Fibrin-Platelet Clots in Acute Ischemic Stroke. Predictors and Clinical Significance in a Mechanical Thrombectomy Series

Abstract

Introduction: The histological composition of the clot influences its mechanical properties, affects the efficacy of endovascular treatment (EVT), and could determine the clinical outcome of patients with acute ischemic stroke (AIS). Insights into clot composition may guide therapeutic decision-making prior to EVT and facilitate revascularization therapies.Material and Methods: Consecutive patients with AIS recorded in a prospective single-center reperfusion registry from December 2015 to December 2019 and treated with EVT were included. Baseline, laboratory [including post-procedural C-reactive protein (CRP)], radiological, and angiographic variables were analyzed. We aimed to study the relationship between histological composition of the clot with basal neuroimaging, laboratory markers, and recanalization technique. The secondary outcome was to analyze the correlation between clot composition and functional outcome at 3 months assessed by the modified Rankin scale (mRS).Results: From the study period, 360 AIS patients treated with EVT were included, of whom 189 (53%) fulfilled the inclusion criteria. One hundred (53%) cases of fibrin-predominant clot (FPC) were recorded. Full recanalization in FPC cases was achieved with higher probability when stent retrievers (SR) were selected as the first-line device (68.2%, p = 0.039). Patients with FPC had higher levels of CRP (p = 0.02), lower frequency of the hyperdense middle cerebral artery (HMCA) in baseline imaging (p = 0.039), and higher rates of mortality (p = 0.012). The multivariate analysis showed that the absence of HMCA (OR = 0.420; 95% CI 0.197–0.898; p = 0.025) and higher levels of CRP (OR = 1.01; 95% CI 1.003–1.019; p = 0.008) were predictors of FPC. Leukocytes and platelet counts were not associated with clot histology.Conclusions: The absence of HMCA and higher levels of CRP were markers of FPC. In patients with FPC, complete recanalization was most likely to be achieved when a SR was selected as first line of treatment. Mortality was higher in patients within this histologic group.

High thrombus platelet content is associated with a lower rate of first pass effect in stroke treated by endovascular therapy

“…11 Furthermore, recent results from in vitro simulation of EVT also indicate that platelet thrombus content could impair EVT, notably by increasing thrombus stiffness and friction. 12,13 In line with other published series, 14,15 we report a different impact of thrombus platelet content according to the front-line strategy used, as this variable affected significantly the FPE rate in the CA but not in the SR group. In addition, and contrarily to others, who used a semi-quantitative technique 7 or in vitro model, 16 we did not find any difference in RBC content according to FPE status.…”

Fibrin-Targeted Nanoparticles for Finding, Visualizing and Characterizing Blood Clots in Acute Ischemic Stroke

“…Therefore, the nanoparticles developed in this work could be a valuable imaging tool, capable of predicting the effectiveness of rtPA based on the fibrin content of blood clots. On the other hand, recent studies have proven that the fibrin content in blood clots influences the success of recanalization in mechanical thrombectomy [ 8 ]. It was observed that the post-procedure serum levels of C-reactive protein were associated with the fibrin content in clots, and therefore could be used to indirectly predict fibrin-rich clots in ischemic stroke patients [ 8 ].…”

“…On the other hand, recent studies have proven that the fibrin content in blood clots influences the success of recanalization in mechanical thrombectomy [ 8 ]. It was observed that the post-procedure serum levels of C-reactive protein were associated with the fibrin content in clots, and therefore could be used to indirectly predict fibrin-rich clots in ischemic stroke patients [ 8 ]. Instead, the nanoparticles developed in this work could be used to directly visualize and identify fibrin-rich clots before submitting the patient to recanalization therapy, thus representing a potentially useful tool in both mechanical and pharmaceutical recanalization therapies.…”

“…Mechanical thrombectomy is currently the most successful treatment for the recanalization of large-vessel occlusions in ischemic stroke patients. The successful removal of a blood clot via mechanical thrombectomy is associated with the mechanical properties of the blood clot, which are also dependent on the fibrin content of the clot [ 8 ]. In this regard, clinical studies have demonstrated that the administration of rtPA before mechanical thrombectomy resulted in a reduction in the size of the retrieved clot and in a modification of its components, but not in a better recanalization rate [ 9 , 10 ].…”

“…For instance, large atherothrombotic strokes, caused by the disruption of an atheroma plaque that is rich in platelets, show the lowest recanalization rates [ 19 ]. In addition, fibrin content also influences the efficacy of mechanical thrombectomy, which is reflected by a higher recanalization rate in patients with fibrin-rich clots analyzed via clot histology [ 8 ]. Thus, direct visualization of the fibrin content in a thrombus may be beneficial for both diagnosis and recanalization therapy.…”