Thrombus Length Estimation on Delayed Gadolinium-Enhanced T1

Diagnostic Performance of Carotid Ring Sign on CT-Angiography in Internal Carotid True Occlusion

BACKGROUND

To differentiate between pseudo occlusion (PO) and true occlusion (TO) of internal carotid artery (ICA) is important in thrombectomy treatment planning for patients with acute ischemic stroke. Although delayed contrast filling has been differentiated carotid PO from TO, its application has been limited by the implementations of multiphasic computed tomography angiography. In this study, we hypothesized that carotid ring sign, which is readily acquired from single-phasic CTA, can sufficiently differentiate carotid TO from PO.

METHODS

One thousand four hundred and twenty patients with anterior circulation stroke receiving endovascular therapy were consecutively recruited through a hospital- and web-based registry. Two hundred patients with nonvisualization of the proximal ICA were included in the analysis after a retrospective screening. Diagnosis of PO or TO of the cervical segment of ICA was made based on digital subtraction angiography. Diagnostic performances of carotid ring sign on arterial-phasic CTA and delayed contrast filling on multiphasic computed tomography angiography were evaluated and compared.

RESULTS

One-hundred twelve patients had ICA PO and 88 had TO. Carotid ring sign was more common in patients with TO (70.5% versus 6.3%; P<0.001), whereas delayed contrast filling was more common in PO (94.9% versus 7.7%; P<0.001). The sensitivity and specificity of carotid ring sign in diagnosing carotid TO were 0.70 and 0.94, respectively, whereas sensitivity and specificity of delayed contrast filling was 0.95 and 0.92 in judging carotid PO.

CONCLUSIONS

Carotid ring sign is a potent imaging marker in diagnosing ICA TO. Carotid ring sign could be complementary to delayed contrast filling sign in differentiating TO from PO, in particular in centers with only single-phasic CTA.

Could emergency admission plasma D-dimer level predict first pass effect of stent retriever thrombectomy in acute ischemic stroke?

BACKGROUND

Evidence on plasma biomarkers to identify first pass effect (FPE) in patients with acute ischemic stroke (AIS) with large vessel occlusion (LVO) treated with thrombectomy is limited.

PURPOSE

To evaluate whether plasma D-dimer could predict FPE.

MATERIAL AND METHODS

Consecutive patients with LVO who underwent first-line stent retriever thrombectomy at our center between January 2018 and August 2021 were enrolled. Patients were classified into the FPE (modified Thrombolysis in Cerebral Infarction [mTICI] ≥2c) group or non-FPE (mTICI 0-2b) group based on angiographic outcomes. Logistic regression analysis was performed to determine the predictors of FPE. The overall ability of D-dimer levels in predicting FPE was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

In total, 313 patients were included; 88 (28.1%) patients achieved FPE. Compared to those with non-FPE, patients with FPE had more diabetes mellitus history, lower D-dimer levels, higher clot burden score, a higher proportion of M1 middle cerebral artery, and a higher proportion of main stem occlusion pattern (P <0.05). After adjusting for potential variables, D-dimer levels (OR=0.81, 95% CI=0.52-0.96), clot burden score (OR=1.76, 95% CI=1.38-2.87), and main stem occlusion pattern (OR=1.85, 95% CI=1.19-2.62) remained independently associated with FPE. Based on the ROC analysis, the D-dimer as a predictor for predicting FPE presented with a specificity of 79%, a negative predictive value of 87%, and an area under the curve of 0.761.

CONCLUSION

Low emergency admission plasma D-dimer level is an independent predictor of FPE in patients with AIS treated with stent retriever thrombectomy.

Negative correlation between early recovery and lipoprotein-associated phospholipase A2 levels after intravenous thrombolysis

Objective

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is considered a biomarker for systemic inflammation and the risk of myocardial infarction and stroke. However, little is known about the effect of acute vascular events on marker levels. The purpose of this study was to assess the potential association of early recovery with Lp-PLA2 levels in patients with acute ischemic stroke (AIS) after intravenous thrombolysis (IVT).

