Hemodynamic evaluation of the effect of percutaneous transluminal angioplasty for atherosclerotic disease of the vertebrobasilar arterial system.

The relationship between clinical improvement after percutaneous transluminal angioplasty (PTA) and hemodynamic condition in vertebrobasilar insufficiency was evaluated in 43 patients between 45 and 86 years of age with clinically symptomatic atherosclerotic stenotic lesions in the posterior circulation. The 43 patients had a total of 51 stenotic lesions, including 17 in the first segment of the vertebral artery, 32 in the fourth segment of the vertebral artery, and two in the basilar artery. Angiography was performed and cerebral perfusion was measured with technetium-99m-hexamethyl-propyleneamine oxime single photon emission computed tomography before and after administration of 10 mg/kg acetazolamide prior to and more than 7 months after PTA. Mean stenosis was 81.3 +/- 7.4% before PTA, but only 41.5 +/- 17.4% at follow-up. Eighteen of the 24 patients with improved neurological condition after PTA had subnormal (< mean - 2 SDs) cerebral perfusion before PTA. Twenty of these 24 patients had subnormal vasodilatory response to administration of acetazolamide before PTA. Clinical improvement following PTA was noted in only one of the 12 patients with a single stenotic lesion of the first segment, but in 23 of the 31 patients with intracranial stenotic or multiple stenotic lesions. PTA in the posterior circulation is indicated for patients with atherosclerotic stenotic intracranial lesion or multiple stenotic lesions who have subnormal cerebral perfusion and low vasodilatory response to administration of acetazolamide.