Ruptured dissecting aneurysm in communicating internal carotid artery segments treated using a stent-assisted endovascular technique

Abstract

Hemorrhagic intracranial dissecting aneurysms are known to have a poor natural history and an increased tendency to rebleed. The communicating segment of the internal carotid artery (ICA) is an infrequent site of dissection that is difficult to manage using deconstructive endovascular treatment because of the need to preserve important vascular branches. We report two cases of ruptured dissecting aneurysms that occurred in communicating segments of the ICA and treated using a reconstructive endovascular technique involving stent-assisted coiling. Case 1 was a 59-year-old woman who was diagnosed with subarachnoid hemorrhage (SAH). Digital subtraction angiography (DSA) indicated a ruptured dissecting aneurysm that arose from the left communicating segment of the ICA. Stent-assisted coiling was performed and followed by a second overlapping stent technique. No deterioration was observed on DSA after one week of follow-up or on magnetic resonance angiography (MRA) after four months of follow-up. The patient was discharged without neurological complications (Glasgow Outcome Scale 5). Case 2 was a 34-year-old man who was admitted with a diagnosis of SAH. DSA revealed a suspected lesion of a ruptured dissecting aneurysm of the left communicating segment of the ICA. Stent-assisted coiling was performed, and partial occlusion was achieved. No deterioration was observed on DSA after two weeks of follow-up or on MRA after six months of follow-up. The patient was discharged without neurological complications (Glasgow Outcome Scale 5). These cases suggest that using stent-assisted coiling could be a feasible modality for treating ruptured ICA dissecting aneurysms in the communicating segment.

Introduction

Hemorrhagic intracranial dissecting aneurysms have been reported to account for 1% to 10% of adult patients with subarachnoid hemorrhage (SAH). ¹ Hemorrhagic dissecting aneurysms are known to have a poor natural history due to an increased tendency for rebleeding during the acute period of SAH. The rate of rebleeding within the first 24 hours has been reported to be as high as 40%.^1–4 Rebleeding is a fatal complication with a mortality rate of nearly 50%.^1,2,4–6 Therefore, urgent treatment is mandatory to prevent rebleeding. The communicating segment of the internal carotid artery (ICA) is an infrequent site of dissection that is difficult to manage using deconstructive endovascular techniques, such as internal trapping, because of the need to preserve important vascular branches of the anterior choroidal or posterior communicating artery.

Here, we report two cases of ruptured dissecting aneurysm arising from the communicating segment of the ICA that were treated with stent-assisted coiling, a reconstructive endovascular technique.

Case presentation

All procedures were performed under general anesthesia. A biplane angiographic unit (Artis Zee biplane system, Siemens, Munich, Germany) was used. The right femoral artery was accessed using a 6-Fr 80 cm-long Shuttle sheath (Cook, Bloomington, IN, USA). A 6-Fr guiding catheter (Envoy; Cordis, Miami Lakes, FL, USA) was then placed in the petrous segment of the ICA. An XT-27 microcatheter (Stryker, Fremont, CA, USA) was navigated distal to the lesion over a Synchro 0.014 microwire (Stryker, Fremont, CA, USA) in order to deploy the Neuroform stent (4.5 × 15 mm) (Boston Scientific Target, Fremont, CA, USA). An SL-10 microcatheter (Boston Scientific, Natick, MA, USA) was used to select the lesion. In case of aneurysm rupture, an initial 3000 IU bolus of heparin was administered after three-dimensional rotational digital subtraction angiography (DSA). An additional 1000 IU bolus of heparin was administered hourly to maintain an activated clotting time of ≥250 seconds. Antiplatelet therapy was administered after the procedure, and a 300 mg loading dose of aspirin and clopidogrel was administered orally or via a nasogastric tube. Postoperatively, dual antiplatelet therapy (100 mg/day aspirin, 75 mg/day clopidogrel) was maintained. Resistance to antiplatelet agents was measured using Verify Now platelet inhibition assays (Accumetrics, San Diego, CA, USA). If the patient was resistant to the antiplatelet agents, 200 mg/day of oral cilostazol was administered.

Case 1

A 59-year-old woman was admitted to the emergency room with severe headache (Hunt-Hess grade 2). A computed tomography (CT) scan showed an SAH (Figure 1). DSA suggested a ruptured dissecting aneurysm arising from the left distal ICA that involved the posterior communicating and anterior choroidal arteries. Stent-assisted coiling was performed and followed by a second overlapping stent technique and partial occlusion. No deterioration was observed on DSA after one week of follow-up or on magnetic resonance angiography (MRA) after four months of follow-up. The patient was discharged without neurological complications (Glasgow Outcome Scale 5).

Figure 1.

(Case 1) Initial non-contrast computed tomography (CT) (a) showed a subarachnoid hemorrhage (SAH) on the left Sylvian fissure and basal cistern. Fusiform dilation of the left communicating segment of the internal carotid artery (ICA) was observed on CT angiography (b). Digital subtraction angiography (DSA) ((c) and (d)) demonstrated a fusiform dilation of the left communicating segment of the ICA. Post-procedural DSA ((e) and (f)) revealed the lesion was partially occluded by stent-assisted coiling. No deterioration was observed on DSA (g) after one week of follow-up or on magnetic resonance angiography (h) after four months of follow-up.

