Proportion of ischaemic patients with LVO#
The proportion of ischaemic patients with LVO may be estimated in various ways. Estimates are likely to be swayed by the population being studied (e.g. treatment trial results may under-estimate nLVO as very low severity patients may not be selected for the trial). Below are various estimates of the relative occurrence of LVO and nLVO.
Analysis of SAMueL data#
Data from SAMueL using NIHSS 11+ as a surrogate for LVO:
Admission type |
All arrivals |
Arrival within 6 hrs known onset |
Arrival within 4 hrs known onset |
|---|---|---|---|
Proportion all admissions |
100 |
42.9 |
37.1 |
Proportion haemorrhagic |
11.5 |
13.6 |
14.1 |
Proportion ischaemic |
88.5 |
86.4 |
85.9 |
Proportion ischaemic with NIHSS 0-10 |
74.9 |
67.4 |
65.7 |
Proportion ischaemic with NIHSS 11+ |
25.1 |
32.6 |
34.3 |
For original analysis see: https://samuel-book.github.io/samuel-1/descriptive_stats/10_using_nihss_10_for_lvo.html
RACECAT pre-hospital diagnosis of LVO#
A breakdown on stroke type from the design of the RACE test for pre-hopsital diagnosis of LVO (de la Ossa Herrero et al., 2013). Note - there appears to be some discrepancies between reporting of the results between the text and the detailed breakdown by RACE score in figure 2 of the paper.
Trial recruited from patients who presented at the emergency department within 6 hours from symptoms onset.
In the text: Of 357 patients in the analysis, the stroke subtype was ischemic stroke in 240 (67.2%), hemorrhagic stroke in 52 (14.6%), transient ischemic attack in 20 (5.6%), and stroke mimic in 45 (12.6%). LVO was detected in 76 patients (31.7% of ischaemic strokes).
In figure 2: Of 357 patients in the analysis, the stroke subtype was ischemic stroke in 260 (72.8), hemorrhagic stroke in 52 (14.6%), and stroke mimic in 45 (12.6%). LVO was detected in 99 patients (38.1% of ischaemic strokes).
It appears that TIAs may be counted in with ischaemic strokes in this analysis.
Estimating the number of UK stroke patients eligible for endovascular thrombectomy (review/analysis)#
McMeekin et al. (2017) review the evdidence for estimating the number of UK stroke patients eligible for endovascular thrombectomy. They estimate:
40% of ischaemic stroke patients have LVO; 80% of which have NIHSS >=6 and may be suitable for thrombectomy. This is equivalent to 32% of admitted patients having LVO suitable for thrombectomy.
Thrombolysis meta-analysis (Emberson et al.)#
In Emberson’s meta-analysis of thrombolysis trials, 52.6% of all participants had a NIHSS of 11+ (a surrogate for LVO).
References#
de la Ossa Herrero N, Carrera D, Gorchs M, Querol M, Millán M, Gomis M, et al. Design and Validation of a Prehospital Stroke Scale to Predict Large Arterial Occlusion The Rapid Arterial Occlusion Evaluation Scale. Stroke; a journal of cerebral circulation. 2013 Nov 26;45.
Emberson J, Lees KR, Lyden P, et al. Effect of treatment delay, age, and stroke severity on the effects of intravenous thrombolysis with alteplase for acute ischaemic stroke: A meta-analysis of individual patient data from randomised trials. The Lancet 2014;384:1929–35. doi:10.1016/S0140-6736(14)60584-5
McMeekin P, White P, James MA, Price CI, Flynn D, Ford GA. Estimating the number of UK stroke patients eligible for endovascular thrombectomy. European Stroke Journal. 2017;2:319–26.
SAMueL-1 data, from SSNAP, on mRS before stroke (DOI: 10.5281/zenodo.6896710): https://samuel-book.github.io/samuel-1/descriptive_stats/08_prestroke_mrs.html