Aneurysms with persistent filling after failed treatment with the Pipeline embolization device

View More View Less
  • 1 Department of Neurological Surgery, Thomas Jefferson University and Jefferson Hospital for Neuroscience, Philadelphia, Pennsylvania; and
  • 2 Departments of Neurosurgery and
  • 3 Radiology, University of Miami, Florida
Full access

OBJECTIVE

The Pipeline embolization device (PED) has become a valuable tool in the treatment of cerebral aneurysms. Although failures with PED treatment have been reported, the characteristics and course of these aneurysms remain a topic of uncertainty.

METHODS

Electronic medical records and imaging studies were reviewed for all patients treated with the PED between July 2010 and March 2015 to identify characteristics of patients and aneurysms with residual filling after PED treatment.

RESULTS

Of 316 cases treated at a single institution, 281 patients had a long-term follow-up. A total of 52 (16.4%) aneurysms with residual filling were identified and constituted the study population. The mean patient age in this population was 58.8 years. The mean aneurysm size was 10.1 mm ± 7.15 mm. Twelve aneurysms were fusiform (23%). Of the aneurysms with residual filling, there were 20 carotid ophthalmic (CO) aneurysms (20% of all CO aneurysms treated), 10 other paraclinoid aneurysms (16.4% of all paraclinoid aneurysms), 7 posterior communicating artery (PCoA) aneurysms (21.9% of all PCoA aneurysms), 7 cavernous internal carotid artery (ICA) aneurysms (14.9% of all cavernous ICA aneurysms), 4 vertebrobasilar (VB) junction aneurysms (14.8% of all VB junction aneurysms), and 3 middle cerebral artery (MCA) aneurysms (25% of all MCA aneurysms). Eleven patients underwent placement of more than one PED (21.2%), with a mean number of devices of 1.28 per case. Eight of 12 aneurysms were previously treated with a stent (15.4%). Nineteen patients underwent re-treatment (36.5%); the 33 patients who did not undergo re-treatment (63.5%) were monitored by angiography or noninvasive imaging. In multivariate analysis, age older than 65 years (OR 2.65, 95% CI 1.33–5.28; p = 0.05), prior stent placement across the target aneurysm (OR 2.94, 95% CI 1.15–7.51; p = 0.02), aneurysm location in the distal anterior circulation (MCA, PCoA, and anterior choroidal artery: OR 2.72, 95% CI 1.19–6.18; p = 0.017), and longer follow-up duration (OR 1.06, 95% CI 1.03–1.09; p < 0.001) were associated with incomplete aneurysm occlusion.

CONCLUSIONS

While the PED can allow for treatment of large, broad-necked aneurysms with high efficacy, treatment failures do occur (16.4%). Aneurysm size, shape, and previous treatment may influence treatment outcome.

ABBREVIATIONS AChA = anterior choroidal artery; FD = flow diverter; ICA = internal carotid artery; MCA = middle cerebral artery; PCoA = posterior communicating artery; PED = Pipeline embolization device; SAH = subarachnoid hemorrhage.

OBJECTIVE

The Pipeline embolization device (PED) has become a valuable tool in the treatment of cerebral aneurysms. Although failures with PED treatment have been reported, the characteristics and course of these aneurysms remain a topic of uncertainty.

METHODS

Electronic medical records and imaging studies were reviewed for all patients treated with the PED between July 2010 and March 2015 to identify characteristics of patients and aneurysms with residual filling after PED treatment.

RESULTS

Of 316 cases treated at a single institution, 281 patients had a long-term follow-up. A total of 52 (16.4%) aneurysms with residual filling were identified and constituted the study population. The mean patient age in this population was 58.8 years. The mean aneurysm size was 10.1 mm ± 7.15 mm. Twelve aneurysms were fusiform (23%). Of the aneurysms with residual filling, there were 20 carotid ophthalmic (CO) aneurysms (20% of all CO aneurysms treated), 10 other paraclinoid aneurysms (16.4% of all paraclinoid aneurysms), 7 posterior communicating artery (PCoA) aneurysms (21.9% of all PCoA aneurysms), 7 cavernous internal carotid artery (ICA) aneurysms (14.9% of all cavernous ICA aneurysms), 4 vertebrobasilar (VB) junction aneurysms (14.8% of all VB junction aneurysms), and 3 middle cerebral artery (MCA) aneurysms (25% of all MCA aneurysms). Eleven patients underwent placement of more than one PED (21.2%), with a mean number of devices of 1.28 per case. Eight of 12 aneurysms were previously treated with a stent (15.4%). Nineteen patients underwent re-treatment (36.5%); the 33 patients who did not undergo re-treatment (63.5%) were monitored by angiography or noninvasive imaging. In multivariate analysis, age older than 65 years (OR 2.65, 95% CI 1.33–5.28; p = 0.05), prior stent placement across the target aneurysm (OR 2.94, 95% CI 1.15–7.51; p = 0.02), aneurysm location in the distal anterior circulation (MCA, PCoA, and anterior choroidal artery: OR 2.72, 95% CI 1.19–6.18; p = 0.017), and longer follow-up duration (OR 1.06, 95% CI 1.03–1.09; p < 0.001) were associated with incomplete aneurysm occlusion.

CONCLUSIONS

While the PED can allow for treatment of large, broad-necked aneurysms with high efficacy, treatment failures do occur (16.4%). Aneurysm size, shape, and previous treatment may influence treatment outcome.

