Demographic and clinical characteristics of included patients (n=259)
| Age (years), mean (SD) | 74.8 (10.6) |
| Male gender, n (%) | 146 (56.4) |
| Elective surgery, n (%) | 184 (71.0) |
| Length of stay (days), median (IQR) | 6.0 (3.0–10.0) |
| VKA, n (%) | |
| Acenocoumarol | 205 (79.2) |
| Phenprocoumon | 54 (20.8) |
| Indication for VKA use, n (%) | |
| Atrial fibrillation | 173 (66.8) |
| Venous thromboembolism | 23 (8.9) |
| Mechanical heart valve | 9 (3.5) |
| Multiple* | 21 (8.1) |
| Other | 33 (12.7) |
| Comorbidities, n (%) | |
| iCVA/TIA | 37 (14.3) |
| Thrombophilia | 7 (2.7) |
| Heart failure | 20 (7.8) |
| Hypertension | 132 (51.0) |
| Diabetes mellitus | 63 (24.3) |
| Active cancer/malignancy | 55 (21.2) |
| Thromboembolic risk, n (%) | |
| Low | 138 (53.3) |
| Moderate | 38 (14.7) |
| High | 40 (15.4) |
| Unknown† | 43 (16.6) |
| Type of surgical procedure, n (%) | |
| Gastrointestinal | 52 (20.1) |
| Orthopaedic | 89 (34.4) |
| Plastic | 3 (1.2) |
| Cardiac | 9 (3.5) |
| Neurosurgery | 5 (1.9) |
| Breast | 6 (2.3) |
| Vascular | 36 (13.9) |
| Urologic | 43 (16.6) |
| Dental/ENT/HN | 2 (0.8) |
| Other | 14 (5.4) |
*Combination of two of the following indications: atrial fibrillation, venous thromboembolism and mechanical heart valve.
†33 patients used VKA for other indications than AT9 provides TE-risk stratification, 10 patient records provided insufficient information to determine TE-risk.
ENT, ear, nose and throat; HN, head and neck.; iCVA, ischaemic cerebrovascular accident; TIA, transient ischaemic attack; TE, thromboembolic event; VKA, vitamin-K antagonist.