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I just wanted to hear everybody's thoughts on the MR CLEAN study published in the NEJM
MR CLEAN = Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands
http://www.nejm.org/doi/full/10.1056/NEJMoa1411587
I know that all of the subgroup analysis and details of the study will be released at the ISC shortly, and the word on the street is that there are multiple other successful thrombectomy trials in acute stroke. These results with be announced with unthwarted enthusiasm. People will call for a new era in stroke treatment.
I should preface this by saying that I am not a stroke specialist. You may or may not remember my posts in prior threads regarding IMS3 and MR rescue. My general feeling based on experience with innumerable unsuccessful thrombectomy procedures (and rare successful cases) is relatively straight-forward:
1) Early reperfusion in a patient with impending infarction with no significant early infarct on NC CT can be beneficial, and when this happens, the patient improves on the table or shortly afterwards.
2) Reperfusion of infarcted tissue is deleterious. It worsens edema, possibly extends the infarct as the edema tamponades collaterals, and causes complications, extended hospital stay, et cetera.
This is the only reasonable explanation for the data in IMS3 and MR rescue, as these trials had excellent recanalization results, and the patients were reasonably selected-the procedure must have caused undocumented deleterious effects which negate the benefits. Undoubtedly, patients were included in those trials who improved on the table after intervention. This was either 1) sufficiently rare as to be diluted by unsuccessful cases or 2) negated by undocumented side effects of the procedure. If a patient has a slight extension of the infarct due to reperfusion injury and ends up being modified rankin 4 instead of 3 at 90 days, this does not show up as an adverse event in the trial data.
There is a lot of wishful thinking in the field of stroke, and stroke neurologists or interventional radiologists will often take credit for a patient's delayed improvement (i.e. natural history). I have literally heard an interventional radiologist take credit for a patient's improvement during inpatient rehab-as though their handiwork somehow helped the physical therapist. People seem to forget that it is not uncommon for patients to significantly improve over time with conservative treatment only. They also tend to believe that an unsuccessful procedure was a "wash" and at least did not harm the patient so long as there was no significant post-procedural hemorrhage.
Anyways, I found out that the median ASPECTS score for the non contrast CT in the MR CLEAN study in the thrombectomy group was 9. In other words, these patients had essentially stone-cold normal CTs.
there are a few things I do not know...
1) Was the NC CT done at the time of tPA or at the time of randomization (which was significantly later)?
2) Was subgroup analysis done based on ASPECTS score?
3) was the subgroup at 5-6 hours for groin puncture time also positive?
Because the benefit in the trial was modest, perhaps we should make the cutoff ASPECTS 10 (no sign of infraction on CT) and the time cutoff < 5 hours (groin puncture time), although I am a proponent of tissue over time.
I call for a warning against extending the results of the study beyond what they actually show and performing potentially harmful procedures on patients unlikely to benefit from them. Let us not forget the big picture. If I were to rank stroke treatments/preventatitive measures based on their overall ability to prevent neuronal injury and stroke morbidity in the general population, it would be something like this:
#1) broccoli
2) sodium restriction
3) the treadmill
4) smoking cessation
5) Physical therapy
6) lisinopril
7) aspirin
8) coumadin
9) plavix
10) aggrenox
11) simvastatin
tPA and thrombectomy are definitely far below these treatments in terms of their overall efficacy and importance as they will only be used on the minority of stroke patients and with modest success. You will never hear a nursing home attendant say "you know...we haven't gotten a lot of stroke patients since they made thrombectomy the standard of care."
...but if we could get people to make significant lifestyle changes and to control vascular risk factors, we could cut down on stroke morbidity enourmously.
-soul of m patel
MR CLEAN = Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands
http://www.nejm.org/doi/full/10.1056/NEJMoa1411587
I know that all of the subgroup analysis and details of the study will be released at the ISC shortly, and the word on the street is that there are multiple other successful thrombectomy trials in acute stroke. These results with be announced with unthwarted enthusiasm. People will call for a new era in stroke treatment.
I should preface this by saying that I am not a stroke specialist. You may or may not remember my posts in prior threads regarding IMS3 and MR rescue. My general feeling based on experience with innumerable unsuccessful thrombectomy procedures (and rare successful cases) is relatively straight-forward:
1) Early reperfusion in a patient with impending infarction with no significant early infarct on NC CT can be beneficial, and when this happens, the patient improves on the table or shortly afterwards.
2) Reperfusion of infarcted tissue is deleterious. It worsens edema, possibly extends the infarct as the edema tamponades collaterals, and causes complications, extended hospital stay, et cetera.
This is the only reasonable explanation for the data in IMS3 and MR rescue, as these trials had excellent recanalization results, and the patients were reasonably selected-the procedure must have caused undocumented deleterious effects which negate the benefits. Undoubtedly, patients were included in those trials who improved on the table after intervention. This was either 1) sufficiently rare as to be diluted by unsuccessful cases or 2) negated by undocumented side effects of the procedure. If a patient has a slight extension of the infarct due to reperfusion injury and ends up being modified rankin 4 instead of 3 at 90 days, this does not show up as an adverse event in the trial data.
There is a lot of wishful thinking in the field of stroke, and stroke neurologists or interventional radiologists will often take credit for a patient's delayed improvement (i.e. natural history). I have literally heard an interventional radiologist take credit for a patient's improvement during inpatient rehab-as though their handiwork somehow helped the physical therapist. People seem to forget that it is not uncommon for patients to significantly improve over time with conservative treatment only. They also tend to believe that an unsuccessful procedure was a "wash" and at least did not harm the patient so long as there was no significant post-procedural hemorrhage.
Anyways, I found out that the median ASPECTS score for the non contrast CT in the MR CLEAN study in the thrombectomy group was 9. In other words, these patients had essentially stone-cold normal CTs.
there are a few things I do not know...
1) Was the NC CT done at the time of tPA or at the time of randomization (which was significantly later)?
2) Was subgroup analysis done based on ASPECTS score?
3) was the subgroup at 5-6 hours for groin puncture time also positive?
Because the benefit in the trial was modest, perhaps we should make the cutoff ASPECTS 10 (no sign of infraction on CT) and the time cutoff < 5 hours (groin puncture time), although I am a proponent of tissue over time.
I call for a warning against extending the results of the study beyond what they actually show and performing potentially harmful procedures on patients unlikely to benefit from them. Let us not forget the big picture. If I were to rank stroke treatments/preventatitive measures based on their overall ability to prevent neuronal injury and stroke morbidity in the general population, it would be something like this:
#1) broccoli
2) sodium restriction
3) the treadmill
4) smoking cessation
5) Physical therapy
6) lisinopril
7) aspirin
8) coumadin
9) plavix
10) aggrenox
11) simvastatin
tPA and thrombectomy are definitely far below these treatments in terms of their overall efficacy and importance as they will only be used on the minority of stroke patients and with modest success. You will never hear a nursing home attendant say "you know...we haven't gotten a lot of stroke patients since they made thrombectomy the standard of care."
...but if we could get people to make significant lifestyle changes and to control vascular risk factors, we could cut down on stroke morbidity enourmously.
-soul of m patel