Proposed risk stratification strategy for perioperative thromboembolism (adapted from Douketis et al1,12 )
| Risk stratum for thrombotic events . | Indication for anticoagulant therapy . | ||
|---|---|---|---|
| Mechanical heart valve . | Atrial fibrillation . | VTE . | |
| High risk | Any mitral valve prosthesis | CHADS2 score of 5 or 6* | Recent (within 3 mo) VTE |
| Any caged-ball or tilting disc aortic valve prosthesis | Recent (within 3 mo) stroke or TIA | “Severe” thrombophilia† | |
| Recent (within 6 mo) stroke or TIA | Rheumatic valvular heart disease | ||
| Moderate risk | Bileaflet aortic valve prosthesis and ≥ 1 of the following risk factors: atrial fibrillation, prior stroke or TIA, hypertension, diabetes, CHF, age > 75 y | CHADS2 score of 3 or 4* | VTE within the past 3-12 mo Recurrent VTE Active cancer (treated within 6 mo or palliative) “Nonsevere” thrombophilia† |
| Low risk | Bileaflet aortic valve prosthesis without atrial fibrillation and no other risk factors for stroke | CHADS2 score of 0-2* | VTE > 12 mo previous and no other risk factors |
| Risk stratum for thrombotic events . | Indication for anticoagulant therapy . | ||
|---|---|---|---|
| Mechanical heart valve . | Atrial fibrillation . | VTE . | |
| High risk | Any mitral valve prosthesis | CHADS2 score of 5 or 6* | Recent (within 3 mo) VTE |
| Any caged-ball or tilting disc aortic valve prosthesis | Recent (within 3 mo) stroke or TIA | “Severe” thrombophilia† | |
| Recent (within 6 mo) stroke or TIA | Rheumatic valvular heart disease | ||
| Moderate risk | Bileaflet aortic valve prosthesis and ≥ 1 of the following risk factors: atrial fibrillation, prior stroke or TIA, hypertension, diabetes, CHF, age > 75 y | CHADS2 score of 3 or 4* | VTE within the past 3-12 mo Recurrent VTE Active cancer (treated within 6 mo or palliative) “Nonsevere” thrombophilia† |
| Low risk | Bileaflet aortic valve prosthesis without atrial fibrillation and no other risk factors for stroke | CHADS2 score of 0-2* | VTE > 12 mo previous and no other risk factors |
CHF indicates congestive heart failure; TIA, transient ischemic attack and VTE, venous thromboembolism.
The CHADS2 score is calculated by the cumulative score for congestive heart failure (1 point), hypertension (1 point), age > 75 y (1 point), diabetes mellitus (1 point), and previous stroke or TIA (2 points).13
“Severe” thrombophilias include deficiency of protein C, protein S, or antithrombin, antiphospholipid antibodies, or multiple abnormalities (eg, compound heterozygosity for factor V Leiden and prothrombin G20210A). “Nonsevere” thrombophilias include heterozygosity for factor V Leiden or prothrombin G20210A. The clinical relevance for these inherited risk factors in predicting risk of recurrent VTE, however, is unclear.14