Characterization and Natural History of Patients with Internal Carotid Occlusion: A Comparative Study

To characterize patients with internal carotid occlusion (ICO) with respect to demographic data, associated diseases, medical management, and risk factors and to compare these patients with those with nonsignificant stenosis (NSS; less than 50% stenosis). Secondary end points were new neurologic events, progression of contralateral degree of stenosis, cardiovascular symptoms, and death during follow-up.

Retrospective analysis was performed using data collected from clinical records and added to a prospective database. Missing data were obtained during phone interviews or requested medical appointments.

From 2005 to 2013, 213 patients with ICO and 172 with NSS were studied (medium follow-up 37.81 months). Among the patients with ICO, a greater proportion were men, had a history of smoking, and presented with peripheral arterial disease and a lower creatinine clearance compared with those with NSS (P < 0.05). At the time of diagnosis, 76.1% of the patients with ICO were symptomatic compared with 35.5% of those with NSS (P = 0.000001). The patients in the ICO group exhibited significant progression of contralateral stenosis compared with those in the control group with progression on any side (15.0% vs. 2.3%, P = 0.00011). In addition, 18 patients in the ICO group (8.5%) exhibited new neurological symptoms compared with 13 (7.6%) in the NSS group (P = 0.41). When the ICO and NSS groups were combined, 10.8% of the initially symptomatic patients presented with new symptoms compared with 4.3% of those who were initially asymptomatic (P = 0.0218). The number of deaths was significantly higher among the patients in the ICO group (14.1% vs. 6.4%, P = 0.0150).

Patients presenting with ICO have more risk factors and higher mortality by any cause. Initially, symptomatic patients will likely present with more neurological symptoms during follow-up, independent of carotid morphology, ICO, or NSS. Efforts must be made to identify those at risk before occlusion and to prevent secondary events and death.