Delivering thrombectomy for acute stroke using cardiology services
BMJ 2015; 351 doi: https://doi.org/10.1136/bmj.h3969 (Published 27 July 2015) Cite this as: BMJ 2015;351:h3969
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With the emerging evidence of thrombectomy for selected patients with acute ischaemic stroke, Apps & colleagues recently suggest that the coronary primary angioplasty network could be utilized to provide the demand for this service1.
We would argue that the skill in endovascularly opening arteries quickly is not generic as implied by the authors. Despite the similar size of the coronary and cerebral arteries, significant differences exist which needs to be appreciated. The cerebral arteries are much more delicate owing to their thinner tunica media and adventitia and there can be great tortuosity proximally, making catheter navigation particularly challenging. There is thus both a systems and practitioner learning curve specific for thrombectomy to ensure that is performed timely, safely and effectively2. It is not surprising that high volume centres have better outcomes3.
The Royal Victoria Hospital in Belfast was the only UK centre to have participated in any of the recently published five randomized trials showing benefit of thrombectomy4-8. We agree with the authors that speed is paramount; our local target metric is CT to final recanalization of <60 minutes. It should also be noted that patient selection based on imaging requires not just the identification of proximal arterial occlusion, but also quantifying the extent of infarcted versus ischaemic (i.e salvageable) brain.
For the results of the trials to be replicated elsewhere, we suggest practitioners need to first be fully competent in neurointerventional techniques. This is too time sensitive and delicate a procedure for a first foray into the intracranial circulation. The brain is a much too valuable piece of real estate for that.
Paul A Burns, Consultant Interventional Neuroradiologist, Royal Victoria Hospital, Belfast
paul.burns@belfasttrust.hscni.net
Peter A Flynn, Consultant Interventional Neuroradiologist, Royal Victoria Hospital, Belfast
Ian M Rennie, Consultant Interventional Neuroradiologist, Royal Victoria Hospital, Belfast
References:
1 Apps A, Soroosh F, Tito K. delivering thrombectomy for acute stroke using cardiology services. BMJ, 2015; 351:h3969
2 Eesa M, Burns PA, Almekhlafi MA et al. Mechanical thrombectomy with the Solitaire stent: is there a learning curve in achieving rapid recanalization times? JNIS, 2014; 6:649-651
3 Gupta R, Horev A, Nguyen T et al. Higher volume endovascular stroke centres have faster times to treatment, higher reperfusion rates and higher rates of good clinical outcomes. JNIS, 2013; 5:294-297
4 Berkhemer OA, Fransen PSS, Beumer D et al. A randomized trial of intraarterial treatment of acute ischemic stroke. NEJM, 2015; 372:11-20
5 Goyal M, Demchuk AM, Menon BK et al. Randomized assessment of rapid endovascular treatment of ischemic stroke. NEJM, 2015; 372:1019-1030
6 Campbell BCV, Mitchell PJ, Kleinig TJ et al. Endovascular therapy for ischemic stroke with perfusion-imaging selection. NEJM, 2015; 372:1009-1018
7 Saver JL, Goyal M, Bonafe A et al. Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. NEJM, 2015; 372:2285-2295
8 Jovin TG, Chamorro A, Cobo E et al. Thrombectomy within 8 hours after symptom onset in ischemic stroke. NEJM, 2015; 372:2296-2306
Competing interests: Organisational research grant received from University of Calgary during participation in the ESCAPE endovascular stroke trial
We read your leading article1 with interest. As suggested in the last paragraph we have already quantified the group eligible for thrombectomy.
Following publication of the Multicentre Randomised Clinical Trial of Endovascular Treatment of Acute Stroke in the Netherlands (MR CLEAN) and other studies, we studied all admissions to this Hyper Acute Stroke Unit to assess how many would be eligible for endovascular therapy if the trial criteria were applied. These were: aged ≥ 18yrs; pre-morbid modified Rankin Scale of 0 or 1; presentation ≤ 6 hours of known symptom onset; National Institute of Health Stroke Scale score ≥ 5; normal coagulation and Alberta Stroke Program Early CT Score ≥ 7. All trials selected patients with thrombi in the major intracranial vessels such as the internal carotid arteries and the first two segments of the middle cerebral arteries. As CT angiogram and perfusion studies are not done routinely in this centre, it was not possible to select only these patients. Data were collected from that routinely available on all our referrals.
In the first three months of 2015, 311 stroke patients were admitted, of which 265 had ischaemic strokes. 23 (9%) of patients fulfilled all the above criteria and would therefore have been eligible for thrombectomy. 5 of 23 (2%) had radiological evidence of a suitable thrombus on a non-contrast CT head.
Thus we found that, at Northwick Park Hospital, one of the busiest such units in England, up to 9% of acute ischaemic stroke patients might have been eligible for intra-arterial therapy. In this centre this represents about one patient every five days. After the application of CT angiogram and CT perfusion criteria, this number might fall.
