Targeting the Clot in Acute Stroke

Lövblad, Karl‐Olof

doi:10.3174/ajnr.a5600

Cited by 6 publications

(7 citation statements)

References 7 publications

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“…The composition and physical properties of the clot can play a key role in the response to MT. 9,[23][24][25] We observed a stronger advantage of fast over slow retrieval with fibrin-rich clots. These clots probably account for a large part of MT failures because they are firm and sticky.…”

Section: Discussionmentioning

confidence: 73%

“…9,23,24 Fast retrieval, by mobilizing the clot suddenly, may have contributed to better clot trapping. Because imaging features of fibrin-rich thrombi are correlated with decreased revascularization rates, 25,26 a fast retrieval might be recommended in such cases, to enhance first-pass revascularization. This is all the more important in that there is the potential for thrombus compression and increasing difficulty of subsequent retrieval after each thrombectomy attempt.…”

Section: Discussionmentioning

confidence: 99%

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Fast Stent Retrieval Improves Recanalization Rates of Thrombectomy: Experimental Study on Different Thrombi

Soize

Mirza²,

Gunning³

et al. 2020

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE: About 20% of patients with acute ischemic stroke due to large-artery occlusion do not achieve recanalization with mechanical thrombectomy. We aimed to determine whether the speed of retrieval of the stent retriever influences the efficacy in removing different clot types.MATERIALS AND METHODS: Sixty mechanical thrombectomies were performed using an in vitro pulsatile cerebrovascular circulation model with controlled pressure and flow rate. Experiments were dichotomized into fast and slow retrieval using a wedging technique, in which the stent retriever and distal catheter are retrieved together. We used 3 different clot types: erythrocyte-rich, fibrin-rich, and friable clots. Primary end points were complete (TICI 3) and successful (TICI 2b-3) recanalizations. Secondary measures were distal and new territory embolizations.RESULTS: Fast retrieval was more frequently associated with complete (RR ¼ 1.83; 95% CI, 1.12-2.99) and successful recanalization (RR ¼ 1.50; 95% CI, 1.03-2.19) than slow retrieval, without a difference in distal embolization (RR ¼ 0.75; 95% CI, 0.29-1.90). There were no emboli in a new territory. The advantage of fast retrieval over slow retrieval differed according to the clot composition, with a stronger effect with fibrin-rich clots with regard to complete (RR ¼ 4.00; 95% CI, 1.11-14.35; Pint ¼ .04) and successful (Pint ¼ .10) recanalization. CONCLUSIONS:In our experimental model, a fast removal improved recanalization rates of mechanical thrombectomy, especially in the case of fibrin-rich clots. An in vivo confirmation is warranted to see whether our findings can have an impact in clinical practice. ABBREVIATIONS: DC ¼ distal catheter; MT ¼ mechanical thrombectomy; RR ¼ relative risk; Pint ¼ P interaction; RBC ¼ red blood cell; SR ¼ stent retriever M echanical thrombectomy (MT) is considered the first-line therapy for selected patients with acute ischemic stroke with a proximal cerebral artery occlusion. [1][2][3] The dramatic technological improvements, such as the combined use of stent retrievers (SRs) and distal catheters (DCs), have led to recanalization rates unreached before. 4,5 With the goal of increasing clot entrapment, techniques in which the thrombus is wedged between the SR and DC have become more popular. [6][7][8] Nevertheless, a successful

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Section: Discussionmentioning

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Fast Stent Retrieval Improves Recanalization Rates of Thrombectomy: Experimental Study on Different Thrombi

Soize

Mirza²,

Gunning³

et al. 2020

AJNR Am J Neuroradiol

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“…After 48 hours, the patients showed delayed positive findings on follow-up images. 20 This indicates that the initial ischemic change due to distal VA occlusion was not sufficient to be detected on early DWI images, but the lesion eventually developed over time and showed positive findings on later DWI images. Patients with delayed positive findings of the medulla on DWI were closely associated with early MR examination after symptom onset.…”

Section: Discussionmentioning

confidence: 96%

“…We also observed false-negative results on initial DWI in 7 patients (25.0%) with symptomatic medulla stroke. After 48 hours, the patients showed delayed positive findings on follow-up images [ 20 ]. This indicates that the initial ischemic change due to distal VA occlusion was not sufficient to be detected on early DWI images, but the lesion eventually developed over time and showed positive findings on later DWI images.…”

