Arch Orthop Trauma Surg DOI 10.1007/s00402-008-0751-2
ORTHOPAEDIC SURGERY
Deep vein thrombosis after total hip arthroplasty in Korean patients and D-dimer as a screening tool Myung-Chul Yoo · Yoon-Je Cho · Elie Ghanem · Alankar Ramteke · Kang-Il Kim
Received: 27 March 2008 © Springer-Verlag 2008
Abstract Introduction This prospective study was designed to conWrm risk factors and to assess the incidence of deep vein thrombosis after total hip and surface replacement arthroplasty in Korean patients not receiving anticoagulation prophylaxis and to determine eYcacy of plasma D-dimer levels as a screening test. Materials and methods From May 2003 to August 2004, 221 consecutive patients undergoing unilateral total hip arthroplasty and hip resurfacing were evaluated. All patients underwent ultrasonography preoperatively and venography and/or ultrasonography on postoperative day 7. Plasma D-dimer levels were estimated by latex immunoassay preoperatively and on days 3 and 7 postoperatively. Results Of the 221 patients in our cohort, 23 developed deep vein thrombosis (10.4%). Age (r = 0.245, P < 0.001) and gender (r = 0.155, P = 0.021) signiWcantly correlated with deep vein thrombosis. Rise in incidence paralleled increase in age (X2 = 32.860, P < 0.001). D-dimer levels on postoperative days 3 ( = 0.364, P < 0.001) and 7 ( = 0.470, P < 0.001) were signiWcantly correlated to the development of DVT. Conclusion While incidence of deep vein thrombosis in Korean population after THA was lower than that in the West; it increased with age, and in female gender. SigniWcant
M.-C. Yoo · E. Ghanem · A. Ramteke · K.-I. Kim (&) Department of Orthopaedic Surgery, Center for Joint Diseases, Kyung Hee University East-West Neo Medical Center, 149 Sangil-dong, Gangdong-gu, Seoul 134-727, South Korea e-mail:
[email protected];
[email protected] Y.-J. Cho Department of Orthopaedic Surgery, Kyung Hee University Medical Center, Seoul 130-702, South Korea
correlation was found between D-dimer levels and the development of deep vein thrombosis. Keywords Total hip arthroplasty · Hip resurfacing · Deep vein thrombosis · D-dimer · Korean patients
Introduction Deep vein thrombosis (DVT) is a serious complication following major hip surgeries in Western populations. The occurrence of DVT among patients not receiving postoperative chemoprophylaxis ranges from 28 to 70% [9, 11, 37]. Despite the high incidence of DVT in the Western world, it has received little attention in Korea and in other East Asian countries. In these countries, there is a presumed low prevalence of the occurrence of the disease following total hip arthroplasty [23, 26, 43]. However, due to recent changes in the dietary habits and the transition to a more westernized lifestyle, the incidence of DVT and pulmonary embolism in these countries has risen during the past three decades [15, 26, 43]. Since prophylactic measures provide incomplete protection against DVT [1, 10, 26], early diagnosis is imperative. There are several methods for detecting DVT including venography, B-mode ultrasonography, color-Xow Doppler imaging, and MR angiography. Although venography is the most accurate method for detection, its invasive nature and the exposure of patients to radiation makes adopting it as a screening test extremely impractical. Furthermore, intravenous injection of radiocontrast dye may cause side eVects including injury to the kidneys, skin, and veins [13, 19, 51]. Ultrasonography (USG) has become the most popular modality for surveillance of DVT after THR and TKR [7, 27]. It is a painless non invasive diagnostic imaging
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technique that provides a two-dimensional cross-sectional representation of tissue and direct visualization of the thrombus. Venous USG can reliably detect thrombi in the proximal veins of symptomatic patients but its eYcacy as a screening tool remains controversial because of concerns related to its ability to accurately detect proximal thrombi in asymptomatic patients. Other potential problems with USG as screening tool are due to its dependence on the skills of the operator [27]. Thus if USG has to be used as a reliable screening tool these problems can be addressed by determining the reliability of USG at a given institution where the study is conducted. A study to determine the reliability by performing a venography and duplex USG on a cohort of patients can validate the clinical relevance of a randomized clinical trial [36]. In recent years, time-eYcient methods, including observing plasma D-dimer levels, have been introduced for the detection of DVT in high-risk asymptomatic patients. D-dimer is one of the compounds formed when Wbrinolytic proteins, such as plasmin, degrade cross-linked Wbrin strands [42, 47, 48]. It is detected using a variety of available latex agglutination, ELISA, or immunoturbidometry assays. Both Western [2, 11] and Asian studies [33, 34] have found plasma D-dimer levels to be signiWcantly higher postoperatively in those patients who developed DVT compared to those who did not. Thus D-dimer level is a potentially useful tool as the Wrst screening examination in the assessment of DVT and prediction of consequent fatal PE after hip replacement arthroplasty [34]. The present study was prospectively designed to assess the incidence of DVT after total hip (THA) and surface replacement arthroplasty to conWrm certain risk factors in Korean patients not receiving anticoagulation prophylaxis and also to determine the eYcacy of plasma D-dimer levels as a screening test. It evaluated the sensitivity, speciWcity, and predictive value of plasma D-dimer level in routine postoperative screening for DVT on days 3 and 7. D-dimer cut-oV values with the best negative predictive value were calculated for both postoperative days, especially those values that were found to be signiWcant in ruling out DVT.
