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Targeting the Clot in Acute Stroke

Targeting the Clot in Acute Stroke LETTERS ecent stroke trials have undeniably shown that thrombec- due to its sensitivity for hemorrhage. The dense artery sign is a Rtomy is not just a safe method for treating acute stroke but well-established sign of acute occlusion that corresponds to the 1,2 also can extend the accepted time window considerably. While presence of an occluding clot. The morphology and direction of most imaging techniques have rightly focused on first detecting the clot and the associated vessel morphology can be assessed by hemorrhage or other sources of potential stroke mimics or the CTA; however, more exact information on clot composition eventuality of cerebral hypoperfusion amenable to restoration might be extracted by further evaluation of the imaging charac- 5,6 through vascular techniques, very little research has focused on teristics of the clot. Indeed, relatively simple measures of den- the thrombus itself. This is strange because it is the thrombus that sity could be helpful, but it may be difficult to differentiate high has been the target of both pharmaceutical and interventional density due to red blood hemoglobin content from calcific therapies because it is known to be the cause of the event. Imaging changes. Therefore, additional measurements such as postcontrast techniques such as CT perfusion and MR perfusion readily doc- images to assess eventual porosity or investigate calcification with ument the presence or absence of areas of perturbed perfusion dual-energy CT could quickly provide additional findings to help that may be larger or smaller than expected, but these techniques show clot composition that would guide an improved choice for would require a successful neuroprotective agent to fulfill their thrombectomy-device selection. As with any imaging technique cho- promises as techniques for full revascularization. sen to assess stroke, this will only provide another part of the infor- Currently, imaging needs to just demonstrate the absence of mation needed and is not a solution but could provide insight into a hemorrhagic event and the presence of a clot for a decision to clot composition to guide therapy. Also, as with most other imaging proceed to the angiography room. While the large-scale imple- techniques, it should not interfere by prolonging unnecessary imag- mentation of clot extraction using interventional techniques has ing time and thus time to therapeutic decision. allowed major advances with major improvement in clinical out- comes with fewer hemorrhages, selecting the right device for the right occlusion type will play a more important role. On the one REFERENCES hand, as has been the case with aneurysm treatment-planning, 1. Jovin TG, Chamorro A, Cobo E, et al; REVASCAT Trial Investigators. probably the clot location and thus its orientation will have an Thrombectomy within 8 hours after symptom onset in ischemic impact on the choice of catheters; it is also possible that looking at stroke. N Engl J Med 2015;372:2296–306 CrossRef Medline 2. Nogueira RG, Jadhav AP, Haussen DC, et al; DAWN Trial Investiga- the clot itself and trying to deduce its composition could be help- tors. Thrombectomy 6 to 24 hours after stroke with a mismatch be- ful for deciding which patients undergo which therapy. Indeed, if tween deficit and infarct. N Engl J Med 2018;378:11–21 CrossRef a clot is more calcific, more fibrinous, or contains more blood Medline cells, the management types may differ because the consistency 3. Liu H, Mei W, Huang Y, et al. Susceptibility vessel sign predicts poor will have an impact on retrieval and eventually on distal migration clinical outcome for acute stroke patients untreated by thromboly- that might occur during the procedure. While in vitro studies may sis. Exp Ther Med 2017;14:5207–13 CrossRef Medline 4. Bouchez L, Sztajzel R, Vargas MI, et al. CT imaging selection in acute indeed be helpful to determine clot composition, determining the stroke. Eur J Radiol 2017;96:153–61 CrossRef Medline exact morphology and consistency of the clot will be necessary. 5. Bouchez L, Lovblad KO, Kulcsar Z. Pretherapeutic characterization Indeed, some data are also available for MR imaging with the of the clot in acute stroke. J Neuroradiol 2016;43:163– 66 CrossRef susceptibility vessel sign, which demonstrates high erythrocyte Medline content. Using modern CT techniques may be a way to further 6. Bouchez L, Altrichter S, Pellaton A, et al. Can clot density predict recanalization in acute ischemic stroke treated with intravenous characterize these clots: Indeed, CT is, currently, the preferred tPA? Clinical and Translational Neuroscience 2017;1:1–6 CrossRef technique of choice for the first evaluation of a patient with stroke, X K.-O. Lo¨vblad Division of Diagnostic and Interventional Neuroradiology Geneva University Hospitals http://dx.doi.org/10.3174/ajnr.A5600 Geneva, Switzerland AJNR Am J Neuroradiol 39:E77 Jun 2018 www.ajnr.org E77 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png American Journal of Neuroradiology American Journal of Neuroradiology

Targeting the Clot in Acute Stroke

Lövblad, K.-O.
American Journal of Neuroradiology , Volume 39 (6) – Jun 1, 2018
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References (8)

