Distribution of intraarterially administered papaverine in endovascular treatment of delayed cerebral vasospasm.

The distribution of selectively administered papaverine was determined in nine patients with delayed cerebral vasospasm in the territories of the anterior (ACA) and/or middle cerebral arteries (MCA) secondary to aneurysmal subarachnoid hemorrhage by simultaneous infusion with technetium-99m-hexamethyl-propyleneamine oxime (99mTc-HMPAO). Four of the nine patients had a ruptured anterior communicating artery aneurysm, four had an internal carotid artery aneurysm, and the remaining one had a MCA aneurysm. Trapping of anterior communicating artery was carried out in one case and clipping of aneurysms in other eight cases. Neurological deterioration with hemiparesis, paraparesis, and/or somnolence appeared between postsurgical Days 8 and 13 due to delayed cerebral vasospasm in all patients. Intraarterial infusion of 40 mg of papaverine containing 37 MBq of 99mTc-HMPAO was performed from the C1 segment in seven of the nine patients and from the C4 segment in the other two patients. 99mTc-HMPAO was distributed in the territories of the ACA and MCA in the two patients who were treated with intraarterial infusion of papaverine from the C4 segment, but was distributed only to the territory of the ACA in four patients who were treated with intraarterial infusion of papaverine from the C1 segment at 1 ml/min. In contrast, 99mTc-HMPAO was distributed in the territories of the ACA and MCA in the three patients who were treated with papaverine from the C1 segment at 2 ml/min, although most 99mTc-HMPAO was distributed in the territory of the ACA. Vasospasm of the ACA can be treated by intraarterial infusion of papaverine from the C1 segment at 1 ml/min when selective catheterization to the ACA is difficult to perform.