ABBREVIATIONS AChA = anterior choroidal artery; FD = flow diverter; ICA = internal carotid artery; MCA = middle cerebral artery; PCoA = posterior communicating artery; PED = Pipeline embolization device; SAH = subarachnoid hemorrhage.

Flow diverters (FDs) are being used with increasing frequency, especially to target large and complex aneurysms that are not amenable to treatment with conventional endovascular methods.6,8,9,28 The Pipeline embolization device (PED) is the first FD approved by the FDA following the results of the PUFS (Pipeline for Uncoilable or Failed Aneurysms) trial for the management of large or giant wide-necked intracranial aneurysms in the internal carotid artery (ICA) from the petrous to the superior hypophyseal segments. Although initially indicated for a limited type of aneurysms, use of the PED is being extended for the management of a variety of aneurysms in different settings.3–5,7 The main factors that are considered in deciding if an aneurysm is suitable for treatment with the PED include aneurysm size, location, geometry and shape, and rupture status.14 Studies have shown a high technical success rate and a high rate of aneurysm occlusion accompanied by low recurrence and re-treatment rates.8,10,18 Current evidence also supports the PED as a safe device associated with low morbidity and mortality.8,19,24,29 Although treatment failure with flow diversion has been reported, the characteristics of these aneurysms with persistent filling have not been well established. Furthermore, the course of these aneurysms remains a topic of uncertainty. The initial thrombosis caused by FDs does not result in immediate cure of the aneurysm; rather, FDs act as a scaffold for endothelial overgrowth at the aneurysm neck, resulting intraaneurysmal flow stasis and thrombosis while promoting remodeling of the parent vessel. This parent vessel reconstruction results in gradual occlusion of the aneurysm, but there are concerns regarding delayed rupture or expanding mass effect, especially in failed cases.20 In this study, we aimed to evaluate the characteristics of aneurysms with persistent filling after treatment with the PED and identify factors associated with incomplete aneurysm occlusion.

Methods

Patient Selection

Patients with a history of intracranial aneurysms treated with the PED between July 2010 and March 2015 at a single institution (Thomas Jefferson University and Jefferson Hospital for Neuroscience) were identified. Electronic medical records and imaging studies were reviewed for all patients treated with the PED during this time period. A total of 316 cerebral aneurysms treated with the PED were identified. Patients who were lost to follow-up or died after treatment were excluded from the study (n = 35). A retrospective analysis of the 281 patients who had a registered follow-up was conducted to identify the latest aneurysm occlusion status and re-treatment status. The study population was divided into 2 groups: a complete aneurysm occlusion group (n = 229) and a group including aneurysms with persistent filling (n = 52). Baseline patient characteristics, aneurysm characteristics, and procedural characteristics were recorded. The study protocol was approved by the institutional review board.

Variables and Outcomes

The outcomes of interest in this study were to 1) evaluate the rate of persistent aneurysm filling with the PED at each patient’s latest follow-up, 2) identify characteristics and predictors of persistent aneurysm filling, 3) analyze the outcomes in cases with failed treatment with the PED, and 4) evaluate the rate of re-treatment as well as risk factors for aneurysm re-treatment.

Aneurysms with persistent filling included incompletely occluded aneurysms on the latest follow-up imaging study (digital subtraction angiography and MR angiography) and aneurysms that were re-treated during follow-up due to incomplete aneurysm occlusion with the initial PED intervention. Follow-up digital subtraction angiography was initially performed 6 months after PED deployment, and then planned depending on occlusion status to monitor for any persistent filling, recanalization, or residual filling. Aneurysm occlusion at follow-up was categorized as complete (100%), near-complete (≥ 90%), or incomplete (< 90%). All near-completely (> 90%) occluded aneurysms were included within the complete occlusion group in the statistical analysis.

Baseline characteristics that were evaluated and entered into univariate and multivariate analyses included patient age, sex, smoking status, hypertension, aneurysm size, aneurysm form (saccular, fusiform, dissecting pseudoaneurysm), aneurysm location, prior subarachnoid hemorrhage (SAH), SAH in the setting of flow diversion, previous aneurysm treatment (prior coiling, prior stent placement), simultaneous coil deployment with PED treatment, usage of balloon assistance with flow diversion, number of PEDs deployed, preoperative platelet reactivity units, and duration of follow-up.

Statistical Analysis

Data are presented as the mean and standard deviation for continuous variables, and as frequency for categorical variables. Analysis was carried out using the unpaired t-test, Wilcoxon rank-sum, chi-square, and Fisher’s exact tests as appropriate. Univariate analysis was used to test covariates predictive of the following dependent variables: persistent filling following PED placement and re-treatment. Interaction and confounding was assessed through stratification and relevant expansion covariates. Factors predictive in univariate analysis (p < 0.15) were entered into a multivariate logistic regression analysis; p ≤ 0.05 was considered statistically significant. Statistical analysis was carried out with Stata (version 10.0, StataCorp).

Results

Characteristics of Aneurysms With Persistent Filling

A total of 52 aneurysms with residual filling were identified, representing 16.4% of all treated aneurysms and 18.5% of the patients who underwent follow-up imaging (mean follow-up period 17.4 ± 11.6 months). The mean patient age in this population was 58.7 ± 13.9 years. The mean aneurysm size was 10.1 ± 7.15 mm. Twelve aneurysms were fusiform or dissecting pseudoaneurysms (23.1%), and 40 aneurysms were saccular (76.9%).