Methods

Forty-three consecutive AIS patients who had their first stroke and were hospitalized within 5 hours of the onset of stroke were enrolled. All patients were treated with IVT using alteplase or urokinase. Plasma Lp-PLA2 levels were measured within 24 hours after IVT. Variables that showed a significant association with Lp-PLA2 in univariate analysis were included in the multivariate ordered logistic regression model.

Results

Early recovery was associated with Lp-PLA2 levels after IVT, and Lp-PLA2 levels tended to decrease with increased probability of early recovery. This study is the first to report a negative correlation between early recovery and Lp-PLA2 levels after IVT.

Conclusion

Early recovery after IVT was negatively correlated with Lp-PLA2 A2 levels.

Multiphysics Modelling and Simulation of Thrombolysis via Activated Platelet-Targeted Nanomedicine

PURPOSE

This study establishes a multiphysics simulation platform for both conventional and targeted thrombolysis using tissue plasminogen activator (tPA). Based on our computational results, the effects of therapeutic parameters on the dynamics of thrombolysis and the risk of side effects are investigated.

METHODS

The model extends our previously developed one-dimensional(1D) mathematical models for fibrinolysis by incorporating targeted thrombolysis. It consists of two parts: (i) a coupled mathematical model of systemic pharmacokinetics (PK) and pharmacodynamics (PD) and local PD in a 1D occluded artery, and (ii) a mechanistic model for a targeted thrombolytic system via activated platelet-targeted tPA-loaded nanovesicles (tPA-NV), with model parameters derived from our in vitro experiments. A total of 16 therapeutic scenarios are simulated by varying the clot location and composition as well as the dosing regimen with free tPA or tPA-NV.

RESULTS

Our simulation results indicate that tPA-NV offers several advantages over free tPA for thrombolysis. It reduces systemic exposure of tPA, thereby minimising the risk of bleeding complications. Simulations with different tPA-NV doses reveal that tPA-NV at 10% of the recommended dose can be as effective as the standard regimen with the full recommended dose of free tPA, demonstrating the potential of our tPA-NV as a new thrombolytic strategy with a reduced tPA dose. Moreover, faster recanalisation can be achieved with tPA-NV, especially for platelet-rich(or fibrin-poor) clots.

CONCLUSIONS

Our simulation platform for thrombolysis with well-tuned model parameters can be used to evaluate and optimise treatment regimens of existing and new thrombolytic therapies via benefit/risk assessment under various therapeutic scenarios.

Accelerated sonothrombolysis with Definity in a xenographic porcine cerebral thromboembolism model

Adjuvant ultrasound at 2 MHz with or without an ultrasound contrast agent improves the rate of thrombus resolution by recombinant tissue plasminogen activator (rt-PA) in laboratory and clinical studies. A sub-megahertz approach can further expand this therapy to a subset of patients with an insufficient temporal bone window, improving efficacy in unselected patient populations. The aim of this study was to determine if a clinical ultrasound contrast agent (UCA), Definity, and 220 kHz pulsed ultrasound accelerated rt-PA thrombolysis in a preclinical animal model of vascular occlusion. The effect of Definity and ultrasound on thrombus clearance was first investigated in vitro and subsequently tested in a xenographic porcine cerebral thromboembolism model in vivo. Two different microcatheter designs (end-hole, multi-side-hole) were used to infuse rt-PA and Definity at the proximal edge or directly into clots, respectively. Sonothrombolysis with Definity increased clot mass loss relative to saline or rt-PA alone in vitro, only when rt-PA was administered directly into clots via a multi-side-hole microcatheter. Combined treatment with rt-PA, Definity, and ultrasound in vivo increased the rate of reperfusion up to 45 min faster than clots treated with rt-PA or saline. In this porcine cerebral thromboembolism model employing retracted human clots, 220 kHz ultrasound, in conjunction with Definity increased the probability of early successful reperfusion with rt-PA.

