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A look at patterns of change in intracranial hemodynamics after Pipeline implantation reveals that increases in mean flow velocity in the ipsilateral middle cerebral artery (MCA) may be linked to greater hemorrhage risk, according to new results.

Yet the study is too small to inspire any clinical conclusions, Christoph J. Griessenauer, MD (Harvard Medical School, Boston, MA), commented to Neurovascular Exchange.

For their paper published recently in the Journal of NeuroInterventional Surgery, investigators led by Denise Brunozzi, MD (University of Illinois at Chicago, IL), reviewed the data on patients with aneurysms located proximal to the internal carotid artery terminus that were treated using the Pipeline device (Medtronic) between 2015 and 2016. They identified the 10 patients whose MCA flow velocities were measured using transcranial Doppler and evaluated bilateral MCA flow velocities, the ratio of ipsilateral to contralateral MCA flow velocity, and the bilateral MCA pulsatility index before and after Pipeline deployment in these patients.

Patients’ mean age was 52 years. Two had delayed ipsilateral intraparenchymal hemorrhage within 48 hours after receiving Pipeline. These same patients also had a larger increase in ipsilateral MCA mean flow velocity compared with patients without delayed hemorrhage (39.5% vs 5.5%).

In addition, patients with delayed ipsilateral intraparenchymal hemorrhage had a higher ipsilateral MCA pulsatility index (1.55 vs 0.98) and a higher ratio of ipsilateral to contralateral MCA mean flow velocity (1.35 vs 1.04) prior to deployment of the Pipeline device.

Clinical Utility Uncertain

Speaking with NVX, Griessenauer encouraged the authors to measure intracranial hemodynamics in a larger series of patients to see what patterns emerge.

For now, he added, it remains unclear how the information could be used in practice, even if patterns do emerge. “Unless you have a reliable tool that tells you beforehand that maybe you shouldn’t put a Pipeline in, this doesn’t really tell you anything,” he said. “You can’t just remove it after, even if you initially have a lower middle cerebral artery mean flow velocity and you see it go up after you implant. Your hands are tied. You can maybe keep patients around a bit longer [to observe them].”

Griessenauer also pointed out that as interventionalists have gained experience using flow diverters and concomitant antiplatelet therapy and as the devices have been redesigned for easier use, delayed ipsilateral intraparenchymal hemorrhage is becoming less and less of a problem. He himself has performed upward of 100 interventions with the Pipeline and has yet to see one, he reported.

 

Source:
Brunozzi D, Shakur SF, Hussein AE, et al. Middle cerebral artery flow velocity increases more in patients with delayed intraparenchymal hemorrhage after Pipeline. J NeuroIntervent Surg. 2017;Epub ahead of print.

Disclosures:
Brunozzi and Griessenauer report no relevant conflicts of interest.

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