Ophthalmic Artery Flow Pattern-related Stump Pressure and Ischemic Tolerance during Balloon Test Occlusion of the Internal Carotid Artery

Very few studies have described the blood flow pattern in the ipsilateral ophthalmic artery (OphA) during internal carotid artery (ICA) balloon test occlusion performed to estimate the risk of cerebral ischemia associated with therapeutic ICA sacrifice. This study aimed to investigate the relationship between ipsilateral OphA flow patterns just after ICA temporary occlusion and balloon test occlusion findings. We retrospectively reviewed 32 balloon test occlusion procedures performed at our institution between 2010 and 2019, and analyzed the OphA flow patterns and the conventional balloon test occlusion assessment items: neurological symptoms, stump pressure, stump-pressure ratio, collateral circulations, and venous phase delay. The flow patterns were categorized as type I (retrograde flow reaching the middle cerebral artery [MCA]), type II (retrograde flow to the ICA not reaching the MCA), or type III (no retrograde flow). Tolerance to balloon test occlusion was observed in 4/21 patients (19.0%), 4/6 patients (66.7%), and all five patients with types I, II, and III flows, respectively. The mean pressure ratios during balloon test occlusion in flow types I, II, and III were 35.6% ± 3.5%, 56.4% ± 6.5%, and 69.4% ± 7.1%, respectively (P <0.001). The mean stump pressures in flow types I, II, and III were 36.2 ± 3.6 mmHg, 46.6 ± 6.7 mmHg, and 66.6 ± 7.3 mmHg, respectively (P = 0.003). The mean venous phase delay in flow types I, II, and III were 0.99 ± 0.14 s, 0.25 ± 0.25 s, and 0.0 ± 0.28 s, respectively (P = 0.004). All the above variables showed significant flow-related differences. These results suggest that the OphA flow patterns may provide an additional diagnostic criterion for balloon test occlusion.

Giant serpentine aneurysm of the distal anterior cerebral artery

We report a case of a 38-year-old man with a giant serpentine aneurysm arising from the distal anterior cerebral artery. This aneurysm grew from a fusiform aneurysm to a huge aneurysm within 5 months before manifesting as a mass lesion. The aneurysm was largely filled with thrombus, and 4 distal branches arose from the aneurysm dome. Selective balloon test occlusion of the distal anterior cerebral artery using an intravascular technique was performed to confirm the tolerance of the brain tissue. The balloon test occlusion elicited adequate leptomeningeal collateral circulation and no neurologic symptoms; thus, the aneurysm was treated with trapping and resection. The patient had no ischemic complications after the surgery and returned to his job 1 month later. No ischemia developed in the 2 years after surgery. Selective balloon test occlusion of the distal cerebral artery using an intravascular technique can be a very useful tool in planning the therapeutic strategy for a complicated distal cerebral aneurysm.