Thrombectomy

Last updated November 09, 2023

Mechanical thrombectomy, or simply thrombectomy, is the removal of a blood clot (thrombus) from a blood vessel, often and especially endovascularly as an interventional radiology procedure called endovascular thrombectomy (EVT). It thus contrasts with thrombolysis (clot dissolution) by thrombolytic medications (e.g., alteplase, reteplase), as either alternative or complement thereto. It is commonly performed in the cerebral arteries (interventional neuroradiology) as treatment to reverse the ischemia in some ischemic strokes (i.e., those in which the blockage is a suitable candidate for such retrieval). Open vascular surgery versions of thrombectomy also exist. The effectiveness of thrombectomy for strokes was confirmed in several randomised clinical trials conducted at various medical centers throughout the United States, as reported in a seminal multistudy report in 2015.^[1]

Applications in brain

Ischemic stroke represents the fifth most common cause of death in the western world and the number one cause of long-term disability. Until recent times, systemic intravenous fibrinolysis was the only evidence-based therapy for patients with acute onset of stroke due to large vessel occlusion.

In 2015, the results of five trials from different countries were published in the New England Journal of Medicine , demonstrating the safety and efficacy of mechanical thrombectomy with stent-retrievers in improving outcomes and reducing mortality for patients who present within six hours from their time last known well. It is now a widespread procedure performed in many hospitals around the globe, especially comprehensive stroke centers, although many other hospitals are not yet able to supply the service enough to meet the need.^[2] Large obstacles to making EVT more widely available are both systematic hurdles at the prehospital stages^[2] and the intrahospital barrier of a scarcity of interventional neuroradiologists.^[2]^[3] They concern TTR (time to reperfusion), which is the same underlying problem as the golden hour in general, albeit several hours in the case of TTR: that is, EVT performed within 2 or 3 hours can help vastly, whereas EVT performed after 6 to 12 hours is often (although not always) too late to prevent the permanent sequelae of the ischemia.^[2] In this respect, the dissemination of EVT into clinical practice shows how translational medicine has various layers, some easier to solve and some harder: it was in some respects straightforward to develop the technology of EVT in the 2000s and 2010s (that is, the catheter tips and procedures),^[2] but it is not easy to revamp the standard of care in prehospital settings (such as awareness among family members and bystanders, optimal techniques for emergency medical services, and so on),^[2] which deployment of timely EVT requires.^[2]

In 2018 the DAWN and DEFUSE-3 trials were published. These trials showed that mechanical thrombectomy is a safe and effective treatment for individuals who have an acute ischemic stroke, even (in some cases) out to 24 hours after symptom onset.^[4]^[5]

Stent-retriever thrombectomy

The procedure can be performed with general anesthesia or under conscious sedation in an angiographic room. A system of coaxial catheters is pushed inside the arterial circulation, usually through a percutaneous access to the right femoral artery. A microcatheter is finally positioned beyond the occluded segment and a stent-retriever is deployed to catch the thrombus; finally, the stent is pulled out from the artery, usually under continuous aspiration in the larger catheters.^{[ citation needed ]}

Direct aspiration

A different technique for mechanical thrombectomy in the brain is direct aspiration. It is performed by pushing a large soft aspiration catheter into the occluded vessel and applying direct aspiration to retrieve the thrombus; it can be combined with the stent-retriever technique to achieve higher recanalization rates, but the complexity of the procedure increases.^{[ citation needed ]}

Direct aspiration has not been studied as thoroughly as stent-retriever thrombectomy, but it is still widely performed because of its relative simplicity and low cost.^{[ citation needed ]}

Delivery

Patients in London who suffered stroke were found to be much more likely to get thrombectomy in 2022 than those in other parts of England. 42% of thrombectomy units only operated during office hours and Monday to Friday, largely due to a shortage of neuroinerventionalists.^[3]

Related Research Articles

A transient ischemic attack (TIA), commonly known as a mini-stroke, is a minor stroke whose noticeable symptoms usually end in less than an hour. TIA causes the same symptoms associated with strokes, such as weakness or numbness on one side of the body, sudden dimming or loss of vision, difficulty speaking or understanding language, slurred speech, or confusion.

Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets (thrombocytes) and fibrin to form a blood clot to prevent blood loss. Even when a blood vessel is not injured, blood clots may form in the body under certain conditions. A clot, or a piece of the clot, that breaks free and begins to travel around the body is known as an embolus.

Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.

Thrombolysis, also called fibrinolytic therapy, is the breakdown (lysis) of blood clots formed in blood vessels, using medication. It is used in ST elevation myocardial infarction, stroke, and in cases of severe venous thromboembolism.