Publisher
American Journal of Neuroradiology
ISSN
0195-6108
eISSN
1936-959X
DOI
10.3174/ajnr.A5600
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Abstract

LETTERS ecent stroke trials have undeniably shown that thrombec- due to its sensitivity for hemorrhage. The dense artery sign is a Rtomy is not just a safe method for treating acute stroke but well-established sign of acute occlusion that corresponds to the 1,2 also can extend the accepted time window considerably. While presence of an occluding clot. The morphology and direction of most imaging techniques have rightly focused on first detecting the clot and the associated vessel morphology can be assessed by hemorrhage or other sources of potential stroke mimics or the CTA; however, more exact information on clot composition eventuality of cerebral hypoperfusion amenable to restoration might be extracted by further evaluation of the imaging charac- 5,6 through vascular techniques, very little research has focused on teristics of the clot. Indeed, relatively simple measures of den- the thrombus itself. This is strange because it is the thrombus that sity could be helpful, but it may be difficult to differentiate high has been the target of both pharmaceutical and interventional density due to red blood hemoglobin content from calcific therapies because it is known to be the cause of the event. Imaging changes. Therefore, additional measurements such as postcontrast techniques such as CT perfusion and MR perfusion readily doc- images to assess eventual porosity or investigate calcification with ument the presence or absence of areas of perturbed perfusion dual-energy CT could quickly provide additional findings to help that may be larger or smaller than expected, but these techniques show clot composition that would guide an improved choice for would require a successful neuroprotective agent to fulfill their thrombectomy-device selection. As with any imaging technique cho- promises as techniques for full revascularization. sen to assess stroke, this will only provide another part of the infor- Currently, imaging needs to just demonstrate the absence of mation needed and is not a solution but could provide insight into a hemorrhagic event and the presence of a clot for a decision to clot composition to guide therapy. Also, as with most other imaging proceed to the angiography room. While the large-scale imple- techniques, it should not interfere by prolonging unnecessary imag- mentation of clot extraction using interventional techniques has ing time and thus time to therapeutic decision. allowed major advances with major improvement in clinical out- comes with fewer hemorrhages, selecting the right device for the right occlusion type will play a more important role. On the one REFERENCES hand, as has been the case with aneurysm treatment-planning, 1. Jovin TG, Chamorro A, Cobo E, et al; REVASCAT Trial Investigators. probably the clot location and thus its orientation will have an Thrombectomy within 8 hours after symptom onset in ischemic impact on the choice of catheters; it is also possible that looking at stroke. N Engl J Med 2015;372:2296–306 CrossRef Medline 2. Nogueira RG, Jadhav AP, Haussen DC, et al; DAWN Trial Investiga- the clot itself and trying to deduce its composition could be help- tors. Thrombectomy 6 to 24 hours after stroke with a mismatch be- ful for deciding which patients undergo which therapy. Indeed, if tween deficit and infarct. N Engl J Med 2018;378:11–21 CrossRef a clot is more calcific, more fibrinous, or contains more blood Medline cells, the management types may differ because the consistency 3. Liu H, Mei W, Huang Y, et al. Susceptibility vessel sign predicts poor will have an impact on retrieval and eventually on distal migration clinical outcome for acute stroke patients untreated by thromboly- that might occur during the procedure. While in vitro studies may sis. Exp Ther Med 2017;14:5207–13 CrossRef Medline 4. Bouchez L, Sztajzel R, Vargas MI, et al. CT imaging selection in acute indeed be helpful to determine clot composition, determining the stroke. Eur J Radiol 2017;96:153–61 CrossRef Medline exact morphology and consistency of the clot will be necessary. 5. Bouchez L, Lovblad KO, Kulcsar Z. Pretherapeutic characterization Indeed, some data are also available for MR imaging with the of the clot in acute stroke. J Neuroradiol 2016;43:163– 66 CrossRef susceptibility vessel sign, which demonstrates high erythrocyte Medline content. Using modern CT techniques may be a way to further 6. Bouchez L, Altrichter S, Pellaton A, et al. Can clot density predict recanalization in acute ischemic stroke treated with intravenous characterize these clots: Indeed, CT is, currently, the preferred tPA? Clinical and Translational Neuroscience 2017;1:1–6 CrossRef technique of choice for the first evaluation of a patient with stroke, X K.-O. Lo¨vblad Division of Diagnostic and Interventional Neuroradiology Geneva University Hospitals http://dx.doi.org/10.3174/ajnr.A5600 Geneva, Switzerland AJNR Am J Neuroradiol 39:E77 Jun 2018 www.ajnr.org E77

Journal

American Journal of Neuroradiology – American Journal of Neuroradiology

Published: Jun 1, 2018

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