Persistent aneurysm growth following pipeline embolization device assisted coiling of a fusiform vertebral artery aneurysm: a word of caution!

Flow Redirection Endoluminal Device Flow Diverter Placement for Recurrent Dolichoectatic Vertebrobasilar Artery Aneurysm Treated with Multiple Low-Profile Visualized Intraluminal Support Stents: A Case Study

Objective

We report a case of dolichoectatic vertebrobasilar aneurysms treated with multiple low-profile visualized intraluminal support (LVIS) stents followed by flow redirection endoluminal device (FRED) flow diverter to prevent the growth of the thrombosed aneurysm.

Case Presentation

A 71-year-old man developed diplopia due to oculomotor nerve palsy after 11 years of follow-up for an enlarging thrombosed dolichoectatic vertebrobasilar artery aneurysm. He initially had a fusiform thrombosed aneurysm from the right vertebral artery to the basilar artery. This lesion was tortuous and strongly compressed the pons. A total of 11 LVISs were deployed from the right posterior cerebral artery to the right vertebral artery. Six months after surgery, there was no enlargement of the thrombosed aneurysm on MRI and the contrast leakage out of the stent was markedly reduced in DSA compared to immediately after surgery. One year and seven months after surgery, contrast leakage out of the stent was increased in DSA. The FRED was placed within the overlapped LVISs, and contrast leakage was somewhat reduced. After 2 years and 7 months from the initial treatment, the contrast leakage was still observed. However, there was no enlargement of the aneurysm and no complications related to treatments were observed.

Conclusion

Treatment with multiple LVIS stents followed by FRED flow diverter treatment for dolichoectatic vertebrobasilar aneurysms (DVAs) may be one of the treatment options for controlling the growth of thrombotic aneurysms without complications, but the long-term prognosis of this case is unclear, and careful follow-up is mandatory.

Treatment of Anterior Circulation Aneurysms in the Internal Carotid Artery With Flow Diverters

Several studies have shown the efficacy and feasibility of flow diversion for the endovascular treatment of wide-necked and otherwise anatomically challenging intracranial aneurysms (IA). Technological advances have led to successful long-term occlusion rates and a safety profile for flow-diverter stents that parallels other endovascular and open surgical options for these lesions. With growing indications for use of the Pipeline Embolization Device (PED, Medtronic, Dublin, Ireland) to include IAs up to the internal carotid artery (ICA) terminus, understanding the nuances of this technology is increasingly relevant. Furthermore, there is a growing body of literature on the use of flow diversion to treat distal (up to A2, M2, and P2), ruptured, and posterior circulation aneurysms, although these applications are "off-label" at present. In this manuscript, we discuss the expanding role of flow diversion in the ICA and compare this technique with other endovascular options for the treatment of ICA IAs. We also discuss technical nuances of the deployment of flow diverters for the treatment of challenging lesions and in difficult and tortuous anatomy.

Update on flow diverters for the endovascular management of cerebral aneurysms

Flow diversion has become a well-accepted option for the treatment of cerebral aneurysms. Given the significant treatment effect of flow diverters, numerous options have emerged since the initial Pipeline embolization device studies. In this review, the authors describe the available flow diverters, both endoluminal and intrasaccular, addressing nuances of device design and function and presenting data on complications and outcomes, where available. They also discuss possible future directions of flow diversion.

Natural History of Vertebrobasilar Dolichoectatic and Fusiform Aneurysms: A Systematic Review and Meta-Analysis

Background and Purpose: Vertebrobasilar non-saccular and dolichoectatic aneurysms (VBDA) are a rare type of aneurysm and are generally associated with poor prognosis. In order to better characterize the natural history of VBDAs, we performed a systematic review and meta-analysis of the literature to determine rates of mortality, growth, rupture, ischemia, and intraparenchymal hemorrhage. Materials and Methods: We searched the literature for longitudinal natural history studies of VBDA patients reporting clinical and imaging outcomes. Studied outcomes included annualized rates of growth, rupture, ischemic stroke, intracerebral hemorrhage (ICH), and mortality. We also studied the association between aneurysm morphology (dolichoectatic versus fusiform) and natural history. Meta-analysis was performed using a random-effects model using summary statistics from included studies. Results: Fifteen studies with 827 patients and 5,093 patient-years were included. The overall annual mortality rate among patients with VBDAs was 13%/year (95% CI 8–19). Patients with fusiform aneurysms had a higher mortality rate than those with dolichoectatic aneurysms, but this did not reach statistical significance (12 vs. 8%, p = 0.11). The overall growth rate was 6%/year (95% CI 4–13). Patients with fusiform aneurysms had higher growth rates than those with dolichoectatic aneurysms (12 vs. 3%, p < 0.0001). The overall rupture rate was 3%/year (95% CI 1–5). Patients with fusiform aneurysms had higher rupture rates than those with dolichoectatic aneurysms (3 vs. 0%, p < 0.0001). The overall rate of ischemic stroke was 6%/year (95% CI 4–9). Patients with dolichoectatic aneurysms had higher ischemic stroke rates than those with fusiform aneurysms, but this did not reach statistical significance (8 vs. 4%, p = 0.13). The overall rate of ICH was 2%/year (95% CI 0–8) with no difference in rates between dolichoectatic and fusiform aneurysms (2 vs. 2%, p = 0.65). Conclusion: In general, the natural history of ­VBDAs is poor. However, dolichoectatic and fusiform ­VBDAs appear to have distinct natural histories with substantially higher growth and rupture associated with fusiform aneurysms. These findings suggest that these aneurysms should be considered separate entities. Further studies on the natural history of vertebrobasilar dolichoectatic and fusiform aneurysms with more complete follow-up are needed to better understand the risk factors for progression of these aneurysms.

