Thrombectomy

Continuing Education Activity

Thrombectomy involves removing a clot from a blood vessel, most commonly from the brain, heart, or lungs. Stroke and myocardial infarction remain two of the leading causes of death worldwide and are increasingly treated through techniques that include intravascular thrombolytics, mechanical thrombectomy, or a combination of both. This activity reviews the evaluation and management of a vascular thrombus using mechanical thrombectomy and highlights the role of the healthcare team in managing patients with this condition.

Objectives:

• Identify the indications for performing a mechanical thrombectomy.
• Describe the equipment, personnel, preparation, and technique in regards to mechanical thrombectomy.
• Review the potential complications and their clinical significance when performing a thrombectomy.
• Describe some interprofessional team strategies for improving care coordination and communication to advance mechanical thrombectomy and improve outcomes.

Introduction

Thrombectomy is a mechanical interventional procedure by which a blood clot or thrombus is removed under image guidance using endovascular devices. Thrombectomy is most commonly used in acute cerebral ischemic stroke, although it is also a procedure used for clot removal in acute myocardial infarction (MI) and pulmonary embolism (PE). Mechanical thrombectomy utilizes various techniques. Most commonly, it uses different catheter-based therapies, including stent-retrieval, direct aspiration, or a combination of both.

Indications

Cerebral Stroke

The primary purpose of mechanical thrombectomy in ischemic cerebral stroke is rescuing the ischemic penumbra. The indications for mechanical thrombectomy have recently significantly increased, with recent literature proving its efficacy and superiority over intravenous (IV) thrombolytics. Some noteworthy trials are the DAWN, DEFUSE-3, CTP, and CRISP studies.[1][2] The American Heart Association/American Stroke Association guidelines for the early management of acute ischemic stroke recommends the following criteria for endovascular mechanical thrombectomy therapy:[3][4]

1. Pre-stroke modified Rankin scale <2
2. NIH stroke scale score ≥ 6; Alberta stroke program early CT score ≥ 6
3. Start of the procedure within 6 hours of symptom onset
4. Causative occlusion of the internal carotid artery or the proximal middle cerebral artery (M1)
5. Age 18 years or older

The DAWN and DEFUSE-3 trials demonstrated that mechanical thrombectomy improved clinical outcomes versus standard care alone in select patients with large vessel ischemic stroke presenting up to 24 hours after the start of symptoms. The current indications have extended the time of thrombectomy to 24 hours after the symptom onset.[1][2]

Myocardial Infarction

Unlike in the case of cerebral stroke, recommendations for mechanical thrombectomy, specifically aspiration thrombectomy in cases of acute MI, remain doubtful. The TAPAS study (Thrombus Aspiration During Percutaneous Coronary Intervention in Acute Myocardial Infarction Study) suggested that routine thrombus aspiration improves microvascular reperfusion with improved outcomes at 30 days (the one-year follow up reported improved clinical outcomes) compared to traditional percutaneous coronary intervention (PCI) for a wide range of patients.[5] However, the results from two subsequent studies, the TOTAL (ThrOmbecTomy with PCI vs. PCI ALone in patients with STEMI), and TASTE (Thrombus Aspiration in ST-Elevation myocardial infarction) trials indicated no significant improvement in clinical outcomes for acute MI patients undergoing aspiration thrombectomy.[6][7][6]

The TOTAL trial compared PCI alone vs. PCI with thrombectomy in ST-elevation myocardial infarction 12 hours after MI onset and revealed an increased risk of stroke with routine thrombectomy in acute MI within 30 days of follow up.[6] Researchers found similar findings when patients with a high thrombus burden.[8] Based on these latter studies, the AHA downgraded the guideline recommendation for thrombectomy from class IIa to class III (routine TA is not recommended in acute MI cases before primary PCI).

