Endovascular intervention for delayed stenosis of extracranial-intracranial bypass saphenous vein grafts.

PURPOSE

Bypass graft stenosis is an uncommon but significant issue which can be encountered following extracranial-intracranial (EC-IC) bypass surgery and carries significant potential for morbidity and mortality. Angioplasty for graft stenosis (with or without stenting) has been extensively discussed in the cardiothoracic literature but its application for neurosurgical purposes has not been well documented.

METHODS

Cases of EC-IC bypass undergoing endovascular intervention for graft stenosis were retrospectively reviewed; a literature search was performed. Diagnosis, pathology and indications for intervention were reviewed.

RESULTS

Three patients underwent 13 endovascular interventions for EC-IC saphenous vein graft stenosis. The indication for the initial bypass was an unsecured intracranial aneurysm in all cases, using an interposition saphenous vein graft. The initial endovascular procedure was needed 9-23 weeks after the bypass surgery, a timeframe suggestive of intimal hyperplasia as the underlying etiology of stenosis. There were nine cases of angioplasty alone, three with stent placement and one case in which vasodilators were infused. Non-invasive phase contrast quantitative MR angiography was effective in predicting graft stenosis. Despite intervention, two grafts ultimately occluded and a third has remained patent only after multiple angioplasties and placement of a drug eluting coronary stent.

CONCLUSION

Although rare, bypass graft stenosis can occur in the subacute period, and likely represents a flow related venopathy. Given the challenges of re-do bypass surgery, endovascular intervention is an attractive treatment option. However, although repeated interventions with diligent follow-up may allow graft salvage, failure of endovascular intervention can also ultimately result in graft occlusion.