Editing Thrombectomy

{{short description|Removal of a blood clot from a blood vessel}}
{{Use American English|date=August 2024}}
{{Use mdy dates|date=August 2024}}
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'''Mechanical thrombectomy''', or simply '''thrombectomy''', is the removal of a [[blood clot]] (thrombus) from a [[blood vessel]], often and especially [[endovascular]]ly as an [[interventional radiology]] procedure called '''endovascular thrombectomy''' ('''EVT'''). It thus contrasts with [[thrombolysis]] (clot dissolution) by thrombolytic [[medication]]s (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 [[stroke#Ischemic|ischemic strokes]] (i.e., those in which the blockage is a suitable candidate for such retrieval).<!--only 10%-15%, according to ref Holland-2023-03-01 cited herein, but in that subset it is very important and worthwhile--> 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.<ref>{{cite journal |last1=Saver |first1=Jeffrey L. |last2=Goyal |first2=Mayank |last3=Bonafe |first3=Alain |last4=Diener |first4=Hans-Christoph |last5=Levy |first5=Elad I. |last6=Pereira |first6=Vitor M. |last7=Albers |first7=Gregory W. |last8=Cognard |first8=Christophe |last9=Cohen |first9=David J. |last10=Hacke |first10=Werner |last11=Jansen |first11=Olav |last12=Jovin |first12=Tudor G. |last13=Mattle |first13=Heinrich P. |last14=Nogueira |first14=Raul G. |last15=Siddiqui |first15=Adnan H. |last16=Yavagal |first16=Dileep R. |last17=Baxter |first17=Blaise W. |last18=Devlin |first18=Thomas G. |last19=Lopes |first19=Demetrius K. |last20=Reddy |first20=Vivek K. |last21=du Mesnil de Rochemont |first21=Richard |last22=Singer |first22=Oliver C. |last23=Jahan |first23=Reza |title=Stent-Retriever Thrombectomy after Intravenous t-PA vs. t-PA Alone in Stroke |journal=New England Journal of Medicine |date=11 June 2015 |volume=372 |issue=24 |pages=2285–2295 |doi=10.1056/NEJMoa1415061 |pmid=25882376 |url=https://boris.unibe.ch/69540/1/Saver-2015-Stent-Retriever%20Thrombectomy%20after.pdf }}</ref>

== 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.

=== History ===
The world's first thrombectomy (in case of blood clot in the brain) was performed in 1994 at Sahlgrenska University Hospital, Gothenburg, Sweden by senior physician Gunnar Wikholm.<ref>{{cite journal |last1=Wikholm |first1=Gunnar |last2= |first2= |title=Transarterial Embolectomy in Acute Stroke |journal=American Journal of Neuroradiology |date=1 May 2003|volume=24 |issue= 5|pages= 892-894|doi= |pmid= |pmc= }}</ref><ref>{{cite journal |last1=Rentzos |first1=Aleandros |last2=Wikholm |first2=Gunnar |title=Embolectomy for Acute Ischemic Stroke in the Anterior Cerebral Circulation: The Gothenburg Experience during 2000-2011 |journal=American Journal of Neuroradiology |date=October 2014|volume=35 |issue=10 |pages= 1936-1941|doi=10.3174/ajnr.A3997 |pmid= |pmc=7966239 }}</ref>

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.<ref name="Holland-2023-03-01">{{cite news |last1=Holland |first1=Eva |title=This Revolutionary Stroke Treatment Will Save Millions of Lives. Eventually. |url=https://www.nytimes.com/2023/03/01/magazine/evt-stroke-treatment.html |access-date=1 March 2023 |work=The New York Times |date=1 March 2023}}</ref> Large obstacles to making EVT more widely available are both systematic hurdles at the prehospital stages<ref name="Holland-2023-03-01"/> and the intrahospital barrier of a scarcity of interventional neuroradiologists.<ref name="Holland-2023-03-01"/><ref name="Moore-2022-07-27"/> They concern TTR (time to reperfusion), which is the same underlying problem as the [[golden hour (medicine)|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 [[sequela|sequelae]] of the ischemia.<ref name="Holland-2023-03-01"/> 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),<ref name="Holland-2023-03-01"/> but it is not easy to revamp the standard of care in prehospital settings (such as [[FAST (stroke)|awareness among family members and bystanders]], optimal techniques for [[emergency medical services]], and so on),<ref name="Holland-2023-03-01"/> which deployment of timely EVT requires.<ref name="Holland-2023-03-01"/>

