Of the 498 patients 6.6% experienced one or more symptomatic cardiovascular complications (deep vein thrombosis, pulmonary embolism (PE), myocardial infarction, and stroke, transient ischemic attack or retinal vein thrombosis). In the degenerative OA group 4.7% (95% Cl: 2.6–6.8%) had a cardiovascular event and in the secondary OA + revision group the rate was 13.4% (95% Cl: 10.2–16.6). The rate of complications directly related to the surgery (dislocation, perioperative fracture, bleeding, aseptic loosening, deep infection, peroneal palsy or superficial wound infection) was 15.4% (95% Cl: 12.3–18.6). In the degenerative OA and secondary OA/revision group the rates were: 14.2% and 19.6% respectively. Nine (1.8%) patients died, five of cardiovascular reasons (disseminated intravascular coagulation, PE followed by renal failure, PE followed by cerebral ischemia and stroke), the first three in close relation to the operation.
Patients and methods: A total of 500 (430 primary THR and 70 revision THR) consecutive patients were included in the study performed between January 2004 and May 2005 in Frederiksborg County (Denmark). They were to be followed for 90 days after surgery. Patients were interviewed before surgery for medical history and on days 5 (while in hospital) and 90 (by telephone call) for signs and symptoms of acute myocardial infarction (AMI), pulmonary embolism (PE), deep-vein thrombosis (DVT), transitory cerebral ischemia (TCI)/stroke and retinal vein thrombosis (RVT). The validity of the events was confirmed using files from hospital, general practitioner and international criteria. Results: Overall, 498 patients were followed-up for 90 days, 2 patients having withdrawn consent. In-hospital pharmacological thromboprophylaxis was performed in 499 patients. Twenty-four patients (4.8%) experienced at least one serious TEC up to day 90: 2 (0.4%) patients died from surgical-related complications (no autopsy was performed); 1 (0.2%) patient experienced AMI, 5 (1.0%) had PE, 10 (2.0%) DVT, 4 (0.8%) TCI, and 2 (0.4%) RVT. Moreover, 2 patients experienced two TEC: AMI followed by TCI in a first patient, PE and TCI in a second patient. The first event occurred up to day 5 in 9 patients (38%) and after day 5 in 15 patients (62%). Five patients (1%) had clinically relevant bleeding complications: 3 patients had a single, minor, upper gastrointestinal bleeding episode while in hospital, one patient developed a huge expanding haematoma at the operation site treated with hip spica and another patient a peritoneal haematoma leading to re-operation. Conclusion: This study performed in an unselected population clearly shows that THR still results in serious TEC in spite of a wide use of modern anaesthesia techniques, thrombosis prophylaxis and early mobilisation. In the future, we need to better identify at-risk patients in order to optimise their management, in particular post-discharge care, and reduce the risk of serious TEC.
To target postoperative patients in need for prolonged pharmacologic thromboprophylaxis due to persistent coagulation activation, we developed and evaluated a qualitative test method, which detects the urinary excretion of prothrombin fragment 1+2 (uF1+2). The test was developed as a dip-stick device consisting of a one step rapid lateral flow immunoassay with visual readout on one test line and one control line. The assay time was between 5 and 10 minutes. Spot urine samples were collected in 113 patients undergoing elective hip arthroplasty preoperatively and on day 5 after operation. Specimens were frozen immediately and stored until batch analysis. Pharmacologic thromboprophylaxis was administered according to national guidelines until day 7±2 after the operation. The results of the new dip-stick device were compared with the results of a laboratory based enzyme-linked-immunosorbent-assay (ELISA) method and a predetermined cut-off value. Patients were followed for development of vascular thrombotic complications/unexpected death until day 90 after the operation. 10 (8.8%) patients experienced an event during the study: 2 (1.8%) died unexpectedly and 8 (7.1%) had a vascular thrombotic event. All patients with clinical events had significantly raised postoperative levels of uF1+2. The clinical accuracy of the dip-stick test was acceptable with a sensitivity of 100% and a negative predictive value of 100%. Compared to the standard ELISA method the dip-stick test had a sensitivity of 93% and a specificity of 48%. Laboratory ELISA analysis of urinary excretion of uF1+2 is neither feasible nor applicable in postoperative patients. Bed-side testing of persistent coagulation activation, however, could help to determine the need for prolonged thromboprophylaxis. The new dip-stick urine test was very easy to use, had a high negative predictive value and sensitivity and thus appears to be safe. However, the number of false positive test results prompts a fine-tuning of the test device. In terms of clinical applicability the test was acceptable. The study showed that about one third of the patients could be excluded from further extension of thromboprophylaxis beyond the first week.