Value of thrombus imaging in predicting the outcomes of patients with large-vessel occlusive strokes after endovascular therapy

BACKGROUND

Acute ischemic stroke leads to serious long-term disability and high mortality, especially in patients with large-vessel occlusive strokes. Nowadays, endovascular therapy is considered as an alternative treatment for these patients. Several studies have used thrombus characteristics based on non-contrast computed tomography (NCCT) and computed tomography angiography (CTA) to predict prognosis in ischemic stroke. We conducted a systematic review to identify potential imaging predictive factors for successful recanalization and improved clinical outcome after endovascular therapy in patients with large-vessel occlusion (LVO) in anterior arterial circulation.

METHODS

The PubMed databases were searched for related studies reported between September 18, 2009, and September 18, 2019.

RESULTS

We selected 11 studies on revascularization and 12 studies on clinical outcome. Patients with thrombus of higher Hounsfield unit (HU), shorter length, higher clot burden score, and increased thrombus permeability may achieve higher recanalization and improved clinical outcome, but the matter is still under debate.

CONCLUSION

Imaging of thrombus can be used as an aseessment tool to predict the outcomes and it needs further studies in the future.

Novel Technique for Detection of Actual Position of Clot During Endovascular Clot Retrieval: Assessment of Microcatheter Withdrawing Angiography

BACKGROUND

When endovascular clot retrievals are performed using a stent retriever and/or an aspiration catheter, identifying the accurate position of a clot is extremely important for a successful immediate recanalization. Herein, we report a new technique called microcatheter withdrawing angiography, which facilitates the identification of the precise position of a clot. The negative shadow appearance of the clot on angiography was referred to as the actual crab claw sign.

METHODS

When a 0.027-inch microcatheter penetrated the clot after inserting a 0.014-inch microwire, selective angiography was conducted using the microcatheter. Simultaneously, the microcatheter was slowly withdrawn with continuous contrast media injection, while the microwire was kept in the distal vessel. The precise position of the clot was found, which was referred to as the actual crab claw sign. Next, we conducted in vitro and in vivo analyses.

RESULTS

The actual crab claw sign could be identified in the vascular model and in actual clinical settings. Therefore the sweet spot of the stent retriever could be set over the clot, and an accurate contact aspiration could be performed using an aspirator.

CONCLUSIONS

Microcatheter withdrawing angiography can help identify the actual crab claw sign. This technique has a higher success rate and faster recanalization than conventional strategy, particularly in challenging cases of unsuccessful recanalization during the first attempt.

Computational simulations of thrombolysis in acute stroke: Effect of clot size and location on recanalisation

Acute ischaemic stroke can be treated by intravenous thrombolysis whereby tissue plasminogen activator (tPA) is infused to dissolve clots that block blood supply to the brain. In this study, we aim to examine the influence of clot location and size on lysis pattern and recanalisation by using a recently developed computational modelling framework for thrombolysis under physiological flow conditions. An image-based patient-specific model is reconstructed which consists of the internal carotid bifurcation with the A1 segment of anterior cerebral arteries and M1 segment of middle cerebral arteries, and the M1 bifurcation containing the M2 segments. By varying the clot size and location, 7 scenarios are simulated mimicking thrombolysis of M1 and M2 occlusions. Our results show that initial breakthrough always occurs along the inner curvature of the occluded cerebral artery, due to prolonged tPA residence time in the recirculation zone. For a given occlusion site, lysis completion time appears to increase almost quadratically with the initial clot volume; whereas for a given clot volume, the simulated M2 occlusions take up to 30% longer for complete lysis compared to the corresponding M1 occlusions.

Does Clot Burden Score on Baseline T2*-MRI Impact Clinical Outcome in Acute Ischemic Stroke Treated with Mechanical Thrombectomy?

