Danielle de Sa Boasquevisque, MD

Boeckh-Behrens T, Pree D, Lummel N, Friedrich B, Maegerlein C, Kreiser K, et al. Vertebral Artery Patency and Thrombectomy in Basilar Artery Occlusions: Is There a Need for Contralateral Flow Arrest? Stroke. 2019;50:389–395.

Patients with basilar artery occlusion (BAO) comprise 10-20% of all large vessel occlusion cases but carry high mortality and morbidity rates, reaching up to 95% if recanalization is not achieved. The optimal approach for treatment of this life-threatening condition – including the optimal time-window – is still heavily debated. Mechanical thrombectomy is currently the standard of care for this population in most stroke centers, despite the lack of evidence compared to anterior circulation.

Studies up until now showed that some factors are related to better recanalization rates in this population and hence, better prognosis. These variables were hyperdense basilar artery, short thrombus length, early initiation of endovascular therapy and contact aspiration. Some case-reports have also suggested that anatomic and hemodynamic factors related to reversal flow and patency of vertebral arteries could affect recanalization success.

The primary objective of this study by Boeckh-Behrens et al. was to to investigate the association between low flow condition contralateral to the catheter-bearing vertebral artery and  successful recanalization post-mechanical thrombectomy (MT) in a population individuals with acute basilar artery occlusion. The authors hypothesized that patients with low flow condition defined as either aplastic or hypoplastic vertebral artery (< 50% of the dominant artery) contralateral to the catheter position have more chances to achieve complete recanalization once they have less risk of distal emboli.

All patients were subjected to digital subtraction angiography. The complete vertebrobasilar axis recanalization was defined as grade 9 (on a scale of 1 to 9), and it could be achieved with or without residual branch occlusion.

Elena Zapata-Arriaza, MD
@ElenaZaps

Compagne KCJ, van der Sluijs PM, van den Wijngaard IR, Roozenbeek B, Mulder MJHL, van Zwam WH, et al. Endovascular Treatment: The Role of Dominant Caliber M2 Segment Occlusion in Ischemic Stroke. Stroke. 2019;50:419–427.

Despite the recently demonstrated benefit of endovascular treatment (EVT) for proximal large vessel occlusion (LVO) of the anterior circulation (ICA and M1), evidence for treatment benefit of more distal occlusions, including the M2 segment of the middle cerebral artery (MCA), is limited, and further studies are necessary to address this question. In addition, the efficacy and safety of EVT in M2 occlusions remain unproven.

To determine the efficacy and safety of EVT in M2 occlusions, the authors performed an observational study with data obtained from the MR CLEAN registry. Only patients with a documented M1 or M2 target occlusion on baseline digital subtraction angiography (DSA) were included.

Caliber dominance was considered present if 1 M2 branch had a larger diameter than the other on DSA or if the perfusion defect associated with the occluded M2 branch was larger than 50% of MCA territory. Only when the diameters of both the inferior and superior branches were equal and the associated perfusion defect was ≈50% of MCA territory, the branches were considered codominant. DSA-only procedures were cases in which the target occlusion resolved or migrated too distally (M3 or M4 branches) caused by contrast flushing or manipulation with the catheter, without actual performing of intended EVT.

Sami Al Kasab, MD

Singh R-J, Chakraborty D, Dey S, Ganesh A, Al Sultan AS, Eesa M, et al. Intraluminal Thrombi in the Cervico-Cephalic Arteries: Clinical-Imaging Manifestations, Treatment Strategies, and Outcome. Stroke. 2018;50:357–364.

With the increased imaging of the head and neck vasculature as part routine stroke/TIA workup, diagnosis of intraluminal thrombus (ILT) has become more common. The presence of ILT in the cervico-cephalic vasculature in patients with TIA or stroke poses a diagnostic and therapeutic challenge. In this study, Singh et al. report the clinical and imaging manifestation of ILT and provide recommendations on therapeutic options. The study was conducted at the University of Calgary. Patients with suspected TIA or stroke between April 2015 and September 2017 were included in these analyses. Diagnosis of ILT was made by CTA of the head and neck performed routinely on admission, which was evaluated by a neuroradiologist, once the diagnosis of ILT was made, it was confirmed by a second neuroradioloigst.

A total of 3750 patients were evaluated during the study period; ILT was identified in 61 patients (1.6%). Median age was 67 years (IQR, 56-73); 40 (65.6%) patients were men. Patients with ILT had high prevalence of hypertension, smoking and dyslipidemia (47.5%, 44.3%, and 41% respectively). The most common presentation was ischemic stroke (80.3%), and most strokes were mild with median NIHSS of 2 (IQR, 1-4). The most common location of ILT was extracranial internal carotid artery (65.6%), followed by extracranial vertebral artery (11.2%). The most common cause of ILT was atherosclerosis in the affected artery (82 %) manifested by ulcerated plaque with or without luminal stenosis. Ulcerated plaque was identified in 6.6% of patients only. 51/61 (83.6%) were found to have ≥50% underlying stenosis, arterial dissection was identified in 6.6% of cases and 1 patient (1.6%) had cardio-embolic etiology.

Ravinder-Jeet Singh, MBBS, DM

Kaesmacher J, Chaloulos-Iakovidis P, Panos L, Mordasini P, Michel P, Hajdu SD, et al. Mechanical Thrombectomy in Ischemic Stroke Patients With Alberta Stroke Program Early Computed Tomography Score 0-5. Stroke. 2019;50:880-888.

Early and successful reperfusion leads to favourable outcome among patients with stroke having intracranial large artery occlusion. However, restoring blood flow to an infarcted tissue has a potential to induce reperfusion injury-related complications manifesting by development of malignant edema, intracerebral hemorrhage (ICH) or both. The risk is greater among those with larger pre-treatment infarct size, which is frequently defined using low ASPECTS scores (<6) or large cores (for example, >70-100 ml) on blood-flow imaging (CT/MR perfusion). Due to safety concerns, these patients were excluded from recent endovascular thrombectomy (EVT) trials. Contrary to general perception, recent literature demonstrates good safety of EVT in these patients and work by Kaesmacher et al1 is further addition to EVT safety and efficacy data in this group.

From a multicenter registry (BEYOND-SWIFT; N=2046), authors identified 237 patients who had ASPECTS 0-5 and underwent EVT. Overall, nearly equal proportion of patients had favorable outcome (mRS 0-3) and death (40.1% and 40.9%, respectively). Obviously, these patients had lower rates of favorable outcome than the group with ASPECTS 6-10 (40.1 vs 61.2%; P<0.001) and also had higher mortality (40.9 vs 21.2%; P<0.001), however, authors demonstrated no safety concerns of EVT with respect to rates of symptomatic ICH (7.2% vs 6.0%; P=0.466). The effect on all outcomes was clearly influenced by achievement of the successful reperfusion (TICI 2b/3), presence of which resulted in higher rates of favorable outcome, lower mortality and lower symptomatic ICH rates. On further inspection of the data, functional benefits were predominantly observed in ASPECTS 5 patients, nonetheless, mortality benefits were still observed in those with further lower ASPECTS scores (4 or even 0-3 group) when successful reperfusion was achieved.  Patients with ASPECTS 0-5 had longer procedure duration (groin puncture to reperfusion), lower successful reperfusion rates and higher frequency of procedural complications during EVT than ASPECTS 6-10 patients. Larger clot burden and higher cervical artery dissection rates leading to procedural challenges might be few of the explanations for this observation.