<span class="mw-page-title-main">Vascular surgery</span> Medical specialty, operative procedures for the treatment of vascular disorders

Vascular surgery is a surgical subspecialty in which vascular diseases involving the arteries, veins, or lymphatic vessels, are managed by medical therapy, minimally-invasive catheter procedures and surgical reconstruction. The specialty evolved from general and cardiovascular surgery where it refined the management of just the vessels, no longer treating the heart or other organs. Modern vascular surgery includes open surgery techniques, endovascular techniques and medical management of vascular diseases - unlike the parent specialities. The vascular surgeon is trained in the diagnosis and management of diseases affecting all parts of the vascular system excluding the coronaries and intracranial vasculature. Vascular surgeons also are called to assist other physicians to carry out surgery near vessels, or to salvage vascular injuries that include hemorrhage control, dissection, occlusion or simply for safe exposure of vascular structures.

Interventional cardiology is a branch of cardiology that deals specifically with the catheter based treatment of structural heart diseases. Andreas Gruentzig is considered the father of interventional cardiology after the development of angioplasty by interventional radiologist Charles Dotter.

A pseudoaneurysm, also known as a false aneurysm, is a locally contained hematoma outside an artery or the heart due to damage to the vessel wall. The injury passes through all three layers of the arterial wall, causing a leak, which is contained by a new, weak "wall" formed by the products of the clotting cascade. A pseudoaneurysm does not contain any layer of the vessel wall.

Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms. It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure.

Alteplase, sold under the brand name Activase among others, is a biosynthetic form of human tissue-type plasminogen activator (t-PA). It is a thrombolytic medication used to treat acute ischemic stroke, acute ST-elevation myocardial infarction, pulmonary embolism associated with low blood pressure, and blocked central venous catheter. It is given by injection into a vein or artery. Alteplase is the same as the normal human plasminogen activator produced in vascular endothelial cells and is synthesized via recombinant DNA technology in Chinese hamster ovary cells (CHO). Alteplase causes the breakdown of a clot by inducing fibrinolysis.

<span class="mw-page-title-main">Cerebral infarction</span> Medical condition

Cerebral infarction is the pathologic process that results in an area of necrotic tissue in the brain. It is caused by disrupted blood supply (ischemia) and restricted oxygen supply (hypoxia), most commonly due to thromboembolism, and manifests clinically as ischemic stroke. In response to ischemia, the brain degenerates by the process of liquefactive necrosis.

<span class="mw-page-title-main">Percutaneous coronary intervention</span> Medical techniques used to manage coronary occlusion

Percutaneous coronary intervention (PCI) is a non-surgical procedure used to treat narrowing of the coronary arteries of the heart found in coronary artery disease. The process involves combining coronary angioplasty with stenting, which is the insertion of a permanent wire-meshed tube that is either drug eluting (DES) or composed of bare metal (BMS). The stent delivery balloon from the angioplasty catheter is inflated with media to force contact between the struts of the stent and the vessel wall, thus widening the blood vessel diameter. After accessing the blood stream through the femoral or radial artery, the procedure uses coronary catheterization to visualise the blood vessels on X-ray imaging. After this, an interventional cardiologist can perform a coronary angioplasty, using a balloon catheter in which a deflated balloon is advanced into the obstructed artery and inflated to relieve the narrowing; certain devices such as stents can be deployed to keep the blood vessel open.

Animal models of ischemic stroke are procedures inducing cerebral ischemia. The aim is the study of basic processes or potential therapeutic interventions in this disease, and the extension of the pathophysiological knowledge on and/or the improvement of medical treatment of human ischemic stroke. Ischemic stroke has a complex pathophysiology involving the interplay of many different cells and tissues such as neurons, glia, endothelium, and the immune system. These events cannot be mimicked satisfactorily in vitro yet. Thus a large portion of stroke research is conducted on animals.

Carotid artery stenting is an endovascular procedure where a stent is deployed within the lumen of the carotid artery to treat narrowing of the carotid artery and decrease the risk of stroke. It is used to treat narrowing of the carotid artery in high-risk patients, when carotid endarterectomy is considered too risky.

Embolectomy is the emergency interventional or surgical removal of emboli which are blocking blood circulation. It usually involves removal of thrombi, and is then referred to as thromboembolectomy or thrombectomy. Embolectomy is an emergency procedure often as the last resort because permanent occlusion of a significant blood flow to an organ leads to necrosis. Other involved therapeutic options are anticoagulation and thrombolysis.

Acute limb ischaemia (ALI) occurs when there is a sudden lack of blood flow to a limb, within 14 days of symptoms onset. It is different from another condition which is more chronic called critical limb ischemia (CLD). CLD is the end stage of peripheral vascular disease where there is still some collateral circulation (alternate circulation pathways} that bring some blood to the distal parts of the limbs. While limbs in both acute and chronic limb ischemia may be pulseless, a chronically ischemic limb is typically warm and pink due to a well-developed collateral artery network and does not need emergency intervention to avoid limb loss.

