Findings from the off-label study suggest the potential to treat more patients endovascularly and to treat them sooner.
Acutely ruptured intracranial aneurysms can be safely treated with a flow diverter plus antiplatelet monotherapy, according to a small retrospective series.
However, the study authors acknowledge that their findings, published online December 14, 2018, ahead of print in the Journal of NeuroInterventional Surgery, remain very preliminary. If these results can be confirmed in larger trials, they could represent a paradigm shift that extends endovascular interventions to a much wider group of patients.
“There is a small but significant group of patients with ruptured aneurysms for whom traditional techniques, either endovascular or open microsurgical, will not be able to safely secure their aneurysms. These patients represent a current unmet need,” lead author Nathan W. Manning, MD (Prince of Wales Hospital, Randwick, Australia), told Neurovascular Exchange in an email.
For such patients, the Pipeline Flex with Shield Technology (Medtronic Neurovascular) is a potential solution.
Typically, procedures employing flow diverters are conducted with the use of dual antiplatelet therapy (DAPT). But Pipeline Flex is coated with phosphorylcholine, which is a major constituent of red-blood-cell membranes that has been shown to reduce platelet adhesion and activation. Given its potentially reduced thrombogenicity, the study investigators theorized that procedures might be safety performed using single antiplatelet therapy (SAPT).
“SAPT, and in particular, aspirin SAPT gives you confidence that any further invasive procedures the patient needs, such as [cerebrospinal fluid] diversion, can be performed safely,” noted Manning.
The study investigators retrospectively identified 14 patients (12 women, median age 64 years) who underwent acute treatment for aneurysmal subarachnoid hemorrhage (SAH) with the flow-diverter stent and SAPT from prospectively maintained databases at three Australian neurointerventional centers.
Aneurysm morphology was saccular in seven patients, fusiform in five, and blister in two. Aneurysms arose from the anterior circulation in 57.1% of patients, and 42.9% were poor grade subarachnoid hemorrhages (World Federation of Neurological Societies grade ≥ IV). Median time to treatment was 1 day.
At the end of an early-acute follow-up period of a median of 7 days after SAH, complete or near complete aneurysm occlusion (defined as Raymond-Roy grading scale score < 3) was achieved in 85.7% of patients. Permanent, treatment-related morbidity occurred in one patient, and there was one treatment-related death.
A postoperative heparin infusion was used in five patients and was associated with a higher rate of all complications (80.0% vs. 11.1%; P = 0.023) and symptomatic complications (60% vs. 0.0%; P = 0.028).
There were no symptomatic ischemic or hemorrhagic complications in the patients who did not receive postoperative heparin infusion. Overall, 64.3% of patients were functionally independent on discharge from the treatment center.
“Our protocol evolved over time and appears to have increased in success with less complications,” indicated Manning. “Of the last nine patients, there were no symptomatic complications and no deaths.”
SAPT Changes the Paradigm
“The patients in our study represent the ‘worst of the worst’ ruptured -aneurysm patients and for this subgroup, this may be a real breakthrough,” Manning pointed out. “If you look in the literature, what you see is these patients typically do not get treated for approximately 1 week after their rupture. This is due to the concern of using DAPT.
“However, in our study, patients were treated as soon as they could be, and typically on the day of their bleed or the next day,” he continued. “To my mind that is a huge advantage. Essentially, this allows you to get early aneurysm control, which has always been our goal for every other patient, in this really tough group of patients.”
If these outcomes can be supported in larger trials, they could lead to a paradigm shift, Manning suggested. “What it essentially means is that no ruptured aneurysm is untreatable now from an endovascular point of view.”
Manning said he hopes that findings like these will encourage manufacturers to continue to innovate and develop increasingly safer endovascular tools. “Those better products are going to allow us to help patients we previously couldn’t help and improve what we currently offer. That’s the whole point of innovation,” he noted.
Manning NW, Cheung A, Phillips TJ, et al. Pipeline Shield with single antiplatelet therapy in aneurysmal subarachnoid haemorrhage: multicentre experience. J NeuroIntervent Surg. 2018;Epub ahead of print.
Manning reports being a paid proctor for Pipeline and a consultant for Medtronic.