Of the aneurysms with residual filling, there were 20 carotid ophthalmic (CO) aneurysms (20% of all CO aneurysms), 10 other paraclinoid aneurysms (16.4% of all paraclinoid aneurysms), 7 posterior communicating artery (PCoA) aneurysms (21.9% of all PCoA aneurysms), 7 cavernous ICA aneurysms (14.9% of all cavernous ICA aneurysms), 4 vertebrobasilar (VB) junction aneurysms (14.8% of all VB junction aneurysms), 3 middle cerebral artery (MCA) aneurysms (25% of all MCA aneurysms), and 1 anterior choroidal artery aneurysm (AChA; 50% of all AChA aneurysms). Distal anterior circulation aneurysms (located in the PCoA artery, AChA, or MCA) were the only aneurysms with less than 80% occlusion.

Twelve aneurysms were previously treated (23.1%); 8 were treated with prior stent placement (15.4%). Eleven patients had placement of more than one PED (212%) with a mean number of devices of 1.28 per case. Nineteen (36.5%) of the 52 aneurysms had a side branch in continuation with the aneurysm sac.

There was a significantly higher rate of patients older than 65 years for aneurysms with persistent filling compared with occluded aneurysms (40.4% vs 23.6%, p = 0.018), a higher rate of prior stent placement in incompletely occluded aneurysms (15.4% vs 5.7%, p = 0.019), and a significantly longer follow-up duration for aneurysms with persistent filling (23.3 ± 11.8 vs 16 ± 11.1 months, p < 0.001). Incompletely occluded aneurysms were less likely to be concomitantly treated with coiling during the same procedure (1.9% vs 9.2%, p = 0.08). Baseline characteristics are detailed in Tables 1 and 2.

TABLE 1.

Patient characteristics

VariableAll Aneurysms (n = 281)Occluded Aneurysms (n = 229)Aneurysms w/Persistent Filling (n = 52)p Value
Sex0.4
 Male48 (17.1)41 (17.9)7 (13.5)
 Female233 (82.9)188 (82.1)45 (86.5)
Age in yrs
 Mean58.7 ± 13.955.9 ± 13.358.8 ± 13.90.15
 >50193 (68.7)158 (69)35 (67.3)0.89
 >6575 (26.7)54 (23.6)21 (40.4)0.018
Hypertension139 (49.5)110 (48)29 (55.8)0.3
Smoking139 (49.5)114 (49.8)25 (48.1)0.6
Mean platelet reactive units131.4 ± 72.2131.9 ± 72.9129.1 ± 70.30.8
Mean follow-up period in mos17.4 ± 11.616 ± 11.123.3 ± 11.8<0.001

Values presented as no. (%) or mean ± SD.

TABLE 2.

Aneurysm characteristics

VariableAll Aneurysms (n = 281)Occluded Aneurysms (n = 229)Aneurysms w/Persistent Filling (n = 52)p Value
Aneurysm size in mm
 Mean ± SD9.3 ± 6.39.1 ± 6.110.1 ± 7.10.3
  >7134 (47.7)105 (45.8)29 (55.8)0.4
  >1097 (34.5)77 (33.6)20 (38.5)0.7
  >1546 (16.4)35 (15.3)11 (21.1)0.4
  >259 (3.2)7 (3.1)2 (3.8)0.8
Saccular aneurysm235 (83.6)195 (85.1)40 (76.9)0.2
Fusiform/dissecting aneurysm46 (16.4)34 (14.8)12 (23.1)0.2
Previous SAH33 (11.7)25 (10.9)8 (15.4)0.4
Acute SAH18 (6.4)15 (6.5)3 (5.8)0.9
Previous treatment63 (22.4)51 (22.3)12 (23.1)0.96
Prior coiling45 (16)36 (15.7)9 (17.3)0.8
Prior stent21 (7.5)13 (5.7)8 (15.4)0.019
Mean no. of PEDs deployed1.271.281.281
Multiple PEDs deployed56 (19.9)46 (20.1)11 (19.2)0.8
Concomitant coiling w/ PED22 (7.8)21 (9.2)1 (1.9)0.08
Balloon usage w/ PED22 (7.8)19 (8.3)3 (5.8)0.5

Values presented as no. (%) except where indicated.

Predictors of Persistent Aneurysm Filling

In univariate analysis, age older than 65 years (OR 2.11, 95% CI 1.12–3.97; p = 0.02), prior stent placement across the target aneurysm (OR 2.94, 95% CI 1.15–7.51; p = 0.02), and longer follow-up duration (OR 1.06, 95% CI 1.03–1.09; p < 0.001) were associated with incomplete aneurysm occlusion. In addition, there was a trend toward higher odds of persistent aneurysm filling, with the association approaching significance in fusiform/dissecting aneurysms (OR 1.67, 95% CI 0.78–3.49; p = 0.17), aneurysms located in the distal anterior circulation (MCA, PCoA, and AChA: OR 1.67, 95% CI 0.79–3.48; p = 0.18), and aneurysms treated with PEDs without coiling versus PED + concomitant coiling (OR 5.32, 95% CI 0.70–40.51; p = 0.1). Aneurysm size had no significant association with aneurysm occlusion status (OR 1.02, 95% CI 0.98–1.06; p = 0.31) (Tables 2 and 3).

TABLE 3.