Background and Purpose

A long clot, defined by a low (0-6) clot burden score (CBS) assessed by T2*-MR sequence, is associated with worse clinical outcome after intravenous thrombolysis (IVT) for acute ischemic stroke than is a small clot (CBS, 7-10). The added benefit of mechanical thrombectomy (MT) might be higher in patients with long clot. The aim of this pre-specified post hoc analysis of the THRombectomie des Artères CErebrales (THRACE) trial was to assess the association between T2*-CBS, successful recanalization and clinical outcome.

Methods

Of 414 patients randomized in the THRACE trial, 281 patients were included in this analysis. Associations between T2*-CBS and clinical outcome on the modified Rankin Scale (mRS) at 3 months were tested.

Results

High T2*-CBS, i.e., small clot, was associated with a shift toward better outcome on the mRS; proportional odds ratio (POR) per point CBS was 1.19 (95% confidence interval [CI], 1.05 to 1.34) in the whole population, 1.34 (95% CI, 1.13 to 1.59) in IVT group, and 1.04 (95% CI, 0.87 to 1.23) in IVTMT group. After adjustment for baseline prognostic variables, the effect of the full scale T2*-CBS was not statistically significant in the whole population and for the IVTMT group but remains significant for the IVT group (POR, 1.32; 95% CI, 1.11 to 1.58).

Conclusions

A small clot, as assessed using T2*-CBS, is associated with improved outcome and may be used as a prognostic marker. Despite the worst outcome with long clot, the relative benefit of MT over IVT seemed to increase with low T2*-CBS and longer clot.

Pseudo-Occlusion of the Internal Carotid Artery Predicts Poor Outcome After Reperfusion Therapy

Background and Purpose—

This study aimed to evaluate the occurrence rate of the internal carotid artery pseudo-occlusion (ICA-PO) on 4-dimensional–computed tomography angiography and to investigate its relationship with clinical outcome after reperfusion therapy.

Methods—

In this case–control study, we retrospectively reviewed our prospectively collected database for consecutive acute ischemic stroke patients who received reperfusion therapy between June 2009 and February 2017. ICA-PO was defined when the arterial segment was not opacified on peak arterial phase yet was subsequently patent after artery peak phase on 4-dimensional–computed tomography angiography. Poor outcome was defined as 3-month modified Rankin Scale of 4 to 6. Binary logistic regression was used to investigate the relationship of ICA-PO with poor outcome and the rate of reperfusion, respectively.

Results—

A total of 143 patients with isolated middle cerebral artery occlusion were included and 30 (21.0%) had ICA-PO. Patients with ICA-PO were more likely to have poor outcome (80.0% versus 37.2%; P <0.001) and a lower rate of reperfusion (45.8% versus 69.0%; P =0.033) than those without. Binary logistic regression revealed that ICA-PO was independently associated with poor outcome (odds ratio, 7.957; 95% confidence interval, 1.655–34.869; P =0.009) and reperfusion at 24 hours (odds ratio, 0.150; 95% confidence interval, 0.045–0.500; P =0.002) after adjustment. Among patients with no reperfusion, all ICA-PO patients obtained poor outcome, whereas only 45.2% non-PO patients underwent poor outcome ( P =0.001).

Conclusions—

Four dimensional-computed tomography angiography is a useful noninvasive technique to identify ICA-PO. Patients with ICA-PO are prone to undergo poor outcome from reperfusion therapy, especially when reperfusion is not achieved.

Slow Collateral Flow Is Associated with Thrombus Extension in Patients with Acute Large-Artery Occlusion

BACKGROUND AND PURPOSE

It is still poorly understood about the dynamic changes of the thrombus after intravenous thrombolysis and how the remaining thrombus affects clinical outcome in human stroke. Collateral flow was assumed to help to deliver endo/exogenous tissue-type plasminogen activator to the clot. We aimed to analyze the impact of collateral flow on the dynamic changes of the thrombus in patients with acute large-artery occlusion who received intravenous thrombolysis.

