The PROTECT-MT randomized controlled trial (RCT) has presented results indicating potentially worse functional outcomes following stroke thrombectomy when using a balloon guide catheter (BGC) compared to a conventional guide catheter. These findings, presented at the 16th World Stroke Congress (WSC), suggest uncertainty around BGC usage in mechanical thrombectomy for acute ischemic stroke caused by anterior-circulation large vessel occlusion (LVO).
Trial Design and Methods
The investigator-initiated, multicenter, prospective, open-label PROTECT-MT RCT aimed to evaluate the effectiveness and safety of BGC-based thrombectomy procedures for ischemic stroke. The trial compared BGC use to conventional guide catheters, with the primary endpoint being an ordinal shift analysis of modified Rankin scale (mRS) scores at 90 days post-stroke. An estimated 1,074 stroke patients with temporary, proximal LVO within 24 hours of symptom onset were to be randomized 1:1 to either the BGC (intervention) or conventional guide catheter (control) group.
Early Termination and Results
Recruitment began in February 2023 but was suspended in November 2023 by the trial's independent data and safety monitoring board (DSMB) due to safety concerns. The steering committee halted recruitment completely in April 2024 after these concerns persisted, with 329 patients randomized. Unblinded results presented at WSC 2024 indicated that BGC use was associated with inferior functional outcomes compared to conventional guide catheters. The 90-day mRS shift analysis showed an adjusted common odds ratio (OR) of 0.66 (95% confidence interval [CI], 0.45–0.98; p=0.037), suggesting worse outcomes in the BGC group. Dichotomized mRS results also showed that scores of 0–3 were achieved in 41% of patients in the BGC group versus 56% in the conventional guide catheter group (OR, 0.56; 95% CI, 0.35–0.88), and scores of 0–4 were achieved in 57% versus 73% (OR, 0.47; 95% CI, 0.28–0.78), respectively.
Additional Observations and Limitations
Rates of embolization in new territories (ENT), reperfusion quality, and first-pass effects were comparable between the two groups. However, the BGC group experienced a longer average procedure time and an increased rate of severe vasospasm in the internal carotid artery (ICA). Pengfei Yang (Naval Medical University/Changhai Hospital, Shanghai, China) highlighted several limitations, including the early termination of the trial, discrepancies in device types and operator experience, and the trial's exclusive conduct in China, where intracranial atherosclerotic disease (ICAD) is a more common cause of ischemic stroke.
Conclusion
Despite being the largest RCT to date assessing the impact of BGCs versus conventional guide catheters on thrombectomy-related functional outcomes in LVO stroke patients, the investigators concluded that further research is necessary to fully elucidate the role of BGC usage in interventional stroke care. The findings of PROTECT-MT have been published in The Lancet.
