Treating and Identifying Large Vessel Occlusion Quickly

September 17, 2018

The assistant professor of neurology and neurosurgery spoke about the need to identify LVO in the field, quickly, to improve care.

Tudor Jovin, MD

Large vessel occlusion, while not the most commonly occurring type of acute stroke, presents the highest risk of disability for patients, increasing the need for quick treatment.

Although, in recent years, there have been multiple developments to address the need to treat these patients. As Tudor Jovin, MD, noted, there are now many effective tools for identifying and treating this condition. The assistant professor of neurology and neurosurgery at the University of Pittsburgh School of Medicine, co-director of the Center for Endovascular Therapy at the University of Pittsburgh Medical Center said that haste has been the area for most improvement.

To provide some insight into the new approaches to large vessel occlusion and the debates around how to decrease the time it takes to treat these patients, Jovin spoke with NeurologyLive in an interview.

NeurologyLive: What have you been keeping your eye on with regard to large vessel occlusion stroke?

Tudor Jovin, MD: This is the type of stroke that causes the highest level of disability, and there are some potentially new, exciting approaches. One approach is the combination of neuroprotection and reperfusion. There have been a plethora of negative trials looking at reperfusion in the past, but all these trials have not controlled for the most powerful outcome, which is reperfusion or even the presence of an occlusion. Now we have very effective tools for reperfusion of the brain. Basically, the same thing that these failed neuroprotectant drugs that were tested on the past. Meaning, reversible MCA occlusion, which was previously tried and failing, there is now a human reversible MCA occlusion, which is acute stroke due to large vessel occlusion treated with embolectomy, because most of these vessels are now being opened up.

There’s a new era, most of us believe, of testing neuroprotectant drugs in patients with large vessel occlusion who are being reperfused or treated with reperfusion therapy. These trials are underway, there’s a lot of exciting drugs that are either being evaluated or have trials in planning, so this a very exciting approach. I suspect if neuroprotection is proven to be effective, in these patients with large vessel occlusion combined with reperfusion, I suspect that there will be a reappraisal of neuroprotection in stroke in general, but that still remains to be seen.

What has been the state of the system of care with stroke? Are there still challenges in treating patients in a timely manner?

The other critical aspect of acute stroke treatment has to do with systems of care. There are still a lot of patients who, despite hugely beneficial treatment effects and despite the fact that pretty much all categories of patients that are being evaluated within the early time window, benefit from thrombectomy. We still take way too long, and we still don’t get enough patients to the hospital. And when we get them to the hospital, we take way too long to get them to a thrombectomy center. Even within the thrombectomy center, we take too long for them to get to the procedure suite. A big component and a big directional development of acute stroke therapies have to do with systems of care.

That starts with a pre-hospital evaluation from when the call to 9-1-1 was made, to first medical contact, to delivery to the hospital. The big debate now in the field is: Where should these patients be delivered? The key component to this is being able to identify, in the field before they come to the hospital if they do indeed have a large vessel occlusion. Then the debate becomes: Should you take them directly to a thrombectomy center, or do you take them to the closest primary center where they can receive intravenous tPA and transfer them from there?

One thing that has become undisputed in this field is that this procedure is exquisitely time sensitive. Especially when you take non-selective patients that you treat within 6 hours. There’s a very strong time sensitivity that goes along with treatment benefit, with earlier treated patients deriving much more significant benefit. The treatment paradigms that identify large vessel occlusion patients and send them as quickly as possible to a thrombectomy center are now sort of the Holy Grail of acute stroke with large vessel occlusion treatments.

There are several ways to identify large vessel occlusion in the field and starting with hospital and pre-hospital scales. There are several that have been developed and validated, with the best-known and best validated being the RACE-Scale developed in Barcelona, Spain. There is also an abbreviated NIH-Stroke Scales that has been shown to be well correlated with a large vessel occlusion. The idea is that based on these scales you can conclude there’s a high likelihood of large vessel occlusion. The prevailing opinion, although not proven yet, is that these patients benefit from direct transfer to an endovascular center as opposed to going to a primary center where you receive intravenous CPA, and then you get transferred to an endovascular center. The reason why most people believe the direct transfer is a superior option is that it’s obviously much shorter and time is of the essence. This is one of the biggest areas of debate now in acute stroke treatment. How do we identify patients in the field with large vessel occlusion, and when we identify them, where should we take them?

Have there been any other developments to aid in the field identification of large vessel occlusion?

There are. Some of them are based on transcranial dopplers and helmets that are based on tissue impediments, physiological characteristics such as EEG and things like that. They all have to be very simple and reproducible and pre-hospital providers have to be comfortable with them. This is an area of tremendous growth in our field. The devices that we have at our disposal now are pretty effective, and most high-volume centers report reperfusion rates of 80% to 90%. We can always do better, and there’s probably room for improvement. The devices are going to be less for rates of reperfusion and more for speed because we still take some time, we have significantly come down with times, but we can still do better in terms of speed of reperfusion. The main approach is now in endovascular therapy is stent retrievers which kind of the tried and true method. They were overwhelmingly the devices used in trials that have shown superiority over medical therapy. But, increasingly, there is aspiration that is being used, just sucking out the clot, and some of the debates try to qualify aspiration as good or better than retrievers. Certainly, there are some economic advantages, as they’re cheaper than using aspiration.

Transcript edited for clarity.