Pulmonary Embolism

The use of mechanical thrombectomy in PE remains under investigation; pivotal clinical trials have provided evidence to the safety and efficacy of mechanical thrombectomy in some patients. The FLARE (FlowTriever Pulmonary Embolectomy Clinical Study) study concluded that a mechanical thrombectomy mechanism appears safe and effective in persons with acute intermediate-risk PE.[9] The current recommendations are for patients with absolute contraindications for systemic thrombolytics, prohibitive risk of bleeding, or lack of time (2 hours) for the systemic effect of thrombolytic agents.

Contraindications

• Intracranial hemorrhage
• Large infarct core with minimal penumbra
• Small vessel occlusion
• Coagulopathies that can not be corrected
• Elevated blood pressure (systolic pressure >185 mmHg or diastolic pressure >110 mmHg) that can not be corrected

Equipment

An array of devices are used in thrombectomy. These include guide catheters, stent-retrievers, microcatheters, aspiration catheters, and aspiration pump systems.

Aspiration Catheters

Large-bore catheters suction out the thrombus using negative pressure aspiration. The selection of aspiration catheters includes a large variety of devices from different manufacturers.[10] The selection of the catheter depends on the patient's anatomy and the location of the occlusion. For MI, it is uncertain whether one aspiration catheter provides any significant advantage over the others.                                                     

Aspiration Pump

An aspiration pump machine or a 16 to 20 mL syringe serves to apply negative pressure to suction the thrombus.[11]

Microcatheters/ Guidewires

These are small catheters advanced into a guiding catheter through a system where the catheter passes over the wire, which aids in the more complex and complete occlusions in the coronary and peripheral vasculature.

Stent Retrieval Tool

Solitaire utilizes a stent retrieval tool, by which an expandable stent is deployed, secures itself to the thrombus, and then can extract the clot. A systematic review revealed no significant difference in efficacy or safety between two different stent retrieval devices.[12] Another stent retriever is the first device indicated for the treatment of symptom onset up to 24 hours.[13][14]

Other Devices Used

Other innovative thrombectomy devices remove clots in large vessels through high-flow volume capped aspiration and self-expanding mesh discs. The device is indicated for use in the peripheral vasculature and pulmonary arteries. The FLARE trial provided evidence for the safety and efficacy of such devices in acute, intermediate-risk PE patients.[9]

Over the wire systems are used to remove a significant clot burden from large diameter vessels and involve functions such as coring out clot from vein walls. Such systems are composed of a catheter and a sheath. The catheter consists of a coring element and a collecting bag. Once the catheter is advanced to the occlusion level, it is further advanced through the clot and is unsheathed and expanded. Upon retraction of the catheter, the coring element releases the clot from the vessel walls, while the proximal collecting bag serves to prevent the spread of any embolic clot material.[15]

Personnel

• Interventional radiologist
• Interventional neurosurgeon
• Interventional cardiologist
• Endovascular nurse
• Endovascular technician
• Anesthesiologist
• Anesthetist

Technique or Treatment

Shared principles guide the procedure of mechanical thrombectomy; however, certain modifications are made based on the type of intervention performed. The procedure begins with the insertion of a balloon-guided catheter commonly through a groin puncture. It is advanced until it reaches the thrombus. A guidewire is then advanced through the thrombus, and a microcatheter is passed over the guidewire through the thrombus. The guidewire is withdrawn, while the stent is deployed. The retrievable stent opens up, and its projections grip the thrombus, effectively securing it to the stent. Contrast is injected through the initial balloon catheter to observe flow distal to the removed occlusion. The balloon is then inflated to temporarily restrict flow as the stent and microcatheter are removed slowly through the guide catheter, with concurrent aspiration. An angiogram is performed to check for the complete removal of the thrombus.[16]

