Abstract
INTRODUCTION
Venous thromboembolism (VTE), especially, deep vein thrombosis (DVT) in lower extremities, often seriously combined with pulmonary embolism (PE), is a major and critical complication after total hip arthroplasty (THA). For better disgonsis of VTEs, D-dimer test is one of the useful methods. The aim of this study was to evaluate the efficacy of D-dimer levels before THA.
MATERIALS AND METHODS
Medical records of patients with osteoarthritis who received THA between April 2009 and March 2010 were reviewed. Value of D-dimer at preoperative day 1, postoperative day 3 and 14 was examined in those patients. D-dimer levels were examined by Latex Immunity Nephelometry Measurement Method and the Kit (Sysmex Corporation, Kobe, Japan). A total of 327 patients with D-dimer values were examined. The values D-dimer of the available patients were under 1.0 μg/ml. Ninety-nine patients (30%) had a high D-dimer level. DVT was diagnosed by doppler ultrasonography at preoperative day 1, postoperative day 3 and 14. The sensitivity and specificity of D-dimer in different cutoffs were verified by Receiver Operating Characteristic (ROC) curve. The ROC curve was constructed to describe the relationship between the sensitivity and the false positive rate for different values of D-dimer to patients suspected of VTEs. The study protocol was approved by the institutional ethics committee.
RESULTS
Eighty-two patients (83%) were females and 17 (18%) were males. Mean age was 67.3 (51–88) years. Mean value of D-dimer was 2.6 (1.1–10.3) μg/mL.
DVT was detected in 21 patients (21%) at the preoperative day 1 (DVT positive group). Average of age of this (or DVT positive) group was 71.9 (52–88) years. There was significant difference in D-dimer level between DVT negative group, DVT was not detected at the preoperative day 1, and DVT positive group (p<0.05). The areas under the receiver operating characteristic curve of D-dimer were larger than those of other parameters in the ROC curve (p=0.76). The cutoff value from the Youden index was 1.95 μg/mL, and the sensitivity and specificity values were 84.2% and 62.7%, respectively. The incidence of DVT in the positive group was 19% and 16%, respectively.
DISCUSSION AND CONCLUSION
Even DVT in the calf has the potential to propagate proximally, which led to a risk of PE. Therefore, screening for detection of DVT is important, even if the DVT was asymptomatic distal DVT. In some countries, it is thought that if the value of D-dimer is less than 0.5 μg/mL, VTEs are excluded in patients without surgeries, but some D-dimer kits, frequently used in Japan, have different cutoff values for the exclusion of DVT. Assessment of D-dimer is simple and reliable, as to be one of the beneficial methods to detect high-risk patients of VT and/or occult DVT before THA. In conclusion, it is important to evaluate preoperative screening of VTE before THA, as the existence of pre-operative DVT has high risk of postoperative DVT occurrences. The D-dimer test is one of useful methods to evaluate the perioperative state of the patients with VTE risk.
