THUNDER Results Presented for Penumbra’s Thunderbolt CAVT System in Stroke Patients

July 22, 2026—Penumbra, Inc. announced the results of the THUNDER investigational device exemption (IDE) study evaluating the safety and effectiveness of the company’s Thunderbolt computer assisted vacuum thrombectomy (CAVT) system in stroke patients with emergent large vessel occlusion (ELVO). The single-arm, prospective, multicenter study used core-lab adjudication and enrolled 216 patients across 29 centers in the United States.

The data were presented during a late-breaking session at the Society of NeuroInterventional Surgery 23rd annual meeting. In June, Penumbra announced FDA clearance and CE Mark approval for the Thunderbolt CAVT platform for the treatment of acute ischemic stroke.

According to the company, THUNDER met its predefined performance goal with 87.5% of cases achieving successful reperfusion, defined as modified thrombolysis in cerebral infarction (mTICI) 2b-3, after treatment with Thunderbolt.

Penumbra reported that after treatment with Thunderbolt, mTICI 2c-3 was achieved in 70.4% of procedures, which is associated with significantly better functional recovery and lower complication rates.

Additionally, first-pass mTICI 2b-3 was 64.8%; median time-to-revascularization was 20 minutes; the rate of complete clot ingestion was 83%; the rate of device- and procedure-related serious adverse events was 2.8%; the rate of symptomatic intracranial hemorrhage was 0.9%; and the rate of all-cause mortality at 90 days was 11.7%.

Donald Frei, MD, and David Fiorella, MD, serve as coprincipal investigators of THUNDER.

“Mechanical thrombectomy is considered frontline treatment for stroke; however, current technologies may not fatigue and completely ingest the clot quickly or effectively at the site of the occlusion,” commented Dr. Frei in Penumbra’s press release. “The THUNDER study demonstrated a high rate of complete clot ingestion with Thunderbolt, along with a low rate of complications—an important combination when striving for optimal patient outcomes.”

Dr. Fiorella added, “In the THUNDER study, we observed that modulated aspiration facilitated consistent and complete clot removal when used in conjunction with standard-sized aspiration thrombectomy catheters. Through this study, our early experience with Thunderbolt suggests that this technology could significantly advance treatment for stroke patients.”