The technology

Advice

Innovations
Current NHS pathway
Population, setting and intended user
Costs
Resource consequences

The technology

This briefing describes 21 technologies for delivering mechanical thrombectomy (MT) for acute ischaemic stroke. Further background information on the condition and the intervention is in the NHS England clinical commissioning policy on mechanical thrombectomy for acute ischaemic stroke (all ages).

There are 2 types of MT devices:

Aspiration catheters are flexible with a large inner distal diameter. A guide wire is inserted into the patient, followed by a small access catheter. The access catheter is then used to guide the aspiration catheter to the right place. When the clot is reached, it is broken into smaller pieces that can be aspirated through the catheter using a pump or manual suction.
Stent retrievers have an expanding wire mesh tube and are intended to remove the clot in 1 piece. The retriever is placed using a delivery catheter, and once in place the mesh expands. The clot is trapped in the expanding mesh and is then withdrawn into the catheter.

In some cases, both types of devices may be used to remove the clot.

All the devices in this briefing have a Class III CE mark and their key features are summarised in table 1 for aspiration catheters and table 2 for stent retrievers.

Table 1 Summary of key features of included aspiration catheters

Device

(Company)

Aspiration method

Available models

Distal inner diameter in inches

Working length in cm

ARC

ARC Mini (Medtronic)

Manual

ARCA-132

ARCA-160

0.061

0.035

132

160

Navien (Medtronic)

Manual

RFXA058

RFXA072

0.058

0.072

125 or 130

Sofia (MicroVention)

Manual

DA5115ST

DA5125ST

DA6115ST

0.055

0.070

115

125

115

Sofia Plus (MicroVention)

Manual

DA6125ST

DA6131ST

0.070

125

131

ACE reperfusion catheter (Penumbra)

External pump

ACE60

ACE64

ACE68

0.060

0.064

0.068

132

MAX reperfusion catheter (Penumbra)

3MAX

4MAX

5MAX

0.035

0.041

0.054

153

139

132

AXS Catalyst Distal Access Catheter (Stryker)

Manual

AXS Catalyst 5

AXS Catalyst 6

0.058

0.060

115

132

Table 2 Summary of key features of included stent retrievers

Device

(Company)

Available models

Stent diameter and length in mm

Delivery catheter: minimum inner diameter in inches

Aperio

(Acandis; UK supplier: Neurologic)

01‑000700

01‑000701

01‑000702

01‑000703

3.5×28

4.5×30

4.5×40

6×40

0.0165 to 0.021

0.021 to 0.027

Catch +

(Balt; UK supplier Sela Medical)

Catch+ Mini

Catch+

Catch+ Maxi

3×15

4×20

6×30

0.017
0.021

0.024

EmboTrap II

(Cerenovus Johnson and Johnson)

ET‑007‑521

ET‑007‑533

5×21

5×33

0.021

ReVive SE

(Cerenovus Johnson and Johnson)

ReVive SE

4.5×30

0.021 to 0.027

Solitaire 2

(Medtronic)

SFR2‑4‑15

SFR2‑4‑20

SFR2‑4‑40

SFR2‑6‑20

SFR2‑6‑30

4×15

4×20

4×40

6×20

6×30

0.021

0.027

Solitaire Platinum

(Medtronic)

SRD3‑4‑20‑05

SRD3‑4‑20‑10

SRD3‑4‑40‑10

SRD3‑6‑20‑10

SRD3‑6‑24‑06

SRD3‑6‑40‑10

4×20

4×40

6×20

6×24

6×40

0.021

0.027

ERIC

(MicroVention)

ERIC 3

ERIC 4

ERIC 6

3×15

3×20

4×24

4×30

6×44

0.017

0.021

0.027

3D Revascularization

(Penumbra)

PSR3D

4.5×20

0.024

pREset

(Phenox)

PRE‑4‑20

PRE‑6‑30

4×20

6×30

0.021

pREset LITE

(Phenox)

PRE‑LT‑3‑20

PRE‑LT‑4‑20

3×20

4×20

0.0165

Tigertriever

(Rapid Medical; UK supplier: Neurologic)

TRPP3166

TRPP3155

3×23

6×32

0.017

0.021

Trevo ProVue

(Stryker)

90184

4×20

0.021

Trevo XP ProVue

(Stryker)

90182

90183

90185

90186

4×20

3×20

4×30

6×25

0.021

0.017

0.021

0.027

Innovations

MT devices offer an additional or alternative option for restoring blood flow compared with current care. They can be used in people for whom pharmacological treatments such as thrombolysis are likely to be ineffective (for example, because the clot is too large) or inappropriate (for example, because of recent surgery or in people who are taking oral anticoagulants). Thrombolysis (pharmacological treatments to dissolve the clot) must be given within 4.5 hours of stroke onset. Clot retrieval should be done within 6 hours.

Current NHS pathway

People with suspected acute stroke should be admitted to the nearest accident and emergency department with a hyperacute stroke unit or a specialist stroke unit for immediate brain imaging (usually within 1 hour). If imaging confirms a diagnosis of acute ischaemic stroke then urgent thrombolysis should be given to try to restore blood flow in the brain.

Other forms of pharmacological therapy are often used, whether or not thrombolysis has been attempted. This usually consists of short-term antiplatelet treatment (such as aspirin for 2 weeks), followed by an antithrombotic treatment that the patient will generally have for the rest of their life.

As well as pharmacological therapy, people with acute ischaemic stroke will also have therapy intended to minimise brain damage, such as oxygen therapy, blood pressure control and blood sugar control.

