Antithrombotic therapy in cardiac embolism

Application of Flat-Panel Volume Computed Tomography to Evaluate Cerebral Hemorrhage After Mechanical Thrombectomy of Acute Embolic Stroke of the Anterior Circulation

OBJECTIVE

The aim of the study was to evaluate cerebral hemorrhage (CH) and contrast media leakage (CML or commonly synonymous with "contrast staining") differentiation on flat-panel volume computed tomography (FPVCT) after intra-arterial mechanical thrombectomy.

METHODS

We evaluated patients with hyperattenuation on FPVCT after intra-arterial mechanical thrombectomy between 2018 and 2021 by multiple parameters on CT angiography, FPVCT, CT, and/or magnetic resonance imaging.

RESULTS

The CH (n = 43) versus CML (n = 24) groups revealed: (1) regional anatomical characteristics (preserved and distorted): 7 of 43 (9.6%) and 36 of 43 (83.7%) versus 22 of 24 (91.7%) and 2 of 24 (8.3%, P < 0.001); (2) thrombus in proximal two-thirds versus distal one-thirds M1 segment of middle cerebral artery (preserved and distorted): 17 of 21 (81.0%) and 4 of 21 (19.0%) versus 5 of 11 (45.5%) and 6 of 11 (54.5%, P = 0.040); and (3) average density ratio: 1.83 ± 0.65 versus 1.35 ± 0.13 (P = 0.004).

CONCLUSIONS

Contrast media leakage can be differentiated from CH by preserved regional anatomical characteristics and relatively low average density ratio on FPVCT. Patients with CML who have embolism in proximal two thirds of M1 segment are more likely to develop hyperattenuation with preserved regional anatomy.

The effect of different drugs on the preparation and biological outcomes of plasma rich in growth factors

Chronic diseases are the major contributors to the global burden of disease and involve prodigious consumption of various drugs that usually affect platelet function. The autologous technology of plasma rich in growth factors (PRGF) provides a biological approach using autologous platelets as a reservoir and local delivery of proteins to promote tissue healing. The purpose of this study was to evaluate the effect of the consumption of acetylsalicylic acid, acenocoumarol and glucosamine sulfate on the preparation as well as on the biological properties of the PRGF technology. Clotting time and platelet activation of PRGF was evaluated. The latter was performed by flow cytometry. PRGF growth factor content and the release of various biomolecules by gingival fibroblasts were quantified by enzyme-linked immunosorbent assay. Cell proliferation was evaluated by means of a fluorescence-based method and cell migration was performed on culture inserts. None of the parameters evaluated was modified by the consumption of any of the three drugs tested; only the plasma of patients who had consumed acetylsalicylic acid and acenocoumarol expressed greater gingival fibroblast migration compared to plasma control. The intake of acetylsalicylic acid, acenocoumarol and glucosamine sulfate does not alter the preparation and biological properties of the autologous technology of PRGF.

Latest developments in anticoagulant drug discovery

Thromboembolic diseases have increased in number over the past years. Oral anticoagulants impair the formation and progression of thrombotic processes and are therefore of great importance in the treatment of these diseases. Until recently, vitamin K antagonists were used to block the coagulation system. But these agents display a lot of interactions besides their narrow therapeutic range and have potential risk of hemorrhage complications. Therefore, other factors of the coagulation cascade are currently being explored as therapeutic targets for the development of novel anticoagulants. This review will provide an overview of new drugs promising more effectiveness in the treatment of arterial and venous embolism. Furthermore, pharmacodynamics and drug interactions regarding new anticoagulants will be reported.

CHADS(2) and CHA(2)DS(2)VASc scores as predictors of cardioembolic sources in secondary stroke prevention

INTRODUCTION AND OBJECTIVES

Cardioembolism is one of the most common causes of ischemic stroke, with an estimated prevalence of 20-30%, and correct diagnosis is essential given the therapeutic implications. Although stroke risk scores (CHADS2 and more recently CHA2DS2-VASc) have been validated in heterogeneous populations of patients with atrial fibrillation, their accuracy has not been ascertained for secondary stroke prevention. We set out to assess the sensitivity and specificity of the CHADS2 and CHA2DS2-VASc stroke risk scores as predictors of cardioembolic sources, documented by transesophageal echocardiography (TEE) in a population with ischemic stroke.

METHODS

The CHADS2 and CHA2DS2-VASc scores were applied to all patients admitted to the stroke unit/neurology ward of a Portuguese tertiary hospital with atrial fibrillation (diagnosed previously or during or after admission) who underwent TEE between January and August 2011. The presence of a cardioembolic source was defined as the observation by TEE of spontaneous echo contrast in the left atrium and atrial appendage or thrombi in the left cardiac chambers.

RESULTS

We studied 94 patients, 66.0% male, mean age 64.4 years (standard deviation 14.2). A cardioembolic source was detected in 20 patients. ROC curve analysis identified as predictors of cardioembolic source CHADS2 score ≥4 (sensitivity of 75.0%, specificity of 66.0%, p=0.014) and CHA2DS2-VASc score ≥5 (sensitivity of 83.3%, specificity of 58.0%, p=0.009).

CONCLUSIONS

Both scores showed acceptable sensitivity as predictors of embolic risk in the context of secondary prevention of cardioembolic stroke. The CHA2DS2-VASc score has higher sensitivity than CHADS2 but lower specificity.

Antithrombotic medication for cardioembolic stroke prevention

Embolism of cardiac origin accounts for about 20% of ischemic strokes. Nonvalvular atrial fibrillation is the most frequent cause of cardioembolic stroke. Approximately 1% of population is affected by atrial fibrillation, and its prevalence is growing with ageing in the modern world. Strokes due to cardioembolism are in general severe and prone to early recurrence and have a higher long-term risk of recurrence and mortality. Despite its enormous preventive potential, continuous oral anticoagulation is prescribed for less than half of patients with atrial fibrillation who have risk factors for cardioembolism and no contraindications for anticoagulation. Available evidence does not support routine immediate anticoagulation of acute cardioembolic stroke. Anticoagulation therapy's associated risk of hemorrhage and monitoring requirements have encouraged the investigation of alternative therapies for individuals with atrial fibrillation. New anticoagulants being tested for prevention of stroke are low-molecular-weight heparins (LMWH), unfractionated heparin, factor Xa inhibitors, or direct thrombin inhibitors like dabigatran etexilate and rivaroxaban. The later exhibit stable pharmacokinetics obviating the need for coagulation monitoring or dose titration, and they lack clinically significant food or drug interaction. Moreover, they offer another potential that includes fixed dosing, oral administration, and rapid onset of action. There are several concerns regarding potential harm, including an increased risk for hepatotoxicity, clinically significant bleeding, and acute coronary events. Therefore, additional trials and postmarketing surveillance will be needed.