I always wondered whether it may be possible that just as clot-busting medicine preceded clot-removing endovascular surgery for acute heart attack, so the same sequence of events would unfold for acute stroke caused by a clot in the proximal artery. And so it has – endovascular clot removal improved functional outcomes following thrombolytic stroke in two recent trials.  Survival also improved in the larger trial, while the other was under-powered for this end-point. The larger trial also showed an improvement in the visual-analogue scale of the EQ-5D. The favourable effects confirmed the result of a previous trial in the Netherlands, and both trials were stopped earlier than planned as a result of the weight of positive evidence. In order to be eligible for this treatment a patient must have good collateral flow distal to the block and a relatively small infarct. Time is of the essence and the interval between CT scan and endovascular clot removal in the trials was little over an hour; a logistic challenge.
How should the NHS respond to this information? NICE has already considered the issue, but this preceded the above results that are hot off the press. Nevertheless NICE advocated that the treatment may be used with appropriate safeguards. This decision was informed by safety evidence from numerous, mostly non-experimental, studies along with ‘proof of principle’ evidence that recanalisation of thrombosed arteries is enhanced by endovascular treatment. It is clear that some UK centres are offering this therapy and participating in a UK-based RCT. One suspects that the data-monitoring committee of this RCT will be reconvened. The treatment has the potential to be cost-effective, based on a previous study that pieced information together from multiple sources. This can now be updated with direct evidence from RCTs. The survival rate was improved by eight percentage points in the above trial, and if this is taken at face value, and if the mean duration of each life gained is 7 years, then the (undiscounted) DALY gain is (7 x 0.08) = 0.56. So even before considering quality of life, the treatment is cost-effective if it costs less than about £11,000 at the NICE willingness-to-pay threshold. The stage seems set for phased introduction of this therapy, since the main areas of uncertainty are likely to migrate from clinical effectiveness to appropriate service delivery. I hesitate to say it, but this technical development is likely to add to the argument for further consolidation of stroke units.
How should the NHS in England proceed? We propose an integrated and co-ordinated response between NICE and NHS England as follows:
— Richard Lilford, CLAHRC WM Director
- Campbell BCV, Mitchell PJ, Kleinig TJ, et al. Endovascular Therapy for Ischemic Stroke with Perfusion-Imaging Selection. N Eng J Med. 2015; 372: 1009-18.
- Goyal M, et al. Randomized Assessment of Rapid Endovascular Treatment of Ischemic Stroke. N Eng J Med. 2015. 372: 1019-30.
- Berkhemer OA, Fransen PS, Beumer D, et al. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med. 2015; 372: 11-20
- National Institute for Health and Care Excellence. Mechanical clot retrieval for treating acute ischaemic stroke. NICE interventional procedure guidance IPG458. 2013.
- The University of Glasgow. Pragmatic Ischaemic Stroke Thrombectomy Evaluation: PISTE. 2015. [Online].
- Nguyen-Huynh MN, & Johnston SC. Is mechanical clot removal or disruption a cost-effective treatment for acute stroke? AJNR Am J Neuroradiol. 2011; 32(2): 244-9.