MATERIALS AND METHODS

We reviewed consecutive patients with acute ischemic stroke with M1 segment or distal internal carotid artery occlusion who underwent multimodal MR imaging or CT perfusion before and 24 hours after intravenous thrombolysis without recanalization. Patients were divided into 3 groups (thrombus extension, shortening, and no change) according to thrombus-length change between baseline and 24 hours. Collateral flow was measured with arrival time delay and the collateral scoring system. Poor outcome was defined as a 3-month modified Rankin Scale score of ≥3.

RESULTS

Among 51 patients, 18 (35.3%) had thrombus extension, 14 (27%) had thrombus shortening, and 19 (37.3%) had thrombus without change. Arrival time delay was independently associated with thrombus extension (OR = 1.499; 95% CI, 1.053-2.135; P = .025). Similarly, the collateral score on the peak artery phase was independently associated with thrombus extension (OR = 0.456; 95% CI, 0.211-0.984; P = .045), whereas baseline National Institutes of Health Stroke Scale score (OR = 0.768; 95% CI, 0.614-0.961; P = .021) and baseline thrombus length (OR = 1.193; 95% CI, 1.021-1.394; P = .026) were associated with thrombus shortening. All patients with thrombus extension had poor outcomes.

CONCLUSIONS

Slow collateral flow was related to thrombus extension in patients with large-artery occlusion without recanalization after intravenous thrombolysis.

Associations Between Collateral Status and Thrombus Characteristics and Their Impact in Anterior Circulation Stroke

BACKGROUND AND PURPOSE

Thrombus characteristics and collateral score are associated with functional outcome in patients with acute ischemic stroke. It has been suggested that they affect each other. The aim of this study is to evaluate the association between clot burden score, thrombus perviousness, and collateral score and to determine whether collateral score influences the association of thrombus characteristics with functional outcome.

METHODS

Patients with baseline thin-slice noncontrast computed tomography and computed tomographic angiography images from the MR CLEAN trial (Multicenter Randomized Clinical Trial of Endovascular Treatment of Acute Ischemic Stroke in the Netherlands) were included (n=195). Collateral score and clot burden scores were determined on baseline computed tomographic angiography. Thrombus attenuation increase was determined by comparing thrombus density on noncontrast computed tomography and computed tomographic angiography using a semiautomated method. The association of collateral score with clot burden score and thrombus attenuation increase was evaluated with linear regression. Mediation and effect modification analyses were used to assess the influence of collateral score on the association of clot burden score and thrombus attenuation increase with functional outcome.

RESULTS

A higher clot burden score (B=0.063; 95% confidence interval, 0.008-0.118) and a higher thrombus attenuation increase (B=0.014; 95% confidence interval, 0.003-0.026) were associated with higher collateral score. Collateral score mediated the association of clot burden score with functional outcome. The association between thrombus attenuation increase and functional outcome was modified by the collateral score, and this association was stronger in patients with moderate and good collaterals.

CONCLUSIONS

Patients with lower thrombus burden and higher thrombus perviousness scores had higher collateral score. The positive effect of thrombus perviousness on clinical outcome was only present in patients with moderate and high collateral scores.

CLINICAL TRIAL REGISTRATION

URL: http://www.trialregister.nl. Unique identifier: NTR1804 and URL: http://www.controlled-trials.com Unique identifier: ISRCTN10888758.