The ADAPT (A Direct Aspiration First Pass Technique) is an alternate technique that uses direct aspiration with a large-bore catheter as a first pass step in removing the thrombus. This novel technique demonstrates the ongoing development and adaptations of mechanical thrombectomy. First, a large guide catheter is advanced to the thrombus' level, passing over a microwire and microcatheter. Next, aspiration is applied to the system using an aspiration pump or a syringe. Lack of flow means contact with the thrombus. The large bore catheter is advanced slightly for 1 to 2 mm to encircle the thrombus. Aspiration is again applied. Evidence of thrombus retrieval is through cessation of flow in the system. If the thrombus is not retrieved, repeat attempts and utilization of adjuncts such as a stent retriever are quickly implemented to remove the thrombus.[17][18]

Complications

Symptomatic intracerebral hemorrhage is a potential adverse event of mechanical thrombectomy resulting from instrument manipulation. Despite this complication, the risk of symptomatic intracerebral bleeding is not significantly different from the medical standard of care.

• Dislodging of embolic material distal to the occlusion.
• Stenosis at the thrombectomy site can also occur as complications from thrombectomy.
• Vessel perforation and dissection can occur.
• Groin and retroperitoneal hematomas can occur at the puncture site.
• Reocclusion secondary to a high platelet count on admission, pre-existing stenosis, or embolic material around the thrombectomy site.

Although these acute complications are not common, they indicate a poor prognosis.[19]

Clinical Significance

The use of mechanical thrombectomy is considered the standard of care for large vessel occlusion. The MR CLEAN trial (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) published in 2015 was a large multicenter randomized trial that compared patients who underwent intraarterial treatment plus usual care with those who underwent standard medical treatment.[20]

Intraarterial intervention, including mechanical thrombectomy, resulted in a higher rate (13.5%) of functional independence in acute ischemic stroke than in the control group, supporting the safety and efficacy of an intraarterial intervention. However, subsequent trials have shown that intracranial hemorrhage's risk due to intraoperative complications remains a concern. Improvements in health-related quality of life and cognitive function are additional outcomes observed in long term follow-up for patients suffering an ischemic stroke.[21]

Enhancing Healthcare Team Outcomes

Interprofessional communication and parallel workflows are critical parts of stroke treatment and the safe and timely use of mechanical thrombectomy in stroke treatment. The length of time to successful revascularization is a vital metric in determining a successful outcome for the patient. The ESCAPE clinical trial (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion with Emphasis on Minimizing CT to Recanalization Times) demonstrated that improved workflow could improve both functional outcomes and mortality.[22] [Level 1]

While the neuro interventionalist is responsible for performing the thrombectomy, technologists, nursing staff, procedure room assistants play a critical role in ensuring promptness and success of the procedure. The treatment team consists of an anesthesiologist, at least one neuro interventionalist, a technologist, and a radiology nurse. The parallel workflow model ensures that several of the roles carried out by these individuals occur simultaneously.[22] 

An example of a parallel workflow is as follows: device preparation by the neuro interventionalist occurs at the same time the groin puncture site is sterile prepared, and the technologist drapes the patient. The nurse simultaneously retrieves bags of heparinized saline. The technologist or neuro interventionalist helps in the connection of the bags. The anesthesiologist would, at the same time, work to administer conscious sedation or general anesthesia to the patient. Implementation of this improved parallel workflow, the primary use of conscious sedation (whenever possible over general anesthesia), and the stroke cart availability has shown to produce a reduction of 29 minutes from room entry to reperfusion compared to a process where steps take place in succession.[23] [Level 2]

Review Questions

• Access free multiple choice questions on this topic.
• Comment on this article.

References

1.

Nogueira RG, Jadhav AP, Haussen DC, Bonafe A, Budzik RF, Bhuva P, Yavagal DR, Ribo M, Cognard C, Hanel RA, Sila CA, Hassan AE, Millan M, Levy EI, Mitchell P, Chen M, English JD, Shah QA, Silver FL, Pereira VM, Mehta BP, Baxter BW, Abraham MG, Cardona P, Veznedaroglu E, Hellinger FR, Feng L, Kirmani JF, Lopes DK, Jankowitz BT, Frankel MR, Costalat V, Vora NA, Yoo AJ, Malik AM, Furlan AJ, Rubiera M, Aghaebrahim A, Olivot JM, Tekle WG, Shields R, Graves T, Lewis RJ, Smith WS, Liebeskind DS, Saver JL, Jovin TG., DAWN Trial Investigators. Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct. N Engl J Med. 2018 Jan 04;378(1):11-21. [PubMed: 29129157]

2.