Case 2

A 34-year-old man was admitted to the emergency room with stupor mentality (Hunt-Hess grade 4). A CT scan showed an SAH, and DSA revealed a suspected lesion of a ruptured dissecting aneurysm arising from the left communicating segment of the ICA (Figure 2). The aneurysm consisted of two aneurysmal dilations (2.5 cm and 2.9 cm) that presented as pearl signs. Stent-assisted coiling was performed using the consecutive jailing technique. Partial occlusion was also performed. No deterioration was observed on DSA after two weeks of follow-up or on MRA after six months of follow-up. The patient was discharged without neurological complications (Glasgow Outcome Scale 5).

Figure 2.

(Case 2) Initial non-contrast computed tomography (CT) showed diffuse subarachnoid hemorrhage (SAH) (a). Fusiform dilation consisting of two aneurysmal dilations that presented as pearl signs was observed on CT angiography of the left communicating segment of the internal carotid artery (ICA) (b). Digital subtraction angiography (DSA) ((c) and (e)) demonstrated fusiform dilatation and a linear filling defect that was suspected of having been caused by an intimal flap ((d) white arrow) in the left communicating segment of the ICA. The illustration (f) is a schematic representation of the DSA (e). A post-procedural DSA ((g) and (h)) revealed that stent-assisted coiling had partially occluded the lesion. No deterioration was observed on DSA (i) after two weeks of follow-up or on magnetic resonance angiography (j) after six months of follow-up.

Discussion

The communicating segment is the terminal portion of the ICA. It extends from the origin of the posterior communicating artery to the bifurcation of the ICA and is an infrequent site of dissecting aneurysms. Several studies have reported that 76% to 93% of dissecting aneurysms occur in the posterior circulation.^3,7–11 Among those that occur in the anterior circulation, the most common site of dissecting aneurysms is the middle cerebral artery (MCA), followed by the ICA.^12–15

The characteristic radiological signs include a double lumen, intimal flap, and mural hematoma. ² Diagnosing an intracranial dissecting aneurysm is challenging because the vessel wall is thin and may have no double lumen or intimal flap. Additionally, the characteristic signs can be difficult to detect because of the small size of the intracranial arteries and because they tend to develop rapid morphological changes over time. ¹⁶ Therefore, a definite diagnosis of an intracranial dissecting aneurysm requires imaging of the arterial wall and lumen as well as serial follow-up imaging, the results of which should be compared with the baseline images. ² However, we diagnosed case 1 as a dissecting aneurysm without additional imaging studies because no vascular abnormality was present other than fusiform dilation in the location associated with the SAH, and urgent treatment was required to prevent fatal rebleeding. Ohkuma et al. also noted that dissecting aneurysms of the ICA should be considered as a possible cause in patients with SAH of unknown cause. ¹⁴ However, we diagnosed case 2 as a dissecting aneurysm based on DSA results, which showed a suspected linear filling defect of the intimal flap in the left communicating segment of the ICA.

Therapeutic approaches for an SAH caused by a dissecting aneurysm differ from those used to treat an SAH caused by a saccular aneurysm. The goal of treatment is to cease blood flow in the dissected lesion. Many centers consider endovascular parent artery occlusion (PAO) the first therapeutic option. ² Balloon test occlusion (BTO) is performed before PAO to confirm sufficient collateral blood supply, but PAO is a limited therapeutic option when BTO fails. In addition, ischemic complications may develop in 5% to 10% of patients who have undergone successful BTO. ¹⁷ Endovascular trapping combined with bypass surgery is considered a good treatment option for patients with ICA lesions. However, this procedure can potentially result in the occlusion of the posterior communicating artery or anterior choroidal artery and subsequent cerebral ischemia when used in the communicating segment. Combining endovascular trapping with bypass surgery may therefore be an inappropriate modality for ICA dissection in the communicating artery segment. Endovascular techniques involving stent placement or stent-assisted coiling are also available as a therapeutic option in cases with insufficient collateral blood supply or in which important vessel branches must be preserved. However, reconstructive endovascular techniques are often difficult to perform in intracranial dissecting aneurysms because these lesions are usually non-saccular aneurysms or pseudoaneurysms. Additionally, endovascular devices, such as a stent, require antiplatelet medication to be administered for several months after the procedure, and this exposes patients to an increased risk of hemorrhagic complications.^2,18,19

In the two cases presented here, we hypothesized that the dissecting aneurysm of the ICA would be difficult to manage using deconstructive treatment, including PAO and trapping with bypass surgery, because there was a need to preserve the posterior communicating artery and the anterior choroidal artery. Flow-diversion devices were viewed as an alternative therapeutic option because several reports have shown that a flow diverter is a feasible therapeutic option in SAH. However, the use of a flow-diverting stent to treat a ruptured cerebral aneurysm has not yet been approved in Korea. For this reason, we excluded the use of flow-diversion devices. We therefore used stent-assisted coiling in our two cases. Although reconstructive endovascular techniques are not optimal treatments for ruptured intracranial dissecting aneurysms, they may be feasible as temporary therapeutic options aimed at preventing rebleeding and reducing mortality during the acute period of SAH. After the procedure, the patients were discharged without neurological complications, and no recurrence was observed in follow-up imaging in either case. However, stent-assisted coiling may not guarantee long-term durability. Therefore, serial imaging is mandatory during the follow-up period to confirm morphologic changes in the lesion and to determine whether additional treatment is needed.

Conclusion

An intracranial hemorrhagic dissecting aneurysm requires urgent treatment to prevent rebleeding. During the acute period of SAH, reconstructive endovascular techniques could be a feasible temporary therapeutic option, and serial follow-up is mandatory in such cases to monitor the progression of the lesion.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.