Endovascular electrocoagulation for treating a blister-like microaneurysm with an extremely narrow neck: A case report

Abstract

BACKGROUND

Intracranial blister-like microaneurysms are an extremely rare disease. Rupture of intracranial aneurysms can lead to subarachnoid hemorrhage (SAH). Patients with SAH may experience severe neurological symptoms, including severe headache, nausea, vomiting, transient or persistent loss of consciousness, limb weakness, and blurred vision. Ruptured aneurysms should be surgically treated as soon as possible. Intravascular electrocoagulation is becoming a promising treatment method for intracranial blister-like microaneurysms. The short-term follow-up results demonstrated that this method is safe and effective. This article presents a case of endovascular electrocoagulation for the treatment of a blister-like microaneurysm.

CASE SUMMARY

This article reports the case of 71-year-old female patient with an intracranial aneurysm. The patient experienced a sudden headache with vomiting for 3 hours. Brain computed tomography (CT) scan showed a subarachnoid hemorrhage. She was diagnosed with rupture of an aneurysm and subarachnoid hemorrhage. The aneurysm was located in the choroidal segment of the right internal carotid artery. The size of the aneurysm was 2.00 mm × 1.80 mm × 1.97 mm, and the neck of the aneurysm was less than 0.5 mm wide. We successfully treated this aneurysm with endovascular electrocoagulation, and the patient was safely returned to the ward and discharged after subsequent supportive treatment. CT angiography reexamination 3 months after surgery revealed no contrast agent extravasation in the original lesion, with a good prognosis.

CONCLUSION

Endovascular electrocoagulation is an effective and safe method for the treatment of intracranial blister-like microaneurysms.

Key Words: Microaneurysm; Blister-like; Endovascular electrocoagulation; Extremely narrow neck; Case report

Core Tip: Microaneurysms with a diameter of less than 2 mm and a neck of less than 0.5 mm are very rare. This type of microaneurysm is characterized by a small lumen and thin wall and is extremely challenging for surgeons. This article introduces the process of endovascular electrocoagulation for the treatment of aneurysms and provides a feasible solution for the treatment of microaneurysms.

INTRODUCTION

The incidence of intracranial aneurysms is 1%-2%[1]. Microaneurysms with a diameter of less than 3 mm account for 15% of ruptured hemorrhagic aneurysms[2]. Microaneurysms are characterized by a small lumen and thin wall, which leads to limited operational space and difficulty in microcatheter placement, thus increasing the risk associated with endovascular interventional therapy[3]. Schuette et al[4] retrospectively analyzed 347 cases of aneurysms and reported that the risk of intraoperative rupture of aneurysms with a diameter of < 4 mm was 5 times greater than that of larger aneurysms. Brinjikji et al[5] conducted a meta-analysis of endovascular treatment for tiny aneurysms and reported that 95.3% of the 422 aneurysms showed complete or near-complete occlusion after embolization. Rupture of an intracranial aneurysm can cause subarachnoid hemorrhage, which in turn causes severe neurological damage or even death. Subarachnoid hemorrhage from a ruptured intracranial aneurysm is a life-threatening stroke that affects younger patients than those affected by other forms of stroke[6]. The risk of intracranial aneurysms is increased among people with a family history; the risk becomes higher if two or more first-degree relatives have experienced such an event[7]. Factors associated with an increased risk of aneurysm rupture include hypertension, smoking, alcohol abuse, the use of sympathomimetic drugs, and an aneurysm larger than 7 mm[8]. Aneurysmal subarachnoid hemorrhage is more common among women than men, and the incidence increases with age to a peak among people in their 50s[9]. However, very few cases exist in which endovascular electrocoagulation technology has been used to treat blood blister-like microaneurysms. This case demonstrates that endovascular electrocoagulation is an effective and safe approach for treating blood blister-like microaneurysms.

CASE PRESENTATION

Chief complaints

A 71-year-old female experienced a sudden headache with vomiting for 3 hours.

