Perioperative thrombotic risk

Thrombotic risk	Indication for anticoagulant therapy
Thrombotic risk	Mechanical heart valve	Atrial fibrillation	VTE
High thrombotic risk*	Any mitral valve prosthesis Any caged-ball or tilting disc aortic valve prosthesis Recent (within 6 months) stroke or transient ischemic attack	CHADS₂ score 5-6 CHA₂DS₂-VASc score 7-9 Recent (within 3 months) stroke or transient ischemic attack Rheumatic valvular heart disease	Recent (within 3 months) VTE Severe thrombophilia (eg, deficiency of protein C, protein S, or antithrombin; antiphospholipid antibodies; multiple abnormalities)
Moderate thrombotic risk	Bileaflet aortic valve prosthesis and 1 or more of the of following risk factors: atrial fibrillation, prior stroke or transient ischemic attack, hypertension, diabetes, congestive heart failure, age >75 years	CHADS₂ score 3-4 CHA₂DS₂-VASc score 4-6	VTE within the past 3 to 12 months Nonsevere thrombophilia (eg, heterozygous factor V Leiden or prothrombin gene mutation) Recurrent VTE Active cancer (treated within 6 months or palliative)
Low thrombotic risk	Bileaflet aortic valve prosthesis without atrial fibrillation and no other risk factors for stroke	CHADS₂ score 0-2 CHA₂DS₂-VASc score 0-3 (assuming no prior stroke or transient ischemic attack)	VTE >12 months previous and no other risk factors

The risk classification is largely based on indirect evidence and is intended to be used as a starting point to estimate risk. Patient-specific factors and clinical judgment should also be incorporated into the risk estimate. The source guideline used CHADS₂ scores for risk estimation; additional information from CHA₂DS₂-VASc scores may also inform risk, but these scores have not been directly compared in a clinical trial. Refer to UpToDate topics on perioperative anticoagulation management for details.

VTE: venous thromboembolism; CHADS₂: congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, and stroke or transient ischemic attack; CHA₂DS₂-VASc: congestive heart failure, hypertension, age ≥75 years (2 points), diabetes mellitus, prior stroke or transient ischemic attack or thromboembolism (2 points), vascular disease (peripheral artery disease, myocardial infarction, or aortic plaque), age 65 to 74 years, sex category female.
* Very high-risk patients may also include those with a prior stroke or transient ischemic attack occurring <3 months before the planned surgery and a CHADS₂ score >5 or CHA₂DS₂-VASc score >6 (those with prior thromboembolism during temporary interruption of anticoagulation, or those undergoing certain types of surgery associated with an increased risk for stroke or other thromboembolism [eg, cardiac valve replacement, carotid endarterectomy, major vascular surgery]).

Modified from Douketis JD, Spyropoulos AC, Spencer FA, et al. Perioperative management of antithrombotic therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012; 141(2 Suppl):e326S. Copyright © 2012. Reproduced with permission from the American College of Chest Physicians.

Graphic 86930 Version 7.0