The Pipeline Embolization Device: learning curve and predictors of complications and aneurysm obliteration

The Pipeline Embolization Device (PED) has emerged as a promising treatment for intracranial aneurysms.

To assess the safety and efficacy of the PED, to analyze the effect of operator experience on the complication rate, and to identify predictors of complications and obliteration.

A total of 109 patients with 120 aneurysms were treated with PED at our institution. The patient population was divided into 3 consecutive equal groups to assess whether overall and major complication rates decreased over time: group 1, patients 1 through 37; group 2, patients 38 through 73; and group 3, patients 74 through 109.

The number of PEDs used was 1.40 per aneurysm. Symptomatic and major procedure-related complications occurred in 11% and 3.7% of patients, respectively. The rate of complications decreased from 16.2% in group 1 to 5.6% in group 3, and the rate of major complications fell dramatically from 10.8% in group 1 to 0% in groups 2 and 3 (P < .05). Procedure time significantly decreased over time (P = .04). In multivariate analysis, previously treated aneurysms were predictive of procedural complications (P = .02). At the latest follow-up, 65.8% of aneurysms were completely occluded, 9.6% were nearly completely occluded, and 24.6% were incompletely occluded. In multivariate analysis, fusiform aneurysms (P = .05) and shorter angiographic follow-up (P = .03) were negative predictors of aneurysm obliteration.

PED therapy may have an acceptable safety-efficacy profile. The risk of complications appears to decrease dramatically with physician experience, supporting the existence of a learning curve. Patients with previously treated aneurysms have higher complication rates, whereas fusiform aneurysms achieve lower obliteration rates.