University Medical Center New Orleans became the first hospital in the country to use the THUNDERBOLT, a computer-assisted vacuum thrombectomy platform recently cleared by the FDA. The device is designed to treat acute ischemic stroke by using modulated aspiration driven by computer algorithms to detect and fatigue blood clots. The goal is to achieve complete clot ingestion without repeated catheter passes.
Young Lee, MD, a cerebrovascular neurosurgeon at UMC New Orleans, performed the first stroke thrombectomy using the THUNDERBOLT system. The workflow is quite similar to aspirating with a constant suction device, but the new system uses modulated aspiration instead of constant suction. The computer algorithms essentially act like doing multiple passes several times a second, sucking and releasing based on how the clot is being pulled in.
The first cases were actually quite difficult. The first case involved a patient with a history of intracranial atherosclerotic disease and an M1 clot that extended into both M2s. The THUNDERBOLT helped remove the M1 clot and allowed access to the M2 clot, achieving a TICI 3 reperfusion. The second case was also an M2 occlusion, and the team achieved a TICI 2c reperfusion.
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Dr. Lee said one of the most important things is having Penumbra representatives there with the device for the first few cases. He believes the company requires this and thinks it is essential for the workflow to go smoothly without delays. He also noted that if the computer-modulated aspiration isn't working for some reason, the machine can also do continuous aspiration, so clinicians are not losing out on what they already had.
Dr. Lee explained that in the past, the assumption was very simple: blood vessel, clot, suck the clot out. However, since the landmark trials in 2016, they have come to realize that clots are not homogenous. Some are more fibrous, some have calcium inside, and some are soft. A single approach not tailored to the specific clot type tends not to work well for certain clots, like those in intracranial atherosclerotic disease.
The THUNDERBOLT system detects the clot and fatigues it, then tries to suck it completely into the catheter. The other big advantage is that once complete clot ingestion happens, you can actually see it. The catheter that was corked and not flowing before will suddenly show blood flowing. You don't need to pull the catheter out to go after more clot. Once it's sucked in, you can inject through the guide catheter, see what's more distal, and just advance the catheter.
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Dr. Lee noted that the stroke field has evolved from stent retriever-first approaches to aspiration-dominant workflows. He believes THUNDERBOLT is just adding to that trend, now making it less likely to need four or five passes. You can sometimes achieve the equivalent of five passes in one or two, which is a huge advantage.
For clinicians considering the new device, the safety considerations involve using the same reperfusion catheters as before. Whatever you were doing to stay safe in the past, do the same thing. Also, understand that you don't have to pull the catheter out each time. If you get complete clot ingestion, don't pull it, because doing so can increase the risk of embolization to new territories.
Dr. Lee said the biggest question in the field is whether there is a technology deficit preventing the safe treatment of medium to distal vessel occlusions. Three major trials—ESCAPE-MeVO, DISTAL, and DISCOUNT—have shown negative results, though a trial out of China this year showed positive results. Penumbra is running the FORWARD study, enrolling around 250 patients at 40 sites, looking at whether their reperfusion catheters can achieve meaningful reperfusion in M2 occlusions.
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The FORWARD study is enrolling up to 250 patients at 40 sites, looking at Penumbra's reperfusion catheters, which come in various sizes. The target is to see how well they address M2 occlusions and provide evidence that there's hope for medium to distal vessel occlusions. Dr. Lee said medium vessels are smaller and more fragile, so they're more susceptible to injury.
Dr. Lee mentioned that THUNDERBOLT started in peripheral intervention before it was cleared for neuro interventional radiology. He is interested in exploring its use in severe cerebral sinus venous thrombosis, where anticoagulation alone is often not enough for comatose patients. He noted that neuro interventional radiologists are not as familiar with larger catheters going into the venous sinuses to suck clots out, but if they could achieve complete clot ingestion, they wouldn't have to pass the catheter a thousand times.