Albers GW, Marks MP, Kemp S, Christensen S, Tsai JP, Ortega-Gutierrez S, McTaggart RA, Torbey MT, Kim-Tenser M, Leslie-Mazwi T, Sarraj A, Kasner SE, Ansari SA, Yeatts SD, Hamilton S, Mlynash M, Heit JJ, Zaharchuk G, Kim S, Carrozzella J, Palesch YY, Demchuk AM, Bammer R, Lavori PW, Broderick JP, Lansberg MG., DEFUSE 3 Investigators. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med. 2018 Feb 22;378(8):708-718. [PMC free article: PMC6590673] [PubMed: 29364767]

3.

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. Guidelines for the Early Management of Patients With Acute Ischemic Stroke: 2019 Update to the 2018 Guidelines for the Early Management of Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2019 Dec;50(12):e344-e418. [PubMed: 31662037]

4.

Albers GW, Lansberg MG, Kemp S, Tsai JP, Lavori P, Christensen S, Mlynash M, Kim S, Hamilton S, Yeatts SD, Palesch Y, Bammer R, Broderick J, Marks MP. A multicenter randomized controlled trial of endovascular therapy following imaging evaluation for ischemic stroke (DEFUSE 3). Int J Stroke. 2017 Oct;12(8):896-905. [PMC free article: PMC5916787] [PubMed: 28946832]

5.

Vlaar PJ, Svilaas T, van der Horst IC, Diercks GF, Fokkema ML, de Smet BJ, van den Heuvel AF, Anthonio RL, Jessurun GA, Tan ES, Suurmeijer AJ, Zijlstra F. Cardiac death and reinfarction after 1 year in the Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS): a 1-year follow-up study. Lancet. 2008 Jun 07;371(9628):1915-20. [PubMed: 18539223]

6.

Jolly SS, Cairns JA, Yusuf S, Meeks B, Pogue J, Rokoss MJ, Kedev S, Thabane L, Stankovic G, Moreno R, Gershlick A, Chowdhary S, Lavi S, Niemelä K, Steg PG, Bernat I, Xu Y, Cantor WJ, Overgaard CB, Naber CK, Cheema AN, Welsh RC, Bertrand OF, Avezum A, Bhindi R, Pancholy S, Rao SV, Natarajan MK, ten Berg JM, Shestakovska O, Gao P, Widimsky P, Džavík V., TOTAL Investigators. Randomized trial of primary PCI with or without routine manual thrombectomy. N Engl J Med. 2015 Apr 09;372(15):1389-98. [PMC free article: PMC4995102] [PubMed: 25853743]

7.

Olivecrona GK, Lagerqvist B, Fröbert O, Gudnason T, Maeng M, Råmunddal T, Haupt J, Kellerth T, Stewart J, Sarno G, Jensen J, Östlund O, James SK. Impact of thrombus aspiration during ST-Elevation Myocardial Infarction: a six month composite endpoint and risk of stroke analyses of the TASTE trial. BMC Cardiovasc Disord. 2016 Apr 01;16:62. [PMC free article: PMC4818511] [PubMed: 27036735]

8.

Jolly SS, Cairns JA, Lavi S, Cantor WJ, Bernat I, Cheema AN, Moreno R, Kedev S, Stankovic G, Rao SV, Meeks B, Chowdhary S, Gao P, Sibbald M, Velianou JL, Mehta SR, Tsang M, Sheth T, Džavík V., TOTAL Investigators. Thrombus Aspiration in Patients With High Thrombus Burden in the TOTAL Trial. J Am Coll Cardiol. 2018 Oct 02;72(14):1589-1596. [PubMed: 30261959]

9.

