To investigate the clinical and procedural predictors of poor outcome in unexpected aneurysm rupture during coil embolization.

Methods Our institutional database for coil embolization of intracranial aneurysms from 1996 to 2014 July was retrospectively reviewed. Among 1836 patients, there were 39 aneurysm ruptured during the procedures. The average age was 55.4yo (27–82); 30 females and 9 males; 26 presented with hemorrhage, and 13 without hemorrhage. The most common location was Acom. All embolization procedures were conducted under general anesthesia except 4 cases.

Results The aneurysm rupture was confirmed by contrast extra-vasation in 33 cases, and 6 by the other findings such as vital sign changes and intra-procedural CT. The cause of the ruptures includes; coils in 24 cases, micro-wire 6, others in 9. The ruptures were controlled by heparin reverse, additional coiling, balloon inflation, and their combinations.

Clinical factors associated with poor clinical outcome (mRS4–6) were age (p = 0.008) and HH Grade 4/(p = 0.027). Also aneurysm rupture requiring EVD in the angio-suite was associated with poor outcome (p = 0.007). Aneurysm rupture group by coils had higher mortality than by micro-wires and other causes (p = 0/025). In this analysis, we divided coiling into 3 phases; framing, filling, and finishing. Framing phase was defined as first two large aneurysm coils placements, and filling phase was defined as the last part of embolization with 3mm or smaller diameter coils. In the three phases, the aneurysm ruptures during finishing phase (p = 0.034, OR 11.06 [1.06–114.1]) was associated with poor clinical outcome (mRS4–6).

Conclusion Aneurysm rupture with coils was associated with poor clinical outcome than with wires and other causes. Aneurysm rupture during the finishing phase is particularly dangerous.

Disclosures M. Okawa: None. S. Tateshima: 2; C; Covidien, Reverse Medical, Pulsar Vascular, Blockade Medical, Silkroad Medical, Century Medical. S. James: None. V. Szeder: None. N. Gonzalez: None. R. Jahan: 2; C; Covidien, Medina Medical. G. Duckwiler: 2; C; Covidien, Asahi Intec.