低强度华法林在老年非瓣膜性心房颤动卒中高风险患者卒中一级预防中的疗效和安全性观察

目的   探讨低强度华法林在老年非瓣膜性心房颤动卒中高风险患者卒中一级预防中的疗效及安全性。 方法  本研究连续入组首都医科大学附属北京天坛医院2010年1月～2014年1月,心内科、老年科住院部及抗凝门诊确诊的治疗时间＞1年的非瓣膜性心房颤动卒中高风险患者80例,根据患者接受治疗情况分为低强度华法林治疗组和阿司匹林对照组各40例,其中华法林组控制凝血酶原时间国际标准化比值（international normalized ratio,INR）为1.6～2.5,比较两组患者缺血性卒中及全身大出血等不良反应的发生率。 结果  两组间在性别、年龄、伴随疾病等方面差异无显著性。低强度华法林治疗组心源性脑栓塞发生率为2.5%,阿司匹林治疗组为7.5%,两组比较差异无显著性（P＞0.05）。低强度华法林治疗组无其他部位栓塞发生,而阿司匹林治疗组患者其他部位栓塞仅1例,两组比较差异无显著性（P＞0.05）。两组均无心源性短暂性脑缺血发作发生。低强度华法林治疗组与阿司匹林治疗组均无严重脑出血、肾出血、其他器官出血等并发症发生。 结论  低强度华法林在非瓣膜性心房颤动卒中高风险患者卒中一级预防中疗效性与安全性方面可能与阿司匹林相当。     

Effectiveness of Nonvitamin K Antagonist Oral Anticoagulants and Warfarin for Preventing Further Cerebral Microbleeds in Acute Ischemic Stroke Patients with Nonvalvular Atrial Fibrillation and At Least One Microbleed: CMB-NOW Multisite Pilot Trial

BackgroundNonvitamin K antagonist oral anticoagulants (NOACs) are considered superior, or at least noninferior, to warfarin in preventing stroke or systemic embolism in patients with nonvalvular atrial fibrillation. Here, we recruited acute ischemic stroke patients with nonvalvular atrial fibrillation and at least one cerebral microbleed (CMB), and evaluated the proportion of patients who had an increased number of CMBs (%) after receiving anticoagulant therapy with NOACs or with warfarin for 12 months.MethodsThis was a multicenter, prospective, observational cohort study at 20 centers, conducted between 2015 and 2017, in which we recruited 85 patients with at least one CMB detected by 1.5T magnetic resonance imaging (T2*WI) at baseline, who received NOACs or warfarin for at least 12 months. We compared the proportions of patients with increased numbers of CMBs in the NOACs and warfarin treatment groups.ResultsThe proportions of patients with increased numbers of CMBs at month 12 of treatment were 28.6% and 66.7% in the NOACs and warfarin groups, respectively. The new CMBs showed no specific regional localization in either group. In the NOACs and warfarin groups, physicians prescribed lower-than-standard dosing in 13.3% and 50% of the cases, respectively. The administration of reduced doses at physicians’ discretion did not appear to alter the incidence of new CMBs.DiscussionThis is the first evidence to suggest efficacy of NOACs for preventing further CMBs in patients with at least one CMB, although no statistical evaluation was carried out.     

Benefits and risks of oral anticoagulation for stroke prevention in nonvalvular atrial fibrillation

Nonvalvular atrial fibrillation is the most common clinically significant cardiac arrhythmia in the United States. It increases both the risk for and the severity of strokes and is associated with substantial morbidity, mortality, decreased quality of life, and related health care costs. Guidelines recommend anticoagulation therapy for the majority of patients with atrial fibrillation. Clinical trials have established that vitamin K antagonists are effective for stroke prevention for patients with atrial fibrillation for whom anticoagulation is recommended. However, vitamin K antagonists remain underutilized for a variety of reasons, including drug, physician, and patient factors. While vitamin K antagonists considerably reduce the risk of stroke, the absolute risk reduction varies according to individual patient risk factors. Accurately assessing each patient's true risk of stroke and bleeding is essential when determining which (if any) antithrombotic strategy should be used. Several stroke risk stratification schemes exist; of these, CHADS₂ is widely employed and simple. New, more sophisticated schemes may generate more precise risk estimates and better identify those patients for whom anticoagulant therapy offers a net clinical benefit. More studies are needed to determine the utility of bleeding risk stratification systems, as well as the role of surgical and interventional alternatives to anticoagulation treatment. Several novel oral anticoagulants are in (or have completed) phase 3 clinical trials. Dabigatran etexilate, approved in the United States in October 2010 for reducing the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation, now offers the first oral alternative to warfarin for patients with atrial fibrillation.