Flow disruption with WEB is increasingly used for the treatment of intracranial aneurysms. We examined factors leading to aneurysm occlusion and WEB shape change during a mid-term follow-up.

Patients with a minimum 12-month angiographic follow-up were included. Through a univariate and multivariate analysis, independent predictors of adequate occlusion (RR1/RR2) and WEB shape change (decrease of the height of the device) were assessed.

Eighty-six patients/aneurysms were included. The mean size was 5.5mm (range: 3–11.5mm). The most common locations were MCA (43/86=50%), BT (13/86=15.1%), and AcomA (12/86=14%). Twenty-one patients (21/86=24%) presented acute SAH. Immediate and long-term RR1/RR2 occlusion rates were 49% (42/86) and 80% (68/86), respectively. WEB shape change was detected among 22% (19/86) of cases. At the binary logistic regression, wide ostium (≥ 4mm) (OR=0.2, 95% CI=0.01–1, P=0.04) and regular aneurysm morphology (OR=5.9, 95% CI=1.4–24, P=0.01) were independent factors of incomplete and adequate aneurysm occlusion, respectively. In addition, irregular morphology (OR=5.4, 95% CI=1.4–19, P=0.01) and wide ostium (OR=9.8, 95% CI=1.6–60, P=0.03) significantly increased the probability of the WEB shape change. Decrease of the WEB height was higher among incomplete occluded aneurysms (6/12=50% vs 13/74=17.5%), but it was not an independent prognosticator of occlusion at the multivariate model.

The likelihood of good occlusion was 5 times lower in the presence of a wide ostium, whereas aneurysms with regular morphology were 6 times more likely to be occluded. WEB shape modification was strongly influenced by the aneurysm shape and ostium size, and it was not independently associated with the angiographic occlusion (Fig. 1, Fig. 2, Fig. 3).