Prevention of Vasospasm with Nimodipine

Vasospasm is a secondary complication of subarachnoid hemorrhage (SAH), occurring 4–14 days after the bleeding [18,42]. Angiographic investigations have revealed the incidence of “angiographic vasospasm” to be 30%–70% [3,14,17,25,35, 36,42]. This correlates well with the blood flow velocity changes in the basal arteries detected by transcranial Doppler sonography (TCD). A velocity increase of more than twice the baseline value as a sign of a marked vessel diameter reduction is found in TCD in about 70% of patients [1,18–20,37]. Angiographic vasospasm and “Doppler sonographic vasospasm” do not correlate with the clinical symptoms. Only 15%–30% [11,12,21,22] of patients with vasospasm after aneurysmal SAH develop a “clinical or symptomatic vasospasm” with transient or permanent delayed ischemic deficits (DIDs).