Penumbra today announced the results of THUNDER, which is an investigational device exemption (IDE) study intended to evaluate the safety and effectiveness of Thunderbolt—the company’s novel computer-assisted vacuum thrombectomy (CAVT) system—in stroke patients with emergent large vessel occlusion (LVO). These late-breaking data were presented during the ongoing Society of NeuroInterventional Surgery (SNIS) annual meeting (20–24 July, Seattle, USA).
“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,” said Donald Frei (Swedish Medical Center, Denver, USA), co-principal investigator of THUNDER. “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.”
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. Notably, post-Thunderbolt treatment, mTICI 2c–3—which, Penumbra adds, is associated with significantly better functional recovery and lower complication rates—was achieved 70.4% of the time.
Additionally, the study saw a 64.8% rate of first-pass mTICI 2b–3 and a median time to revascularisation of 20 minutes. The complete clot ingestion rate was 83%, demonstrating that the Thunderbolt system reliably facilitates the removal of clot, according to Penumbra. Furthermore, device/procedure-related serious adverse events occurred at a rate of 2.8%, symptomatic intracranial haemorrhage (sICH) occurred at a rate of 0.9%, and the rate of all-cause mortality at 90 days was 11.7%, which Penumbra highlights as being comparatively low versus other thrombectomy therapies.
“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,” said co-principal investigator David Fiorella (Stony Brook University Hospital, Stony Brook, USA), who presented these first-time data at SNIS 2026. “Through this study, our early experience with Thunderbolt suggests that this technology could significantly advance treatment for stroke patients.”
THUNDER is a single-arm, prospective, multicentre study with core-lab adjudication evaluating the safety and effectiveness of Thunderbolt—which features Penumbra’s CAVT technology—in stroke patients with emergent LVOs. The study enrolled 216 patients across 29 US centres.
“The THUNDER study provides robust clinical evidence supporting the safety and effectiveness of Thunderbolt for revascularisation in emergent LVO stroke,” added James Benenati, chief medical officer at Penumbra. “These findings reinforce modulated aspiration as a significant advancement in mechanical thrombectomy and suggest it could expand physicians’ treatment options to achieve rapid, effective revascularisation in stroke, which is critical for patient outcomes.”