Predictive value of thrombus volume for recanalization in stent retriever thrombectomy

This retrospective study investigated whether the volume or density of the thrombus is predictive of recanalization in stent retriever (SR) treatment. Consecutive patients treated with SR thrombectomy as the first endovascular modality were enrolled. The thrombus volume and density were measured on thin-section noncontrast computed tomography using 3-dimensional software. The patients were grouped by recanalization status and the number of SR passes. Among 165 patients, recanalization was achieved with the first pass in 68 (50.0%), 2–3 passes in 43 (31.6%), and ≥4 passes in 25 (18.4%) patients. The thrombus volume was smaller in patients with (107.5 mm³) than without (173.7 mm³, p = 0.025) recanalization, and tended to be larger with increasing number of passes (p for trend = 0.001). The thrombus volume was an independent predictor of first-pass recanalization (odds ratio 0.93 per 10 mm³, 95% confidence interval 0.89–0.97). However, the thrombus density was not associated with recanalization success. Recanalization within 3 passes was associated with a favorable outcome. In conclusion, the thrombus volume was significantly related to recanalization in SR thrombectomy. Measuring the thrombus volume was particularly predictive of first-pass recanalization, which was associated with a higher likelihood of a favorable outcome.

Assessment of thrombus length in acute ischemic stroke by post-contrast magnetic resonance angiography

OBJECTIVES

Post-contrast magnetic resonance angiography (PC-MRA) enables visualization of vessel segments distal to an intra-arterial thrombus in acute ischemic stroke. We hypothesized that PC-MRA also allows clot length measurement in different intracranial vessels.

METHODS

Patients with MRI-confirmed ischemic stroke and intracranial artery occlusion within 24 hours of symptom onset were prospectively evaluated. PC-MRA was added to a standard stroke MRI protocol. Thrombus length was measured on thick slab maximum intensity projection images. Clinical outcome at hospital discharge was assessed by modified Rankin Scale (mRS).

RESULTS

Thirty-four patients (median age 72 years) presenting with a median National Institutes of Health Stroke Scale score of 11 and a median onset to imaging time of 116 min were included. PC-MRA enabled precise depiction of proximal and distal terminus of the thrombus in 31 patients (91%), whereas in three patients (9%) PC-MRA presented a partial occlusion. Median thrombus length in patients with complete occlusion was 9.9 mm. In patients with poor outcome (mRS ≥3) median thrombus length was significantly longer than in those with good outcome (mRS ≤2;P=0.011).

CONCLUSIONS

PC-MRA demonstrates intra-arterial thrombus length at different vessel occlusion sites. Longer thrombus length is associated with poor clinical outcome.

CLINICAL TRIAL REGISTRATION

NCT02077582; Results.

Assessing the efficacy of endovascular therapy in stroke treatments: updates from the new generation of trials

INTRODUCTION

For the past 20 years, intravenous recombinant tissue plasminogen activator (rt-PA) has been the only proven treatment for acute ischemic stroke. Large arteries such as the internal carotid artery, the middle cerebral artery and the basilar artery supply blood to large volumes of brain tissue. When occluded, these vessels may have low response rates to rt-PA resulting in devastating injury and death. Areas covered: In 2013, three trials evaluating the efficacy of mechanical thrombectomy in acute stroke were neutral, however, lessons learned from these trials resulted in a second generation of five trials in 2015 and a sixth in 2016 which all demonstrated significant benefit for select patients. Here we will review the evidence behind these new trials and. introduce new questions such as models of care, techniques of thrombectomy, the role of rt-PA, modes of anesthesia, the management of late presenting and wake up strokes among other real world challenges facing stroke medicine now that the thrombectomy is an evidence based treamtnent Expert commentary: The mechanical thrombectomy is now the new standard of care and with that comes the need to find ways to provide it to all who will benefit.

Single-pass endovascular thrombectomy for massive carotid-cerebral occlusion

Acute concomitant occlusions of the extracranial internal carotid artery and intracranial vessels frequently require multiple passes with stent-retrievers for mechanical thrombectomy. Due to the large clot burden associated with these occlusions, their response to intravenous thrombolysis is poor. We herein report a successful case of evacuating a massive clot (>14 cm) in a single-pass using a stent-retrieval device.

