Basilar Artery Occlusion:

Clinical Management & Therapy

Basilar artery occlusion (BAO) is an infrequent form of acute stroke, which invariably leads to death or long-term disability if not recanalized. A traditional recanalization approach based on historical controls and pathophysiological consideration is local intra-arterial thrombolysis (IAT) in eligible patients. This necessitates diagnostic evaluation and treatment in stroke centers equipped with an interventional neuroradiological service on a 24-hour basis.

Basilar artery thrombosis is a devastating form of stroke with high morbidity and mortality.

Challenges due to delayed recognition and progressive infarction of the brain stem can occur frequently in these cases. MR imaging can help determine who are the patients who would benefit from Thrombectomy.

Pathophysiology is typically different in posterior circulation when compared to anterior circulation as the mechanism is related to an underlying atheromatous plaque with in situ thrombosis or rupture of the plaque with subsequent thrombo-embolic disease rather than a thrombo-embolic cardiac phenomenon encountered in anterior circulation acute large vessel occlusion.

Case Presentation and Investigation

47-year-old male of indeterminate handedness with past medical history significant for HTN who was last seen normal at 8:00 am (17/11/2022).

He was found collapsed at 11:00 am and brought to a local hospital in Ajman with GCS 8 points, intubated; he had CT/CTA that showed proximal BA occlusion (scan done around 13:30 pm). He was transferred to CCAD for further management.

Material and Method

On arrival, patient was on full sedation, intubated, ventilated, with pinpointed symmetrical pupils, GCS 3. CTB showed bilateral (L>R) cerebellar infarcts, L-PCA territory infarct). The patient was referred for hyperacute MRI to look for DWI/FLAIR mismatch.

The MRI showed DWI positive bilateral cerebellar and occipital ischemic changes, but brainstem was largely spared with a small DWI density in the posterior right lower pons.

There were no matching FLAIR changes in the brainstem, and only L-PICA/SCA and L-PCA territory ischemia was visible on FLAIR.

The patient was last known well at 8:00 am today therefore is outside of the window for IV TPA.

He underwent successful mechanical thrombectomy, angioplasty of the proximal basilar artery occlusion and severe stenosis.

Pre-Thrombectomy Acquisition

Complete occlusion of the basilar artery distal to the PICA

Post-Thrombectomy Acquisition

Successful aspiration thrombectomy using the ADAPT technique (TICI grade 0 to TICI grade 3) after first pass which was approximately 15 minutes post right groin access. However, complete re-occlusion of the basilar artery proximal to mid basilar segment after approximately 25 minutes of watchful observation.

Due to the recoil and rebound of the occlusion, the physician proceeded to perform angioplasty of the occluded segment of the basilar artery given the etiology is likely in situ thrombosis of severe atheromatous plaque. This resulted in complete reconstitution of flow albeit markedly tenuous due to residual severe stenosis to greater than 80% at the proximal to mid basilar segment.

Discussion

3 weeks later, the patient returned for follow-up exam to evaluate for angioplasty and / or stenting.

Follow-up angiography revealed significant improvement of the atheromatous heterogeneous eccentric plaque of the proximal basilar artery just distal to the vertebrobasilar junction with residual narrowing measuring less than 50%. Therefore, no endovascular angioplasty or stenting is warranted at this time.

Conclusion

MRI is crucial in evaluating patients with suspected VB occlusions. Patients with large pontine or brainstem infarcts would have poor outcome or prognosis.

Immediate transfer to Neurointerventional suite for revascularization is paramount to preserve function and leads to better outcomes.

Pathophysiology is typically different in posterior circulation when compared to anterior circulation as the mechanism is related to an underlying atheromatous plaque with in situ thrombosis or rupture of the plaque with subsequent thrombo-embolic disease rather than a thromboembolic cardiac phenomenon encountered in anterior circulation acute large vessel occlusion.

Angioplasty should be one considered as an early armamentarium in the treatment of VB large vessel occlusions.

Subsequent early follow-up is crucial to ensure remodeling and adequate perfusion of the basilar artery post the initial acute phase treatment, possibly requiring further additional treatment by angioplasty and/or stenting.

Furthermore, ARTIS icono provides a better image quality for syngo DynaCT, which will help us make final decisions. You also have the syngo DynaCT Sine Spin which provides a better image quality in the infratentorial region. And, you have faster protocols, which reduces movement artefacts, and leads to better decisions. Having neuro systems that provide excellent basic imaging information, and advanced tools like perfusion in the angio suite, is an asset in the armamentarium of stroke evaluation and treatment.