ISCHEMIC STROKE / ACUTE THERAPY
Mechanical recanalization
Created 26/07/2022, last revision 21/04/2023
Introduction
- mechanical recanalization (thrombectomy/endovascular treatment) is an essential therapeutic method for large vessel occlusions (LVO)
- the goal is to achieve rapid and complete recanalization – TICI 2b/3 (AHA/ASA 2019 I/A)
- mechanical treatment is performed after preceding IVT (bridging therapy) or as direct thrombectomy (dMT) if IVT is contraindicated (ESO-ESMINT 2019)
- start treatment ASAP! → see here
- intravenous thrombolysis (IVT) should not be omitted before thrombectomy in eligible patients
- ESO guidelines 2021 prefer TNK 0.25mg/kg over t-PA 0.9 mg/kg in patients scheduled for thrombectomy
Time ≤ 6 hours from onset of symptoms
- the effectiveness of MT performed ≤6h from the onset of stroke was demonstrated by trials using retrievers (published in 2015)
- EXTEND-IA, ESCAPE a SWIFT PRIME, THRACE a REVASCAT
- trials showed high efficacy (recanalization rate up to 90%) + low risk of sICH (MR CLEAN 6%, ESCAPE 3.6%, EXTEND IA 0%, REVASCAT 1.9%)
- the absolute effect of treatment in achieving patient independence is 14-31%!
- stent retrievers and/or PENUMBRA are currently used (according to the ASTER and COMPASS trials, the efficacy is the same as for retrievers)
Time > 6 hours from onset of symptoms
Content available only for logged-in subscribers (registration will be available soon) |
Content available only for logged-in subscribers (registration will be available soon) |
- randomized trials SELECT2 (2023), ANGEL-ASPECT (2023), and RESCUE-JAPAN LIMIT trial (2022) demonstrated a significant effect of MT in patients with large infarcts
- ASPECTS 3-5 or core (CBF/ADC) ≥ 50 mL (ASPECT-ANGEL)
- an update of guidelines can be expected soon
- thrombolysis facilitates the effect of MT
- the MR-CLEAN NoIV, SWIFT-DIRECT, and DIRECT-SAFE trials failed to show the superiority of dMT
- meta-analyses show better outcomes with combination therapy compared to dMT [Vidale, 2020] [Katsanos, 2019] [Wang, 2020]
- IVT led to peripheral thrombus migration in 54% of patients in the INTERRSeCT trial, of which 27% had significant thrombus shift and was associated with a better outcome, and 27% had a moderate shift with no effect on the outcome [Ohara, 2020]
- sometimes, thrombus displacement more peripherally may not lead to clinical improvement and may make subsequent endovascular procedures difficult or impossible [Flint, 2020]
- thrombolysis should not significantly delay the start of MT → do not wait for its effect and immediately transfer the patient to the center performing MT (ESO-ESMINT 2019, AHA/ASA 2019)
- the RACECAT trial should answer whether it is better to thrombolyse the patients in the Stroke Center and then transport them to the Comprehensive Stroke Center (“drip and ship”) or transport the patient directly to the CSC (“mothership”)
Overview of mechanical recanalization methods
|
Methods rarely used or obsolete :
|
Advantages and disadvantages of MT
- wider therapeutic window
- high recanalization potential
- can be used in patients with a major IVT contraindication (e.g., after recent surgery, during anticoagulation therapy) or where IVT has failed
- effective in tPA-resistant occlusions
- can be used in combination with other revascularization procedures (IVT + IAT + mechanical recanalization)
- results highly depend on the neurointerventionalist´s experience
- high costs and requirements for instrumentation and personnel
- later initiation of therapy compared to IVT
- complications associated with endovascular procedures (dissection, perforation, etc.)
- risk of thrombus fragmentation leading to multiple distal embolizations
Indications
Content available only for logged-in subscribers (registration will be available soon) |
- patients with low ASPECT score – TENSION, IN EXTREMIS (LASTE part)
- patients with minor deficit – IN EXTREMIS (MOSTE part), ENDOLOW
- concomitant neuroprotection
- overall negative results of the ESCAPE-NA1 trial with nerinetide (NA1); some benefit was reported in patients without prior IVT (interaction of NA1 with alteplase?) → see here
- IVT in patients with basilar artery occlusion during the extended time window – POST-ETERNAL
Contraindications
Contraindications are derived from individual trials with thrombectomy, which differ slightly from each other.
