Intracranial Vertebral Artery Dissecting Aneurysms:Morphological Characteristics And Endovascular Treatment

Intracranial vertebral artery dissections are the most common intracranial artery dissections.Their clinical manifestations include posterior circulation ischemia,subarachnoid hemorrhage,and posterior fossa mass effect.Intracranial vertebral artery dissecting aneurysms(IVADAs)are intracranial vertebral artery dissections with fusiform or saccular aneurysmal dilatation,which are an important cause of posterior circulation ischemia and subarachnoid hemorrhage in young and middle-aged patients.Morphological characteristics can be associated with stability and treatment outcomes of IVADAs.However,studies about morphological characteristics or treatment outcomes of IVADAs are limited.Further investigation is needed to guide clinical practice.With progress in the development of devices and technologies for endovascular treatment,the outcome of IVADAs has improved substantially in recent years.However,the effectiveness and safety of endovascular treatment of IVADAs still need to be further evaluated.This study evaluated the morphological characteristics and effectiveness and safety of endovascular treatment of IVADAs in three parts.Part 1 Morphological characteristics associated with ruptured IVADAsBackground and Objective: Morphological risk factors for the rupture of IVADAs have not been well characterized.In this study,we aim to identify morphological characteristics associated with IVADA rupture.Methods: We conducted a retrospective study of 249 consecutive patients with single IVADAs(31 ruptured and 218 unruptured)admitted to Beijing Tiantan Hospital between January 2016 and December 2020.Various morphological parameters were measured using three-dimensional digital subtraction angiography images.Univariate and multivariate logistic regression analyses were performed to identify morphological characteristics associated with IVADA rupture.Results: Univariate regression analysis revealed that the coexistence of significant proximal and distal stenosis and posterior inferior cerebellar artery(PICA)involvement were associated with IVADA rupture,while the origin from the dominant vertebral artery was inversely associated with the rupture.Multivariate regression analysis demonstrated that the coexistence of significant proximal and distal stenosis(odds ratio [OR] 22.00,95% confidence interval [CI] 5.60–86.70,p<0.001)and PICA involvement(OR 4.55,95% CI 1.36–15.20,p=0.014)were independently associated with IVADA rupture.Conclusion: The coexistence of significant proximal and distal stenosis and PICA involvement were independently associated with IVADA rupture.These morphological characteristics may facilitate the assessment of rupture risk in patients with IVADAs.Part 2 Periprocedural cerebrovascular complications and 30-day outcomes of endovascular treatment for IVADAsBackground and Objective: The authors undertook an evaluation of periprocedural cerebrovascular complications and 30-day outcomes of endovascular treatment for IVADAs and assessed the relevant risk factors.Methods: The authors included a series of 195 patients who had undergone endovascular treatment for 198 IVADAs at Beijing Tiantan Hospital between January 2016 and December 2020.Clinical data,morphological characteristics,treatment details,and periprocedural cerebrovascular complications including intraprocedural rupture,intraprocedural thrombosis,intracranial hemorrhage(ICH),transient ischemic attack(TIA),and ischemic stroke(IS)were recorded.After evaluation of the 30-day modified Rankin Scale(m RS)scores,the authors applied univariate and multivariate logistic regression analyses to identify the risk factors for complications and 30-day unfavorable clinical outcomes.Results: There were no intraprocedural ruptures,but the authors recorded intraprocedural thrombosis(n=5),ICH(n=3),TIA(n=1),and IS(n=13),comprising an 11.1%(22/198)complication rate.Multivariate logistic regression analysis indicated that hyperlipidemia(OR 3.17,95% CI 1.20–8.41,p=0.020),IS history(OR 5.55,95% CI1.46–21.01,p=0.012),and subarachnoid hemorrhage(OR 4.48,95% CI1.52–13.20,p=0.007)were risk factors for overall complications,whereas aneurysmal height(OR 0.77,95% CI 0.61–0.98,p=0.032)was a protective factor.IS history(OR 4.69,95% CI 1.21–18.12,p=0.025)and subarachnoid hemorrhage(OR 6.91,95% CI 2.38–20.11,p<0.001)were also independent risk factors for thromboembolic complications.Subarachnoid hemorrhage(OR 6.44,95% CI 1.54–26.89,p=0.011)and pre-procedural m RS score > 2(OR 5.07,95% CI 1.01–25.59,p=0.049)were independent risk factors for perforator occlusion stroke.Periprocedural cerebrovascular complications(OR 32.09,95% CI3.00–343.94,p=0.004)and preprocedural m RS score > 2(OR 319.92,95% CI 30.28–3379.98,p<0.001)were independent risk factors for30-day unfavorable clinical outcomes.Conclusion: Hyperlipidemia,IS history,and subarachnoid hemorrhage were independent predictors for overall periprocedural cerebrovascular complications of endovascular treatment for IVADAs,but aneurysmal height was an independent protective factor.IS history and subarachnoid hemorrhage were also independent risk factors for thromboembolic complications.Subarachnoid hemorrhage and preprocedural m RS score > 2 were independent risk factors for perforator occlusion stroke.Preprocedural m RS score > 2 and periprocedural complications were independent risk factors for 30-day unfavorable clinical outcomes.Part 3 Flow diverters vs stent-assisted coiling in unruptured IVADAsBackground and Objective: Flow diverters(FDs)have been used for endovascular reconstruction of unruptured IVADAs with seemingly more favorable angiographic and neurological outcomes compared to stent-assisted coiling(SAC).However,the benefits of FDs over SAC in unruptured IVADAs need further evaluation.Herein we performed a propensity score-matched analysis to compare the effectiveness and safety of these two kinds of devices in unruptured IVADAs.Methods: This was a propensity score-matched,retrospective cohort study.Consecutive patients with unruptured IVADAs treated with FDs or SAC at Beijing Tiantan Hospital between January 2016 and December 2020 were reviewed.Propensity score matching at 1:1 was based on age,significant stenosis adjacent to aneurysmal dilatation,maximum diameter,and posterior inferior cerebellar artery involvement.Periprocedural cerebrovascular complications and angiographic and clinical outcomes were compared between the two matched groups.Results: A total of 124 unruptured IVADAs of 123 patients(median age: 53 [interquartile range 47 – 59] years;101 men)were included.The FD and SAC groups included 65 and 59 IVADAs,respectively.Propensity score matching resulted in 47 matched pairs.The rates of immediate complete occlusion were significantly lower in the matched FD group than in the matched SAC group(6.4% vs 68.1%,p<0.001).The rates of periprocedural cerebrovascular complications were comparable in the two matched groups(6.4% vs 6.4%,p>0.99).At the last follow-up,the rates of complete occlusion(89.4% vs 80.9%,p=0.388)and favorable clinical outcomes(100.0% vs 97.9%,p>0.99)were comparable,while the rates of recanalization were significantly lower in the matched FD group than in the matched SAC group(0.0%vs 12.8%,p=0.031).While the difference in the rates of in-stent stenosis was not statistically significant,the difference in the effect measures was considerable(17.0% vs 6.4%,p=0.180).Conclusion: In unruptured IVADAs,FDs provide comparable rates of periprocedural cerebrovascular complications,favorable clinical outcomes,and follow-up complete occlusion;lower rates of immediate complete occlusion and follow-up recanalization;and likely higher rates of in-stent stenosis compared with SAC.