SF | NEUROLOGY
July 2020 | Vol. 20 No. 2 www.medicalacademic.co.za
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This article was independently sourced by Specialist Forum.
Different strategies to prevent and treat VTE in stroke patients
O
ver the past two decades, the prevalence of AFib has increased worldwide by 33%. Currently an estimated 37 million people have been diagnosed with the condition. However, some studies suggest that the prevalence is likely underestimated as a large proportion of asymptomatic individuals, and those who have transient symptoms, remain undiagnosed. It is predicted that the prevalence of AFib will double by 2030. 2,3
AFib, stroke and DVT Risk factors for AFib include congestive HF, hypertension, increasing age and diabetes. Many of these factors also increase the risk for venous thromboembolism (VTE) and ischaemic stroke in AFib patients.5 VTE is globally the third most frequent acute cardiovascular syndrome behind myocardial infarction and stroke. Cross-sectional data show that the incidence of VTE is almost eight times higher in individuals aged ≥80 years than in those in their 50s.13 According to the American Heart Association, there are two forms of VTE:6 » Deep vein thrombosis (DVT): A blood clot forms in a vein, usually in the deep veins of the legs or pelvis » Pulmonary embolism (PE): The blood clot can dislodge and travel in the blood, particularly to the pulmonary arteries.
Risk of DVT in stroke patients In immobilised post-stroke patients, the incidences of DVTs vary from 10%-75%. Asymptomatic DVT and clinically evident DVT vary in their prevalence, the latter being 2%-10% after an acute stroke. 5 The risk factors for DVT in acute stroke are advanced age, high stroke scale score, hemiparesis, immobility, female gender, AFib, receipt of intravenous or intra-arterial tissue plasminogen activator, and admission to hospital. Hospitalised patients are at increased risk of developing DVT (about 50%), and this increases the risk of PE.5,10
The onset of a DVT after acute stroke can be as early as the second day, peaking between days two and seven. If left untreated, proximal DVT have a 15% risk of death.5 The most common cause of mortality from a DVT after a stroke is a PE, accounting for 13%-25% of early deaths, and their incidence usually ranges from 1%-3% in the first few months after a stroke. 5 Yet, only 50% of the hospitalised patients receive DVT prophylaxis. Prevention of DVT in hospitalised patients decreases the risk of DVT and PE, which in turn decreases mortality and morbidity.10 DVT prophylaxis can be primary or secondary. Primary prophylaxis is the preferred method with the use of medications and mechanical methods to prevent DVT. Secondary prophylaxis is a less commonly used method that includes early detection with screening methods and the treatment of subclinical DVT.10
Preventing VTE in ischaemic stroke patients Khan et al conducted a systematic review examining prophylaxis DVT in patients following an acute stroke.
Initial diagnostic test The initial test for diagnosing peripheral venous thrombosis is ultrasound. The test is accurate, cost effective, safe, and portable. In addition, Doppler techniques provide direct information regarding flow physiology.5 Either computed tomography or magnetic resonance imaging can be used. Particularly when studying central veins. Other screening tests employed are 125-I fibrinogen scanning and contrast venography. A 16-point early clinical prediction scale has been suggested to identify patients at high risk for DVT after an ischaemic stroke but needs further study and validation. New DVTs increased the risk of three-month mortality significantly with no influence on the combined risk of death and dependency. Increased serum C-reactive protein (CRP) levels, alongside a normal fibrinogen level, can predict the development of a new DVT. Such patients may then be reasonably protected with further DVT prophylaxis.
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Arrhythmias – often described as ‘hijackers’ of the heart’s rhythm and pump functions, cause the heart to either beat too fast (tachycardia), too slow (bradycardia), or too irregular (atrial fibrillation [AFib]). AFib is the most frequent form of arrythmia and is associated with an increased risk of stroke, dementia and heart failure (HF).1,2