Tu T, Toma C, Tapson VF, Adams C, Jaber WA, Silver M, Khandhar S, Amin R, Weinberg M, Engelhardt T, Hunter M, Holmes D, Hoots G, Hamdalla H, Maholic RL, Lilly SM, Ouriel K, Rosenfield K., FLARE Investigators. A Prospective, Single-Arm, Multicenter Trial of Catheter-Directed Mechanical Thrombectomy for Intermediate-Risk Acute Pulmonary Embolism: The FLARE Study. JACC Cardiovasc Interv. 2019 May 13;12(9):859-869. [PubMed: 31072507]

10.

Schramm P, Navia P, Papa R, Zamarro J, Tomasello A, Weber W, Fiehler J, Michel P, Pereira VM, Krings T, Gralla J, Santalucia P, Pierot L, Lo TH. ADAPT technique with ACE68 and ACE64 reperfusion catheters in ischemic stroke treatment: results from the PROMISE study. J Neurointerv Surg. 2019 Mar;11(3):226-231. [PMC free article: PMC6582710] [PubMed: 30061367]

11.

Kim YS, Kwak HS, Chung GH, Hwang SB. Manual aspiration thrombectomy using the Penumbra catheter in patients with acute M1 occlusion: A single-center study. Interv Neuroradiol. 2015 Dec;21(6):694-9. [PMC free article: PMC4757361] [PubMed: 26494405]

12.

Caranfa JT, Nguyen E, Ali R, Francis I, Zichichi A, Bosco E, Coleman CI, Baker WL, Kohn CG. Mechanical endovascular therapy for acute ischemic stroke: An indirect treatment comparison between Solitaire and Penumbra thrombectomy devices. PLoS One. 2018;13(3):e0191657. [PMC free article: PMC5841644] [PubMed: 29513676]

13.

Yi HJ, Lee DH, Kim SU. Effectiveness of Trevo stent retriever in acute ischemic stroke: Comparison with Solitaire stent. Medicine (Baltimore). 2018 May;97(20):e10747. [PMC free article: PMC5976322] [PubMed: 29768352]

14.

Zaidat OO, Castonguay AC, Nogueira RG, Haussen DC, English JD, Satti SR, Chen J, Farid H, Borders C, Veznedaroglu E, Binning MJ, Puri A, Vora NA, Budzik RF, Dabus G, Linfante I, Janardhan V, Alshekhlee A, Abraham MG, Edgell R, Taqi MA, Khoury RE, Mokin M, Majjhoo AQ, Kabbani MR, Froehler MT, Finch I, Ansari SA, Novakovic R, Nguyen TN. TREVO stent-retriever mechanical thrombectomy for acute ischemic stroke secondary to large vessel occlusion registry. J Neurointerv Surg. 2018 Jun;10(6):516-524. [PMC free article: PMC5969387] [PubMed: 28963367]

15.

Nezami N, Jarmakani H, Latich I, Groenwald M, Perez Lozada JC. Vertebroplasty-associated cement leak leading to iatrogenic venous compression and thrombosis. J Vasc Surg Cases Innov Tech. 2019 Dec;5(4):561-565. [PMC free article: PMC6911956] [PubMed: 31872163]

16.

Lambrinos A, Schaink AK, Dhalla I, Krings T, Casaubon LK, Sikich N, Lum C, Bharatha A, Pereira VM, Stotts G, Saposnik G, Kelloway L, Xie X, Hill MD. Mechanical Thrombectomy in Acute Ischemic Stroke: A Systematic Review. Can J Neurol Sci. 2016 Jul;43(4):455-60. [PMC free article: PMC4926268] [PubMed: 27071728]

17.

Nikoubashman O, Nikoubashman A, Büsen M, Wiesmann M. Necessary Catheter Diameters for Mechanical Thrombectomy with ADAPT. AJNR Am J Neuroradiol. 2017 Dec;38(12):2277-2281. [PMC free article: PMC7963740] [PubMed: 29025728]

18.

