Mechanical thrombectomy (MT) is an effective treatment for acute ischemic stroke from large vessel occlusion (LVO). While embolization to a new territory (ENT) after MT is well-documented, data on embolization in the same distal territory (EDT) are limited. Achieving modified Treatment In Cerebral Infarction (mTICI) 3 reperfusion presents significant clinical benefits over mTICI 2b/2c, necessitating strategies to reduce both ENT and EDT. Previous studies suggest higher rates of EDTs with contact aspiration compared with stentrievers. However, comprehensive comparison studies in clinical practice are scarce. This study compares the rates of overall clot emboli (OCE) between these MT strategies.
We thank Drs. De Simone and Ranieri for their comments and interest in our article.1 Our hypothesis does not support a dysfunction of aquaporin (AQP) 4 in idiopathic intracranial hypertension (IIH); rather, an unknown type of AQP (e.g., aquaglyceroporin) may be involved at the venodural junction and may trigger the hydrodynamic cascade of IIH. We agree that a direct discharge of glymphatic fluid into the venous blood has not been documented in studies of CSF hydrodynamics2; however, the techniques used to demonstrate the existence of the glymphatic and lymphatic systems of the brain were not able to detect any venous CSF outflow, leading some to question even the existence of a venous CSF outflow pathway in the brain.3 Based on our clinical experience (i.e., cerebral venous thrombosis) and on previous experimental studies, we feel that a direct discharge of glymphatic fluid into venous blood seems highly likely.4
Distal vessel occlusions represent about 25–40% of acute ischemic stroke (AIS), either as primary occlusion or secondary occlusion complicating mechanical thrombectomy (MT) for large vessel occlusion.
Objective
Our aim was to evaluate safety and effectiveness of MT associated with the best medical treatment (BMT) in the management of AIS patients with distal vessel occlusion in comparison with the BMT alone.
Methods
Retrospective analysis was conducted on AIS patients treated by MT+BMT for primary distal vessel occlusion between 2015 and 2020, and were compared with a historic cohort managed by BMT alone between 2006 and 2015 selected based on the same inclusion criteria. A secondary analysis was conducted using propensity score matching (PSM) including the following: NIHSS, age and treatment with intravenous thrombolysis (IVT) as covariates.
Results
Of 650 patients screened, 44 patients with primary distal vessel occlusions treated by MT+BMT were selected and compared with 36 patients who received BMT alone. After PSM, 28 patients in each group were matched without significant difference. Good clinical outcome defined as mRS ≤2 was achieved by 53.6% of the MT+BMT group and 57% of the BMT group (OR, 0.87; 95%CI, 0.3–2.4; P=1.00). The mortality rate was comparable in both groups (7% vs 10.7% in MT+BMT and BMT patients, respectively; OR=0.64; 95%CI, 0.1–4; P=1.00). Symptomatic intracranial haemorrhage (ICH) was seen in only one patient treated by MT+BMT (3.6%).
Conclusion
Mechanical thrombectomy seems to be comparable with the best medical treatment regarding the effectiveness and safety in the management of patients with distal vessel occlusions.
References
Sarraj A, Sangha N, Hussain MS, et al. Endovascular therapy for acute ischemic stroke with occlusion of the middle cerebral artery M2 segment. JAMA Neurol 2016;73:1291–1296. Saver JL, Chapot R, Agid R, et al. Thrombectomy for distal, medium vessel occlusions: a consensus statement on present knowledge and promising directions. Stroke 2020;51:2872–2884. Ospel JM, Menon BK, Demchuk AM, et al. Clinical course of acute ischemic stroke due to medium vessel occlusion with and without intravenous alteplase treatment. Stroke 2020;51:3232–3240.
Disclosure
Pr F. Clarençon reports conflict of interest with Medtronic, Guerbet, Balt Extrusion, Penumbra (payment for readings), Codman Neurovascular and Microvention (core lab). Dr N. Sourour is consultant for Medtronic, Balt Extrusion, Microvention, Stock/Stock Options: Medina. The other authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.
Tectal arteriovenous malformations (TAVMs) are rare lesions deeply located close to eloquent structures making them challenging to treat.
Aim of Study
To present clinical revealing conditions, angiographic features and treatment strategies of TAVMs through a single center retrospective case series.
Methods
TAVMs were defined as a nidus located in the parenchyma or on the pia mater of the posterior midbrain. Records of consecutive patients admitted with TAVMs over a 21-years' period were retrospectively analyzed.
Results
Thirteen patients (1.63% of the complete cohort; 10 males), mean age 48 years, were included. All patients presented with intracranial hemorrhage. Two patients (15%) died after an early recurrent bleeding. Mean size of the TAVMs was 10.1±5 mm. Multiple arterial feeders was noted in every cases. Eleven patients underwent an exclusion treatment; 8 via embolization (6 via arterial access and 2 via venous access) and 4 via stereotactic radiosurgery (SRS) (1 patient received both). Overall success treatment rate was 7/11 patients (64% overall; 63% in the embolization group, 25% in the SRS group). Two hemorrhagic events lead to a worsened outcome, one during embolization and one several years after SRS. All other patients remained clinically stable or improved.
Conclusion
TAVMs are rare but stereotypic lesions found in a hemorrhagic context. Multiple arterial feeders are always present. Endovascular therapy seems to be an effective technic with relatively low morbidity; SRS had a low success rate but was only use in a limited number of patients.
References
Chaynes P. Microsurgical anatomy of the venous drainage of the mesencephalodiencephalic junction. Neurosurgery 2004;54:678–85; discussion 685–686. Thines L, et al. Challenges in the management of ruptured and unruptured brainstem arteriovenous malformations: outcome after conservative, single-modality, or multimodality treatments. Neurosurgery 2012;70:155–61; discussion 161. Cohen-Inbar O, et al. Stereotactic radiosurgery for brainstem arteriovenous malformations: a multicenter study. Neurosurgery 2017;81:910–20. Madhugiri VS, et al. Brainstem arteriovenous malformations: lesion characteristics and treatment outcomes. J Neurosurg 2018;128:126–36. Han SJ, et al. Brainstem arteriovenous malformations: anatomical subtypes, assessment of 'occlusion in situ' technique, and microsurgical results. J Neurosurg 2015;122:107–17.
