Common carotid occlusion. Assessment of the distal vessels.

In patients with common carotid artery (CCA) occlusion, successful vascular reconstruction can be performed if there is a patent internal or external carotid distal to the occlusion. Preoperative selection of suitable candidates is often difficult because of the inability to visualize patent distal vessels with conventional angiography. In reviewing 24 patients operated upon for CCA occlusion since 1962, the distal internal or external carotid arteries were visualized in only four (17%) of the preoperative angiograms. When these 24 patients were explored, the internal carotid was found to be patent in 11 (46%) patients and the external patent in 15 (62%) cases. Of the 15 patients reconstructed, thromboendarterectomy was performed in six and saphenous vein bypass in nine. In the remaining nine patients, exploration revealed both the internal and external carotids to be thrombosed and unsuitable for CCA reconstruction. Recently we have used rapid sequential computerized tomography (RSCT) scanning to aid in the evaluation of the nonvisualized internal carotid artery (ICA). In two patients with CCA occlusion, RSCT correctly diagnosed patency of the ICA although it appeared to be occluded on angiography. Preliminary data suggest that RSCT will permit accurate preoperative selection of those CCA occlusion patients who are suitable surgical candidates and eliminate the need for surgical exploration.