We retrospectively analyzed a series of 17 patients with acute VAOs and BAOs treated via MT at the departments of neurosurgery, Jiangyin Hospital from January 2017 to December 2020. This study was approved by our hospital’s Research Committee. Patients as well as relatives were made aware our intention to include them in a study during follow-up visits at outpatient department. Written informed consents as well as concerns for publication were obtained from all the patients and the hospital. In all patients, information such as sex and age, time from admission to onset of femoral artery access, number of thrombus removed, time of femoral artery access to recanalization, pre- and post -operative National Institutes of Health Stroke Scale (NIHSS), pre- and post-operative thrombolysis in cerebral infarction (TICI) as well as modified Rankin Scale (mRS) were documented and analyzed.
Indications And Contraindications
Indications for MT included: (1) Clinical diagnosis is in line with acute ischemic stroke in the posterior circulation, hospitalized within 24 hours of onset, and neurological deficits related to posterior circulation ischemia such as dizziness, gaze disturbance, visual field defect, visual impairment, coma, etc.; (2) If cerebrovascular evaluation with computer tomographic angiography (CTA) showed that the BA and/or VA was occluded, and a head computer tomography (CT) scan ruled out intracranial hemorrhage; (3) If the patient’s family agreed to an informed consent and signed the surgical consent form.
Contraindications for MT: (1) If a head CT indicates the presence of intracranial hemorrhage or large-area cerebral infarction in the posterior circulation (> 2/3 of the pons or midbrain volume or cerebellar hemisphere infarction); (2) If there was a history of active bleeding or a tendency to hemorrhage; (3) Severe disability, mRS > 2 points;(4) Severe renal insufficiency; (5) If the patient had a clear history of contrast agent allergy.
After the patient was admitted in the hospital, a neurologist will complete the physical examination, neurological functional assessment as well as the NIHSS score in the emergency room. The emergency physician will also perform a head CT scan to rule out intracranial hemorrhage, as well as a head and neck CTA to identify BAO (Fig. 1A&B) and/or VAO. Also, preoperative magnetic resonance images (MRIs) were performed in all patients to detection brainstem infarction. In all patients, preoperative CTA revealed the presence of great vessel occlusion such as the arteries above. Time from admission to onset of femoral artery puncture/accesses were documented before the commencement of endovascular operations.
Anatomical Divisions Of The Vertebrobasilar Artery
The VA is characteristically divided into 4 segments such as V1-V4[25, 26]: V1; also denoted as the pre-foraminal segment (starts from the subclavian artery to the transverse foramen of C6), V2; also denoted as the foraminal segment (starts from the transverse foramen of C6 to the transverse foramen of C2), V3; also denoted as the atlantic, extradural or extraspinal segment (starts from C2, where the artery loops, turns lateral and upwards into the transverse foramen and progress via C1 to penetrate the dura, V4; also denoted as the intradural or intracranial segment (starts from the dura at the lateral border of the posterior atlanto-occipital membrane to their convergence on the medulla to constitute the BA).
All procures were carried out under general anesthesia. The entire operations were carried out strictly as previously described by Luo et a. After securing the femoral artery access, a 6F/8F guide catheters were maneuvered into the BA or the VAs via the subclavian arteries and initial angiographies performed to determine the locations of the occlusions (Fig. 1C). Using a coaxial system, we advance 0.21 inch microcatheters (Rebar microcatheter; Covidien, California, USA) and 0.014 inch microguide wires (Transend; Stryker, Kalamazoo, Michigan) into the thrombi as far as the distal ends of the occluded vessels. Angiographies were then performed to confirm that the distal vasculars were patent and no pathology were found in the lumens.
In all patients, solitaire Abs or FRs (ev3, Irvine, California) were utilized for the MT. The Solitaire devices were carefully maneuvered to the occluded segments via the microcatheters and the stent retrievers unsheathed to allowed for complete expansion through the thrombi. The devices often created bypasses that restored blood flow across the occluded segments. Again, we performed angiography to determine patency of the distal arteries, after which we resheathed fully deployed the solitaire devices. Thrombectomies were done via the withdrawal of the solitaire devices and the delivery microcatheters as a single unit. If the angiography showed that the occluded arteries were patent (Fig. 1D), and blood flow rates were basically normal (TICI 2b and above), then the procedures were completed.
If the angiography still showed stenosis of the BA or VA and the anterior blood flow does not meet a TICI score of 2b, then balloon angioplasty (GatewayTM, Boston Scientific Place, Natick, MA) was first performed. If angiography still showed no patency, the stent placements were performed to ensure that, the flow rates met TICI score of 2b or above. In all patients who underwent the MTs, the number of thrombus removed were documented. Also, the time from femoral artery puncture/access to recanalization of the occluded arteries were documented.
Post Procedure Management, Efficacy Evaluation And Follow-up
Heparin infusion was used during and immediately after the operation. Intravenous tirofiban used during the operation was also maintained after the operation. Aspirin 300 mg and clopidogrel 300 mg were inserted in the anus immediately after the operation. All the patients were admitted to the intensive care unit (ICU) for monitoring and treatment, and transferred to the general ward after their conditions were stable. In all patients, immediate postoperative CT scans were performed to rule bleeding 24hours after the operation. CTAs were also performed to confirm recanalization (Fig. 1E). Also, post-operative MRIs were performed to assess infarctions after the procedure (Fig. 1F).
Also in all patients, TICI grade were scored as follows[22, 27]: 0 ; no recanalization (no perfusion or anterograde flow beyond the occlusion site) 1; minimal recanalization (contrast medium passes the area of occlusion but fails to opacify the entire cerebral bed distal to the obstruction during the angiographic run), 2 ; partial recanalization (2a: partial filling, < 50% of territory visualized, 2b: partial filling, ≥ 50% of territory visualized) and 3; complete recanalization (total reperfusion with normal filling). At the ICU, NIHSS of all the patients were assessed 7 days after the operation.
Also, mRS was used to evaluate the prognosis of patients up to 90 days after the operation.
The mRS scores were assessed as follows[22, 28]: 0; no symptoms, 1; no clinically relevant disability, 2; slight disability (able to look after own affairs without aid but not to a full extent), 3; moderate disability (requires some aid but able to walk unaided), 4; moderately severe disability (unable to attend to own bodily needs or to walk without aid); 5, severe disability (requires constant nursing care); and 6, dead.
SPSS 17.0 statistical software was used to analyze the data. Normally distributed data were analyzed into X ± S. Data comparison before and after surgery was performed by paired t-test. Non-normally distributed data were analyzed into medians, and P < 0.05 was considered statistically significant.