1. Is Aspirin Enough? Rate of Asymptomatic and Symptomatic DVT and PE After Total Joint Arthroplasty
Pardi B1,2, Schwartz B1,2, Savin D1,2,Rodriguez J1,2, Shah R2,3, Goldstein J2,3, Goldstein W2,3
1-University of Illinois-Chicago, 2-Advocate Lutheran General Hospital, 3-Illinois Bone and Joint Institute
ABSTRACT
METHODS
Table 3. DVT/PE rate divided into above and below knee thrombus groups anatomically by the various prophylactic modalities.
Figure 1. Total Number of DVTs/PEs for each drug compared to total number of patients on each drug
INTRODUCTION: Thromboembolic events, such as deep venous thrombosis (DVT) and pulmonary embolism (PE) after total joint arthroplasty (TJA) are potentially devastating complications. Tremendous effort and allocation of healthcare resources has been put forth to prevent these events. The goal of this study was to evaluate the efficacy of five different anticoagulation regimens at preventing DVT and PE after TJA.
METHODS: We conducted a single surgeon retrospective review on 638 primary unilateral TJA from January 2013 to October Patient demographics, choice of anticoagulation (aspirin (ASA), warfarin, enoxaparin, rivaroxaban and aspirin with portable pneumatic compression devices), and the use of intravenous transexamic acid (TXA) were collected. All patients underwent a lower extremity doppler ultrasound at 3 weeks postoperatively to document asymptomatic and symptomatic DVT. Routine diagnostic tests were obtained if there was clinical suspicion of a thromboembolic event. Statistical analysis was performed using SPSS.
RESULTS: This study evaluated 638 patients with unilateral TJA divided into five groups based on choice of anticoagulation including: 122 patients using ASA, 248 patients using warfarin, 211 patients using enoxaparin, 18 patients using rivaroxaban, and 39 patients using ASA and portable pneumatic compression devices. The overall 3-week DVT (including asympatomatic and symptomatic patients) and PE rates were 5.6% and 0.3%, respectively. The following rates of DVT/PE were found among each group: ASA without pneumatic compression devices 12.3%, warfarin 2.8%, enoxaparin 5.7%, rivaroxaban 5.6%, and ASA with pumps 7.7%. There was a statistically significant difference in DVT rates comparing ASA without pneumatic compression devices with enoxaparin (p=0.033) and ASA without pneumatic compression devices with warfarin (p=<0.001). There was no significant difference comparing ASA with pneumatic compression devices to any other form of anticoagulation. 2 patients experienced symptomatic PE (1 using enoxaparin, 1 using warfarin). Intraoperative TXA was received by 431 patients. TXA did not affect DVT or PE rate (p>0.05).
CONCLUSIONS: The results of this study demonstrate that ASA without portable pneumatic compression devices has higher rates of asymptomatic or symptomatic DVTs compared to warfarin and enoxaparin. ASA with pneumatic compression devices did not demonstrate a significant difference in asymptomatic or symptomatic rates of DVT. The authors prefer the use of ASA with portable pneumatic compression devices after TJA. The present study is limited in its power to detect differences in PE rates between the different anticoagulant patient populations.
This is a single surgeon retrospective review of 638 primary unilateral TJA from January 2013 to October 2014.
Patient demographics, type of anticoagulation (aspirin, warfarin, enoxaparin, rivaroxaban, and aspirin with portable pneumatic compression devices), and use of tranexamic acid (TXA) were obtained from the electronic medical record from Lutheran General Hospital and Illinois Bone and Joint Institute Clinic.
All patients had a lower extremity doppler ultrasound at the 3 week postoperative visit to document asymptomatic and symptomatic DVT.
All patient charts were reviewed for in hospital data suggestive of DVT or PE including lower extremity doppler ultrasound, computed tomography scans and ventilation and perfusion studies.
Statistical analysis was performed using SPSS to demonstrate statistical significance.
ASA had the highest rate of above knee thrombus at 2.5%, followed by Enoxaparin at 1.9%. Due to limited sample size no attempt was made at performing statistical significance of rates of above knee thrombus.
CONCLUSION
RESULTS
Figure 2. Percentage of patients found to have a DVT/PE on a specific drug
The results of this study demonstrate that ASA without portable compression devices has significantly higher rates of DVTs/PEs (symptomatic and asymptomatic) compared to warfarin and enoxaparin.
The rate of above knee thrombus was small but higher in the ASA without compression devices group compared to warfarin and enoxaparin. However the small sample size limits the significance of this finding.
There was no statistically significant difference in rates of asymptomatic or symptomatic DVT/PE comparing ASA with portable pneumatic compression devices to other anticoagulants. However, the ASA and pneumatic compression devices group was relatively small.
A weakness of our study is the sample size is to small to detect differences in PE rates. Another weakness is that we compared all DVT/PE both symptomatic and asymptomatic.
Other studies such as the paper by Raphael 4 support ASA 325mg twice daily as an appropriate option for most patients. While other authors suggest a risk stratification model for deciding who is safe to receive ASA as prophylaxis6.
The authors of our study prefer the use of ASA with portable pneumatic compression devices for VTE prophylaxis after TJA.
Future research should work to obtain a complete profile of the various anticoagulation options. Risk of bleeding must also be considered and compared between the options to make an overall decision of which option may be safest.