Turk AS, Spiotta A, Frei D, Mocco J, Baxter B, Fiorella D, Siddiqui A, Mokin M, Dewan M, Woo H, Turner R, Hawk H, Miranpuri A, Chaudry I. Initial clinical experience with the ADAPT technique: A direct aspiration first pass technique for stroke thrombectomy. J Neurointerv Surg. 2018 Jul;10(Suppl 1):i20-i25. [PubMed: 30037948]

19.

Tawil SE, Muir KW. Thrombolysis and thrombectomy for acute ischaemic stroke. Clin Med (Lond). 2017 Apr;17(2):161-165. [PMC free article: PMC6297620] [PubMed: 28365630]

20.

Berkhemer OA, Fransen PS, Beumer D, van den Berg LA, Lingsma HF, Yoo AJ, Schonewille WJ, Vos JA, Nederkoorn PJ, Wermer MJ, van Walderveen MA, Staals J, Hofmeijer J, van Oostayen JA, Lycklama à Nijeholt GJ, Boiten J, Brouwer PA, Emmer BJ, de Bruijn SF, van Dijk LC, Kappelle LJ, Lo RH, van Dijk EJ, de Vries J, de Kort PL, van Rooij WJ, van den Berg JS, van Hasselt BA, Aerden LA, Dallinga RJ, Visser MC, Bot JC, Vroomen PC, Eshghi O, Schreuder TH, Heijboer RJ, Keizer K, Tielbeek AV, den Hertog HM, Gerrits DG, van den Berg-Vos RM, Karas GB, Steyerberg EW, Flach HZ, Marquering HA, Sprengers ME, Jenniskens SF, Beenen LF, van den Berg R, Koudstaal PJ, van Zwam WH, Roos YB, van der Lugt A, van Oostenbrugge RJ, Majoie CB, Dippel DW., MR CLEAN Investigators. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med. 2015 Jan 01;372(1):11-20. [PubMed: 25517348]

21.

McCarthy DJ, Diaz A, Sheinberg DL, Snelling B, Luther EM, Chen SH, Yavagal DR, Peterson EC, Starke RM. Long-Term Outcomes of Mechanical Thrombectomy for Stroke: A Meta-Analysis. ScientificWorldJournal. 2019;2019:7403104. [PMC free article: PMC6521543] [PubMed: 31186620]

22.

Goyal M, Demchuk AM, Menon BK, Eesa M, Rempel JL, Thornton J, Roy D, Jovin TG, Willinsky RA, Sapkota BL, Dowlatshahi D, Frei DF, Kamal NR, Montanera WJ, Poppe AY, Ryckborst KJ, Silver FL, Shuaib A, Tampieri D, Williams D, Bang OY, Baxter BW, Burns PA, Choe H, Heo JH, Holmstedt CA, Jankowitz B, Kelly M, Linares G, Mandzia JL, Shankar J, Sohn SI, Swartz RH, Barber PA, Coutts SB, Smith EE, Morrish WF, Weill A, Subramaniam S, Mitha AP, Wong JH, Lowerison MW, Sajobi TT, Hill MD., ESCAPE Trial Investigators. Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med. 2015 Mar 12;372(11):1019-30. [PubMed: 25671798]

23.

Settecase F, McCoy DB, Darflinger R, Alexander MD, Cooke DL, Dowd CF, Hetts SW, Higashida RT, Halbach VV, Amans MR. Improving mechanical thrombectomy time metrics in the angiography suite: Stroke cart, parallel workflows, and conscious sedation. Interv Neuroradiol. 2018 Apr;24(2):168-177. [PMC free article: PMC5847005] [PubMed: 29145742]

Disclosure: Shibin Mathews declares no relevant financial relationships with ineligible companies.

Disclosure: Orlando De Jesus declares no relevant financial relationships with ineligible companies.