We applaud the authors’ suggestion that, as in Europe, anyone who can be trained to have the requisite skills be employed to treat these patients and that institutional and trade boundaries should not be allowed to interfere with this. It is also important to ensure that care to the remaining 91% of stroke patients is not compromised by diluting the benefits of systems that have already been shown to be effective.2
References
1. BMJ 2015;351:h3969
2. BMJ 2014;349:g4757 doi: 10.1136/bmj.g4757
Competing interests: No competing interests
We welcome Apps and colleagues’ efforts to highlight the growing demand for wider and more comprehensive availability of acute thrombectomy services in light of the multitude of recent stroke trials demonstrating its beneficial efficacy over thrombolysis1. Their proposal to involve cardiology services is certainly an interesting potential solution, however there are a number of issues to consider.
Whilst we wholeheartedly agree the focus should be placed on timely intervention, streamlining of stroke services in light of the current literature with specialist expertise is necessary. The results of the SWIFT PRIME trial, in particular shows us that this is possible, by achieving sub-60 minute median imaging to groin puncture times, which clearly contributed to the significantly better clinical outcomes2.
It should not be underestimated that one of the biggest driving factors contributing to the success of the recent trials is careful patient selection based on advanced neuroimaging, which is the necessary starting point. In particular, the use of inclusion criteria based on more physiological imaging parameters and recruitment of centres performing high volumes of such cases were features of improved clinical outcomes2,3,4,5,6. Therefore, specialist expertise is an essential factor in image analysis prior to thrombectomy, based upon years of subspecialty neuroradiology training. The consequences of a missed or incorrect diagnosis are high, as are the financial implications of futile interventions to our health care system7.
Furthermore, whilst generic vascular catheter skills may be translatable between disciplines, particularly for the initial steps of a thrombectomy procedure, navigating the cerebral vasculature is not as always straightforward. Without a doubt, anyone with the right training can ‘open a vessel’, but the risks of vessel injury or perforation leading to intraparenchymal and subarachnoid haemorrhage are high and the consequences devastating. Neuroradiologists have a wealth of expertise in dealing with these complications daily from the very nature of our other day-to-day acute work. This is based upon applied skills from performing multiple routine and acute diagnostic and therapeutic cerebral angiograms, and from dealing with the disasters that not infrequently occur.
Ultimately, we should concentrate on providing the best possible high-quality specialist expertise in order to provide the best outcomes for our patients. It is not a question of who can do these procedures, but who is best trained and qualified to do so. It is about careful patient selection, risk assessment and understanding the end organ. Therefore, solutions to the current problem of provision are through forming networks of competent and qualified interventional neuroradiologists and through further training of neuroradiology subspecialty trainees who have the relevant interests and experience in this area.
Lalani Carlton Jones, Neuroradiology subspecialty trainee, The National Hospital for Neurology and Neurosurgery
Kyriakos Lobotesis, Consultant Neuroradiologist and Interventional Lead, Imperial College Healthcare NHS Trust
References
1. Apps A, Firoozan S, Kabir T, Delivering thrombectomy for acute stroke using cardiology services. BMJ 2015; 351:h3969
2. Saver JL, Goyal M, Bonafe A, Diener HC, Levy EI, Pereira VM, et al; SWIFT PRIME Investigators. Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. N Engl J Med. 2015;372:2285–2295. doi: 10.1056/NEJMoa1415061.
3. Berkhemer OA, Fransen PS, Beumer D, van den Berg LA, Lingsma HF, Yoo AJ, et al; MR CLEAN Investigators. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med. 2015;372:11–20. doi: 10.1056/NEJMoa1411587.
4. Goyal M, Demchuk AM, Menon BK, Eesa M, Rempel JL, Thornton J, et al; ESCAPE Trial Investigators. Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med. 2015;372:1019– 1030. doi: 10.1056/NEJMoa1414905.
5. Campbell BC, Mitchell PJ, Kleinig TJ, Dewey HM, Churilov L, Yassi N, et al; EXTEND-IA Investigators. Endovascular therapy for ischemic stroke with perfusion-imaging selection. N Engl J Med. 2015;372:1009– 1018. doi: 10.1056/NEJMoa1414792.
6. Jovin TG, Chamorro A, Cobo E, de Miquel MA, Molina CA, Rovira A, et al; REVASCAT Trial Investigators. Thrombectomy within 8 hours after symptom onset in ischemic stroke. N Engl J Med. 2015;372:2296– 2306. doi: 10.1056/NEJMoa1503780.
7. Ganesalingam J, Pizzo E, Morris S, Sunderland T, Loboteis K, Cost-Utility analysis of mechanical thrombectomy using stent retrievers in acute ischaemic stroke; Stroke 2015 DOI: 10.1161/STROKEAHA.115.009396
Competing interests: No competing interests
Re: Delivering thrombectomy for acute stroke using cardiology services
Dear Editor
Would it not be easier to understand if the title were: "Thrombectomy in acute stroke, by interventional cardiologists?"
There used to be the PLAIN ENGLISH CAMPAIGN.
I beg to remain
A bear of small brain.
Competing interests: I get lost in verbiage.