E-042 Does fetal-type posterior communicating artery affects compaction of endovascular coil embolization?

Abstract

Objective The fetal-type posterior cerebral artery (PCA) is a common variant of cerebral circulation and it could be categorized to complete and partial fetal-type PCA according to the communication with posterior circulations. As the amount of the blood flow is proportional to the fourth power of the radius of the vessel, the hemodynamics around an aneurysm from fetal type PCA and normal Posterior communicating artery (PcoA) can be assumed as different nature. Therefore, the recurrence rate of the coiled aneurysm can be affected by the type of the PcoA. Methods From January 2012 to December 2016, 1115 aneurysms were treated with endovascular coil embolization at our institute. There were 107 aneurysms arising from PcoA. Ten cases were excluded as it were re-treatment from previous coiling or clipping, and two cases were excluded due to coexisted arteriovenous malformation and moyamoya disease which can alter the blood flow. And 6 cases were lost during the follow-up. All of the cases were followed up with MRA within 1 day, 6 months, and annually until three years after the coiling. Trans-femoral cerebral angiography was performed in cases of suspicious recurrence or patients with the expectation of high recurrences such as a large aneurysm or low packing densities. The primary endpoint was evidence of recurrence of the coiled aneurysm, and the second endpoint was last angiographic follow-up image. Each patient’s medical records were reviewed and morphologic parameters from cerebral angiography were reviewed. As there could be altered blood flow from posterior circulation, normal PcoA and partial fetal-type PCA can be assumed to have low blood flow and complete fetal-type PCA have high flow. Therefore, correlation of recurrence rate between two groups was also analyzed. Result Among 89 patients, 43 patients had normal PcoA and 46 patients had fetal type PCA. Among the fetal type PCA, 22 cases were complete fetal type PCA and remaining 24 were partial fetal type PCA. The mean diameter of normal PcoA was 0.61 mm whereas fetal type PCA was 1.54 mm. There were total 12 cases of recurrence, 6 cases were from normal PcoA and 3 cases each from complete and partial fetal type PCA. There was no statistical significance between each group in medical history and morphologic parameters except the diameter of PCA. (p=0.015) Analysis of low flow group and high flow group also had no statistical significance. Even packing density did not show any correlation with recurrence of coining. Conclusion Theoretically, there is almost 40 times more blood flow through fetal type PCA than that of normal PcoA, there was no statistical difference among them. Although this phenomenon cannot be explained by the amount of blood flow around the PcoA, we could presume that recurrence of the coiled aneurysm around the PcoA has complexed mechanism. From this result, we suggest that coiling the aneurysm from fetal type PCA should not be considered as high risk for recurrence. Disclosures J. Chung: None. J. Park: None. W. Park: None. J. Ahn: None.