Branch vessel occlusion in aneurysm treatment with flow diverter stent

Risk factor analysis of changes in blood flow in the A1 segment of the anterior cerebral artery after flow-diverter coverage of it

Few studies have explored the effect of a flow-diverter device (FD) on blood flow in the A1 segment of the anterior cerebral artery (ACA), after treatment of intracranial aneurysms in the bifurcation region of the internal carotid artery (ICA). The main objective of this article is to investigate the factors that affect A1 blood flow after FD covers the A1 artery. This is a single-center, retrospective study. Data were collected retrospectively from our center, and patients whose FDs were placed for treatment from the terminal of the ICA to the M1 segment were analyzed. A total of 42 patients were included in the study. Immediate post-procedural angiography following device placement revealed decreased blood flow in the A1 of 15 (35.7%) patients and complete occlusion of the A1 segment in 11 (26.2%) patients. During an average follow-up period of 9.8 months, the A1 segment was ultimately occluded in 25 patients (59.5%) and decreased blood flow in 4 patients (9.5%). When using FD to cover the A1 artery for the treatment of intracranial aneurysms, patients with preoperative opening of the anterior communicating artery (AcomA) are more prone to occlusion or decreased blood flow of the A1 artery, compared to patients without opening.

Flow-diverter stents in intracranial aneurysm treatment: impact on covered cerebral artery branches

OBJECTIVE

Flow diverter stents (FDSs) have attracted interest for intracranial aneurysm (IA) treatment; however, occlusion of side branches and related complications have been reported. This study aimed to investigate the effects of FDSs in IA management when different branches of intracranial arteries are covered.

MATERIALS AND METHODS

A cross-sectional study was conducted using PUBMED, Embase, Web of Science, and Cochrane databases to include randomized or nonrandomized comparative-designed studies from January 2000 to August 2022 which reported outcomes of occlusion/narrowing of branches after IA treatment using FDSs. The PRISMA guidelines were used for our report. A random-effects meta-analysis was conducted to pool the outcomes, which included incidence rates of occlusion/narrowing of FDS-covered branches, branch occlusion-related symptoms, obliteration of IAs, and ideal clinical outcomes (modified Rankin Scale score ≤2).

RESULTS

The authors identified 57 studies involving 3789 patients with IA managed by FDSs covering different branches. During the median imaging follow-up at 12 months, the IA obliteration rate was satisfactory (>70%) when covering the ophthalmic artery (OA), posterior communicating artery (PComA), anterior choroidal artery (AChoA) or anterior cerebral artery (ACA), but not the middle cerebral artery-M2 segment (MCA-M2; 69.5%; 95% CI: 60.8-77.5%) and posterior inferior cerebellar artery (PICA; 59.1%, 13/22). The overall ideal clinical outcome was observed in 97.4% of patients (95% CI: 95.5-98.9%). Higher rates of occlusion/narrowing of branches were identified when FDSs covered the ACA (66.6%; 95% CI: 45.1-85.3%), PComA (44.3%; 95% CI: 34.2-54.6%), or MCA-M2 (39.2%; 95% CI: 24.5-54.7%); the risks were lower when covering the OA (11.8%; 95% CI: 8.8-15.1%), PICA (6.8%; 95% CI: 1.5-14.5%), and AchoA (0.5%; 95% CI: 0.0-2.9%). The risk of branch occlusion-related complications was low (incidence rate <5%) for each of the six evaluated branches.

CONCLUSIONS

Acceptable outcomes were identified following treatment of IAs when FDSs were placed across each of the six studied cerebral arteries. Treatment decisions regarding FDS placement across branch arteries should be made with the risk of complications from branch occlusion in mind.

Flow Diverting Stents in Cerebral Small Caliber Vessels (< 2 mm) for Aneurysm Treatment : A Three Center Retrospective Study

PURPOSE

The off-label use of flow diverting stents (FDS) for treating cerebral aneurysms in small distal vessels is increasing in clinical practice with encouraging results; however, data directly addressing the parent vessel size are still scarce. Our aim was to evaluate the safety and efficacy of FDS placement in anterior and posterior circulation aneurysms with parent arteries ≤ 2 mm in a real-world representative setting.

