Endovascular clot retrieval (ECR)
Citation, DOI & article data
Endovascular clot retrieval (ECR) is increasingly performed in patients presenting with emergent large vessel occlusion (ELVO), especially those with a large ischemic penumbra that is likely to progress to ischemic stroke. To be successful, careful patient selection and dedicated training and equipment are necessary.
Thrombectomy and its efficacy in ischemic stroke have been explored since 2005, however initial trials revealed disappointing results. This was attributed to an inability to confirm large vessel occlusions radiologically combined with insufficiently developed devices and treatment delays 18. It was only in 2015, that multiple randomized controlled trials showed improved clinical outcome in patients with acute stroke due to large vessel occlusion undergoing thrombectomy compared to medical (conservative) treatment alone 3-5. As a result of these trials, endovascular clot retrieval has now become the standard of care for large vessel occlusion strokes involving the anterior circulation.
- acute ischemic stroke due to large vessel occlusion in the anterior circulation within 6 hours of symptom onset
- several trials (e.g. DAWN 13 and DEFUSE3 6) have shown that selected patient groups who fall outside the 6 hour time window also benefit from thrombectomy 12
- acute ischemic stroke due to large vessel occlusion in the posterior circulation remains an area of uncertainty and selection is dependent on clinician judgment in accordance with local guidelines
- intracranial hemorrhage on initial non-contrast CT
- large infarct core with no significant penumbra (i.e. no salvageable brain)
- various patient factors (e.g. pre-morbid functional status, advanced directives, etc...)
Non-contrast enhanced CT is used to exclude hemorrhage and CT angiography to determine large vessel occlusion. Alternatively, MRI and DSA may also demonstrate the occlusion although this is less common due to difficulty with timely access to MRI in most institutions.
Angiographic imaging can also assess collateral vessels which contribute to predicting outcome in some settings 8.
The role of advanced imaging such as CT perfusion to determine the infarct core and penumbra size is still uncertain 10, yet the technique is being ushered into more and more centers based on international guidelines 11.
Positioning/room set up
- stent retrievers
- aspiration devices
- balloon guiding catheter
Although successful technical clot retrieval is essential, appropriate postprocedure care is also critical to avoid complications.
Blood pressure control
Avoiding excessively high blood pressure is important in reducing the risk of secondary hemorrhage. In the acute post-thrombectomy/thrombolysis period a target BP <185/110 mmHg is recommended 14.
If critical carotid stenosis (tandem lesion) has been treated then more aggressive blood pressure control is probably warranted to avoid the possibility of cerebral hyperperfusion as well as hemorrhage 16. There are, however, few universally agreed-upon guidelines and chosen targets will vary according to pre-procedure blood pressure, anticoagulation, pre-ECR thrombolysis, size of the expected infarct and a variety of other factors.
Groin site neurovascular observations and bed rest are required as usual. There is an increased move towards radial artery access for lower complication rates 17.
In a variety of settings, anticoagulation may need to be restarted shortly after clot retrieval (e.g. antiplatelet agents for stenting, anticoagulation for atrial fibrillation). The timing of this is on a case by case balance and involves balancing the risk of thromboembolic complications from delaying anticoagulation versus the increased risk of a cerebral hemorrhage.
The overall complication rate is about 15% 1. Complications include 2,9:
- intracranial hemorrhage (<8%)
- emboli to new territories
- vessel perforation (1 - 5%)
- arterial dissection
- vascular access site complications
- groin hematoma (2 - 11%)
- retroperitoneal hematoma (<6%)
The technical outcome is graded using the mTICI score. Thrombectomy is a highly effective treatment for strokes affecting the anterior circulation, with a number needed to treat (NTT) of 2.6 for an improved functional outcome. In a meta-analysis, 46% of patients treated with mechanical thrombectomy achieved functional independence (modified Rankin scale (mRS) 0–2 at 90 days) compared to 27% for best medical treatment 2. Outcomes in posterior circulation strokes remain mixed. One randomized controlled trial of basilar stroke patients found 44.2% of patients managed with mechanical thrombectomy achieving a 90-day modified Rankin scale of 0-3, in contrast to 37.7% in those receiving medical treatment with no statistically significant difference found between groups 19.
