neurology
Mechanical thrombectomy
in acute ischaemic stroke
Mechanical thrombectomy using state of the art devices has revolutionised the
treatment of patients with severe disabling strokes due to large vessel occlusion with proven
efficacy in re-establishing intracranial circulation and improving patient outcomes
Sanjeev Nayak
MBBS MRCP FRCR
EQNR EDINR
Consultant
Neuroradiologist,
Royal Stoke University
Hospital, University
Hospitals of North
Midlands NHS Trust, UK
Stroke is the second single most common cause of
death in the world, with 6.7 million stroke-related
deaths each year. 1 The burden of disease
(disability, illness and premature deaths) caused
by stroke is set to double worldwide by 2030. 1
Stroke affects 152,000 people annually in the UK;
that is 1 person every 3 minutes 27 seconds. 2
Large vessel occlusion often causes severe strokes
and is associated with high mortality, morbidity,
poor clinical outcomes and high societal costs. 3
The benefit of intravenous thrombolysis with
recombinant tissue-type plasminogen activator
for patients with severe stroke due to large artery
occlusion is limited; early recanalisation is
generally less than 30% for carotid, proximal
middle cerebral artery or basilar artery occlusion. 4
An untreated patient with a severe stroke score
(NIHSS >15) would require permanent long-term
rehabilitation care with an in-hospital stay of
60–90 days, which costs hospitals around £31,500
per patient. 5 Patients with such severe strokes
had a 1-year mortality rate of over 50% as the
previous conventional treatment failed in
majority of cases. Among those who survived,
many (>70%) would require nursing home care. 5
Mechanical thrombectomy using state of the
art devices has revolutionised the treatment of
patients with severe disabling strokes due to large
vessel occlusion with proven efficacy in
re-establishing intracranial circulation and
thereby showing improved patient clinical
outcomes. 6 A new era of acute stroke treatment
began in November 2014, when nine published
randomised controlled trials of mechanical
thrombectomy showed better functional outcome
with mechanical thrombectomy compared with
best medical therapy (Table 1), leading to
a revolution in the care of patients with severe
disabling acute large vessel ischaemic stroke. 7
The number needed to treat (NNT) with mechanical
thrombectomy for a benefit to functional
outcome is as low as 3 (range 3–7). 8 This is more
effective than the NNT for percutaneous coronary
intervention in preventing death in acute
coronary syndromes (NNT 30), and the NNT for
carotid endarterectomy to prevent one stroke
(NNT 26). 8 Hence, in comparison, MT is one of
the most effective treatment innovations of
this decade.
This treatment, which offers fresh hope that
clinicians will be able to reverse the effects of
a stroke in some of the most serious cases, was
adopted by the Department of Health in
April 2017, to be rolled out to the rest of the
National Health Service (NHS) in the UK in
due course.
Table 1
Effect of mechanical thrombectomy compared with best
medical therapy on good functional outcome (modified Rankin
Score ≤2 at 90 days)
Trial
Mechanical
Best medical therapy
thrombectomy n (%)
therapy n (%)
MR CLEAN
76 (32.6)
51 (19.1)
REVASCAT
45 (43.7)
29 (28.2)
25 (71)
14 (40)
EXTEND 1A
SWIFT-prime
59 (60)
33 (35)
ESCAPE
87 (53.0)
43 (29.3)
106
85 (42)
THRACE
19
14
THERAPY
PISTE
17 (57)
1035
EASI
20 (50)*
14 (38)**
*19/35 anterior circulation, 1/5 posterior circulation. **14/32 anterior circulation, 0/5 posterior circulation
† Value at 30 days. ‡ Per-protocol population analysis.
Adapted from ref 7
121
HHE 2018 | hospitalhealthcare.com
Adjusted odds ratio
(95% CI) p value
2.16 (1.39–3.38)
2.1 (1.1–4.0)
4.2 (1.4–12) p=0.01
1.70 (1.23–2.33) p<0.001
1.7 (1.3–2.2)
1.55 (1.05–2.30)
p=0.028†
1.4 (0.60–3.3) p=0.55
4.92 (1.23–19.69)
p=0.021‡
p=0.36