Materials and methods Study group A prospective follow-up study of 221 consecutive patients undergoing primary-unilateral total hip arthroplasty (THA) was conducted at our institution from May 2003 to August 2004. The study group included 169 cases of cementless THA and 52 cases of total hip resurfacing arthroplasty. This cohort included 144 males (65.2%) and 77 females (34.8%). The average age of patients at the time of operation
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was 45, with a range from 18 to 69 years. The original diagnoses included 144 hips with avascular necrosis, 62 hips with osteoarthritis, 9 hips with ankylosing spondylitis, and 6 hips with rheumatoid arthritis. No bilateral THAs were included, and additional criteria for exclusion from the study were as following: trauma prior to surgery, obesity (BMI > 30), a history of venous thromboembolism, age greater than 70 years old, presence of hypercoagulopathy or hematological disorders, steroid or hormonal or anticoagulant therapy, congestive heart failure, oral contraceptive therapy, and previous vascular surgery. Studies show that these factors may increase the risk of developing deep vein thrombosis [50]. Sixty-one patients had at least one of the above-mentioned criteria and were already excluded before the study. An automatic pneumatic compression pump was applied to the contralateral limb of every patient during their respective operations. Postoperatively, thromboprophylaxis consisted only of bilateral compression stockings and active quadriceps and ankle motion exercises. In most cases, bedside sitting exercises were started on the second postoperative day. THA and hip resurfacing patients were permitted to walk with crutches within 5 days of surgery. Investigation methods All patients had bilateral real-time B-mode ultrasonography performed with the HDI 5000 system (Philips-ATL, Bothwell, WA, USA) using a 5–12 MHz linear probe on both lower limbs during their preoperative evaluation in order to detect prior DVT. Each lower extremity was scanned from the inguinal ligament, beyond the trifurcation of the popliteal vein, and to the level of the ankle. The criteria for an abnormal duplex scan were visualization of an intraluminal venous thrombus, inability to compress the vein, lack of spontaneous phasic venous Xow, and/or Xow augmentation with compression. A single experienced specialist (RKN) in musculoskeletal radiology performed all investigations in the detection of DVT in both symptomatic and asymptomatic patients and he did not have knowledge of D-dimer results. Ascending venography was performed according to the modiWed technique described by Rabinov and Paulin [38] on postoperative day 7 on both lower limbs of 47 patients that had consented to the procedure. The veins observed were the common femoral, superWcial femoral, popliteal, posterior tibial, and peroneals. The venographic criterion for diagnosis of DVT was a Wlling defect of vascular lumen. A total of 174 patients did not consent to postoperative venography and underwent duplex ultrasonography of both the operated and non-operated extremity in the same manner as the preoperative assessment. Proximal DVT was
Arch Orthop Trauma Surg
deWned as a thrombus in the femoral vein, superWcial femoral vein, and popliteal vein, while a distal DVT included thrombus formation in the veins distal to the popliteal vein. The technique and criteria for interpreting venography and duplex ultrasonography were applied uniformly to all patients. Ten milliliters of blood was drawn from the antecubital vein and collected in citrated vacutainer tubes preoperatively and postoperatively between 8:00 and 9:00 am on days 3 and 7. The blood was centrifuged in the lab at 3,000 rpm for 10 min. Plasma was obtained and stored in a ¡80°C freezer for later processing but no longer than 3 days. Plasma DD levels were measured by STA®-Liatest® D-Di kit (Asnieres, France) immunoassay that permits fast and quantitative DD estimations in individual patients. Lab technicians who were unaware of any previous test results performed all of the assays. Those patients who developed postoperative DVT as detected by postoperative venography or duplex ultrasonography were treated with anticoagulation therapy according to institutional protocol. The study obtained all patient consents and approval from the Institutional Review Board (IRB) committee before beginning the study. Reliability of duplex ultrasonography Venography and duplex ultrasonography were compared statistically to determine the reliability and to validate the use of ultrasonography at our hospital. A single experienced specialist (RKN) in musculoskeletal radiology performed all investigations in the detection of DVT in both symptomatic and asymptomatic patients. This investigation was needed to validate the clinical relevance of the prospective clinical trial.