This study evaluated 638 TJA patients, 395 were female (62%) with an average age of 68 ± 10 at time of surgery. There were 299 Total Knee Arthroplasties (47%) and 339 Total Hip Arthroplasties (53%) performed. Anticoagulant groups studied included 122 patients using ASA, 248 patients using warfarin, 211 patients using enoxaparin, 39 patients using ASA and portable pneumatic compression devices, and 18 patients using rivaroxaban. The overall 3-week DVT (asymptomatic and symptomatic) and PE rates were 36 (5.6%) and 2 (0.3%), respectively. The individual rates of DVT and PE combined observed among the different anticoagulants were: ASA without pneumatic compression devices 12.3% (15/122), warfarin 2.8% (7/248), enoxaparin 5.7% (12/211), rivaroxaban 5.6% (1/18), and ASA with portable pneumatic compression devices 7.7% (3/39). There was a statistically significant difference in DVT/PE rates comparing ASA without pneumatic compression devices with enoxaparin (p=0.033) and ASA without pneumatic compression devices with warfarin (p<0.001). There was no significant difference comparing ASA with pneumatic compression devices to any other form of anticoagulation. Two patients experienced PE (1 using enoxaparin, 1 using warfarin). 431 patients received intraoperative TXA. TXA did not significantly affect DVT/PE rate; 6.7% rate with TXA, 4.3% without TXA (p=0.234). Further classification of VTE was performed based on location of thrombus. Twenty-eight of the thrombi were found to be below the knee, while 8 were above the knee. The rate of above knee thrombus was very low at 1.3%. However, ASA group did have highest rate at 2.5%, followed by enoxaparin at 1.9%. The small sample size for above knee thrombus limited inference comparisons. The mean age of patients in the DVT/PE group was higher but not statistically significant at (71.1 ± 10 years) than that of the non-DVT group (68.0 ± 10 years) p=0.064.
INTRODUCTION
Venous thromboembolism (VTE) can be a serious complication of elective total joint arthroplasty (TJA). Without prophylaxis, the occurrence of all VTE has been estimated to be above 40%, with clinically significant VTE at 4.3% over 35 days following major orthopedic surgery 1. It has been standard of practice to use some form of medical and/or mechanical deep venous thrombosis (DVT) prophylaxis to prevent these common and sometime serious complications 2. However, there has been disagreement over which medications to use for this purpose. Many differences exist between the various agents currently on the market, including effectiveness of VTE prevention, risk of bleeding, reversal of anticoagulation, ease of administration, and patient compliance.
A greater consensus has recently been reached between the American College of Chest Physicians (ACCP) and American Academy of Orthopedic Surgeons (AAOS) guidelines for VTE prophylaxis after TJA. 1,2. Although the ACCP prefers LMWH (low molecular weight heparin), it also recommends using adjusted dose vitamin K antagonist (warfarin), rivaroxaban, aspirin, dabigatran, fondaparinux, apixaban, and low dose unfractionated heparin as VTE prophylaxis. The AAOS does not have a recommendation to use a specific anticoagulatant because the clinical evidence is currently unclear. Both the AAOS and ACCP recommend the use of pneumatic compression devices after TJA. Limitations exist for most anticoagulants including compliance with self administration (LMWH), injection site morbidity (LMWH), blood draws for dose adjustment (warfarin), cost, lack of an antidote for reversal (rivaroxaban), and most importantly the risk of local and nonsurgical site bleeding. The choice of anticoagulant use after TJA must take these multiple factors into account.
The recent acknowledgement of the use of aspirin as an adequate means of thromboprophylaxis for TJA in the 2012 American College of Chest Physicians (ACCP) evidence-based clinical practice guidelines has created new interest in its use1. In some studies of aspirin use authors have found efficacy of aspirin use as VTE prophylaxis 4,5. Aspirin’s oral delivery, lack of need for monitoring, potential lower risk of bleeding, and cost effectiveness have all been positive factors in it gaining popularity as pharmaceutical prophylaxis.
Our objective was to find asymptomatic and symptomatic DVT rates in primary unilateral total joint patients comparing different anticoagulant modalities.
Figures 1 and 2 show the rates of DVT/PE in the various treatment groups. Aspirin without foot pumps has the largest percent of patients found to have a DVT/PE.
REFERENCES
Falck-Ytter Y, Francis CW, Johanson NA, Curley C, Dahl OE, Schulman S, et al. Prevention of VTE in orthopedic surgery patients: Antithrombotic Therapy and Prevention of Thrombosis. American College of Chest Physicians Evidence-Based Clinical Practice Guidelines, 141. , Chest, 9th ed (2012: e278S–325S.
Mont MA, Jacobs JJ. AAOS clinical practice guideline: preventing venous thromboembolic disease in patients undergoing elective hip and knee arthroplasty. J Am Acad Orthop Surg Dec;19(12):777-8.
Markel, David C., et al. "Venous thromboembolism: management by American association of hip and knee surgeons." The Journal of arthroplasty 25.1 (2010): 3-9.
Raphael IJ, Tischler EH, Huang R, Rothman RH, Hozack WJ, Parvizi J.. "Aspirin: An Alternative for Pulmonary Embolism Prophylaxis After Arthroplasty?." Clinical Orthopaedics and Related Research®(2013): 1-7.
Hamilton SC, Whang WW, Anderson BJ, Bradbury TL, Erens GA, Roberson JR.. "Inpatient Enoxaparin and Outpatient Aspirin Chemoprophylaxis Regimen After Primary Hip and Knee Arthroplasty: A Preliminary Study." The Journal of Arthroplasty 27.9 (2012):
Nam, Denis, et al. "The Effectiveness of a Risk Stratification Protocol for Thromboembolism Prophylaxis After Hip and Knee Arthroplasty." The Journal of arthroplasty (2015).
Table 2. Statistical Significance of the treatment groups compared to one another.
Table 1. Demographics and comparison of patients with and without DVT/PE
Aspirin without foot pumps shows significantly higher rate of DVT/PE when compared to both enoxaparin and warfarin.
No significant differences were found between groups in regards to type of procedure, age or TXA use. Overall rate of DVT and PE was 5.6% and 0.3% respectively.