New COMPLETE Registry Findings Offer Important Data on Vessel Size for Device Choice

A new analysis of 643 patients from the COMPLETE registry, a prospective, global, multicenter study, found a wide variation in vessel diameters across different occlusion segments, suggesting corresponding differences in clinical severity. Notably, researchers found that the M1 is on average smaller than previously believed, adding to a body of research suggesting similar variability in vessel size.^1,2 The results were presented in July at the 22nd annual meeting of the Society of Neurointerventional Surgery in Nashville.

“This data confirms what we’ve been seeing in other recent studies showing variation in vessel size in different parts of the brain,” said Dr. David Liebeskind, MD, MBA, a vascular neurologist at the David Geffen School of Medicine, UCLA, and the principal investigator of the analysis. “This gives doctors baseline information they need to make more informed decisions about which devices to use for aspiration, which could help improve safety and long-term outcomes for our patients.”

“Understanding vessel size is crucial. You want to use the biggest aspiration catheter that will safely fit in the vessel, ensuring optimal aspiration efficiency. That’s the sweet spot for getting the best results in thrombectomy,” said Dr. Reza Saber, MD, MPH, a cerebrovascular and neuroendovascular specialist at the Dell Seton Medical Center, University of Texas at Austin, and a coauthor of the analysis. “This data helps us make those choices with more confidence, which means better outcomes for stroke patients.”

Matching catheters to vessel size is increasingly recognized as a key factor in reperfusion outcomes, especially with large-bore catheters in use.³ But detailed data on the distribution of vessel diameters had been limited.

The COMPLETE findings show that vessel diameters varied substantially by segment, often measuring smaller than previously believed. For example, proximal M1 arteries were measured at an average of 2.34 mm, while distal M1 averaged 2.26 mm. M2 diameters decreased from approximately 2.09 mm for proximal to 1.75 mm for distal, on average.

The COMPLETE findings offer clinicians important data to optimize catheter selection and potentially improve the effectiveness of aspiration. Vessel sizing is one of the principles of science-based aspiration thrombectomy (S-BAT) for selecting an aspiration catheter.

These key S-BAT principles for stroke care include:

• Physics: Recognizing energy flows and what actually occurs when catheter meets clot.
• Vessel Sizing: Understanding average vessel sizing and the optimal catheter-to-vessel ratio for effective aspiration.
• Flow Control: Evaluating the consequences of excessively restricting blood flow during a thrombectomy procedure.
• Time: Analyzing procedure time in relation to patient outcomes, and key opportunities to reduce time.

Penumbra has kept these principles at the core of its research and development, providing a full range of neuro thrombectomy catheters designed to optimize lumen size and trackability for the specific vessel for a variety of clinical situations.

For more information on science-based aspiration thrombectomy, check out the S-BAT Info Center.

Important Safety Information

The clinical results presented herein are for informational purposes only, and may not be predictive for all patients. Individual results may vary depending on patient-specific attributes and other factors. Product availability varies by country. Caution: Federal (USA) law restricts these devices to sale by or on the order of a physician. Prior to use, please refer to Instructions for Use (IFU) for complete product indications, contraindications, warnings, precautions, potential adverse events, and detailed instructions for use. For the complete Penumbra IFU Summary Statements, visit: peninc.info/risk. Please contact your local Penumbra representative for more information.

Copyright ©2025 Penumbra, Inc. All rights reserved.

<sup>1. Rai AT, Hogg JP, Cline B, Hobbs G. Cerebrovascular geometry in the anterior circulation: an analysis of diameter, length and the vessel taper. Journal of NeuroInterventional Surgery. 2013;5(4):371-375.
2. Saber H, Froehler MT, Zaidat OO, et al. Variation in Vessel Size and Angiographic Outcomes Following Stent‐Retriever Thrombectomy in Acute Ischemic Stroke: STRATIS Registry. Stroke: Vascular and Interventional Neurology. 2024;(0:e000978). doi: https://doi.org/10.1161/SVIN.123.000978.
3. Kaneko N, Saber H, Hassan A, et alE-005 Vessel size and segmental variations in the COMPLETE registry. Journal of NeuroInterventional Surgery 2025;17:A96-A97.</sup>