Statistical analysis All the data were stored in a computer Wle and statistical analysis was performed using SPSS version 12.0. The data are expressed as mean § standard deviation. A P value less than 0.05 was considered statistically signiWcant for normally distributed data. The relationships between DVT and age, sex, and the type of operation were evaluated for statistical signiWcance. Patient age was stratiWed as following: young, from 18 to 39 years; middle-aged, 40 to 59 years, and elderly, from 60 to 69 years. Then, the incidence of DVT was calculated for each category. Statistical signiWcance between the D-dimer levels of patients who did and did not develop DVT, on postoperative days 3 and 7 was determined using the non-parametric method (Mann–Whitney U test). The sensitivity, speciWcity, and positive and negative predictive values of the
D-dimer levels, assessed on postoperative days 3 and 7, were determined using the standard method of proportions. Multivariate logistic regression analysis was used to determine independent relationships between the postoperative day that D-dimer levels were taken and the formation of DVT. Receiver Operating Characteristics (ROC) curves were constructed to determine the highest sensitivity and speciWcity of the D-dimer value. The sensitivity (ordinate) versus 1-speciWcity (abscissa) for diVerent cut-oV values was plotted and the area under the curve (AUC) was then calculated. An ideal test that generates a sensitivity and speciWcity of 100% generates an AUC of 1, while a noninformative test produces an AUC of 0.5 [20].
Results Of the 221 patients in our cohort, 23 (10.4%) developed DVT. This was detected using venography or duplex ultrasonography performed on postoperative day 7. Out of 169 patients who underwent primary THA, 20 patients (11.8%) developed DVT, while out of 52 patients who underwent resurfacing arthroplasty, 3 patients (5.8%) developed DVT. The diVerence in incidences of DVT among those operative procedures was found to be statistically signiWcant (P < 0.001); hip resurfacing, which does not require intramedullary preparation, had a lower incidence of DVT compared to conventional THA. Venography identiWed 5 out of 47 patients who consented to the procedure as having DVT, while duplex imaging detected DVT in 18 out of 174 patients. There was no signiWcant diVerence between the DVT incidences that were determined using the two techniques (P > 0.05). Among the 23 patients who developed DVT, a total of 4 proximal thrombi and 19 distal thrombi were detected. The posterior tibial veins, the muscular branches of the soleus muscle, peroneal veins, and popliteal veins were the most frequently aVected veins. Sixteen cases involved one vein, eight involved two, and only two cases developed thrombosis in three or more veins. Nineteen cases involved the operated leg, two cases developed DVT in the contralateral limb, and the remaining two patients had involvement of bilateral lower limbs. Out of the 23 patients with documented DVT, only four cases developed symptoms: two cases suVered from leg pain, one case developed leg swelling, and the remaining case had leg pain and pulmonary embolism that was diagnosed clinically and was conWrmed by dynamic chest CT scan and V/Q scan. All four patients who developed DVT had undergone THA. They were subsequently anticoagulated according to institutional protocol with complete resolution of their symptoms. No fatal pulmonary embolisms or deaths due to surgical complications were seen.
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Age (r = 0.245, P < 0.001) and gender (r = 0.155, P = 0.021) were signiWcantly correlated with DVT (Table 1). The postoperative incidence of DVT in each of the three age groups was 5 out of 88 of the young group (5.7%), 7 out of 99 of the middle-aged group (7.1%), and 11 out of 34 of the elderly group (32.4%). Rises in DVT incidence paralleled increase in age (2 = 32.860, P < 0.001). The values of the preoperative D-dimer concentrations ranged from 0.01 to 4.18, with a mean value of 0.59 § 0.66 g/ml and the values are normally distributed. There was no statistically signiWcant relation found between the preoperative values and the incidence of postoperative DVT (P > 0.05). Alternately, univariate analysis of D-dimer levels on postoperative day 3 ( = 0.364, P < 0.001) and day 7 ( = 0.470, P < 0.001) revealed a signiWcant correlation with the development of DVT (Table 2). However, multivariate logistic regression analysis of the postoperative D-dimer levels revealed that levels on day 3 did not correlate to DVT, while the values on day 7 were more indicative of DVT ( = 0.453, P < 0.001). The average D-dimer levels of patients with documented DVT on postoperative days 3 and 7 were 4.01 § 1.89 g/ ml (range 1.18–9.27) and 5.14 § 2.01 g/ml (range 2.55– 9.28), respectively. Those patients who did not develop DVT had D-dimer levels of 2.33 § 1.28 g/ml (range 0.42–7.16) and 2.92 § 1.18 g/ml (range 0.59–7) on postTable 1 Incidence and correlation of variables with DVT Variables
Incidence (%)
ra
P-value
0.245
0.05). The strength of our study lies in that fact that it is prospective and includes a large population of THA patients with strict inclusion and exclusion criteria and the Wrst report of DVT incidence in Korean population as well as in hip resurfacing arthroplasty. While the incidence of DVT in the Korean population after THA was lower than that in the West, the incidence increased with age, a Wnding similar to that of the West. Acknowledgments The authors thank Dr. Kyung-Nam Ryu for the investigations in the detection of DVT and Dr. Gae-Yeol Cho for the statistical analysis.
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