Association between aneurysm location and outcomes

Aneurysm LocationAll Aneurysms (n = 281)Occluded Aneurysms (n = 229)Aneurysms w/Persistent Filling (n = 52)p Value
Cavernous ICA47 (16.7)40 (17.5)7 (13.5)
Ophthalmic ICA100 (35.6)80 (34.9)20 (38.5)
Paraclinoid ICA61 (21.7)51 (22.3)10 (19.2)
MCA12 (4.3)9 (3.9)3 (5.8)0.7
Posterior circulation27 (9.6)23 (10)4 (7.7)
PCoA32 (11.4)25 (10.9)7 (13.5)
AChA2 (0.7)1 (0.4)1 (1.9)
Aneurysm location w/ <80% occlusion*46 (16.4)35 (15.3)11 (23.1)0.18

Values presented as no. (%).

Distal anterior circulation aneurysms.

In multivariate analysis, age older than 65 years (OR 2.65, 95% CI 1.33–5.28; p = 0.05), prior stent placement across the target aneurysm (OR 3.67, 95% CI 1.32–10.22; p = 0.01), aneurysm location in the distal anterior circulation (MCA, PCoA, and AChA: OR 2.72, 95% CI 1.19–6.18; p = 0.017), and longer follow-up duration (OR 1.06, 95% CI 1.03–1.09; p < 0.001) were associated with incomplete aneurysm occlusion.

Predictors of Re-Treatment

In multivariate analysis, aneurysm size > 25 mm (OR 10.57, 95% CI 1.34–83.13; p = 0.02) and longer follow-up duration (OR 1.08, 95% CI 1.03–1.12; p = 0.001) were associated with higher odds of re-treatment. There were significantly higher odds of re-treatment when more than 1 PED was initially deployed (OR 2.69, 95% CI 0.94–7.56; p = 0.05). In univariate analysis, only increasing follow-up duration was significantly associated with higher odds of re-treatment (p < 0.001) (Table 1).

Course of Aneurysms With Persistent Filling

Nineteen incompletely occluded aneurysms were re-treated, representing 6.8% of all treated aneurysms that were followed up and 36.5% of aneurysms with persistent filling. Thirty-three patients with incompletely occluded aneurysms did not undergo re-treatment (63.5%) and were monitored with angiography or noninvasive imaging (MRA) to monitor for occlusion status of the aneurysm. None of the aneurysms with complete occlusion or near-complete occlusion recurred during follow-up. None of the aneurysms with persistent filling presented with rebleeding or new SAH.

Discussion

Aneurysms with persistent filling represented 18.5% of all treated cases with follow-up imaging. This highlights the efficacy of the PED that resulted in a rate of aneurysm occlusion of 81.5% after a 5-year experience with the device. This rate is consistent with those reported in other studies in the literature that have shown a high complete aneurysm occlusion rate, with most studies reporting occlusion rates > 80%,11,16 which compares favorably to that of endovascular coil embolization, where the reported complete occlusion rate is 66% (ISAT; International Subarachnoid Aneurysm Trial).23

None of the aneurysms with complete occlusion or near-complete occlusion recurred during follow-up. Recurrence after successful PED treatment has not been reported in the available short- and medium-term data. This is in contrast to high recurrence rates with coiling (9%–34% at 12 months), which increases with large, giant, wide-necked, and nonsaccular aneurysms; thus, these aneurysms are the target for PED treatment.2 Overall, 6.8% of the 281 aneurysms were re-treated. This re-treatment rate is much lower with PED treatment than with coiling in ISAT (17.4%).23 FDs seem to be more effective than the conventional endovascular techniques in select cases.

Aneurysm location in the distal anterior circulation (PCoA, AChA, and MCA) was a significant predictor of persistent aneurysm filling, and these aneurysms were the only ones with less than 80% occlusion. Parent vessels for such aneurysms are usually small, and aneurysms often arise at major branch points. In addition, the A1 segment of the anterior cerebral artery and M1 segment of the MCA are rich in lenticulostriate perforators, and covering these areas with PEDs could theoretically increase the risk of stroke in the perforators, causing neurological deficits. These factors render PED delivery and deployment more difficult. Also, PEDs (with available sizes from 2.5 to 5 mm) are, in general, designed for parent vessels that are larger than the caliber of distal anterior circulation vessels. In a small vessel, the device may be elongated, and the stent pores may become larger, which might impair the flow diversion effect and lower the chances of aneurysm thrombosis. This could affect the reliability of PED deployment in smaller distal vessels. However, there are some distal anterior circulation aneurysms that are morphologically challenging for either traditional microsurgical or endovascular approaches, and the use of PEDs may have an advantage in these cases. In these cases, placing a single, long FD stent and avoiding telescoping of multiple devices along perforator-rich segments can reduce the risk of perforator occlusion.

The PED was originally approved for the treatment of aneurysms proximal to the PCoA.12 PCoA aneurysms are among the most frequently encountered cerebral aneurysms. A fetal PCoA is an end vessel with no distal collaterals. Since fetal PCoAs represent the only supply to the posterior cerebral artery, care should be taken when treating PCoA aneurysms incorporating a fetal variant.27 In fact, fetal PCoA aneurysms are often treated surgically since endovascular therapy is thought to be associated with a higher treatment risk.27 Several reports have suggested that flow diversion for fetal PCoA aneurysms is ineffective, does not lead to aneurysm occlusion, and has a high potential for serious complications.15,27 Aneurysms arising from fetal PCoAs are less likely to be occluded even after placement of an FD due to the high flow and the high physiological demand for this artery, which maintains a pressure gradient across the ostium.12 PCoA aneurysms with a fetal PCoA are better treated with microsurgical clipping.17 Attempting flow diversion may add procedural risks and make surgical clipping even more technically complex.

