Introduction The ideal treatment modality for both ruptured and unruptured MCA aneurysms is a contentious subject. Both clipping and endovascular therapy (EVT) of these aneurysms are viable options. So far there have been no randomized controlled trials that have compared the results of clipping versus endovascular therapy for MCA aneurysms.

We present a consecutive series of 30 MCA aneurysms (ruptured and unruptured) that were treated using endovascular techniques in our center between Jan 2015–Feb 2016. The use of novel endovascular aneurysm treatment techniques and adjunctive devices is discussed. We also describe the procedural complications and the immediate and short-medium term results of their clinical and imaging follow up.

Materials and methods A retrospective analysis of the PACS database at James Cook University Hospital identified 30 episodes of “embolization of MCA aneurysms” performed in 29 patients between 1 Jan 2015–29 Feb 2016.

The relevant admission case notes, angiography and cross-sectional imaging and follow- up clinic data were reviewed.

Results 30 MCA aneurysms in 29 patients (24 Female, 5 male) with an age range from 26–79 years were treated using EVT during this period. There were 14 ruptured and 16 unruptured MCA aneurysms. 10 of the 14 ruptured MCA aneurysms had associated parenchymal haematomata.

The median size of aneurysm treated was 5 mm (range 1.3 mm –13mm). Adjunctive devices were used in 21 patients comprising of balloons in 15 cases, low profile stents in 4 cases, 1 web device and 1 PCONUS device. Novel endovascular techniques were used in 8 cases which included dual balloon remodeling technique in one case, dual micro-catheter in 4 cases, balloon with dual microcatheters in 2 cases and neck remodeling with guidewire support in one case.

There were no intra, peri-procedural or delayed ruptures, coil prolapse/migration in either of the ruptured or unruptured MCA aneurysms groups.

Intra-procedural clot formation was noted in 3/29 (10.3%) patients which was treated with IV absciximab with no sequalae. 1/29 (3.4%) patients had a groin haematoma post stent assisted embolization secondary to failure of groin closure device.

15/16 patients in the unruptured cohort had no change in their mRs score post procedure at discharge. mRs score of 1/16 patients with groin haematoma who needed surgical evacuation, returned to the pre-operative baseline at clinic review in 3 months.

5/14 patients with aneurysmal SAH died as a result of their original hemorrhage. The remaining 9 returned to a mRs score of 0–2 at clinic review.

Follow up imaging at 1 year is available in 10/29 patients, small neck remnants are noted in 5/10 cases. Two of the remnants have developed in patients with aneurysmal SAH with haematoma at presentation. In the other 3 cases deliberate neck remnants were left at the time of original treatment which have not changed.

Conclusion Endovascular treatment of MCA aneurysms is efficacious and has a good safety profile with acceptable immediate and mid-term results. Continues innovation in endovascular techniques and devices has enabled safe and effective embolization of both ruptured and unruptured MCA aneurysms.

Disclosures R. Padmanabhan: None. S. Power: None.