Vertebral artery pseudoaneurysm: a rare cause of posterior circulation infarction in a middle-aged man

Abstract

Pseudoaneurysm of the vertebral artery is a rare cause of posterior circulation stroke. Treatment for this condition can be achieved through microscopic surgery or endovascular therapy. We report a case of a 36-year-old middle-aged male patient who presented with left limb numbness as the sole complaint. On a magnetic resonance imaging examination, multiple infarcts were observed in the left cerebellar tonsil. A subsequent head and neck computed tomography angiography examination led to the diagnosis of a pseudoaneurysm in the left vertebral artery. Following standard antiplatelet therapy, the patient underwent endovascular intervention. The patient’s left limb numbness gradually subsided after surgery. A follow-up angiography performed 1 week after discharge showed no recurrence. These findings suggest that covered stent placement is an effective method of treating pseudoaneurysm of the vertebral artery.

Introduction

Posterior circulation strokes have a high incidence, accounting for 20% to 25% of all ischemic strokes, with an annual incidence of approximately 18/100,000. This type of stroke is a major cause of death and disability in patients with stroke. Clinical presentations of a posterior circulation stroke vary widely and may include symptoms, such as language impairment, limb weakness, limb numbness, dizziness, vertigo, coughing, vomiting, altered consciousness, gait instability, and difficulty swallowing. ¹

Pseudoaneurysms of the vertebral artery are rare clinical entities that can also lead to ischemic events in the posterior circulation system. The majority of pseudoaneurysms occur post-trauma, with those in the V1 and V2 segments often resulting from penetrating injuries, while those in the V3 and V4 segments more commonly occur after blunt trauma. Some pseudoaneurysms may also have a familial predisposition and are associated with conditions, such as Marfan syndrome and Ehlers–Danlos syndrome, among others. ²

In the past, treatment for such diseases primarily involved microscopic surgery. However, in recent years, various interventional devices, such as flow diverters and covered stents, have made endovascular therapy safe and effective. We report a case of a primary pseudoaneurysm in the left V1 segment of the vertebral artery. This case was ultimately treated with a covered stent.

Case presentation

A 36-year-old middle-aged male patient presented to the hospital without a clear trauma history or any history of rheumatological or connective tissue disease. His main symptom was numbness in the left limb, without weakness, dizziness, headache, nausea, vomiting, choking on liquids, double vision, or gait instability. Blood tests upon admission showed an elevated erythrocyte sedimentation rate of 33 mm/hour, and elevated concentrations of triglycerides (1.93 mmol/L) low-density lipoprotein (3.86 mmol/L, lipoprotein(a) (711.8 mg/L), and uric acid (446 μmol/L). All other blood and biochemical results were within normal ranges. Brain magnetic resonance imaging showed multiple small infarcts in the left cerebellar tonsil (Figure 1(a)). Head and neck computed tomography angiography showed a prominent lesion in the left vertebral artery V1 segment (Figure 1(b), (c)). No signal indicating normal vascular walls around the lesion was found on neck magnetic resonance imaging (Figure 1(d), (e)). These findings suggested pseudoaneurysm formation. Further posterior circulation cerebral embolism occurred because of detachment of tiny clots within the aneurysm.

Figure 1.

(a) Brain magnetic resonance imaging shows multiple small infarcts in the left cerebellar tonsil (arrow). (b) Preoperative head and neck computed tomography angiography shows a protruding lesion measuring 23 × 27 mm at the distal end of the left vertebral artery V1 segment (arrow). (c) Preoperative three-dimensional reconstruction of the left vertebral artery. The arrow shows the lesion. (d) Sagittal image of cervical magnetic resonance T2-weighted imaging. The arrow shows the lesion and (e) axial image of cervical magnetic resonance T2-weighted imaging showing the absence of normal vascular wall structure around the lesion (arrow).

After 5 days of oral antiplatelet therapy with aspirin 100 mg and clopidogrel 75 mg, the patient underwent endovascular intervention. Under local anesthesia, digital subtraction angiography was performed via the femoral artery. This technique confirmed the presence of a pseudoaneurysm in the left vertebral artery V1 segment with a diameter of approximately 26 mm and a narrow neck (Figure 2(a)). An 8 F MPA1 guiding catheter (Cordis, Santa Clara, CA, USA) was placed at the left vertebral artery opening. A covered stent (ClearStream, Wexford, Ireland) was carefully passed through the lesion and fully deployed under fluoroscopic guidance (Figure 2(b)). Immediate angiography during the procedure showed no aneurysmal opacification. Blood flow through the left vertebral artery was unobstructed (Figure 2(c)). Postoperatively, the patient continued to receive dual antiplatelet therapy and intravenous fluid supplementation to prevent thrombotic events. Following the above-mentioned treatment, the patient’s left limb numbness gradually improved. A follow-up examination 1 week after discharge showed that the stent was well-positioned, and the pseudoaneurysm was not visualized (Figure 3(a), (b)).

Figure 2.

(a) Digital subtraction angiography confirms the formation of a pseudoaneurysm in the left vertebral artery (arrow). (b) A guidewire guided the covered stent through the lesion (arrow), precisely positioned it, and then expanded it using a pressure pump, fully releasing it and (c) immediately after stent deployment, angiography was performed, and it confirmed a well-positioned and well-shaped stent (arrow). The pseudoaneurysm was completely isolated, with no evidence of the original abnormal blood flow signal. Blood flow through the left vertebral artery was unobstructed.