History of present illness

The patient developed a headache 3 hours prior, accompanied by 2 episodes of vomiting of the gastric contents. The patient had not experienced loss of consciousness, limb convulsions, or incontinence of urine or feces. An emergency cranial computed tomography (CT) scan revealed a subarachnoid hemorrhage.

History of past illness

The patient had a previous history of good health and denied a history of hypertension, heart disease, diabetes, or cerebrovascular disease.

Personal and family history

The patient had no relevant family history.

Physical examination

The following vital signs were recorded: Respiratory 17 breaths per minute. Pulse 78 beats per minute. Temperature 36.2 °C. Blood pressure 169/78 mmHg. The patient was in a state of shallow coma with a Glasgow Coma Scale score of 12; the eyes were opened in response to verbal stimulation, and irrelevant answers were given. The bilateral pupils were round and equal in size, measuring 2.5 mm in diameter, with a sluggish light reflex. The patient had nuchal rigidity, localized limb pain upon stimulation, and negative bilateral Babinski signs.

Laboratory examinations

Laboratory tests revealed no significant abnormalities.

Imaging examinations

Cranial CT revealed a subarachnoid hemorrhage (Figure 1).

Figure 1 Computed tomography and angiography. A: Computed tomography(CT) scan showing increased density in the posterior horns of the bilateral ventricles and partial sulci, diagnosed as a subarachnoid hemorrhage; B: Cerebral angiography image showing a saccular bulge in the choroidal segment of the internal carotid artery without contrast agent extravasation, which was speculated to be an arterial ampulla. In addition, a blister-like aneurysm ruptured and bled (arrow); C and D: Show that we used microguidewire electrocoagulation surgery to treat the aneurysm (arrow); E: Shows that after the third continuous electrocoagulation, revisualization of the aneurysm was absent (arrow); F: CT scan reexamination 3 days after surgery shows no obvious subarachnoid hemorrhage; G: CT angiography reexamination 3 months after surgery revealed no contrast agent extravasation in the original lesion, with a good prognosis (arrow).

FINAL DIAGNOSIS

The patient was diagnosed with rupture of an aneurysm in the choroidal segment of the right internal carotid artery and subarachnoid hemorrhage.

TREATMENT

The patient was scheduled for cerebral angiography and interventional embolization of the aneurysm. The patient was given 300 mg of aspirin and 300 mg of Plavix before the operation. After general anesthesia was successfully induced, Seldinger puncture was performed on the right femoral artery, and a 6F arterial sheath was inserted. During cerebral angiography, a blister-like microaneurysm was found in the choroidal segment of the internal carotid artery. The size of the aneurysm was 2.00 mm × 1.80 mm × 1.97 mm, and the neck of the aneurysm was less than 0.5 mm wide. The aneurysm neck was so narrow that the Echelon 10 microcatheter could not reach the aneurysm lumen. Thus, we introduced the tip of the ASAHI INTECC 0.014 guidewire into the aneurysm lumen, connected the proximal end to the Solitaire stent detachment system, and coagulated the lesion with a current of 4.8 V and 1.0 mA for 1 minute. After coagulation, repeat angiography was performed, which revealed delayed visualization of the aneurysm. The procedure was repeated for 5 minutes, with further delayed visualization of the aneurysm. Finally, after the third continuous coagulation for 10 minutes, angiography revealed that no contrast agent flowed into the aneurysm lumen. After the site was observed for half an hour, the aneurysm was not revisualized, and the parent artery remained patent.

OUTCOME AND FOLLOW-UP

Three days after the procedure, a follow-up CT revealed no obvious subarachnoid hemorrhage. Three months later, a follow-up cranial computed tomography angiography revealed that the original lesion did not recur and had a good prognosis (Table 1).

Table 1 Imaging examinations of the patient.

