HOUSTON—A flow-diverter device can treat small to medium-sized unruptured aneurysms safely and effectively, according to research presented at the International Stroke Conference 2017. The device has a high rate of aneurysm occlusion and is associated with no aneurysm rupture or recurrence at one year. The treatment also entails low rates of morbidity and mortality at one year.
One flow diverter is the Pipeline embolization device. The Pipeline device is inserted into the blood vessel and incorporates a mesh that covers the mouth of the aneurysm. The mesh allows the inner lining of the blood vessel to grow and patch the aneurysm from the inside. In April 2011, the Pipeline embolization device was approved in the United States for the treatment of aneurysms larger than 10 mm on the carotid artery. Many physicians have used the device to treat smaller aneurysms, but no investigators had examined its safety and efficacy in this indication.
Examining an Off-Label Use of the Device
Ricardo Hanel, MD, PhD, Director of Baptist Neurological Institute in Jacksonville, Florida, and colleagues conducted a prospective, multicenter study to evaluate the safety and efficacy of the Pipeline device in the treatment of small to medium-sized (ie, 12 mm or smaller), wide-necked, unruptured aneurysms on the internal carotid artery or vertebral artery. Eligible patients were between ages 22 and 80 and had an aneurysm neck that was 4 mm or larger. Patients with subarachnoid hemorrhage in the previous 30 days and those who had received an intracranial implant in the area of the target aneurysm within the previous 12 weeks were excluded.
Ricardo Hanel, MD, PhD
The primary efficacy end point was complete aneurysm occlusion without significant parent artery stenosis at one year post procedure. The secondary efficacy end point was device deployment success rate. The primary safety end point was major stroke in the area supplied by the treated artery or neurologic death at one year post treatment. Secondary safety end points included major stroke or neurologic death at 30 days post treatment. Follow-up was conducted at 30 days, six months, one year, two years, and three years.
Dr. Hanel and colleagues enrolled 141 patients into the trial. The population’s mean age was approximately 55, and about 88% of the population was female. Participants had few, if any, symptoms. Approximately 48% of the population had hypertension, 38% had hyperlipidemia, and 44% were current smokers or had smoked within the previous 10 years.
Most Patients Had Complete Occlusion
Mean aneurysm size at baseline was 5 mm. About 84% of the aneurysms were smaller than 7 mm, and 16% were between 7 mm and 12 mm. Approximately 97% of aneurysms were saccular; 12% of saccular aneurysms involved a side branch, and 84% involved a sidewall, but no branch. About 4% of aneurysms were fusiform. About 95% of aneurysms were on the carotid artery. The two most common patient risk factors for treatment were patient preference (63%) and hypertension (48%).
The device was deployed to the target site successfully in about 99% of patients. Mean procedure time was approximately 80 minutes. The mean number of Pipeline devices required to treat each aneurysm was one. Ten patients received multiple Pipeline devices.
The investigators achieved complete occlusion without significant stenosis or retreatment at one year in approximately 84% of patients. This end point was documented by angiogram and adjudicated by an independent core laboratory. The reasons for treatment failure included residual aneurysm (8% of all patients), residual neck (6%), stenosis greater than 50% (1%), and aneurysm retreatment (2%).
At 30 days, three safety events had occurred in two patients. Both patients had a major stroke, and one of them died. The 30-day safety event rate thus was about 1%. One other safety event, a stroke, occurred at 169 days after treatment. The rate of major stroke and death at one year was approximately 2%. Two-year and three-year data are forthcoming.
The study was not designed to define which patients should be treated with a flow diverter, which is “a much broader and harder question,” said Dr. Hanel. Neurologists treat between 20% and 25% of patients with aneurysms smaller than 7 mm. The decision to treat is based on risk factors such as medical history and aneurysm location.
Aneurysms like those in the study “are difficult to treat with current armamentarium devices,” said Ralph L. Sacco, MD, Professor and Olemberg Chair of Neurology at the University of Miami. The current study indicates that the Pipeline device is safe and that these aneurysms can be treated, he added.
Dr. Hanel is a consultant for Medtronic, the manufacturer of the Pipeline device and the funder of the study.
—Erik Greb
Suggested Reading
Becske T, Potts MB, Shapiro M, et al. Pipeline for uncoilable or failed aneurysms: 3-year follow-up results. J Neurosurg. 2016 Oct 14:1-8. [Epub ahead of print].
Brinjikji W, Murad MH, Lanzino G, et al. Endovascular treatment of intracranial aneurysms with flow diverters: a meta-analysis. Stroke. 2013;44(2):442-447.