MCA aneurysms represent the third most common cause of SAH and almost one-fifth of unruptured aneurysms.25 The majority of MCA aneurysms arising at the level of the bifurcation tend to be wide-necked, incorporate one or more side branch vessels, and to have an unfavorable anatomical configuration.13 Wide-necked MCA bifurcation lesions have been classically treated with microsurgery with excellent results. Traditional endovascular approaches can sometimes be challenging with a risk of occluding branch vessels as well as the risk of coil herniation. Flow diversion for MCA aneurysms should be considered when other surgical or endovascular approaches are not an option or do not offer superior outcomes and for lesions that persist after previous surgery or endovascular treatment.28 Occlusion rates with the PED for MCA aneurysms have been reported to be between 55% and 84% (75% in this study). This rate is lower than the occlusion rates reported with clipping (> 90%) in most studies.26 Clinical data should demonstrate better or similar results than clipping to challenge surgical management.

Stent placement negatively affects the safety and efficacy of the PED in the management of recurrent aneurysms. The rate of complete aneurysm occlusion is lower in previously stented aneurysms (50%–65%) with potential for a higher complication rate (14.3%) and technical failure rate.13 If a stent was placed initially, the recurrence would be less eligible for PED treatment and might require surgical clipping to achieve aneurysm occlusion. The presence of a previous stent might reduce the hemodynamic effect of the PED, disrupt the process of wall apposition of the PED to the parent vessel, preventing the endothelialization process inhibiting complete aneurysm occlusion, and complicate the navigation of the delivery catheter into position and the actual deployment of the PED. Moreover, because the PED should be deployed distal to the stent, the distal end of the PED may “catch” on the previously placed stent, which may cause anchoring and stretching of the device, leading to less effective results.

Patients older than 65 years had higher odds of incomplete aneurysm occlusion. This may be related to a weaker neointimal response induced by stent deployment in older patients. It is noteworthy that aneurysms and their locations among older patients were not necessarily more complex or affected by technical features of the procedure.

There was a significantly longer follow-up duration for aneurysms with persistent filling (23.3 months vs 16 months, p < 0.001). This reflects that patients harboring aneurysms with persistent filling were more likely to undergo longer follow-up imaging to monitor the progress of aneurysm occlusion.

The majority of cases require the placement of only one PED, and a single PED should usually be placed, as there was no difference in aneurysm occlusion when more than 1 device was deployed.8 Incompletely occluded aneurysms were less likely to be concomitantly coiled during the same procedure (1.9% vs 9.2%, p = 0.08). Coiling and flow diversion have been shown to be complementary, rather than competitive, modalities for intracranial aneurysm treatment.16 Using coils along with the PED in select cases can be more effective, with a higher occlusion rate and lower re-treatment rate, by promoting endosaccular thrombosis and providing a mechanical scaffold.

The mean size of occluded aneurysms was 9.1 mm versus 10.1 mm in aneurysms with persistent filling. Aneurysm size was not significantly associated with aneurysm occlusion status. The PED is indicated for large and giant aneurysms.23 However, large and giant aneurysms represent a small fraction of all cerebral aneurysms, with the majority of aneurysms in the general population being < 10 mm in size. Traditional endovascular strategies, including coiling and stent-assisted coiling, are usually used for small aneurysms (≤ 7 mm). Some retrospective studies have demonstrated high occlusion rates (75%–90%) and low complication rates (< 5%) with treating these small aneurysms.8 In experienced centers, the PED is demonstrating a better efficacy profile and a similar safety profile to coiling of smaller aneurysms.8 With the increasing use of the PED for the treatment of small, simple aneurysms, the question arises as to whether the use of this device routinely, or even as a first-line treatment for these aneurysms, is as safe and effective as the current standard endovascular techniques. This needs to be further studied.

Good clinical outcomes have been reported with flow diversion of saccular or nonsymptomatic fusiform posterior circulation aneurysms.16 Acceptable morbidity and mortality rates (0%–9.4%) and high efficacy have been shown in these aneurysms, 85.2% in this study, comparable to anterior circulation aneurysms. Treatment with the PED may be a preferable alternative to open surgical treatment for these aneurysms. Because of the large number of perforating vessels in the posterior circulation that supply vital brainstem structures, complex aneurysm anatomy, and aneurysm location, flow diversion should be used with caution. Aneurysm morphology and presentation are critical factors to consider when selecting posterior circulation aneurysms for treatment with the PED.22

Device deployment is successful in 95% to 100% of cases (99% in PUFS).1 Selection of the appropriate diameter and length of the device is essential to ensure proper device function and to minimize the chance for unanticipated stent shortening or migration (https://www.accessdata.fda.gov/cdrh_docs/pdf10/P100018b.pdf). The delivery catheter must recross the PED over the delivery wire to recapture the distal coil tip after complete stent deployment. Up to 50% foreshortening is expected when fully deployed compared with 1.5%–7.1% and 1.8%–5.4% foreshortening in Wingspan and Neuroform16 stents (bench testing conducted by Boston Scientific).

There is a potential risk of an endoleak-like phenomenon with implantation of an undersized device, which results in poor wall apposition. Similarly, implantation of an oversized device may result in poor coverage of the lesion because of an incomplete compaction of the strands.21 Nineteen (36.5%) of the 52 aneurysms had a side branch in continuation with the aneurysm sac. When a branch vessel is incorporated into the target aneurysm, its runoff can potentially contribute to persistent filling of the aneurysm by the very same physiological processes theoretically responsible for the preservation of jailed branch vessels and perforators arising from normal segments. One may expect that final closure of such aneurysms would require concomitant occlusion of the associated branch.

