see also [[Stroke]], [[TPA|thrombolysis]] see: [Dunn stroke management - interventional radiology](x-devonthink-item://17F30988-D196-4E8C-A262-E1D0C4D87D53) and [TNH endovascular clot retrieval](x-devonthink-item://588E7B63-C8C7-4BE0-A715-920786D83B9A) [Rosen - Mechanical Thrombectomy](x-devonthink-item://34BCE5FA-5D8A-4BBE-9655-35F24866FDB1?page=14&istart=5967&ilength=22&search=Mechanical%20Thrombectomy) [Australia New Zealand stroke guidelines](https://informme.org.au/guidelines/living-clinical-guidelines-for-stroke-management) > [!key points] > - used in large vessel occlusion (M1, basilar, internal carotid) > - usually thrombolytics prior to clot retrieval > - Trials: > - MR Clean, EXTEND-IA, ESCAPE, SWIFT PRIME, REVASCAT, DAWN > - show clot retrieval > TPA alone # Indications Lots of long-winded chat below; here’s a simple answer: > - potentially disabiling stroke NIHSS ≥ 6 > - pre-stroke modified rankin scale ≤  1 > - acute ischaemic stroke from occlusion of: > - internal carotid > - M1 > - dominant vertebral > - basilar > - presenting < 24 hours of stroke onset  > - small core infarct, large penumbra *Australian and New Zealand Living Clinical Guidelines for Stroke Management - Chapter 3*: [neurointervention](https://app.magicapp.org/#/guideline/QnoKGn/section/jMmGRj) **Strong recommendation:** “For patients with a disabling clinical deficit due to ischaemic stroke caused by a ==large vessel occlusion== in the *internal carotid artery, proximal middle cerebral artery (M1 and proximal or dominant M2 segments)*, *basilar* artery occlusion, or with tandem occlusion of both the cervical carotid and intracranial large arteries, endovascular thrombectomy should be undertaken when the procedure can be commenced within 24 hours of stroke onset, taking into account individual patient factors. Such factors include: extent and location of brain injury, pre-morbid function, frailty, comorbidities, and patient's and/or family's wishes.” **From Hayes’** 1. ischaemic stroke with large vessel occlusion on CTA - ICA - MCA - m1 btwn carotid terminus and MCA bifurcation - early m2 segment -- after bifurcation but proximal within sylvian fissure - basilar artery 2. independent premorbid function (modified ranking ≤ 1 3. potentially disabling stroke NIHSS ≥ 6 4. presentation within **6-24 hours of stroke onset** - proximal large vessel clot within 6 hours of stroke onset - carefully selected pts with proximal large clot within 6-24 hours of stroke onset may be considered if: - mismatch between clinical deficit and infarct volume/ ischaemic penumbra - CT perfusion or MRI shows penumbra - basilar artery occlusion 5. had [[TPA|thrombolysis]] if eligible for this within 4.5 h 6. accessible to clot retrieval > [Rosens’:](x-devonthink-item://34BCE5FA-5D8A-4BBE-9655-35F24866FDB1?page=15) > *Zero to 6 hours of symptom onset:* > Guidelines from the AHA/**American Stroke Association** (ASA) recommend mechanical thrombectomy for adults with: > (1) no significant prestroke disability (i.e., a mRS score of ≤1); > (2) a causative occlusion of the ICA or the M1 segment of the MCA; > (3) NIHSS score of ≥6; > (4) ASPECTS of ≥6 (associated with better functional outcome at 3 months). > > These guidelines are based on results from 6 recent randomized trials of mechanical thrombectomy using predominantly stent retriever devices (MR CLEAN, SWIFT PRIME, EXTEND-IA, ESCAPE, REVASCAT, THRACE) > > the benefits of thrombectomy are **uncertain** for patients with occlusion of the ICA or proximal MCA (M1), who have a prestroke mRS score greater than 1, or an NIHSS score less than 6, or a larger infarct core (i.e., ASPECTS score <6). Using pooled patient data, the direction of treatment effect for mechanical thrombectomy over standard care appears favorable in M2 occlusions but does not reach statistical significance. therefore, the benefits of thrombectomy for distal MCA occlusion, MCA segment 2 (M2) or MCA segment 3 (M3), are uncertain. Additionally, the benefits are uncertain in those with occlusion of the anterior cerebral arteries, vertebral arteries, basilar artery, or posterior cerebral arteries # management - transport to stroke centre and pre-notification - IV thrombolysis in ED # Evidence multiple RCTs comparing clot retrieval and tPA vs tPA alone showing benefit have been published ​MR CLEAN, EXTEND-IA, ESCAPE, SWIFT PRIME, REVASCAT - ​3 stopped early due to extent of treatment effect - ​all trials had different degrees of selectivity - ​10-20% of total ‘code stroke’ patients eligible - ​trials with the most selective entry criteria had ​smaller numbers of patients - ​greater degree of treatment effects - ​no ICH (1% ICH rate increase in other trials) - treatment effect (increase in mRs 0-2) compared to tPA alone between 10-30% - ​mortality benefit of 5-10% seen in the most selective trials - although this does not appear to be related to time to clot retrieval - the most positive results were achieved in the ==EXTEND 1A trial conducted in Australia and New Zealand== - ​patients with a large ischaemic core (blood flow < 30% of normal brain) were excluded and intervention commenced immediately if there was a significant ischaemic penumbra (Tmax > 6sec) - ​30% absolute increase in independent functioning at 90 days - *NNT to achieve an independent outcome 3.2* - ​clot retrieval for basilar artery occlusions can achieve a 40% good functional outcome with NNT of 2.5 # anatomy of MCA Note that the *MCA segments* should be thought of more as progressive generational branchings (with consequent increase in numbers of branches with each generation), rather than as strict single linear anatomical extensions. ![[Pasted image 20240809010630.png]] - M1: horizontal (sphenoidal) segment) - ICA → lateral direciton parallel to sphenoid wing and terminates by dividing into M2 segments - lenticulostriate perforating vessels - anterior temoporal artery - M2: insular segments - M3 - opercular segments - M4 - cortical segments