Table 1.
Factors associated with no venous thromboembolism (VTE), early VTE and late VTE
| Clinical characteristic | All patients (n = 7621) | No VTE (DVT or PE) | Early (pre-discharge) VTE | Late (post-discharge) VTE | Early versus none | Late versus none | Early versus late | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| n or median | % | n or median | % | n or median | % | n or median | % | P-value | P-value | P-value | |
| Patients | 7621 | 100% | 7411 | 97.2% | 150 | 2.1 | 60 | 0.8% | |||
| Preoperative factors | |||||||||||
| Age, years, median (range) | 60 (17–90) | 60 (17–90) | 65 (23–90) | 62 (26–83) | <0.001 | 0.616 | 0.066 | ||||
| Age ≥75 years | 894 | 11.7% | 860 | 11.6% | 29 | 19.3% | 5 | 8.3% | 0.004 | 0.546 | 0.051 |
| Sex, male | 3690 | 48.4% | 3556 | 48.0% | 98 | 65.3% | 36 | 60.0% | <0.001 | 0.175 | 0.600 |
| Race, White | 5735 | 75.3% | 5561 | 75.0% | 122 | 81.3% | 52 | 86.7% | 0.077 | 0.038 | 0.354 |
| Lack of functional independence | 148 | 1.9% | 138 | 1.9% | 7 | 4.7% | 3 | 5.0% | 0.013 | 0.075 | 1.000 |
| Albumin <4 g/dl | 2837 | 37.2% | 2738 | 36.9% | 77 | 51.3% | 22 | 36.7% | <0.001 | 0.965 | 0.054 |
| Alkaline phosphatase >93 IU/l | 3349 | 43.9% | 3240 | 43.7% | 85 | 56.7% | 24 | 40.0% | 0.002 | 0.563 | 0.029 |
| AST ≥30 IU/l | 2947 | 38.7% | 2847 | 38.4% | 73 | 48.7% | 27 | 45.0% | 0.011 | 0.296 | 0.631 |
| Haematocrit < 39% | 3435 | 45.1% | 3332 | 45.0% | 83 | 55.3% | 20 | 33.3% | 0.011 | 0.071 | 0.004 |
| BUN ≥20 mg/dl | 1205 | 15.8% | 1159 | 15.6% | 34 | 22.7% | 12 | 20.0% | 0.019 | 0.355 | 0.673 |
| ASA class ≥3 | 5074 | 66.6% | 4913 | 66.3% | 120 | 80.0% | 41 | 68.3% | <0.001 | 0.739 | 0.071 |
| Intraoperative factors | |||||||||||
| Operative time, min, median (range) | 220 (7–1029) | 218 (7–1029) | 298 (100–780) | 273 (115–734) | <0.001 | <0.001 | 0.112 | ||||
| Operative time >240 min | 3283 | 43.1% | 3133 | 42.3% | 110 | 73.3% | 40 | 66.7% | <0.001 | <0.001 | 0.398 |
| Any intraoperative transfusion | 1514 | 26.6% | 1431 | 25.9% | 68 | 57.1% | 15 | 31.3% | <0.001 | 0.397 | 0.002 |
| RBC ≥2 units | 1207 | 21.2% | 1134 | 20.5% | 61 | 51.3% | 12 | 25.0% | <0.001 | 0.443 | 0.002 |
| RBC ≥4 units | 523 | 9.2% | 486 | 8.8% | 30 | 25.2% | 7 | 14.6% | <0.001 | 0.159 | 0.135 |
| Extent of hepatectomy | <0.001 | 0.006 | 0.024 | ||||||||
| Partial | 4553 | 59.7% | 4458 | 60.2% | 64 | 42.7% | 31 | 51.7% | |||
| Left | 802 | 10.5% | 787 | 10.6% | 12 | 8.0% | 3 | 5.0% | |||
| Right | 1494 | 19.6% | 1433 | 19.3% | 39 | 26.0% | 22 | 36.7% | |||
| Extended | 772 | 10.1% | 733 | 9.9% | 35 | 23.3% | 4 | 6.7% | |||
| Partial versus left/right/extended | <0.001 | 0.181 | 0.237 | ||||||||
| Right/extended versus left/partial | <0.001 | 0.017 | 0.432 | ||||||||
| Right/extended | 2266 | 29.7% | 2166 | 29.2% | 74 | 49.3% | 26 | 43.3% | |||
| Left/partial | 5355 | 70.3% | 5245 | 70.8% | 76 | 50.7% | 34 | 56.7% | |||
| Biliary resection or anastomosis | 364 | 4.8% | 340 | 4.6% | 20 | 13.3% | 4 | 6.7% | <0.001 | 0.360 | 0.231 |
| Concurrent major GI or abdominal case | 912 | 12.0% | 867 | 11.7% | 36 | 24.0% | 9 | 15.0% | <0.001 | 0.419 | 0.151 |
| Postoperative factors | |||||||||||
| Any transfusion | 494 | 6.5% | 469 | 6.3% | 22 | 14.7% | 3 | 5.0% | <0.001 | 1.000 | 0.060 |
| Bleeding transfusion only | 46 | 0.6% | 39 | 0.5% | 6 | 4.0% | 1 | 1.7% | <0.001 | 0.276 | 0.676 |
| Return to operating room | 335 | 4.4% | 293 | 4.0% | 30 | 20.0% | 12 | 20.0% | <0.001 | <0.001 | 1.000 |
| Renal insufficiency/failure | 169 | 2.2% | 150 | 2.0% | 16 | 10.7% | 3 | 5.0% | <0.001 | 0.124 | 0.288 |
| Any SSI, wound disruption | 895 | 11.7% | 828 | 11.2% | 47 | 31.3% | 20 | 33.3% | <0.001 | <0.001 | 0.779 |
| Organ space infection | 478 | 6.3% | 430 | 5.8% | 33 | 22.0% | 15 | 25.0% | <0.001 | <0.001 | 0.640 |
| Postoperative LoS, days, median (range) | 6 (1–138) | 6 (1–138) | 15 (1–117) | 7 (3–24) | <0.001 | 0.004 | <0.001 | ||||
| Postoperative LoS ≥7 days | 3062 | 40.2% | 2888 | 39.0% | 139 | 92.7% | 35 | 58.3% | <0.001 | 0.002 | <0.001 |
| Death within 30 days | 177 | 2.3% | 162 | 2.2% | 14 | 9.3% | 1 | 1.7% | <0.001 | 1.000 | 0.072 |
P-values in bold indicate significance at P < 0.05.
Non-significant factors: year of operation; diabetes; body mass index; smoking; alcohol use; dyspnoea; stroke; pulmonary disease; sodium; white blood cell count; platelet count; creatinine; partial thrombin time; international normalized ratio; total bilirubin; ascites; varices; pneumonia; steroids; open wound; disseminated cancer; preoperative transfusion; bleeding disorder; operation in preceding 30 days; chief resident involvement; preoperative chemotherapy within 30 days; radiation therapy within 90 days; preoperative weight loss of >10%; admission before operation; postoperative re-intubation/ventilator >48 h; cardiac arrest; myocardial infarction; sepsis, and septic shock.
DVT, deep venous thrombosis; PE, pulmonary embolism; AST, aspartate aminotransferase; BUN, blood urea nitrogen; ASA, American Society of Anesthesiologists; RBC, red blood cells; GI, gastrointestinal; SSI, surgical site infection; LoS, length of stay.