Limitations

This study has limitations, including its retrospective, single-center, purely descriptive design. Loss to follow-up is another major limitation to be accounted for. This study did not serve as a source for any real novel finding or demonstration of a new mechanism. We only report the experience of our tertiary referral center with the PED. Further randomized, controlled prospective studies are necessary to verify our results and help neurointerventionists with decisionmaking while dealing with FDs.

Conclusions

While the PED can allow for treatment of large, wide-necked aneurysms with high efficacy, treatment failures do occur (16.4%). Re-treatment may be required in a few patients (6.8%). Aneurysm location, previous treatment, patient age, and the use of concomitant coiling may influence treatment outcomes.

Disclosures

Dr. Jabbour: consultant for Medtronic.

Author Contributions

Conception and design: Tjoumakaris, Daou, Atallah, Rosenwasser. Acquisition of data: Daou, Starke, Oliver, Montano. Analysis and interpretation of data: Daou, Atallah, Chalouhi, Starke, Oliver, Montano. Drafting the article: Daou, Atallah. Critically revising the article: Daou, Atallah, Chalouhi, Jabbour, Rosenwasser. Reviewed submitted version of manuscript: Tjoumakaris, Daou, Atallah, Chalouhi, Jabbour, Rosenwasser. Approved the final version of the manuscript on behalf of all authors: Tjoumakaris. Statistical analysis: Starke, Oliver, Montano. Administrative/technical/material support: Tjoumakaris. Study supervision: Tjoumakaris, Jabbour, Rosenwasser.

Supplemental Information

Previous Presentations

The abstract was previously presented at the 2016 84th AANS Annual Scientific Meeting, April 30–May 4, 2016, Chicago, Illinois.

References

  • 1

    Becske T, Kallmes DF, Saatci I, McDougall CG, Szikora I, Lanzino G, : Pipeline for uncoilable or failed aneurysms: results from a multicenter clinical trial. Radiology 267:858868, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Campi A, Ramzi N, Molyneux AJ, Summers PE, Kerr RS, Sneade M, : Retreatment of ruptured cerebral aneurysms in patients randomized by coiling or clipping in the International Subarachnoid Aneurysm Trial (ISAT). Stroke 38:15381544, 2007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Chalouhi N, Jabbour P, Gonzalez LF, Dumont AS, Rosenwasser R, Starke RM, : Safety and efficacy of endovascular treatment of basilar tip aneurysms by coiling with and without stent assistance: a review of 235 cases. Neurosurgery 71:785794, 2012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Chalouhi N, Penn DL, Tjoumakaris S, Jabbour P, Gonzalez LF, Starke RM, : Treatment of small ruptured intracranial aneurysms: comparison of surgical and endovascular options. J Am Heart Assoc 1:e002865, 2012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Chalouhi N, Starke RM, Koltz MT, Jabbour PM, Tjoumakaris SI, Dumont AS, : Stent-assisted coiling versus balloon remodeling of wide-neck aneurysms: comparison of angiographic outcomes. AJNR Am J Neuroradiol 34:19871992, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Chalouhi N, Tjoumakaris S, Phillips JL, Starke RM, Hasan D, Wu C, : A single Pipeline Embolization Device is sufficient for treatment of intracranial aneurysms. AJNR Am J Neuroradiol 35:15621566, 2014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Chalouhi N, Tjoumakaris S, Starke RM, Gonzalez LF, Randazzo C, Hasan D, : Comparison of flow diversion and coiling in large unruptured intracranial saccular aneurysms. Stroke 44:21502154, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Chalouhi N, Zanaty M, Whiting A, Yang S, Tjoumakaris S, Hasan D, : Safety and efficacy of the Pipeline Embolization Device in 100 small intracranial aneurysms. J Neurosurg 122:14981502, 2015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Chan RSK, Mak CHK, Wong AKS, Chan KY, Leung KM: Use of the Pipeline Embolization Device to treat recently ruptured dissecting cerebral aneurysms. Interv Neuroradiol 20:436441, 2014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    D’Urso PI, Lanzino G, Cloft HJ, Kallmes DF: Flow diversion for intracranial aneurysms: a review. Stroke 42:23632368, 2011

  • 11

    Giacomini L, Piske RL, Baccin CE, Barroso M, Joaquim AF, Tedeschi H: Neurovascular reconstruction with flow diverter stents for the treatment of 87 intracranial aneurysms: clinical results. Interv Neuroradiol 21:292299, 2015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Golshani K, Ferrell A, Zomorodi A, Smith TP, Britz GW: A review of the management of posterior communicating artery aneurysms in the modern era. Surg Neurol Int 1:88, 2010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Islak C, Kizilkilic O, Kocak B, Saglam M, Yildiz B, Kocer N: Use of buddy wire to facilitate Y-configured stent placement in middle cerebral artery bifurcation aneurysms with daughter branches arising from the sac: a technical note. Oper Neurosurg (Hagerstown) 10:E167E171, 2014