METHODS

We retrospectively reviewed patients treated with FDS at the three participating university hospitals between 2009 and 2021. The inclusion criteria were the placement of at least one FDS in a parent vessel with a maximum diameter of 2 mm or less. The primary clinical safety endpoint was the absence of death, major or minor symptomatic stroke, transient ischemic attack and procedure-related intracranial hemorrhage. Clinical outcome was assessed using the modified Rankin Scale (mRS) score at the follow-up visit at 1 year. The primary efficacy endpoint was defined as complete and near-complete occlusion at the 1‑year follow-up.

RESULTS

We identified 55 patients harboring 56 aneurysms. The primary clinical safety endpoint was obtained in 93% of cases. The hemorrhagic and thromboembolic complication rates were 4% and 9%, respectively. No patient died or had a relevant discrepancy (> 1 point) at the pre-mRS and post-mRS. The primary efficacy endpoint was reached in 80% of cases.

CONCLUSION

The use of FDS in vessels < 2 mm is technically feasible with good aneurysm occlusion rates and an acceptable safety profile. Nevertheless, it is essential to be aware of the of the main complications associated when operating in small diameter vessels.

Acute Intraprocedural Thrombosis After Flow Diverter Stent Implantation: Risk Factors and Relevance of Standard Observation Time for Early Detection and Management

PURPOSE

Acute intraprocedural thrombosis (AIT) is a severe complication of flow diverter stent (FDS) implantation for the treatment of intracranial aneurysms. Even though device-related thromboembolic complications are well known, there are no acknowledged risk factors nor defined surveillance protocols for their early detection. This study aimed to demonstrate that an angiographic active surveillance is effective to detect and treat AIT. Furthermore, we investigated risk factors for the occurrence of AIT.

METHODS

A prospective institutional protocol consisting of a defined observation period of 30 min following FDS deployment was established to detect AIT. Overall incidence, as well as the efficacy and safety of AIT treatment were assessed. Moreover, radiological and clinical outcomes of patients with AIT were analyzed. The influence of various patient- and procedure-related factors on the occurrence of AIT was investigated using multivariable forward logistic regression.

RESULTS

During active surveillance twelve cases of AIT were observed among a total of 161 procedures (incidence: 7.5%). The median time of first observation was 15.5 min (IQR 9.5) after FDS implantation. The early recognition of AIT ensured a prompt treatment with intravenous application of a glycoprotein IIb/IIIa inhibitor, which led to complete thrombus resolution in all cases without hemorrhagic complications. Patients with pre-existing arterial hypertension and side branches originating from the aneurysmal sac had a higher risk of AIT (respectively OR, 9.844; OR, 3.553). There were two cases of re-thrombosis in the short-term postoperative period, of whom one died. The remaining patients with AIT had a good clinical outcome.

CONCLUSION

Active surveillance for 30 min after FDS implantation is an effective strategy for early detection and ensuing treatment of AIT and can thus prevent secondary sequalae. Hypertension and side branches originating from the aneurysmal sac may increase the risk of AIT.

Vertebral artery V3 portion-radial artery-distal common carotid artery (V3-RA-dCCA) bypass for large basilar trunk aneurysm with bilateral proximal common carotid artery occlusion-technical note

BACKGROUND

Large basilar trunk aneurysm caused by bilateral occlusion of the proximal common carotid artery is rare. We treated one case with vertebral V3 portion-radial artery-distal common carotid artery (V3-RA-dCCA) bypass.

CASE DESCRIPTION

Basilar trunk aneurysm and bilateral occlusion of the proximal CCA were found incidentally in a 70-year-old woman. During the next 5 years, the aneurysm gradually enlarged to 12 mm, and blood flow of the anterior circulation was supplied through the posterior communicating artery. V3-RA-dCCA bypass was performed to reduce the stress of blood flow and prevent aneurysm growth and rupture. After exposing the neck portion, forearm of RA, and V3 portion of the vertebral artery, we created a space just below the sternocleidomastoid muscle to bypass the RA. We flushed the RA with albumin to stiffen the artery and temporarily clamped the bilateral sides of the RA to prevent twisting. We anastomosed the V3 and RA with a 9-0 thread and temporarily clamped the V3. After flushing the RA with albumin to prevent twisting, we clamped the external and internal carotid arteries, opened the dCCA with a vascular punch to prevent arterial dissection, and anastomosed the RA to the dCCA. The patency of the bypass was confirmed with Doppler and indocyanine green video angiography. The postoperative course was uneventful, bypass patency was good, and the aneurysm did not expand further.

CONCLUSION

V3-RA-dCCA bypass may be an effective and low-risk treatment for large basilar trunk aneurysms with bilateral occlusion of the proximal common carotid artery.