Proximal Temporary Occlusion Using Balloon Guide Catheter for Mechanical Thrombectomy - PROTECT-MT

Dec 16, 2024
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Author/Summarized by Author:
Amit Saha, MD
Summary Reviewer:
Anthony A. Bavry, MD,MPH,FACC
Trial Sponsor:
Changhai Hospital
Date Published:
11/30/2024
Original Posted Date:
12/16/2024
References

Contribution To Literature:

The PROTECT-MT trial showed that in patients with anterior circulation ischemic stroke due to large vessel occlusion, use of balloon guide catheters during ERT resulted in worse long-term neurologic outcomes compared with conventional guide catheters.

Description:

The goal of the trial was to determine the efficacy and safety of balloon guide catheters compared with standard-tip catheters in endovascular recanalization therapy (ERT) for acute ischemic stroke due to large vessel occlusion.

Study Design

  • Multicenter (China)
  • Randomized
  • Open-label

Patients with acute ischemic stroke due to large vessel occlusion and who were eligible for ERT were randomized in 1:1 fashion to undergo ERT with a balloon (n = 164) or conventional (n = 165) guide catheter. Specific catheter selection within each arm, as well as thrombectomy techniques, were left to the treatment team’s discretion. The trial was terminated early for safety following an interim analysis of the primary outcome.

  • Total number of enrollees: 329 (target enrollment 1,074)
  • Duration of follow-up: 90 days
  • Median patient age: 69 years
  • Percentage female: 39%

Inclusion criteria:

  • Age ≥18 years
  • Acute ischemic stroke due to occlusion of intracranial segment of internal carotid artery or M1 or proximal M2 branches of middle cerebral artery
  • ≤24 hours from symptom onset and eligible for ERT
  • Premorbid modified Rankin scale (mRS) score ≤1

Exclusion criteria:

  • Intracranial hemorrhage
  • Vascular access tortuosity precluding balloon guide catheter use
  • Occlusions in multiple vascular territories
  • Chronic occlusion of or prior intracranial stent in target vessel

Other salient features/characteristics:

  • Intracranial atherosclerosis: 27%
  • Cardioembolic etiology: 46%
  • Median National Institutes of Health Stroke Scale (NIHSS) score: 15
  • Median time from symptom onset: 357 minutes
  • Thrombolytic therapy before ERT: 25%
  • M1 segment occlusion: 63%

Principal Findings:

The primary outcome, median mRS score at 90 days, for balloon vs. conventional guide catheters, was: 4 vs. 3, odds ratio (OR) 0.66 (95% confidence interval [CI] 0.45-0.98), p = 0.037.

Primary outcome by time since symptom onset, balloon vs. conventional guide catheters (p for interaction = 0.0417):

  • <6 hours: OR 1.05 (95% CI 0.60-1.84)
  • ≥6 hours: OR 0.40 (95% CI 0.22-0.71)

Secondary outcomes for balloon vs. conventional guide catheters:

  • mRS 0-3 at 90 days: 41% vs. 56%, OR 0.56 (95% CI 0.35-0.88), p = 0.013
  • Expanded Thrombolysis in Cerebral Infarction (eTICI) ≥2b after first pass reperfusion: 58% vs. 62%, OR 0.84 (95% CI 0.53-1.33), p = 0.45
  • Time from groin puncture to eTICI ≥2b reperfusion: 53 vs. 44 minutes, hazard ratio 0.74 (95% CI 0.58-0.94), p = 0.012
  • Acceptable reperfusion eTICI ≥2b within 45 minutes of groin puncture: 42% vs. 54%, OR 0.60 (95% CI 0.37-0.96), p = 0.035

Safety outcomes for balloon vs. conventional guide catheters:

  • All-cause mortality at 90 days: 24% vs. 16%, relative risk (RR) 1.51 (95% CI 0.97-2.36), p = 0.068
  • Guide catheter-related dissection: 1% vs. 2%, RR 0.50 (95% CI 0.09-2.71), p = 0.41
  • Internal carotid artery vasospasm: 4% vs. 1%, RR 7.04 (95% CI 1.15-43.75), p = 0.037

Interpretation:

The balloon guide catheter is intended to induce temporary antegrade flow arrest during thrombectomy to prevent distal embolization of intracerebral thrombus during ERT. The PROTECT-MT trial was terminated early for safety due to worse functional neurologic status at 90 days in the balloon guide catheter arm. There were also numerically more deaths at 90 days and more frequent procedure-related issues, particularly catheter-related vasospasm and increased time to reperfusion. These data represent the first randomized comparison of balloon and conventional guide catheters in ERT and contrast with prior observational data suggesting equivalent or better outcomes between either approach. It is unclear whether the poorer neurologic outcomes with balloon guide catheters reflect a greater risk of infarct evolution from temporary flow arrest compared to distal embolization, especially in the modern ERT era.

No interactions were observed across treatment strategies such as aspiration thrombectomy or stent retriever, although almost 80% of cases in both arms involved a combination approach. The authors do note high rates of intracranial atherosclerosis in Chinese cohorts. This subgroup appeared to benefit more from conventional guide catheters, but these findings are exploratory. Further studies of balloon guide catheters, particularly those able to accommodate large bore thrombectomy devices, across patient demographics are needed to conclude definitively whether they should be avoided in ERT.

References:

Liu J, Zhou Y, Zhang L, et al. Balloon guide catheters for endovascular thrombectomy in patients with acute ischemic stroke due to large-vessel occlusion in China (PROTECT-MT): a multicenter, open-label, blinded-endpoint, randomized controlled trial. Lancet 2024;404:2165-74.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Vascular Medicine, Aortic Surgery, Interventions and Vascular Medicine

Keywords: Coronary Occlusion, Endovascular Procedures, Ischemic Stroke, Thrombectomy


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