    • Search Google Scholar
    • Export Citation
  • 14

    Jabbour P, Chalouhi N, Tjoumakaris S, Gonzalez LF, Dumont AS, Randazzo C, : The Pipeline Embolization Device: learning curve and predictors of complications and aneurysm obliteration. Neurosurgery 73:113120, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Kan P, Edward D, Puri A, Velat G, Wakhloo A: Treatment failure of fetal posterior communicating artery aneurysms with the pipeline embolization device. J Neurointerv Surg 8:945948, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Kim BM, Shin YS, Baik MW, Lee DH, Jeon P, Baik SK, : Pipeline Embolization Device for large/giant or fusiform aneurysms: an initial multi-center experience in Korea. Neurointervention 11:1017, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Kuzmik GA, Bulsara KR: Microsurgical clipping of true posterior communicating artery aneurysms. Acta Neurochir (Wien) 154:17071710, 2012

  • 18

    Pistocchi S, Blanc R, Bartolini B, Piotin M: Flow diverters at and beyond the level of the circle of Willis for the treatment of intracranial aneurysms. Stroke 43:10321038, 2012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Puri AS, Massari F, Asai T, Marosfoi M, Kan P, Hou SY, : Safety, efficacy, and short-term follow-up of the use of Pipeline Embolization Device in small (<2.5 mm) cerebral vessels for aneurysm treatment: single institution experience. Neuroradiology 58:267275, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Safain MG, Roguski M, Heller RS, Malek AM: Flow diverter therapy with the Pipeline Embolization Device is associated with an elevated rate of delayed fluid-attenuated inversion recovery lesions. Stroke 47:789797, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Shapiro M, Becske T, Nelson PK: Learning from failure: persistence of aneurysms following pipeline embolization J Neurosurg 126:578585, 2017

  • 22

    Siddiqui A, Abla AA, Kan P, Dumont TM, Jahshan S, Britz G, Hopkins NL, : Panacea or problem: flow diverters in the treatment of symptomatic large or giant fusiform vertebrobasilar aneurysms. J Neurosurg 116:12581266, 2012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Sturiale CL, Brinjikji W, Murad MH, Lanzino G: Endovascular treatment of intracranial aneurysms in elderly patients: a systematic review and meta-analysis. Stroke 44:18971902, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Tomasello A, Romero N, Aixut S, Miquel MA, Macho JM, Castaño C, : Endovascular treatment of intracraneal aneurysm with pipeline embolization device: experience in four centres in Barcelona. Neurol Res 38:381388, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    van Gijn J, Rinkel GJ: Subarachnoid haemorrhage: diagnosis, causes and management. Brain 124:249278, 2001

  • 26

    Yang W, Huang J: Treatment of middle cerebral artery (MCA) aneurysms: a review of the literature. Chinese Neurosurg J 1:1, 2015

  • 27

    Zanaty M, Chalouhi N, Starke RM, Jabbour P, Ryken KO, Bulsara KR, : Failure of the pipeline embolization device in posterior communicating artery aneurysms associated with a fetal posterior cerebral artery. Case Rep Vasc Med 2016:4691275, 2016

    • Search Google Scholar
    • Export Citation
  • 28

    Zanaty M, Chalouhi N, Tjoumakaris SI, Gonzalez LF, Rosenwasser R, Jabbour P: Flow diversion for complex middle cerebral artery aneurysms. Neuroradiology 56:381387, 2014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Zanaty M, Daou B, Chalouhi N, Starke RM, Samaniego E, Derdeyn C, : Same-day discharge following treatment with the Pipeline Embolization Device using monitored anesthesia care. World Neurosurg 96:3135, 2016

    • Crossref
    • Search Google Scholar
    • Export Citation

If the inline PDF is not rendering correctly, you can download the PDF file here.

Contributor Notes

Correspondence Stavropoula I. Tjoumakaris: Thomas Jefferson University Hospital, Philadelphia, PA. stavropoula.tjoumakaris@jefferson.edu.

INCLUDE WHEN CITING Published online May 4, 2018; DOI: 10.3171/2017.12.JNS163090.

B.D. and E.A. contributed equally to the study.

Disclosures Dr. Jabbour: consultant for Medtronic.

  • 1

    Becske T, Kallmes DF, Saatci I, McDougall CG, Szikora I, Lanzino G, : Pipeline for uncoilable or failed aneurysms: results from a multicenter clinical trial. Radiology 267:858868, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Campi A, Ramzi N, Molyneux AJ, Summers PE, Kerr RS, Sneade M, : Retreatment of ruptured cerebral aneurysms in patients randomized by coiling or clipping in the International Subarachnoid Aneurysm Trial (ISAT). Stroke 38:15381544, 2007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Chalouhi N, Jabbour P, Gonzalez LF, Dumont AS, Rosenwasser R, Starke RM, : Safety and efficacy of endovascular treatment of basilar tip aneurysms by coiling with and without stent assistance: a review of 235 cases. Neurosurgery 71:785794, 2012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Chalouhi N, Penn DL, Tjoumakaris S, Jabbour P, Gonzalez LF, Starke RM, : Treatment of small ruptured intracranial aneurysms: comparison of surgical and endovascular options. J Am Heart Assoc 1:e002865, 2012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Chalouhi N, Starke RM, Koltz MT, Jabbour PM, Tjoumakaris SI, Dumont AS, : Stent-assisted coiling versus balloon remodeling of wide-neck aneurysms: comparison of angiographic outcomes. AJNR Am J Neuroradiol 34:19871992, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Chalouhi N, Tjoumakaris S, Phillips JL, Starke RM, Hasan D, Wu C, : A single Pipeline Embolization Device is sufficient for treatment of intracranial aneurysms. AJNR Am J Neuroradiol 35:15621566, 2014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Chalouhi N, Tjoumakaris S, Starke RM, Gonzalez LF, Randazzo C, Hasan D, : Comparison of flow diversion and coiling in large unruptured intracranial saccular aneurysms. Stroke 44:21502154, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Chalouhi N, Zanaty M, Whiting A, Yang S, Tjoumakaris S, Hasan D, : Safety and efficacy of the Pipeline Embolization Device in 100 small intracranial aneurysms. J Neurosurg 122:14981502, 2015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Chan RSK, Mak CHK, Wong AKS, Chan KY, Leung KM: Use of the Pipeline Embolization Device to treat recently ruptured dissecting cerebral aneurysms. Interv Neuroradiol 20:436441, 2014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    D’Urso PI, Lanzino G, Cloft HJ, Kallmes DF: Flow diversion for intracranial aneurysms: a review. Stroke 42:23632368, 2011