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.<ref>{{cite journal |last1=Albers |first1=Gregory W. |last2=Marks |first2=Michael P. |last3=Kemp |first3=Stephanie |last4=Christensen |first4=Soren |last5=Tsai |first5=Jenny P. |last6=Ortega-Gutierrez |first6=Santiago |last7=McTaggart |first7=Ryan A. |last8=Torbey |first8=Michel T. |last9=Kim-Tenser |first9=May |last10=Leslie-Mazwi |first10=Thabele |last11=Sarraj |first11=Amrou |last12=Kasner |first12=Scott E. |last13=Ansari |first13=Sameer A. |last14=Yeatts |first14=Sharon D. |last15=Hamilton |first15=Scott |last16=Mlynash |first16=Michael |last17=Heit |first17=Jeremy J. |last18=Zaharchuk |first18=Greg |last19=Kim |first19=Sun |last20=Carrozzella |first20=Janice |last21=Palesch |first21=Yuko Y. |last22=Demchuk |first22=Andrew M. |last23=Bammer |first23=Roland |last24=Lavori |first24=Philip W. |last25=Broderick |first25=Joseph P. |last26=Lansberg |first26=Maarten G. |title=Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging |journal=[[New England Journal of Medicine]] |date=22 February 2018 |volume=378 |issue=8 |pages=708–718 |doi=10.1056/NEJMoa1713973 |pmid=29364767 |pmc=6590673 }}</ref><ref>{{cite journal |last1=Nogueira |first1=Raul G. |last2=Jadhav |first2=Ashutosh P. |last3=Haussen |first3=Diogo C. |last4=Bonafe |first4=Alain |last5=Budzik |first5=Ronald F. |last6=Bhuva |first6=Parita |last7=Yavagal |first7=Dileep R. |last8=Ribo |first8=Marc |last9=Cognard |first9=Christophe |last10=Hanel |first10=Ricardo A. |last11=Sila |first11=Cathy A. |last12=Hassan |first12=Ameer E. |last13=Millan |first13=Monica |last14=Levy |first14=Elad I. |last15=Mitchell |first15=Peter |last16=Chen |first16=Michael |last17=English |first17=Joey D. |last18=Shah |first18=Qaisar A. |last19=Silver |first19=Frank L. |last20=Pereira |first20=Vitor M. |last21=Mehta |first21=Brijesh P. |last22=Baxter |first22=Blaise W. |last23=Abraham |first23=Michael G. |last24=Cardona |first24=Pedro |last25=Veznedaroglu |first25=Erol |last26=Hellinger |first26=Frank R. |last27=Feng |first27=Lei |last28=Kirmani |first28=Jawad F. |last29=Lopes |first29=Demetrius K. |last30=Jankowitz |first30=Brian T. |last31=Frankel |first31=Michael R. |last32=Costalat |first32=Vincent |last33=Vora |first33=Nirav A. |last34=Yoo |first34=Albert J. |last35=Malik |first35=Amer M. |last36=Furlan |first36=Anthony J. |last37=Rubiera |first37=Marta |last38=Aghaebrahim |first38=Amin |last39=Olivot |first39=Jean-Marc |last40=Tekle |first40=Wondwossen G. |last41=Shields |first41=Ryan |last42=Graves |first42=Todd |last43=Lewis |first43=Roger J. |last44=Smith |first44=Wade S. |last45=Liebeskind |first45=David S. |last46=Saver |first46=Jeffrey L. |last47=Jovin |first47=Tudor G. |title=Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct |journal=[[New England Journal of Medicine]] |date=4 January 2018 |volume=378 |issue=1 |pages=11–21 |doi=10.1056/NEJMoa1706442 |pmid=29129157 |doi-access=free }}</ref> Most studies, however, have focused on thrombectomies in anterior circulation strokes. In recent years, increasing evidence on the efficacy of mechanical thrombectomy in posterior circulation strokes has been published.<ref>{{Cite journal|last1=Klail|first1=Tomas |last2=Piechowiak|first2=Eike I.|last3=Krug|first3=Nadja|last4=Maegerlein|first4=Christian|last5=Volker|first5=Maus|last6=Fischer|first6=Sebastian|last7=Lobsien|first7=Donald|last8=Pielenz|first8=Daniel|last9=Styczen|first9=Hanna|last10=Deuschl|first10=Cornelius|last11=Thormann|first11=Maximilian|last12=Diamandis|first12=Elie|last13=Heldner|first13=Mirjam R.|last14=Kaesmacher|first14=Johannes|last15=Mordasini|first15=Pasquale|date=April 2024|title=Endovascular revascularization of vertebrobasilar tandem occlusions in comparison to isolated basilar artery occlusions: A multi-center experience|journal=Interventional Neuroradiology |language=en|doi=10.1177/15910199241240045|pmid=38576395|pmc=11571482}}</ref>

=== 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.{{fact|date=June 2019}}

=== 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.{{fact|date=June 2019}}

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.{{fact|date=June 2019}}

==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 neurointerventionalists.<ref name="Moore-2022-07-27">{{cite news |last=Moore |first=Alison |title=Londoners several times more likely to get life-saving treatment |url=https://www.hsj.co.uk/quality-and-performance/londoners-several-times-more-likely-to-get-life-saving-treatment/7032878.article? |access-date=28 September 2022 |publisher=Health Service Journal |date=27 July 2022}}</ref>

== See also ==
* [[Stroke]]
* [[Embolectomy]]
* [[Pulmonary thromboendarterectomy]]

== References ==
{{Reflist}}

== External links ==

* [https://radiopaedia.org/articles/mechanical-thrombectomy-for-acute-ischaemic-stroke Endovascular clot retrieval, Radiopaedia.org, May 2024]
* [https://masterandfellow.com/video/616ede204e703 Failed thrombectomy]

[[Category:Neurology procedures]]
[[Category:Vascular procedures]]