Flow diverter (surpass) for unruptured intracranial aneurysms: A prospective single-center study in 37 patients - long-term follow-up

Intracranial aneurysms (IA) are mostly saccular lesions of the vessel wall in
the large vessels obtaining blood supply to the brain. IA are mostly located on
vessel bifurcations and are predominantly located in the anterior circulation.
IA can be found in approximately 1-2 % of the population. The IA itself is
normally asymptomatic and is often an incidental finding, but still, a ruptured
IA is the reason for 80-85 % of symptomatic subarachnoid hemorrhage (SAH). SAH
is a dangerous disease accompanied by high morbidity. There are several risk
factors determining the risk for IA rupture and a consecutive SAH as smoking,
hypertension, familiar disposition, polycystic kidney, Age, hypertension, IA
morphology, and multiple aneurysms. Depending on the total risk profile of a
patient the Decision to treat or not to treat is done. There are multiple
treating options for IA and nowadays endovascular treatment became the most
common modality of treatment compared to surgical clipping. Nevertheless,
endovascular coiling carries a high rate for reperfusion, aneurysms growth and
is sometimes not doable without the risk for periprocedural ischemia.
The Surpass Flow Diverter (Surpass; Stryker Neurovascular, Fremont, CA) is a
flow diverter for the reconstruction of the parent artery and aneurysm
occlusion. The implant maintains a high pore density, uniform across the
aneurysm neck, and is unaffected by the diameter of the parent artery. As
implants with various diameters and lengths are available, 1 single implant is
sufficient to treat the target aneurysm(s) and parent artery. The feasibility
and safety of the Surpass were already described from our group in 2013 in a
group of 37 patients with unruptured intracranial aneurysms, a good outcome in
a 7-month follow-up was described.
Still, the biggest issue in endovascular treatment remains reperfusion and the
risk for retreatment, therefor long-term outcome data is crucial.
For this purpose, we would like to investigate the long-term follow-up (5-year)
of the previously described patient population with subtraction CT-angiography
and clinical outcome measures to evaluate if the Surpass can reduce the high
reperfusion rate of endovascular treated aneurysms.

The primary objective is to evaluate long-term reperfusion rate, neurological
outcome and quality of life in patients with unruptured intracranial aneurysm
treated with the Surpass Flow Diverter (Surpass; Stryker Neurovascular,
Fremont, CA).

The 37 patients who received a Surpass Flow Diverter (Surpass; Stryker
Neurovascular, Fremont, CA) will be contacted if they want to participate in
the long term follow-up.
Patients will undergo the DSA. On the same day SF-36 questionnaire will be
taken and the results of the DSA will be discussed.

DSA is currently the golden standard for flow diverter treatment. The radiation
dose is 3.0 mSv. This technique is rather safe with a low chance of
complications. The most common complications are mild, such as puncture site
hematoma and contrast reaction. The chance of major complications is very low.
There is no standard protocol for long term follow-up of patients treated with
flow diversion, nevertheless, possible reperfusion would put the patient at
risk for subarachnoid hemorrhage. Therefore long-term follow up with DSA is
justified.