Section: Discussionmentioning

confidence: 99%

Strong Contrast Stagnation of Unilateral Vertebral Artery on Three-Dimensional Black Blood-Enhanced MRI Predicts Acute Medulla Infarction

et al. 2023

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Purpose: This study aimed to evaluate angiographic and contrast enhancement (CE) patterns on three-dimensional (3D) black blood (BB) contrast-enhanced MRI in patients with acute medulla infarction.Materials and Methods: From January 2020 to August 2021, we retrospectively analyzed stroke 3D BB contrast-enhanced magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) findings of patients visiting the emergency room for symptom evaluation of acute medulla infarction. In total, 28 patients with acute medulla infarction were enrolled in this study. Four types of 3D BB contrast-enhanced MRI and MRA were classified as follows: 1=unilateral contrast-enhanced vertebral artery (VA)+no visualization of VA on MRA; 2=unilateral enhanced VA+hypoplastic VA; 3=no enhanced VA+unilateral complete occlusion of VA; 4=no enhanced VA+normal VA (including hypoplasia) on MRA.Results: Of the 28 patients with acute medulla infarction, 7 (25.0%) showed delayed positive findings after 24 hours on diffusion-weighted imaging (DWI). Of these patients, 19 (67.9%) showed CE of the unilateral VA on 3D BB contrast-enhanced MRI (type 1 and 2). Of the 19 patients with CE of VA on 3D BB contrast-enhanced MRI, 18 showed no visualization of enhanced VA on MRA (type 1), and 1 showed hypoplastic VA. Of the 7 patients with delayed positive findings on DWI, 5 showed CE of the unilateral VA and no visualization of the enhanced VA on MRA (type 1). Symptom onset to door time or initial MR check time was significantly shorter in the groups with delayed positive findings on DWI (P<0.05).Conclusion: Unilateral CE on 3D BB contrast-enhanced MRI and no visualization of the VA on MRA are related to the recent occlusion of the distal VA. These findings suggest that the recent occlusion of the distal VA is related to acute medulla infarction, including delayed visualization on DWI.

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“…Despite significant advances, three quarters of procedures require two or more retrieval attempts, and 20% of EVT procedures fail 2 3. While the precise reasons for EVT failure remain poorly understood, there is mounting evidence that thrombus composition is a key factor influencing repeat thrombectomy maneuvers and consequent treatment failure 3–13. Recent clinical and in vitro data suggest that fibrin/platelet-rich thrombi are more resistant to thrombectomy and lead to poorer revascularization outcomes,3 9 while red blood cell (RBC)-rich thrombi are associated with a reduced number of recanalization maneuvers which in turn yields better clinical outcomes 14–18.…”

Section: Introductionmentioning

confidence: 99%

Impedance-based sensors discriminate among different types of blood thrombi with very high specificity and sensitivity

Messina¹,

Garcia

Rambeau

et al. 2022

J NeuroIntervent Surg

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BackgroundIntracranial occlusion recanalization fails in 20% of endovascular thrombectomy procedures, and thrombus composition is likely to be an important factor. In this study, we demonstrate that the combination of electrical impedance spectroscopy (EIS) and machine learning constitutes a novel and highly accurate method for the identification of different human thrombus types.Methods134 samples, subdivided into four categories, were analyzed by EIS: 29 ‘White’, 26 ‘Mixed’, 12 ‘Red’ thrombi, and 67 liquid ‘Blood’ samples. Thrombi were generated in vitro using citrated human blood from five healthy volunteers. Histological analysis was performed to validate the thrombus categorization based on red blood cell content. A machine learning prediction model was trained on impedance data to differentiate blood samples from any type of thrombus and in between the four sample categories.ResultsHistological analysis confirmed the similarity between the composition of in vitro generated thrombi and retrieved human thrombi. The prediction model yielded a sensitivity/specificity of 90%/99% for distinguishing blood samples from thrombi and a global accuracy of 88% for differentiating among the four sample categories.ConclusionsCombining EIS measurements with machine learning provides a highly effective approach for discriminating among different thrombus types and liquid blood. These findings raise the possibility of developing a probe-like device (eg, a neurovascular guidewire) integrating an impedance-based sensor. This sensor, placed in the distal part of the smart device, would allow the characterization of the probed thrombus on contact. The information could help physicians identify optimal thrombectomy strategies to improve outcomes for stroke patients.

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Targeting the Clot in Acute Stroke

Cited by 6 publications

References 7 publications

Fast Stent Retrieval Improves Recanalization Rates of Thrombectomy: Experimental Study on Different Thrombi

Fast Stent Retrieval Improves Recanalization Rates of Thrombectomy: Experimental Study on Different Thrombi

Strong Contrast Stagnation of Unilateral Vertebral Artery on Three-Dimensional Black Blood-Enhanced MRI Predicts Acute Medulla Infarction

Impedance-based sensors discriminate among different types of blood thrombi with very high specificity and sensitivity

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