Interventional neuroradiology (INR) also known as neurointerventional surgery (NIS), endovascular therapy (EVT), endovascular neurosurgery, and interventional neurology is a medical subspecialty of neurosurgery, neuroradiology, intervention radiology and neurology specializing in minimally invasive image-based technologies and procedures used in diagnosis and treatment of diseases of the head, neck, and spine.

The MERCI Retriever is a medical device designed to treat Ischemic Strokes. The name is an acronym for Mechanical Embolus Removal in Cerebral Ischemia. Designed by University of California, Los Angeles in 2001, MERCI was the first device approved in the U.S. to remove blood clots in patients who had acute brain ischemia.

Demetrius Klee Lopes is a cerebrovascular neurosurgeon specializing in neuroendovascular therapy. At Advocate Health, he serves as medical director of the cerebrovascular and neuroendovascular program and is co-director of their stroke program.

Thrombus perviousness is an imaging biomarker which is used to estimate clot permeability from CT imaging. It reflects the ability of artery-occluding thrombi to let fluid seep into and through them. The more pervious a thrombus, the more fluid it lets through. Thrombus perviousness can be measured using radiological imaging routinely performed in the clinical management of acute ischemic stroke: CT scans without intravenous contrast combined with CT scans after intravenously administered contrast fluid. Pervious thrombi may let more blood pass through to the ischemic brain tissue, and/or have a larger contact surface and histopathology more sensitive for thrombolytic medication. Thus, patients with pervious thrombi may have less brain tissue damage by stroke. The value of thrombus perviousness in acute ischemic stroke treatment is currently being researched.

Elad I. Levy is an American neurosurgeon, researcher, and innovator who played a major role in the development and testing of thrombectomy, which improved quality of life and survival of stroke patients. He has focused his career and research on developing evidence based medicine and literature showing the benefits of thrombectomy for the treatment of stroke. He is currently Professor of Neurosurgery and Radiology, and the L. Nelson Hopkins, MD Professor Endowed Chair of the Department of Neurosurgery at the State University of New York at Buffalo (SUNY).

References

↑ Saver, Jeffrey L.; Goyal, Mayank; Bonafe, Alain; Diener, Hans-Christoph; Levy, Elad I.; Pereira, Vitor M.; Albers, Gregory W.; Cognard, Christophe; Cohen, David J.; Hacke, Werner; Jansen, Olav; Jovin, Tudor G.; Mattle, Heinrich P.; Nogueira, Raul G.; Siddiqui, Adnan H.; Yavagal, Dileep R.; Baxter, Blaise W.; Devlin, Thomas G.; Lopes, Demetrius K.; Reddy, Vivek K.; du Mesnil de Rochemont, Richard; Singer, Oliver C.; Jahan, Reza (11 June 2015). "Stent-Retriever Thrombectomy after Intravenous t-PA vs. t-PA Alone in Stroke" (PDF). New England Journal of Medicine. 372 (24): 2285–2295. doi:10.1056/NEJMoa1415061. PMID 25882376.
1 2 3 4 5 6 7 Holland, Eva (1 March 2023). "This Revolutionary Stroke Treatment Will Save Millions of Lives. Eventually". The New York Times. Retrieved 1 March 2023.
1 2 Moore, Alison (27 July 2022). "Londoners several times more likely to get life-saving treatment". Health Service Journal. Retrieved 28 September 2022.
↑ Albers, Gregory W.; Marks, Michael P.; Kemp, Stephanie; Christensen, Soren; Tsai, Jenny P.; Ortega-Gutierrez, Santiago; McTaggart, Ryan A.; Torbey, Michel T.; Kim-Tenser, May; Leslie-Mazwi, Thabele; Sarraj, Amrou; Kasner, Scott E.; Ansari, Sameer A.; Yeatts, Sharon D.; Hamilton, Scott; Mlynash, Michael; Heit, Jeremy J.; Zaharchuk, Greg; Kim, Sun; Carrozzella, Janice; Palesch, Yuko Y.; Demchuk, Andrew M.; Bammer, Roland; Lavori, Philip W.; Broderick, Joseph P.; Lansberg, Maarten G. (22 February 2018). "Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging". New England Journal of Medicine . 378 (8): 708–718. doi:10.1056/NEJMoa1713973. PMC 6590673 . PMID 29364767.
↑ Nogueira, Raul G.; Jadhav, Ashutosh P.; Haussen, Diogo C.; Bonafe, Alain; Budzik, Ronald F.; Bhuva, Parita; Yavagal, Dileep R.; Ribo, Marc; Cognard, Christophe; Hanel, Ricardo A.; Sila, Cathy A.; Hassan, Ameer E.; Millan, Monica; Levy, Elad I.; Mitchell, Peter; Chen, Michael; English, Joey D.; Shah, Qaisar A.; Silver, Frank L.; Pereira, Vitor M.; Mehta, Brijesh P.; Baxter, Blaise W.; Abraham, Michael G.; Cardona, Pedro; Veznedaroglu, Erol; Hellinger, Frank R.; Feng, Lei; Kirmani, Jawad F.; Lopes, Demetrius K.; Jankowitz, Brian T.; Frankel, Michael R.; Costalat, Vincent; Vora, Nirav A.; Yoo, Albert J.; Malik, Amer M.; Furlan, Anthony J.; Rubiera, Marta; Aghaebrahim, Amin; Olivot, Jean-Marc; Tekle, Wondwossen G.; Shields, Ryan; Graves, Todd; Lewis, Roger J.; Smith, Wade S.; Liebeskind, David S.; Saver, Jeffrey L.; Jovin, Tudor G. (4 January 2018). "Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct". New England Journal of Medicine . 378 (1): 11–21. doi: 10.1056/NEJMoa1706442 . PMID 29129157.