Imaging findings
Content available only for logged-in subscribers (registration will be available soon) |
Personal history, laboratory and clinical findings
Content available only for logged-in subscribers (registration will be available soon) |
Anticoagulant therapy
Content available only for logged-in subscribers (registration will be available soon) |
Thrombectomy procedure
Periprocedural monitoring
- the procedure is performed by a neurointerventionalist and supervised by an anesthesiologist and/or neurologist
- MT is performed in general anesthesia (GA) or conscious sedation (CS)/analgosedation
- decide individually, CS is preferred
- the GOLIATH, ANSTROKE, and SIESTA trials did not indicate a worse outcome with GA compared with CS
- data from an Italian registry show worse outcomes for patients treated in GA [Cappellari, 2020]
- disadvantages of GA:
- neurostatus monitoring is difficult
- delay in initiation of therapy
- higher risk of periprocedural hypotension
- monitor BP every 5 minutes, continuous monitoring of pulse and O2 saturation
- maintain BP < 180/105 mmHg during and after the procedure (24h) (AHA/ASA 2019 IIa/B-NR)
- according to the analysis of MR CLEAN data, optimal SBP appears to be ~ 135 mmHg, and the mean BP during MT was 150 mmHg → see here
- RIGHT-2 and MR ASAP trials are currently ongoing
- a repeated bolus of midazolam (2.5mg) + sufentanil (25ug) is recommended for sedation
- regularly check neurological status (level of consciousness, speech, visual field, motor skills)
Periprocedural anticoagulation
Content available only for logged-in subscribers (registration will be available soon) |
Thrombus extraction
- initial assessment of the location and extent of occlusion and collateral circulation
- after passing the catheter through the thrombus, assess the patency of the distal sections, then thrombectomy is initiated
- perform follow-up angiographic controls after stent passage and at the end of the procedure
- if tight stenosis or occlusion of the ICA is present, acute angioplasty with/without carotid stenting can be performed [Cohen,2015] (AHA/ASA 2019 IIb/B-R)
- fresh occlusion can usually be easily passed through with the guiding wire
- thrombus extraction followed by carotid angioplasty seems to give better results → see here
- subsequent antiplatelet therapy (contraindicated after IVT) is problematic if the stent is inserted
- in addition, moving wires through the stented segment may lead to local complications
- the goal of the procedure is to achieve a TICI of 2b-3
- the procedure can be combined with the administration of intra-arterial thrombolysis (IAT) (AHA/ASA 2019 IIb/C-LD)
- to treat inaccessible segment or distal embolizations [Kaesmacher, 2019]
- good clinical effect of MT with TICI 2a-3 followed by IAT was reported in the CHOICE trial – the effect can be explained by the dissolution of microthrombi in the peripheral circulation
- if recanalization is achieved, wait approx. 15 minutes and perform a control examination to rule out early reocclusion
- with residual occlusion(s) in distal segments, consider the benefit and risk of complications of the continued procedure
- if recanalization is not achieved, the procedure is ended:
- after repeated unsuccessful extractions (approximately 6 attempts)
- when sICH is suspected
- after successful extraction, seek Early Venous Filling (EVF) at follow-up injection
- EVF is defined as the filling of any vein earlier than the late arterial phase (Elands, 2021)
- EVF is a marker of hyperperfusion and increased risk of hemorrhagic transformation
- EVF is assessed simply as present or absent
Quality indicators of the neurointervention program |
|
Postprocedural care
- the sheath is extracted in the angio suite, and the entry is secured with an occluder (Perclose, Mynxgrip, AngioSeal )
- the patient is transported to the ICU; if SAH or ICH is suspected, repeat CT scan
- in the ICU, continue with the close monitoring of vital signs (BP every 15min for the first hour, then every 30 min for at least 24h)
- maintain BP < 180/105 mmHg (AHA/ASA 2018 IIb/B-NR)
- the optimal threshold for SBP remains to be determined ( ∼ 140-180 mmHg) and may vary from case to case
- conflicting results have been published:
- aggressive BP treatment (< 130/80 mmHg) may be beneficial
[Choi, 2019]
- other data show that using an antihypertensive drug to target SBP < 160 mm Hg or 140 mm Hg may not be beneficial (MEDSCAPE)
- aggressive BP treatment (< 130/80 mmHg) may be beneficial
- the optimal threshold for SBP remains to be determined ( ∼ 140-180 mmHg) and may vary from case to case
- monitor neurological status (NIHSS, GCS), search for complications
- if bridging therapy with tPA was used:
- monitor for bleeding (puncture, gingival, GIT, urogenital bleeding, etc.) → see protocol of IV thrombolysis
- NG tube and central venous catheter must not be placed, and arterial puncture should not be performed for the first 24 h
- IM injections should not be administered for approx. 1h after the tPA administration
- CBC + coagulation tests (aPTT, TT, INR) at 6 and 12h, CBC+coagulation tests+metabolic panel the next day
- monitor for bleeding (puncture, gingival, GIT, urogenital bleeding, etc.) → see protocol of IV thrombolysis
- follow-up CT scan in 22-36h
Postprocedural antithrombotic medication
Content available only for logged-in subscribers (registration will be available soon) |