Current Evidence for the Use of Aspirin in Patients with Atrial Fibrillation and a CHA2DS2-Vasc=1

Aspirin was once the mainstay of stroke prevention in patients with atrial fibrillation. Its popularity was based on the results of the SPAF and PATAF trials, which showed the low risks of this therapy and the many benefits it had to offer in terms of embolic complications prevention. Nevertheless, aspirin has lost popularity in atrial fibrillation since the CHADS, CHA2DS2-VASc and HASBLED scoring systems were first introduced. These scoring systems showed a different perspective, which highlighted that thromboembolic risk varied among individuals and that a generalization on antiplatelet therapy for atrial fibrillation was not effective. These caveats gave support to additional treatments based on anticoagulation, including warfarin and direct oral anticoagulants. These treatments gained popularity based on the superiority over warfarin, first described on the BAFTA trial, which nominated the warfarin as the standard of care for atrial fibrillation thromboembolic prevention. Since then, direct anticoagulation therapies have gained popularity based on the results of the ARISTOTLE (apixaban), RE-LY (dabigatran), ROCKET-AF (rivaroxaban), ENGAGE TIMI 48 AF (edoxaban) trials. However, the CHA2DS2-VASc score was generous with aspirin, since it opened a possible recommendation for low CHA2DS2-VASc scores (0-1). This comprehensive literature review is intended to discuss the arguments behind this last statement and to show the available evidence in favor of and against aspirin for non-valvular atrial fibrillation in low thromboembolic risk patients.

NETWORK META-ANALYSIS FOR PARNAPARINE EFFECTIVENESS IN VENOUS THROMBOEMBOLIC PREVENTION IN SURGERY

Цель исследования: сетевой мета-анализ (СМА) рандомизированных контролируемых исследований (РКИ) парнапарина, эноксапарина, надропарина и нефракционированного гепарина (НФГ) в режиме краткосрочных курсов в малых и средних дозах для профилактики венозных тромбоэмболических осложнений (ВТЭО) при хирургических и ортопедических вмешательствах у пациентов с высоким риском тромбоза глубоких вен (ТГВ). Материалы и методы. Выполнен смешанный СМА 21 РКИ парнапарина, эноксапарина, надропарина и НФГ у хирургических больных с кратковременной (1-2 недели) профилактикой ВТЭО. Результаты. По сравнению с НФГ применение парнапарина статистически значимо снижало риск развития ТГВ (на 51%) и «больших» кровотечений (на 83%). Эноксапарин и надропарин подобных преимуществ по сравнению с НФГ не продемонстрировали, что вряд ли связано с недостаточной статистической мощностью исследования. Заключение. При прочих равных условиях парнапарин может рассматриваться в качестве препарата выбора для профилактики ВТЭО в хирургии и ортопедии. Aim: network meta-analysis (NMA) of randomized controlled trials (RCTs) of parnaparin, enoxaparin, supraparin, and unfractionated heparin (UFH) in the regime of short-term courses in small and medium doses for prophylaxis of venous thromboembolic complications (VTEC) at surgical and orthopedic interventions in patients with high risk of deep vein thrombosis (DVT). Materials and methods. Mixed CMA of 21 RCTs of parnaparin, enoxaparin, supraparin and UFH was performed in surgical patients with short-term (1-2 weeks) prophylaxis of VTEС. Results. Parnaparin reduced significantly the odds of DVT (by 51%), and the odds of «large» bleedings (by 83%) compared with UFH. Both enoxaparin and nadroparin did not demonstrate convincing advantages over UFH concerning the efficacy and the safety. This fact is hardly explained due to the insufficient statistical power of the study. Conclusion. We conclude that when other things being equal, parnaparin exposes better therapeutic profile resulting parnaparin might to be considered first for VTEC prevention in surgery and orthopedics.