	Before surgery	During surgery	3 days after surgery	3 months after surgery
Imaging examination	Computed tomography scan showed a subarachnoid hemorrhage	Cerebral angiography revealed an aneurysm in the choroidal segment of the right internal carotid artery; after endovascular electrocoagulation, this site was free of contrast agent extravasation	CT shows no obvious subarachnoid hemorrhage	CT angiography shows no contrast agent extravasation in the original lesion, with a good prognosis

CT: Computed tomography.

DISCUSSION

The wall of the aneurysm is thin and fragile, so the method of clipping the aneurysm carries a high risk. Therefore, they are more amenable to endovascular interventional therapy[10], such as flow diversion, coil therapy, and balloon-assisted or stent-assisted techniques. Flow diversion is a promising treatment option. The principle of this method is that the use of pipeline embolization device can prevent blood from flowing into the aneurysm[11]. However, in this case, the aneurysm was located close to the anterior choroidal artery and posterior communicating artery, flow diversion may affect the blood flow in these branch vessels[12]. Considering that the anterior choroidal artery is involved in supplying blood to important functional areas, a flow diverter device was not used in this patient. Moreover, the high cost of flow diversion is also a factor that cannot be ignored.

Microaneurysms often occur in low-flow arteries and tend to undergo spontaneous embolization, with the potential to transform into benign lesions. Therefore, the risk of such aneurysms is often underestimated. The neck of the aneurysm was less than 0.5 mm wide; thus, the aneurysm neck was too narrow to allow the microcatheter to enter the aneurysm lumen. Therefore, the surgical strategy was adjusted intraoperatively: Microguidewire coagulation was used to occlude the ruptured and bleeding aneurysm. The selection and adjustment of microguidewires are crucial for the success of coagulation procedures. Microguidewires should not only have strong deliverability but also excellent electrical conductivity. Theoretically, greater power and longer coagulation times can promote faster thrombus formation. However, regarding safety considerations, the coagulation power should be reduced to a safe range to avoid damaging the wall of the parent artery. The aneurysm can gradually be occluded by increasing the coagulation time in a stepwise manner.

The mechanism underlying endovascular electrocoagulation for intracranial microaneurysms remains unclear. A possible mechanism is that a certain range of constant direct currents can attract negatively charged factors in the blood, such as platelets, red blood cells, white blood cells, fibrin, and clotting factors, to induce thrombus formation. Additionally, the electrothermal effect generated by an electrical current can accelerate thrombus formation, further promote thrombus degeneration and organization, and transform unstable thrombi into stable thrombi. An appropriate current intensity can promote the formation of thrombi, while the thermal effect over a certain period of time can induce thrombus degeneration and organization, prevent the fibrinolytic process, stabilize the thrombus, and reduce the chance of rerupture and hemorrhage of the aneurysm. The main concern with this technique is whether aneurysm rerupture will occur after the operation, so long-term follow-up is needed. The risk of rerupture is 4% to 14% in the first 24 hours after aneurysmal subarachnoid hemorrhage[13]. The risk of recurrent rupture is closely related to the degree of aneurysm occlusion, with the lowest risk occurring after complete occlusion[14]. Endovascular electrocoagulation therapy is suitable for aneurysms with a diameter of less than 2 mm in which the microcatheter cannot be positioned properly.

In addition, there are several emerging therapies for the treatment of subarachnoid hemorrhage[15]. The use of nanoparticles (NPs) has emerged as a promising new method for targeted drug delivery[16]. Microcatheters can be used to deliver NPs loaded with drugs that promote endothelialization or anti-inflammation at the target site, which significantly increases the local drug concentration, accelerates the healing of aneurysms, and reduces the recurrence rate. We speculate that the combined use of endovascular interventional technology and NPs will lead to better treatment of subarachnoid hemorrhage.

CONCLUSION

The microguidewire coagulation technique is an effective and simple method for treating ruptured microaneurysms with good efficacy and no need for antiplatelet therapy. Short-term follow-up results have demonstrated its safety and effectiveness, but large samples and long-term follow-up data are still needed for verification.