- 1. Evans MRB, White P, Cowley P, Werring DJ. Revolution in acute ischaemic stroke care: a practical guide to mechanical thrombectomy. (2017) Practical neurology. 17 (4): 252-265. doi:10.1136/practneurol-2017-001685 - Pubmed
- 2. Goyal M, Menon BK, et al. Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis of individual patient data from five randomised trials. (2016) Lancet (London, England). 387 (10029): 1723-31. doi:10.1016/S0140-6736(16)00163-X - Pubmed
- 3. Jaechan Park. Acute Ischemic Stroke: Medical, Endovascular, and Surgical Techniques (2017). ISBN: 9789811009655
- 4. Seung-Hoon Lee. Stroke Revisited: Diagnosis and Treatment of Ischemic Stroke (2017). ISBN: 9789811014239
- 5. Brett E. Skolnick, Wayne M. Alves. Handbook of Neuroemergency Clinical Trials, 2e (2018). ISBN: 9780128040645
- 6. Albers GW, Marks MP, et al. for the DEFUSE 3 Investigators. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. (2018) N Engl J Med doi: 10.1056/NEJMoa1713973 - PDF
- 7. Mulder MJHL, Jansen IGH, Goldhoorn RB, Venema E, Chalos V, Compagne KCJ, Roozenbeek B, Lingsma HF, Schonewille WJ, van den Wijngaard IR, Boiten J, Albert Vos J, Roos YBWE, van Oostenbrugge RJ, van Zwam WH, Majoie CBLM, van der Lugt A, Dippel DWJ. Time to Endovascular Treatment and Outcome in Acute Ischemic Stroke: MR CLEAN Registry Results. (2018) Circulation. 138 (3): 232-240. doi:10.1161/CIRCULATIONAHA.117.032600 - Pubmed
- 8. Liebeskind DS, Jahan R, Nogueira RG, Zaidat OO, Saver JL. Impact of collaterals on successful revascularization in Solitaire FR with the intention for thrombectomy. (2014) Stroke. 45 (7): 2036-40. doi:10.1161/STROKEAHA.114.004781 - Pubmed
- 9. Maxim Mokin, Edward C. Jauch, Italo Linfante, Adnan Siddiqui, Elad Levy. Acute Stroke Management in the First 24 Hours. (2019) ISBN: 9780190856519
- 10. Shen J, Li X, Li Y, Wu B. Comparative accuracy of CT perfusion in diagnosing acute ischemic stroke: A systematic review of 27 trials. (2017) PloS one. 12 (5): e0176622. doi:10.1371/journal.pone.0176622 - Pubmed
- 11. Powers WJ, Rabinstein AA, Ackerson T, Adeoye OM, Bambakidis NC, Becker K, Biller J, Brown M, Demaerschalk BM, Hoh B, Jauch EC, Kidwell CS, Leslie-Mazwi TM, Ovbiagele B, Scott PA, Sheth KN, Southerland AM, Summers DV, Tirschwell DL. 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. (2018) Stroke. 49 (3): e46-e110. doi:10.1161/STR.0000000000000158 - Pubmed
- 12. Christopher A. Potter, Achala S. Vagal, Mayank Goyal, Diego B. Nunez, Thabele M. Leslie-Mazwi, Michael H. Lev. CT for Treatment Selection in Acute Ischemic Stroke: A Code Stroke Primer. (2019) RadioGraphics. 39 (6): 1717-1738. doi:10.1148/rg.2019190142 - Pubmed