  • 11

    Giacomini L, Piske RL, Baccin CE, Barroso M, Joaquim AF, Tedeschi H: Neurovascular reconstruction with flow diverter stents for the treatment of 87 intracranial aneurysms: clinical results. Interv Neuroradiol 21:292299, 2015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Golshani K, Ferrell A, Zomorodi A, Smith TP, Britz GW: A review of the management of posterior communicating artery aneurysms in the modern era. Surg Neurol Int 1:88, 2010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Islak C, Kizilkilic O, Kocak B, Saglam M, Yildiz B, Kocer N: Use of buddy wire to facilitate Y-configured stent placement in middle cerebral artery bifurcation aneurysms with daughter branches arising from the sac: a technical note. Oper Neurosurg (Hagerstown) 10:E167E171, 2014

    • Search Google Scholar
    • Export Citation
  • 14

    Jabbour P, Chalouhi N, Tjoumakaris S, Gonzalez LF, Dumont AS, Randazzo C, : The Pipeline Embolization Device: learning curve and predictors of complications and aneurysm obliteration. Neurosurgery 73:113120, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Kan P, Edward D, Puri A, Velat G, Wakhloo A: Treatment failure of fetal posterior communicating artery aneurysms with the pipeline embolization device. J Neurointerv Surg 8:945948, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Kim BM, Shin YS, Baik MW, Lee DH, Jeon P, Baik SK, : Pipeline Embolization Device for large/giant or fusiform aneurysms: an initial multi-center experience in Korea. Neurointervention 11:1017, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Kuzmik GA, Bulsara KR: Microsurgical clipping of true posterior communicating artery aneurysms. Acta Neurochir (Wien) 154:17071710, 2012

  • 18

    Pistocchi S, Blanc R, Bartolini B, Piotin M: Flow diverters at and beyond the level of the circle of Willis for the treatment of intracranial aneurysms. Stroke 43:10321038, 2012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Puri AS, Massari F, Asai T, Marosfoi M, Kan P, Hou SY, : Safety, efficacy, and short-term follow-up of the use of Pipeline Embolization Device in small (<2.5 mm) cerebral vessels for aneurysm treatment: single institution experience. Neuroradiology 58:267275, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Safain MG, Roguski M, Heller RS, Malek AM: Flow diverter therapy with the Pipeline Embolization Device is associated with an elevated rate of delayed fluid-attenuated inversion recovery lesions. Stroke 47:789797, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Shapiro M, Becske T, Nelson PK: Learning from failure: persistence of aneurysms following pipeline embolization J Neurosurg 126:578585, 2017

  • 22

    Siddiqui A, Abla AA, Kan P, Dumont TM, Jahshan S, Britz G, Hopkins NL, : Panacea or problem: flow diverters in the treatment of symptomatic large or giant fusiform vertebrobasilar aneurysms. J Neurosurg 116:12581266, 2012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Sturiale CL, Brinjikji W, Murad MH, Lanzino G: Endovascular treatment of intracranial aneurysms in elderly patients: a systematic review and meta-analysis. Stroke 44:18971902, 2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Tomasello A, Romero N, Aixut S, Miquel MA, Macho JM, Castaño C, : Endovascular treatment of intracraneal aneurysm with pipeline embolization device: experience in four centres in Barcelona. Neurol Res 38:381388, 2016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    van Gijn J, Rinkel GJ: Subarachnoid haemorrhage: diagnosis, causes and management. Brain 124:249278, 2001

  • 26

    Yang W, Huang J: Treatment of middle cerebral artery (MCA) aneurysms: a review of the literature. Chinese Neurosurg J 1:1, 2015

  • 27

    Zanaty M, Chalouhi N, Starke RM, Jabbour P, Ryken KO, Bulsara KR, : Failure of the pipeline embolization device in posterior communicating artery aneurysms associated with a fetal posterior cerebral artery. Case Rep Vasc Med 2016:4691275, 2016

    • Search Google Scholar
    • Export Citation
  • 28

    Zanaty M, Chalouhi N, Tjoumakaris SI, Gonzalez LF, Rosenwasser R, Jabbour P: Flow diversion for complex middle cerebral artery aneurysms. Neuroradiology 56:381387, 2014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Zanaty M, Daou B, Chalouhi N, Starke RM, Samaniego E, Derdeyn C, : Same-day discharge following treatment with the Pipeline Embolization Device using monitored anesthesia care. World Neurosurg 96:3135, 2016

    • Crossref
    • Search Google Scholar
    • Export Citation

Metrics

All Time Past Year Past 30 Days
Abstract Views 376 112 0
Full Text Views 459 182 36
PDF Downloads 245 73 7
EPUB Downloads 0 0 0