loss of consciousness, photophobia, and nuchal rigidity. Blood pressure is 198/112 mmHg. Non-contrast CT brain performed within 6 hours shows the pattern marked **A** in the diagram. CT angiography reveals a 7 mm saccular aneurysm at the anterior communicating artery. Which of the following is the most appropriate immediate management strategy for this patient?