Introduction: Overall risk of ischemic stroke from a chronically occluded internal carotid artery (COICA) is around »7% per year. We propose 1) a radiographic classification of COICA to determine the technical success and safety of endovascular recanalization of symptomatic COICA and 2) assess changes in systemic blood pressure following successful revascularization.
Methods: Radiographic imaging of 100 consecutive subjects with COICA was analyzed. A classification of COICA based on morphology and location of occlusion in addition to presence or absence of reconstitution of the distal ICA was utilized. Sixteen symptomatic COICA in 15 subjects refractory to medical therapy (4/15, 26.7% female) from 2016-17 were included. Carotid occlusion was defined as 100% occlusion of the vessel lumen based on CT or MR angiography and confirmed by digital subtraction angiogram.
Results: Four types (A-D) of radiographic COICA were identified. Type A 29%, Type B 28%, Type C 33%, and Type D 10%. Types A/B were more amenable to safer revascularization than types C/D. Recanalization was successful in 68.75% (11/16 [Type A: 4/4; Type B: 3/3; Type C: 3/4; Type D: 1/5]) of the subjects. Perioperative complications was 4/16, 25%; [0/4 in Type A; 1/3 in type B; 2/4 in type C, and 1/5 in type D]. None of these complications led to permanent morbidity or mortality. Ten of fifteen (62.5%) subjects had improvement in symptoms during 2-6 month follow-up. Eight of ten subjects (80%) with revascularization had significant decrease in systolic blood pressure [SBP) following revascularization [baseline SBP= 141±9 vs. follow-up SBP= 123±8; 95% CI; -25.57 to -10.42; p=0.0001]. The remaining five subjects failing revascularization had no significant change in SBP [Baseline SBP=137±6 vs. follow-up SBP=135±11; 95% CI: -14.92 to 10.9; p=0.73].
Conclusion: This pilot study suggests that our proposed classification of COICA may be a useful guide to determine technical feasibility and safety of revascularization of symptomatic COICA using endovascular techniques. Successful revascularization may lead to significant decrease in SBP post procedure. A phase-2 trial to assess the safety and efficacy of this technique and to validate COICA classification in larger cohort is warranted.