Patients with atrial fibrillation should actively consider anticoagulant therapy to prevent blood clots even when their stroke risk is not particularly high, according to a new study.
Severance Hospital said on the 2nd that a joint research team led by cardiology professors Jung Boyoung, Yu Hee Tae and Kim Dae Hoon analyzed 1,803 atrial fibrillation patients at 18 medical institutions in South Korea and found that blood-thinning treatment with anticoagulants lowered the incidence of complications such as stroke and embolism even in patients at moderate stroke risk.
Atrial fibrillation is an arrhythmia in which the heart's left atrium fails to beat properly and instead quivers. It can cause palpitations, dizziness and shortness of breath, and if left untreated it can allow blood clots to form inside the heart. If such a clot blocks a major blood vessel, it can lead to a stroke. Anticoagulants, which suppress the clotting of blood, are used to prevent this.
Current clinical guidelines classify atrial fibrillation patients as high stroke risk if they are 75 or older or have a history of stroke or systemic embolism, in which a clot formed in the heart or elsewhere blocks another blood vessel. For these patients, anticoagulant therapy is strongly recommended. By contrast, patients with only one of the following conditions — hypertension, diabetes, heart failure or vascular disease — as well as older patients with no accompanying conditions, are considered to be at moderate stroke risk. The reason is a lack of clinical trials demonstrating the therapeutic benefit of anticoagulants. For these patients, the guidelines go no further than saying anticoagulant prescription "may be considered."
The research team randomly assigned the 1,803 moderate-risk atrial fibrillation patients to either an anticoagulant group of 902 patients or a non-anticoagulant group of 901 patients, then followed them for two years. Major clinical events, including stroke, systemic embolism, major bleeding and cardiovascular death, occurred in four patients in the anticoagulant group, a 69% lower risk than in the non-anticoagulant group, where 13 cases occurred.
The gap was particularly wide for ischemic stroke, in which a brain blood vessel is suddenly blocked by a clot, and systemic embolism. One case occurred in the anticoagulant group, compared with 10 in the non-anticoagulant group, a difference in risk of about 90%. The risk of major bleeding, the best-known side effect of anticoagulants, showed no clear difference between the two groups.
The findings confirm through a randomized clinical trial that atrial fibrillation patients with only one stroke risk factor can also prevent stroke and clot-related complications through anticoagulant therapy. The study was presented at the annual congress of the European Society of Cardiology and the World Congress of Cardiology, held recently in Munich, Germany, and was published in the latest issue of the New England Journal of Medicine (NEJM).
Professor Jung Boyoung said the study showed that anticoagulant therapy helps reduce major clinical events even in atrial fibrillation patients with only one stroke risk factor. "This will serve as important evidence in deciding whether to provide anticoagulant therapy to patients at moderate stroke risk," Jung said.
