Abstract Body: Objective:
Iatrogenic vessel dissection (IVD) is an infrequent complication of neuroendovascular therapy. However, differences in risk among disease, patient characteristics, procedures, or treatment conditions remain unclear, and the effect of IVD on patient outcomes is yet to be determined.

Methods:
The Japanese Registry of Neuroendovascular Therapy (JR-NET) 4 database comprises interventional neuroradiology procedures conducted in Japan between 2015 and 2019. We present a retrospective analysis utilizing JR-NET 4 to verify the factors associated with IVD and evaluate their impact on outcomes. There were eight treatment interventions in which IVD cases could be detected and analyzed. We compared the patients’ baseline characteristics, including age, sex, and pre-treatment modified Rankin Scale (mRS), as well as treatment environments such as etiology, anesthesia methods, and detailed therapeutic approaches, between the groups with and without IVD complications. Furthermore, we examined the 30-day mRS of the two groups.

Results:
The total number of treatments used in the analysis was 54,297. The incidence of IVD in all endovascular treatment was 0.64%. The treatments with significantly higher rates of IVD were intracranial percutaneous transluminal angioplasty with or without stenting (PTA/PTAS) (3.2%) , extracranial PTA/PTAS (1.5%), and endovascular treatment for acute ischemic stroke (0.92%). Although the most frequently registered treatment was for cerebral aneurysms (22,406 cases) with an incidence rate of 0.45% for IVD, treatments under local anesthesia with sedation and treatments of flow diverters showed a significantly higher incidence of IVD (p<0.001, p=0.013). Clinical outcome across all treatments, the proportion of patients with modified Rankin Scale (mRS) 5-6 was significantly higher in the IVD group. IVD on aneurysm treatment was associated with mRS 5-6 outcome at 30days: odds ratio=2.9 (95% CI, 1.18-6.43); p=0.013, whereas carotid artery stenting was not: odds ratio=3.97 (95% CI, 0.60-15.3); p=0.079.

Conclusion:
This analysis showed that the incidence of IVD varies depending on the treatment, and that the impact on prognosis also varies.