- 13. Raul G. Nogueira, Ashutosh P. Jadhav, Diogo C. Haussen, Alain Bonafe, Ronald F. Budzik, Parita Bhuva, Dileep R. Yavagal, Marc Ribo, Christophe Cognard, Ricardo A. Hanel, Cathy A. Sila, Ameer E. Hassan, Monica Millan, Elad I. Levy, Peter Mitchell, Michael Chen, Joey D. English, Qaisar A. Shah, Frank L. Silver, Vitor M. Pereira, Brijesh P. Mehta, Blaise W. Baxter, Michael G. Abraham, Pedro Cardona, Erol Veznedaroglu, Frank R. Hellinger, Lei Feng, Jawad F. Kirmani, Demetrius K. Lopes, Brian T. Jankowitz, Michael R. Frankel, Vincent Costalat, Nirav A. Vora, Albert J. Yoo, Amer M. Malik, Anthony J. Furlan, Marta Rubiera, Amin Aghaebrahim, Jean-Marc Olivot, Wondwossen G. Tekle, Ryan Shields, Todd Graves, Roger J. Lewis, Wade S. Smith, David S. Liebeskind, Jeffrey L. Saver, Tudor G. Jovin. Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct. (2017) New England Journal of Medicine. 378 (1): 11-21. doi:10.1056/NEJMoa1706442 - Pubmed
- 14. Gravanis I, Tsirka SE. Tissue-type plasminogen activator as a therapeutic target in stroke. (2008) Expert opinion on therapeutic targets. 12 (2): 159-70. doi:10.1517/1472818.104.22.168 - Pubmed
- 15. Tanya N. Turan, George Cotsonis, Michael J. Lynn, Seemant Chaturvedi, Marc Chimowitz. Relationship Between Blood Pressure and Stroke Recurrence in Patients With Intracranial Arterial Stenosis. (2007) Circulation. 115 (23): 2969-75. doi:10.1161/CIRCULATIONAHA.106.622464 - Pubmed
- 16. Kim KH, Lee CH, Son YJ, Yang HJ, Chung YS, Lee SH. Post-carotid endarterectomy cerebral hyperperfusion syndrome : is it preventable by strict blood pressure control?. (2013) Journal of Korean Neurosurgical Society. 54 (3): 159-63. doi:10.3340/jkns.2013.54.3.159 - Pubmed
- 17. Khanna O, Mouchtouris N, Sweid A, Chalouhi N, Ghosh R, Al Saiegh F, Gooch MR, Tjoumakaris S, Rosenwasser RH, Romo V, Jabbour P. Transradial approach for acute stroke intervention: technical procedure and clinical outcomes. (2020) Stroke and vascular neurology. 5 (1): 103-106. doi:10.1136/svn-2019-000263 - Pubmed
- 18. Moussaddy A, Demchuk AM, Hill MD. Thrombolytic therapies for ischemic stroke: Triumphs and future challenges. (2018) Neuropharmacology. 134 (Pt B): 272-279. doi:10.1016/j.neuropharm.2017.11.010 - Pubmed
- 19. Langezaal LCM, van der Hoeven EJRJ, Mont'Alverne FJA, de Carvalho JJF, Lima FO, Dippel DWJ, van der Lugt A, Lo RTH, Boiten J, Lycklama À Nijeholt GJ, Staals J, van Zwam WH, Nederkoorn PJ, Majoie CBLM, Gerber JC, Mazighi M, Piotin M, Zini A, Vallone S, Hofmeijer J, Martins SO, Nolte CH, Szabo K, Dias FA, Abud DG, Wermer MJH, Remmers MJM, Schneider H, Rueckert CM, de Laat KF, Yoo AJ, van Doormaal PJ, van Es ACGM, Emmer BJ, Michel P, Puetz V, Audebert HJ, Pontes-Neto OM, Vos JA, Kappelle LJ, Algra A, Schonewille WJ. Endovascular Therapy for Stroke Due to Basilar-Artery Occlusion. (2021) The New England journal of medicine. 384 (20): 1910-1920. doi:10.1056/NEJMoa2030297 - Pubmed