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[1] Saver, Jeffrey L.; Goyal, Mayank; Bonafe, Alain; Diener, Hans-Christoph; Levy, Elad I.; Pereira, Vitor M.; Albers, Gregory W.; Cognard, Christophe; Cohen, David J.; Hacke, Werner; Jansen, Olav; Jovin, Tudor G.; Mattle, Heinrich P.; Nogueira, Raul G.; Siddiqui, Adnan H.; Yavagal, Dileep R.; Baxter, Blaise W.; Devlin, Thomas G.; Lopes, Demetrius K.; Reddy, Vivek K.; du Mesnil de Rochemont, Richard; Singer, Oliver C.; Jahan, Reza (11 June 2015). "Stent-Retriever Thrombectomy after Intravenous t-PA vs. t-PA Alone in Stroke" (PDF). New England Journal of Medicine. 372 (24): 2285–2295. doi:10.1056/NEJMoa1415061. PMID 25882376.

[Holland-2023-03-01-2] 1 2 3 4 5 6 7 Holland, Eva (1 March 2023). "This Revolutionary Stroke Treatment Will Save Millions of Lives. Eventually". The New York Times. Retrieved 1 March 2023.

[Moore-2022-07-27-3] 1 2 Moore, Alison (27 July 2022). "Londoners several times more likely to get life-saving treatment". Health Service Journal. Retrieved 28 September 2022.

[4] Albers, Gregory W.; Marks, Michael P.; Kemp, Stephanie; Christensen, Soren; Tsai, Jenny P.; Ortega-Gutierrez, Santiago; McTaggart, Ryan A.; Torbey, Michel T.; Kim-Tenser, May; Leslie-Mazwi, Thabele; Sarraj, Amrou; Kasner, Scott E.; Ansari, Sameer A.; Yeatts, Sharon D.; Hamilton, Scott; Mlynash, Michael; Heit, Jeremy J.; Zaharchuk, Greg; Kim, Sun; Carrozzella, Janice; Palesch, Yuko Y.; Demchuk, Andrew M.; Bammer, Roland; Lavori, Philip W.; Broderick, Joseph P.; Lansberg, Maarten G. (22 February 2018). "Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging". New England Journal of Medicine . 378 (8): 708–718. doi:10.1056/NEJMoa1713973. PMC 6590673 . PMID 29364767.

[5] Nogueira, Raul G.; Jadhav, Ashutosh P.; Haussen, Diogo C.; Bonafe, Alain; Budzik, Ronald F.; Bhuva, Parita; Yavagal, Dileep R.; Ribo, Marc; Cognard, Christophe; Hanel, Ricardo A.; Sila, Cathy A.; Hassan, Ameer E.; Millan, Monica; Levy, Elad I.; Mitchell, Peter; Chen, Michael; English, Joey D.; Shah, Qaisar A.; Silver, Frank L.; Pereira, Vitor M.; Mehta, Brijesh P.; Baxter, Blaise W.; Abraham, Michael G.; Cardona, Pedro; Veznedaroglu, Erol; Hellinger, Frank R.; Feng, Lei; Kirmani, Jawad F.; Lopes, Demetrius K.; Jankowitz, Brian T.; Frankel, Michael R.; Costalat, Vincent; Vora, Nirav A.; Yoo, Albert J.; Malik, Amer M.; Furlan, Anthony J.; Rubiera, Marta; Aghaebrahim, Amin; Olivot, Jean-Marc; Tekle, Wondwossen G.; Shields, Ryan; Graves, Todd; Lewis, Roger J.; Smith, Wade S.; Liebeskind, David S.; Saver, Jeffrey L.; Jovin, Tudor G. (4 January 2018). "Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct". New England Journal of Medicine . 378 (1): 11–21. doi: 10.1056/NEJMoa1706442 . PMID 29129157.

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