Regrowth of a Large Intracranial Aneurysm after On-Label Use of the Pipeline Embolization Device

Recurrence of a large intracranial fusiform aneurysm treated with overlapping Pipeline embolization devices: illustrative case

BACKGROUND

Flow diversion, specifically with the Pipeline embolization device (PED), represents a paradigm shift in the treatment of intracranial aneurysms. Several studies have demonstrated its efficacy and at times superiority to conventional treatment modalities for aneurysms with a fusiform morphology, giant size, or wide neck. However, there may be a nonsignificant risk of recurrence after flow diversion of these historically difficult-to-treat aneurysms, relative to aneurysms with a more favorable morphology and size (i.e., saccular, narrow necked). To date, only three papers in the literature have demonstrated the recurrence of a completely occluded aneurysm on follow-up.

OBSERVATIONS

The authors describe a patient with a giant middle cerebral artery fusiform aneurysm treated with multiple telescoping PEDs. On the 3-month follow-up angiogram, there was complete occlusion of the aneurysm. The patient was lost to follow-up and presented 4 years later with a recurrence of the aneurysm between PED segments, requiring retreatment. The patient represented 3 years posttreatment with the need for repeat treatment of the fusiform aneurysm due to separation of the existing PEDs along with stent reconstruction. At the 20-month follow-up after the third treatment, the initial aneurysm target was found to be occluded.

LESSONS

This case illustrates the need for long-term follow-up, specifically for patients with giant wide-necked or fusiform aneurysms treated with overlapping PEDs.

Hemodynamic Analysis of Pipeline Embolization Device Stent for Treatment of Giant Intracranial Aneurysm under Unsupervised Learning Algorithm

To treat large intracranial aneurysms, pipeline embolization device (PED) stent with unsupervised learning algorithms was utilized. Unsupervised learning model algorithm was used to screen aneurysm health big data, find aneurysm blood flow and PED stent positioning characteristic parameters, and guide PED stent treatment of intracranial aneurysms. The research objects were 100 patients with intracranial large aneurysm admitted to X Hospital of X Province from June 2020 to June 2021, who were enrolled into two groups. One group used the prototype transfer generative adversarial network (PTGAN) model to measure mean blood flow and mean vascular pressure and guide the placement of PED stents (PTGAN group). The other group did not use the model to place PED (control group). The PTGAN model can learn feature information from horizontal and vertical directions, with smooth edges and prominent features, which can effectively extract the main morphological and texture features of aneurysms. Compared with the convolutional neural network (CNN) model, the accuracy of the PTGAN model increased by 8.449% (87.452%-79.003%), and the precision increased by 8.347% (91.23%-82.883%). The recall rate increased by 7.011% (87.231%-80.22%), and the F1 score increased by 8.09% (89.73%-81.64%). After the adoption of the PTGAN model, the average blood flow inside the aneurysm body was 0.22 (m/s). After the adoption of the CNN model, the average blood flow inside the aneurysm body was 0.21 (m/s), and the difference was 0.01 (m/s), which was considerable (p < 0.05). Through this research, it was found that the PTGAN model was better than the CNN model in terms of accuracy, precision, recall, and F1 score values. The PTGAN model was better than the CNN model in detecting the average blood flow rate and average blood pressure after treatment, and the blood flowed smoothly. Postoperative complications and postoperative relief were also better than those of the control group. In summary, based on the unsupervised learning algorithm, the PED stent had a good adoption effect in the treatment of intracranial aneurysms and was suitable for subsequent treatment.

The value of long-term angiographic follow-up following Pipeline embolization of intracranial aneurysms

BACKGROUND

Flow diversion of intracranial aneurysms with the Pipeline Embolization Device (PED) is commonly performed, but the value of long-term angiographic follow-up has not been rigorously evaluated. Here we examine the prevalence of actionable findings of aneurysm recurrence and development of in-stent stenosis in a cohort of patients that underwent long-term angiographic follow-up at multiple time points.

METHODS

Angiographic data from eligible patients were retrospectively assessed for aneurysm occlusion, in-stent stenosis, and aneurysm regrowth or recurrence. Patients were included in this study if they underwent angiographic imaging at 6 months post-treatment and at least one later time point.

RESULTS

100% (132/132) of aneurysms occluded at 6 months remained occluded at final follow-up. 85.7% (6/7), 56.3% (27/48), and 25% (6/24) of aneurysms with entry remnant, subtotal filling, and total filling, respectively, at 6 months were completely occluded at final follow-up. 98.7% (147/149) of PED constructs that demonstrated no stenosis at 6 months demonstrated no stenosis at final angiography, while 44.4% (8/18) of PED constructs demonstrating in-stent stenosis at 6 months had resolution of stenosis on final angiography.

CONCLUSIONS

Among patients who undergo treatment of intracranial aneurysms with PED, the value of long-term angiography in patients demonstrating complete aneurysm occlusion and no in-stent stenosis on 6 month post-treatment angiography is low.