Figure 3.

(a) A follow-up head and neck computed tomography angiography shows no recurrence of the pseudoaneurysm 1 week postoperatively. The arrow shows the stent and (b) three-dimensional reconstruction of the left vertebral artery 1 week postoperatively. The arrow shows the stent.

Patient and family consent was obtained for all treatments mentioned above. This study was a case report involving a single patient whose personal identification information has been anonymized. Therefore, the ethics committee of The Affiliated Huizhou Hospital, Guangzhou Medical University waived the requirement for approval of the study protocol. The reporting of this study conforms to the CARE guidelines. ³

Discussion

Posterior circulation strokes account for 20% to 25% of all ischemic strokes. Common causes of posterior circulation stroke include atherosclerosis, embolism, penetrating small-artery disease, and arterial dissection. Other relatively rare causes include subclavian steal syndrome, large-vessel vasculitides, Fabry disease, mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes, posterior reversible encephalopathy syndrome, and Bow Hunter’s syndrome. ⁴

Pseudoaneurysms of the vertebral artery can also cause symptoms of posterior circulation ischemia and are considered rare conditions in clinical practice.^5,6 Clinical practice requires distinguishing between true and false aneurysms. True aneurysms commonly occur at blood vessel bifurcations, such as the posterior communicating artery, anterior communicating artery, and basilar artery. True aneurysms typically present as spindle-shaped dilations or saccular protrusions while maintaining normal vascular wall structure. False aneurysms can occur at any site in the vasculature and are often associated with trauma. They result from vascular wall injury, leading to blood extravasation, resulting in a hemorrhage that remains connected to the vessel lumen. Over time, the hematoma undergoes organization and fibrosis, forming a pseudoaneurysm wall, which lacks a normal vascular wall structure.

Various causes, such as neck massage, cervical spine surgery, internal jugular vein cannulation, stabbing injuries, gunshot wounds, and others, can lead to pseudoaneurysms in the vertebral artery.^7–12 Primary pseudoaneurysms of the vertebral artery without a history of trauma, surgery, or genetic familial diseases, such as the case reported here, are exceedingly rare clinically. Most vertebral artery pseudoaneurysms occur in the V1 or V3 segments. This is often associated with increased vertebral artery mobility within these regions. Our patient’s lesion was also located in the V1 segment as previously reported. ¹³

The main approaches to treat vertebral artery pseudoaneurysms include traditional microscopic surgery and endovascular intervention. Endovascular treatments may involve flow-diverting devices, covered stents, coil embolization, stent-assisted coil embolization, and Onyx embolization, among others. Traditional microsurgery involves sacrificing the vertebral artery through ligation or preserving it through bypass surgery. In a review of previously published literature, Akinnusotu et al concluded that endovascular treatment has lower rates of complications (15.5% vs 32%) and mortality (0% vs 10.7%) than conventional surgery in treating extracranial vertebral artery aneurysms. However, surgical intervention may still be preferred in certain cases, depending on the morphology and location of the aneurysm. ¹⁴

In this patient, despite a preoperative National Institutes of Health Stroke Scale score of only 1 and a 2-week interval from the initial onset of symptoms, the likelihood of rupture of the pseudoaneurysm was relatively low. In this circumstance, endovascular intervention is recommended because of the possibility of thromboembolism leading to extensive infarction or rupture with massive hemorrhage if regional pressure increases. Additionally, the gradual enlargement of the pseudoaneurysm can cause a mass effect, compressing local nerves and adjacent veins. Endovascular intervention minimizes surgical trauma while addressing thromboembolism, vessel rupture, and compression of the surrounding neurovasculature in a single procedure. Ultimately, we chose to use a covered stent, and immediate postoperative angiography showed no opacification of the pseudoaneurysm. Furthermore, there was no evidence of recurrence in angiography performed 1 week postoperatively. These findings indicate that endovascular placement of a covered stent is an effective method for treating vertebral artery pseudoaneurysms. ¹⁵

Importantly, if abnormal signals around the vertebral artery are found on preoperative computed tomography angiography scans, attention should be paid to differentiating them from solid tumors such as schwannomas. The reconstructed results on computed tomography angiography of schwannomas compressing the ipsilateral vertebral artery may be similar to those of pseudoaneurysms of the vertebral artery. This situation can lead to misdiagnosis. ² The different nature of these two conditions suggests that there should be different treatment approaches, highlighting the importance of an accurate preoperative diagnosis. Patients with vertebral artery pseudoaneurysms may suffer serious consequences if the wrong treatment approach is chosen, such as needle biopsy or microscopic surgery. Therefore, when the nature of such diseases cannot be determined, digital subtraction angiography should be routinely performed before surgery.

Conclusion

Pseudoaneurysms of the vertebral artery are rare clinical cases that can lead to posterior circulation ischemia. Patients with this condition should seek medical attention. Endovascular intervention surgery is an effective method for treating this condition, with lower probabilities of complications and mortality than traditional microscopic surgery. Following the placement of a covered stent, long-term regular oral antiplatelet medication and periodic imaging follow-up are required.