Significance of dual antiplatelet therapy duration following flow diverter treatment

Dual Antiplatelet Therapy (DAPT) prescription following flow-diverter stent treatment of intracranial aneurysms is standard of care since cardiologist demonstrated the superiority of antiplatelet therapy over anticoagulation after stent implantation 30 years ago.¹ But evidence regarding optimal duration of DAPT is scarce. This lack of evidence is probably at the origin of the absence of society recommendation. A national survey of practice was recently conducted and demonstrated heterogeneity in clinical practices across centers.²

There are multiple parameters defining a antiplatelet protocol :

• Number of molecules
• Molecules types
• Initiation time
• DAPT length
• Total length

The Innovative Neurovascular Product Surveillance Registry (INSPIRE registry) is a large scale, long-term observational study platform sponsored by Medtronic Neurovascular designed to continuously monitor the safety and performance of newly commercialized devices. Site data on consecutively treated patients are monitored and safety event data are assessed by an independent clinical events committee, while efficacy is assessed by an independent central core laboratory. It has the ambition to provide real-world evidence to optimize therapeutic strategies by finding the best treatment paradigms based on scientific evidence.³

We have conducted an analysis of 700 patients treated for an unruptured aneurysm with the Pipeline^TM Shield flow diverter stent (from the INSPIRE registry and 2 other Medtronic sponsored registries). Interestingly if we observed two peaks of DAPT length, one at 3 months and one at 6 months, half the population received DAPT for more than 6 months (figure).

Figure. DAPT durations for the 707 Pipeline Shield treated patients in the Medtronic sponsored registries.

This analysis revealed an excellent safety of Pipeline Shield treatments with a rate of neurological death + major ischemic strokes of 1.8% and a major bleeding risk of 2.4%. Most events occurred during the first 30 days after implantation.

The analysis is limited by its retrospective nature because DAPT strategies might have been influenced by the management of adverse events but it brings very valuable data to design future prospective trials thanks to the high number of patients included, the data monitoring and a very high rate of follow-up.

References

1. Schömig, A. et al. A Randomized Comparison of Antiplatelet and Anticoagulant Therapy after the Placement of Coronary-Artery Stents. N. Engl. J. Med. 334, 1084–1089 (1996).
2. Caroff, J. et al. Antithrombotic therapies for neurointerventional surgery: a 2021 French comprehensive national survey. J. NeuroInterventional Surg. 15, 402–407 (2023).
3. Committee, S. et al. The INSPIRE Registry: Entering a New Era of Medical Device Research in the Neurovascular Field. Clin. Neuroradiol. 30, 659–660 (2020).

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