Perspectives: Risk Assessment

Shu Zhang

Shu Zhang


  • Professor of Medicine
  • Chief of Department of Cardiology
  • Director of Arrhythmia Center
  • National Center for Cardiovascular Disease & Beijing Fuwai Hospital
  • Chinese Academy of Medical Sciences & Beijing Union Medical College
  • Beijing, China


Anticoagulants and patient-related risk factors for bleeding

Well-established risk factors for bleeding in patients with atrial fibrillation include increased age, an unstable international normalized ratio (INR), a previous history of major bleeding (especially a history of intracerebral hemorrhage), uncontrolled hypertension, renal dysfunction, use of concomitant medications that predispose to bleeding, and alcohol use. In 2010, the European Society of Cardiology (ESC) published guidelines for management of atrial fibrillation (AF). The ESC recommended use of the HAS-BLED score to evaluate bleeding risk in patients with AF. The HAS-BLED score comprises 9 bleeding risk factors: hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile INR, age >65 years, and drugs that may increase bleeding risk (eg, antiplatelet agents, nonsteroidal anti-inflammatory drugs) and drugs/alcohol concomitantly. The maximum HAS-BLED score is 9, with one point assigned for each risk factor.

In “real-world” clinical practice, these risk factors may influence a physician’s assessment of bleeding risk to varying degrees, although no risk factors are generally referred to as “high” or “low” risk factors for bleeding. In my opinion, uncontrolled hypertension and history of hemorrhagic stroke are the most important risk factors for bleeding. Hypertension is frequently seen in patients with atrial fibrillation and is an important risk factor for both ischemic and hemorrhagic stroke. When we use anticoagulation treatment to reduce the risk for ischemic stroke in elderly patients with both AF and hypertension who are also at high risk of hemorrhagic stroke, uncontrolled hypertension may increase the risk for bleeding events. Hemorrhagic stroke is a major concern in patients on anticoagulants, and may be devastating. Therefore, it is important to perform risk assessment in patients on oral anticoagulation for stroke prevention in atrial fibrillation in order to make treatment decisions based on a balanced evaluation of risks and benefits.

I think it is also important to take a closer look at renal dysfunction as a risk factor for bleeding in patients with AF. The presence of renal dysfunction appears to be an independent risk factor for AF. Recent data from the Atherosclerosis Risk in Communities, or ARIC, study, which included more than 10,000 patients followed for a median of 10 years, showed an increased risk for AF as estimated glomerular filtration rate decreased. This is important for several reasons. First, it highlights the need to monitor renal function in patients with AF. Second, these patients are at increased risk for bleeding due to multiple factors, such as platelet defects and uremia. Therefore, these patients must be carefully evaluated for the risks and benefits of anticoagulation, and it will be beneficial to have a choice of anticoagulants, ideally with good information about dosing in this population, in hope of an improved balance of stroke and bleeding risk.

Regarding selection of an oral anticoagulant, the efficacy of vitamin K antagonists to prevent thromboembolism is well established, however there are concerns about increased risks for thrombosis and bleeding in patients who are not maintained in the therapeutic range, especially patients with unstable INRs and other risk factors as described above. Close attention should be paid to performing an accurate bleeding risk assessment and minimizing all the numerous factors known to increase the risk of hemorrhagic complications.

Risk assessment

Risk assessment

Here you can find validated, interactive tools to help you calculate stroke and bleeding risk of your patients

About the Coagulation Center

The Coagulation Center is an educational resource for healthcare professionals. Guided by a global editorial board of experts, the Coagulation Center offers a range of clinical perspectives on balancing the benefit and risk of anticoagulation in a rapidly changing landscape. Within the Coagulation Center you will find roundtable discussions on anticoagulation management, materials for patient management including patient case studies, tools to help evaluate bleeding risk and stroke risk, and downloadable resources for your practice.