Pipeline embolization device retraction and foreshortening after internal carotid artery blister aneurysm treatment

Background Subarachnoid hemorrhage (SAH) secondary to rupture of a blister aneurysm (BA) results in high morbidity and mortality. Endovascular treatment with the pipeline embolization device (PED) has been described as a new treatment strategy for these lesions. We present the first reported case of PED retraction and foreshortening after treatment of a ruptured internal carotid artery (ICA) BA. Case description A middle-aged patient presented with SAH secondary to ICA BA rupture. The patient was treated with telescoping PED placement across the BA. After 5 days from treatment, the patient developed a new SAH due to re-rupture of the BA. Digital subtraction angiography revealed an increase in caliber of the supraclinoid ICA with associated retraction and foreshortening of the PED that resulted in aneurysm uncovering and growth. Conclusions PED should be oversized during ruptured BA treatment to prevent device retraction and aneurysm regrowth. Frequent imaging follow up after BA treatment with PED is warranted to ensure aneurysm occlusion.

Application of parallel stent placement in the treatment of unruptured vertebrobasilar fusiform aneurysms

OBJECTIVE

Large vertebrobasilar fusiform aneurysms (VFAs) represent a small subset of intracranial aneurysms and are often among the most difficult to treat. Current surgical and endovascular techniques fail to achieve a complete or acceptable result because of complications, including late-onset basilar artery thrombosis and perforator infarction. The parallel-stent placement technique was established in the authors' department, and this study reports the application of this technique in the treatment of unruptured VFAs.

METHODS

Eight patients with 8 unruptured VFAs who underwent parallel stent placement between April 2011 and August 2012 were included. The diameters of the VFAs ranged from 7.9 to 14.0 mm, and the lengths from 27.5 to 54.4 mm. Of the 8 patients with unruptured VFAs, 3 received double or triple parallel stents and 5 patients received a series-connected stent with another 1 or 2 stents deployed parallel to them. Outcomes for these patients were tabulated, based on the modified Rankin Scale (mRS) score and angiographic results.

RESULTS

All of the 25 stents were successfully placed without any treatment-related complications. During follow-up, 5 patients had decreased mRS scores, 2 were unchanged, and 1 was increased for subarachnoid hemorrhage. Immediate and follow-up clinical outcome was completely or partially recovered in most patients. Follow-up angiograms revealed 2 aneurysms were reduced in size and 6 were unchanged after stent placement. No in-stent stenosis, occlusion of the posterior inferior cerebellar artery, or perforators jailed by the stent occurred in any of the aneurysms.

CONCLUSIONS

These results provide encouraging support for the parallel-stent placement technique, which can be envisaged as an alternative strategy against unruptured VFAs. However, testing in more patients is needed.

Imaging Characteristics of Growing and Ruptured Vertebrobasilar Non-Saccular and Dolichoectatic Aneurysms

Background and Purpose—

Vertebrobasilar, nonsaccular, and dolichoectatic aneurysms generally have a poor natural history. We performed a study examining the natural history of vertebrobasilar, nonsaccular, and dolichoectatic aneurysms receiving serial imaging and studied imaging characteristics associated with growth and rupture.

Methods—

We included all vertebrobasilar dolichoectatic, fusiform, and transitional aneurysms with serial imaging follow-up seen at our institution over a 15-year period. Two radiologists and a neurologist evaluated aneurysms for size, type, mural T1 signal, mural thrombus, daughter sac, mass effect, and tortuosity. Primary outcomes were aneurysm growth or rupture. Univariate analysis was performed with chi-squared tests for categorical variables and Student’s t test or analysis of variance for continuous variables. Multivariate logistic regression analysis was performed to identify variables independently associated with aneurysm growth or rupture.

Results—

One hundred and fifty-two patients with 542 patient-years (mean 3.6±3.5 years) of imaging follow-up were included. Aneurysms were fusiform in 45 cases (29.6%), dolichoectatic in 75 cases (49.3%), and transitional in 32 cases (21.1%). Thirty-five aneurysms (23.0%) grew (growth rate=6.5%/year). Eight aneurysms (5.3%) ruptured (rupture rate=1.5%/year). Variables associated with growth and rupture on univariate analysis were size >10 mm (57.6% versus 16.0%, P <0.0001), mural T1 signal (39.7% versus 16.3%, P =0.001), daughter sac (56.3% versus 21.3%), and mural thrombus (45.5% versus 13.4%, P <0.0001). 26.7% of fusiform aneurysms, 9.3% of dolichoectatic aneurysms, and 59.4% of transitional aneurysms grew or ruptured ( P <0.0001). The only variable independently associated with rupture was transitional morphology ( P =0.003).

Conclusions—

Vertebrobasilar, nonsaccular, and dolichoectatic aneurysms are associated with a poor natural history with high growth and rupture rates. Further research is needed to determine the best treatments for this disease.