Association of antithrombotic medications and composition of thrombi retrieved by mechanical thrombectomy in acute ischemic stroke

Timely restoration of blood perfusion through thrombolysis and/or mechanical thrombectomy (MT) is an important step in salvaging ischemic brain in stroke patients. MT has opened an avenue for histological evaluation of thrombi and over the last couple of years our knowledge on the thromboembolus histological and mechanical properties and effects of these properties on the success of MT has grown significantly [ 1 Abbasi M. Kvamme P. Layton K.F. Hanel R.A. Almekhlafi M.A. Delgado J.E. Pereira V.M. Patel B.M. Jahromi B.S. Yoo A.J. Per pass analysis of thrombus composition retrieved by mechanical thrombectomy. Interv. Neuroradiol. 2021; (published ahead of print) Crossref Scopus (2) Google Scholar , 2 Mereuta O.M. Abbasi M. Fitzgerald S. Dai D. Kadirvel R. Hanel R.A. Yoo A.J. Almekhlafi M.A. Layton K.F. Almandoz J.E.D. Histological evaluation of acute ischemic stroke thrombi may indicate the occurrence of vessel wall injury during mechanical thrombectomy. J. Neurointerv. Surg. 2021; (published ahead of print) Crossref Scopus (4) Google Scholar ]. Two major classes of antithrombotic therapies, including antiplatelet and anticoagulant drugs, have been used for both management and prevention of stroke. Antiplatelet drugs are used to avert the formation of platelet-rich arterial thrombi while anticoagulants drug are used to prevent the formation of fibrin-rich thrombi in patients suffering from atrial fibrillation [ [3] Oliveira Filho J. Mullen M.T. Antithrombotic Treatment of Acute Ischemic Stroke and Transient Ischemic Attack. UpToDate, UpToDate Whatham, MA2019 Google Scholar ]. However, to date the effect of long-term antithrombotic therapies on the thrombus components retrieved from AIS patients has not been investigated. In our study, we assessed the association of antiplatelet and anticoagulant therapies with thrombus components. A total of 181 Consecutive patients with acute ischemic stroke (AIS) who underwent MT (including stent-retriever, aspiration or combined stent aspiration technique) were extracted from our prospectively maintained database. Patients' stroke subtypes were determined according to TOAST criteria (the classification of the Trial of Org 10172 in Acute Stroke Treatment) [ [4] Adams Jr., H.P. Bendixen B.H. Kappelle L.J. Biller J. Love B.B. Gordon D.L. Marsh III, E. Classification of subtype of acute ischemic stroke. Definitions for use in a multicenter clinical trial. TOAST. Trial of Org 10172 in Acute Stroke Treatment. Stroke. 1993; 24: 35-41 Crossref PubMed Scopus (7872) Google Scholar ]. The clinical information including gender, age, endovascular procedure, antiplatelet therapy, anticoagulant therapy was collected for each patient. Thrombi retrieved by MT were evaluated histopathologically at our lab. All thrombi were processed using a standard tissue processing protocol, embedded in paraffin and cut into 3 μm sections Two serial sections for each thrombus were stained with MSB (Martius Scarlet Blue) to identify the main components of thrombi including red blood cells, white blood cells, fibrin and platelets. Percentages of each thrombus component were considered continuous variable. Independent t-test, Chi-square test were employed to evaluate the associations.