Clot Imaging in Large Vessel Occlusion Strokes

Advances in mechanical thrombectomy techniques have resulted in improved, recanalization and functional outcomes in acute stroke, as demonstrated in recent, randomized trials comparing mechanical thrombectomy with thrombolysis. In conjunction with the technological advancements in thrombectomy devices, there has been better appreciation of stricter patient selection criteria for endovascular therapy based on pre-procedural imaging, including clot location, infarct volume, and penumbral territory at risk. Pre-procedural imaging performed to assess suitability for endovascular therapy commonly provides information on clot characteristics, such as clot location, length, density, and susceptibility, which can influence and may predict the efficacy of intravenous and endovascular treatments. The purpose of this review is to evaluate the role of clot imaging in acute large vessel occlusion strokes and discuss the relevance of clot imaging to thrombolytic and endovascular therapy.

Computed Tomography-Based Thrombus Imaging for the Prediction of Recanalization after Reperfusion Therapy in Stroke

The prediction of successful recanalization following thrombolytic or endovascular treatment may be helpful to determine the strategy of recanalization treatment in acute stroke. Thrombus can be detected using noncontrast computed tomography (CT) as a hyperdense artery sign or blooming artifact on a T2^*-weighted gradient-recalled image. The detection of thrombus using CT depends on slice thickness. Thrombus burden can be determined in terms of the length, volume, and clot burden score. The thrombus size can be quantitatively measured on thin-section CT or CT angiography/magnetic resonance angiography. The determination of thrombus size may be predictive of successful recanalization/non-recanalization after intravenous thrombolysis and endovascular treatment. However, cut-offs of thrombus size for predicting recanalization/non-recanalization are different among studies, due to different methods of measurements. Thus, a standardized method to measure the thrombus is necessary for thrombus imaging to be useful and reliable in clinical practice. Software-based measurements may provide a reliable and accurate assessment. The measurement should be easy and rapid to be more widely used in practice, which could be achieved by improvement of the user interface. In addition to prediction of recanalization, sequential measurements of thrombus volume before and after the treatment may also be useful to determine the efficacy of new thrombolytic drugs. This manuscript reviews the diagnosis of thrombus, prediction of recanalization using thrombus imaging, and practical considerations for the measurement of thrombus burden and density on CT.

Association of clot burden score with radiographic and clinical outcomes following Solitaire stent retriever thrombectomy: analysis of the SWIFT PRIME trial

BACKGROUND

The clot burden score (CBS) was developed as a tool to evaluate the extent of intracranial thrombus burden in patients with anterior circulation acute ischemic stroke. CBS is based on the presence or absence of contrast opacification on CT angiography (CTA). Its value in predicting radiographic and clinical outcomes in patients given endovascular stroke therapy remains unknown.

OBJECTIVE

To evaluate the relationship between CBS and outcomes after stent retriever thrombectomy in the interventional arm of the SWIFT PRIME trial.

METHODS

CBS was calculated for the endovascular arm (IV tissue plasminogen activator plus Solitaire stent retriever) of SWIFT PRIME using baseline CTA. The cohort of 69 patients was divided into three groups according to their CBS values: CBS 0-5 (n=14), CBS 6-7 (n=23), and CBS 8-9 (n=32).

RESULTS

The mean age of the 69 patients who formed the study cohort was 63.2±13.1 years, mean National Institutes of Health Stroke Scale score was 16.8±4.5, and 55% of the patients were male. There was no difference in clinical characteristics among the three groups, except for the baseline Alberta Stroke Program Early CT Score (p=0.049). The site of proximal occlusion varied significantly among the three groups (p<0.001). Rates of successful recanalization (TICI 2b/3), complete recanalization (TICI 3 only) and of good clinical outcome at 3 months were similar among the three groups (p=0.24, p=0.35, and p=0.52, respectively).

CONCLUSIONS

The combination of IV thrombolysis and stent retriever thrombectomy with the Solitaire device is highly effective in achieving successful recanalization and a good clinical outcome throughout the entire range of CBS values.