We present a case of successful endovascular management of a large ruptured aneurysm originating at the junction of the left VA and left PICA by placement of a flow-diverter across the origin of the aneurysm, with gradual complete recovery and shrinkage of the aneurysm on late follow-up imaging.
The endovascular approach offers a therapeutic alternative that is widely accepted and may be preferable in the treatment of some PICA aneurysms when surgical clipping is considered to have an unacceptable risk[1, 2]. Encouraging short- and long-term results in most of the cases can be achieved by therapeutic occlusion of the PICA or exclusion of the aneurysm from the circulation with preservation of the PICA[7–9]. Anatomical characteristics of the PICA and VA may restrict the use of balloons and stents in the treatment of aneurysms originating from the VA. Rupture of a PICA aneurysm with local or diffuse spasm of the vertebrobasilar system can complicate the course of endovascular treatment.
The use of stents in the treatment of ruptured aneurysms is generally not recommended because of potential risks of spasm and embolic complications, as well as bleeding, since the use of antiplatelet agents during and after the intervention is mandatory. However, results of recently published studies show that stent-assisted coiling or deployment of stents in parent arteries may offer a promising therapeutic alternative in selected cases, even in the setting of subarachnoidal bleeding[10, 11]. Interestingly, several years after the introduction of flow-diverting stents into clinical practice, reports on their use for the treatment of acutely ruptured, predominantly dissecting, and bloodblister-like aneurysms are still relatively sparse[12–14].
Flow-diverting stents redirect blood flow from the aneurysm to the lumen of the parent artery. Such changes of the hemodynamics in the aneurysm and corresponding segment of the parent vessel can lead to spontaneous thrombosis of the lumen of the aneurysm[5, 6]. At present, two flow-diverting stents are available, the Pipeline neuroendovascular device (eV3/Covidien) and the Silk stent (Balt Extrusion). The Silk stent is a tubular structure composed of 48 braided nitinol wires with excellent wall opposition and conformability. Flaring at the ends provides apposition in tight curves. Its high-density mesh is designed to redirect the blood flow and induce remodeling of a continuous arterial wall surface. Four helicoidal radio-opaque markers along the full length of the stent allow assessment and control of deployment.
In this particular case, two therapeutic strategies were considered: neurosurgical and endovascular. Surgical clipping was rejected for this patient because of the unacceptable risk of compromising the flow in VA and/or PICA. Endovascular treatment with coils carried almost the same risks, and the authors wanted to avoid permanent compression on the medulla and stenotic VA that could be caused by a huge mass of coils. Additionally, the risk of re-bleeding has significantly decreased in this phase of the disease.
After the meticulous analysis of the clinical picture and imaging studies, and considering the natural course of the disease if not treated, the authors decided to deploy the flow-diverting stent in the left VA. Experience in the treatment of acutely ruptured aneurysms with only flow-diverting stents is limited. The authors decided to treat a ruptured aneurysm using the flow-diverting stent in spite of all known and assumed risks related to the use of this novel remodeling device. In the patient described here, there were three treatment goals: reduce compression on the brainstem, isolate the lumen of the aneurysm from the parent artery, and preserve flow in the PICA and VA. We assumed that flow in the PICA would not be compromised since the radial force of the stent, even if only partially opened, would be sufficient to preserve VA patency. Finally, we assumed that the risks related to surgical clipping or coil occlusion of this aneurysm were much higher than risks related to deployment of the flow-diverting stent in the VA.