The following NICE guidance has been identified as relevant to this care pathway:

Population, setting and intended user

MT is indicated for people with confirmed acute ischaemic stroke caused by a blockage in 1 or more large artery in the brain. This includes people already treated with intravenous thrombolysis that has not been effective, as well as people who have not had this treatment. MT should be done within 6 hours of the onset of symptoms, but this may be extended to between 12 and 24 hours if advanced brain imaging shows that there is substantial brain tissue that can be salvaged. It is not indicated for transient ischaemic attacks.

The procedure must be done in designated specialised stroke centres. These centres must give the Sentinel Stroke National Audit Programme databases information for all patients admitted with stroke.

Costs

Technology costs

The list prices and associated procedural accessories are shown in table 3. Additional resources are needed for each procedure, including: theatre time, staff time, imaging tests and surgical equipment. It has been estimated that the average total cost of MT is £8,365, which includes the cost of the device and the surgical procedure (Ganesalingham 2015).

Table 3 Cost of included MT devices

Company	Device	List price (excluding VAT)*	Procedural accessories
Acandis; UK supplier: Neurologic	^† Aperio	£2,700	NeuroSlider micro catheters £495
Balt; UK supplier: Sela Medical	^† Catch+ Mini	£3,000	VASCO delivery catheters £435; hybrid guide wires £290
	^† Catch+	£1,900
	^† Catch+ Maxi	£1,900
Cerenovus Johnson and Johnson	^† EmboTrap II	£3,500	ReVive intermediate access catheters £648.90
Cerenovus Johnson and Johnson	^† ReVive SE	£4,936	ReVive intermediate access catheters £648.90
Medtronic	^‡ ARC	£1,349	Information not supplied
	^‡ ARC Mini	£1,249
	^‡ Navien	£613
	^† MindFrame Capture LP	£3,190
	^† Solitaire 2	£3,190
	^† Solitaire Platinum	£3,349
Microvention	^‡ Sofia/Sofia Plus	£550	Headway micro delivery catheter £440
Microvention	^† ERIC	£2,500	Headway micro delivery catheter £440
Penumbra	^‡ ACE60, ACE64, ACE68 reperfusion catheters	£1,275	MAX Pump £7,500; Velocity micro delivery catheter £700; Neuron access catheters £300; MAX canister £190; devices are also available as part of reperfusion kits
	^‡ 3MAX, 4MAX, 5MAX reperfusion catheters	£1,090
	^† 3D Revascularization device	£5,000
Phenox	^† pREset/pREset LITE	£1,995	Information not supplied
Rapid Medical; UK supplier: Neurologic	^† Tigertriever	£3,000	NeuroSlider micro catheters £495
Stryker	^‡ AXS Catalyst DAC	£900	Trevo Pro 14/18 microcatheter £300; Flowgate balloon guide catheter £750; Infinity access catheter £350; devices are also available as part of kits and multipacks
	^† Trevo ProVue	£3,250
	^† Trevo XP ProVue	£3,250
^† Stent retriever. ^‡ Aspiration catheter. * Individual companies may offer commercial terms including lower acquisition costs depending on purchase quantity.

Costs of standard care

NICE's clinical guideline on the diagnosis and management of stroke recommends thrombolysis (alteplase) for the treatment of acute ischaemic stroke. The Sentinel Stroke National Audit Programme estimated the unit costs of thrombolysis to be £875 (2016). The NHS England commissioning policy suggests that around 12% of all people with stroke are eligible for treatment with thrombolysis. This amounts to around 9,600 people admitted with stroke.

Resource consequences

Adopting MT devices will increase treatment costs compared with current standard care. However, if the devices led to improvement in treatment outcomes such as a reduction in long-term disabilities, then this could lead to cost savings.

Changes in facilities and 24-hour infrastructure would be needed if MT devices become used more widely. This would be to ensure standards for providing safe acute ischaemic stroke thrombectomy services. This is likely to result in substantial upfront costs for training interventional neuroradiologists and other staff such as anaesthetists and stroke nurses involved in providing care. Substantial system-wide reorganisation of acute stroke services will be needed.

Two economic studies with a UK perspective were also identified, with the results from these studies summarised in table 5. One study (Lobotesis 2016) found that using stent retrievers (Solitaire) with intravenous thrombolysis was more cost effective than intravenous thrombolysis alone for treating acute ischaemic stroke, based on the results of the SWIFT-PRIME trial. The second study (Ganesalingham 2015) did not focus on a specific stent retriever but looked at MT devices in general, based on the results of 5 RCTs (SWIFT-PRIME, MR CLEAN, ESCAPE, REVASCAT, EXTEND-IA), and found the devices were more cost effective when used together with intravenous thrombolysis compared with intravenous thrombolysis alone. The authors estimated that MT devices would lead to increased costs of £7,431 per patient over 20 years when compared with thrombolysis (using intravenous tissue plasminogen activator). These additional costs were because of the cost of the MT procedure. MT would be cost effective because of improved patient outcomes with an estimated incremental cost-effectiveness ratio of £7,061.

A further 10 economic studies were identified from a non-UK perspective (Achit 2016, Aronsson 2016, Carlsson 2017, de Andres-Nogales 2017, HQA 2016, Kunz 2016, Leppert 2015, MSAC 2016, Shireman 2017, Xie 2016). Two of the studies (de Andres-Nogales 2016, Shireman 2017) focused on stent retrievers (Solitaire) using the results of the SWIFT-PRIME trial and found the device was more cost effective compared with intravenous thrombolysis alone. Therefore, using the device led to an improvement in patient quality of life and less cost. The remaining studies considered MT devices in general compared with intravenous thrombolysis alone. Most of the results came from the 5 RCTs above, although this was often supported by data from other sources such as local registries. In all studies, MT was found to be cost effective. There were no relevant economic studies focusing specifically on aspiration catheters.

MT is used in some specialist stroke centres in the UK. The NHS England commissioning policy estimates that 8,000 people per year in England are eligible for treatment with MT.