ESOC 2023 | Delayed reperfusion in stroke patients: implications for adjunctive therapy

Delayed reperfusion is actually a very interesting concept which we have been looking at at the Stroke Research Center in Bern together with our research group. And delayed reperfusion basically means that after we have a patient who has a stroke and the patient undergoes therapy, which is mechanical thrombectomy with added IVT lysis or without it, the major trials shown that less than 50% of patients experienced complete reperfusion. What does this mean? This means that less than 50% of the patients experienced complete vessel reocclusion of all those same vessels which were affected by the stroke. And then what happens afterwards? So if a patient has incomplete reperfusion, then it can go in two directions. The vessel can either spontaneously, reperfuse and we call this concept delayed reperfusion, or the vessels can stay permanently closed. We call this persistent perfusion deficit.

How we approach this subject is basically that we took the final images on the angiography and we compared those images to the regular images which the patient would get on to 24 hour follow up as it is for most institutions per standard. So then we took these 24 hour follow up images and then we compared the perfusion imaging on the 24 hour versus the final angiography imaging. And then we compare the same topography, the same territory which is affected and then based on perfusion imaging data and perfusion maps which give you a pretty clear incentive of how tissue is responding, how vessels are recanalized, we saw that some of sometimes the vessels actually have delayed reperfusion and sometimes a persistent perfusion deficit.

And in our case, we took a look at the Bern stroke registry data in our institution, we took patients from 2015 to 2020, so like a five-year period and then we saw the delayed reperfusion, so the spontaneous vessel recanalization actually occurs in about 60% of cases. So in more than half of patients who have incomplete vessel reperfusion at the end of the thrombectomy at 24 hours, they will have this spontaneous delayed reperfusion mostly people are wondering, okay, what you’re doing is great, but how does this matter to the patient? What is the implications on the outcome? So that’s exactly the next step. And when we assess this concept of delayed reperfusion, persistent perfusion deficit, then we looked at how does this matter for the outcome of the patient? And one of the usual ways you report an outcome in stroke patients is with the modified Rankin scale score at 90 days or three months. And then when we correlated this data, we saw that patients with delayed reperfusion do very well in the modified Rankin scale score, meaning that they will have functional independence which is classified as modified Rankin score scale score 0-2 at 90 days. And then when we took a look closer look at it, we actually saw that patients who have delayed reperfusion but worse reperfusion scores, so let’s say that 50 to 60% of their territory was reperfused but they have delayed reperfusion, do way better than patients who have better reperfusion score, say 80 or 90% of their vessels were recanalized, but persistent perfusion deficit on the 24 hour follow up. And then we found that there was this actually profound impact of delayed perfusion and that patients who have delayed reperfusion irrespective of the final reperfusion score assessed by the TICI scale do way better than those patients who have persistent perfusion deficit and this was tangible across the entire range of the TICI scale. So irrespective of the reperfusion grade patients with delayed reperfusion had way better outcome than those patients with persistent perfusion deficit.