By C. Lowry Barnes, MD
Introduction
In 2004, updated American College of Chest Physicians (ACCP) guidelines were published1. These recommendations became the de facto "gold standard" for third parties such as hospitals, insurance companies, and attorneys.
The strength of the ACCP guidelines is that evidence-based medicine was truly applied to the process. There were very strict criteria for studies to be referenced. These studies were critically evaluated by experts in the field. Recommendations for use of a treatment were appropriately stratified as to Grade 1 (strong recommendation with benefits outweighing risk, burden, and cost) and Grade 2 (less certainty). A recommendation of "A" was reserved for randomized controlled trials with consistent results that provided a low likelihood of bias; "B," for randomized controlled trials with inconsistent results or with major methodological weaknesses; and "C," for observational studies. Warfarin (adjusted to an international normalized ratio of 2.0 to 3.0), low-molecular-weight heparin, and fondaparinux met Grade-1A criteria for recommendation for total hip replacements and total knee replacements. Additionally, intermittent pneumatic compression received a Grade-1B recommendation for total knee replacements.
Orthopaedic surgeons have reported complications with implementation of these guidelines. Burnett et al.2 reported surgical-site complications when administering low-molecular-weight heparin for ten days (4.7% readmission, 3.4% irrigation and débridement rate, and 5.1% prolonged hospitalization). Parvizi et al.3 have shown that patients with a wound hematoma or persistent wound drainage are at increased risk of postoperative deep joint infection.
Discussion
Orthopaedic surgeons are acutely concerned about postoperative wound complications and infections. Given similar efficacies in the prevention of pulmonary emboli, orthopaedists may prefer less "risky" methods of prophylaxis than those recommended by the ACCP. Additionally, these ACCP guidelines may result in more expense to patients.
Summary
Orthopaedic surgeons must carefully weigh the risks and benefits of proposed prophylaxis for deep venous thrombosis.
American Academy of Orthopaedic Surgeons Guidelines: Prevention of Symptomatic Pulmonary Embolism in Patients Undergoing Total Hip or Total Knee Arthroplasty
By Paul F. Lachiewicz, MD
A work group of the American Academy of Orthopaedic Surgeons, with the assistance of the Center for Clinical Evidence Synthesis at Tufts-New England Medical Center, has proposed a guideline for the prevention of symptomatic (and fatal) pulmonary embolism in patients undergoing total hip and knee arthroplasty1. This guideline includes recommendations from both a consensus process and an analysis of forty-two published papers since 1996. The outcomes of interest included symptomatic and fatal pulmonary embolism, death, and major episodes of bleeding. The guideline recommends the preoperative evaluation of all patients for "standard" and "high" risks of both pulmonary embolism and major bleeding complications. The use of regional anesthesia, mechanical prophylaxis, rapid mobilization, and patient education were consensus recommendations. The choice of a specific medication postoperatively should be based on an individual risk-benefit analysis of pulmonary embolism and major bleeding complications.
Consensus Regarding General Recommendations
Assess all patients preoperatively with regard to their risk (standard or high) of pulmonary embolism (Level III, Grade B)Assess all patients preoperatively with regard to their risk (standard or high) of bleeding complications (Level III, Grade C)Consider vena cava filter placement for patients who have known contraindications to anticoagulation therapy (Level V, Grade C)Consider intraoperative and/or immediate postoperative mechanical compression (Level III, Grade B)Consider regional anesthesia for the procedure (in consultation with anesthesiologist) (Level IV, Grade C)Consider continued use of mechanical prophylaxis postoperatively (Level IV, Grade C)Rapid patient mobilization (Level V, Grade C)Routine screening for thromboembolism is not recommended (Level III, Grade B)Educate the patient about symptoms of thromboembolism (Level V, Grade B)
Assess all patients preoperatively with regard to their risk (standard or high) of pulmonary embolism (Level III, Grade B)
Assess all patients preoperatively with regard to their risk (standard or high) of bleeding complications (Level III, Grade C)
Consider vena cava filter placement for patients who have known contraindications to anticoagulation therapy (Level V, Grade C)
Consider intraoperative and/or immediate postoperative mechanical compression (Level III, Grade B)
Consider regional anesthesia for the procedure (in consultation with anesthesiologist) (Level IV, Grade C)
Consider continued use of mechanical prophylaxis postoperatively (Level IV, Grade C)
Rapid patient mobilization (Level V, Grade C)
Routine screening for thromboembolism is not recommended (Level III, Grade B)
Educate the patient about symptoms of thromboembolism (Level V, Grade B)
Medication Recommendations (in Alphabetical Order) from the Literature Review and Analysis Process
For patients at standard risk of both pulmonary embolism and major bleeding:AspirinLow-molecular-weight heparinPentasaccharidesWarfarin (international normalized ratio goal of =2.0)
Aspirin
Low-molecular-weight heparin
Pentasaccharides
Warfarin (international normalized ratio goal of =2.0)
Level of Evidence: III; Grade of Recommendation: B (choice of prophylactic agent), C (dosing and timing)
For patients at elevated risk of pulmonary embolism and standard risk of major bleeding:Low-molecular-weight heparinPentasaccharidesWarfarin (international normalized ratio goal of =2.0)
Low-molecular-weight heparin
Pentasaccharides
Warfarin (international normalized ratio goal of =2.0)
Level of Evidence: III; Grade of Recommendation: B (choice of prophylactic agent), C (dosage and timing)
For patients at standard risk of pulmonary embolism and elevated risk of bleeding:AspirinWarfarin (international normalized ratio goal of =2.0)None
Aspirin
Warfarin (international normalized ratio goal of =2.0)
None
Level of Evidence: III; Grade of Recommendation: C
For patients at elevated risk of both pulmonary embolism and major bleeding:AspirinWarfarin (international normalized ratio goal of =2.0)None
Aspirin
Warfarin (international normalized ratio goal of =2.0)
None
Level of Evidence: III; Grade of Recommendation: C
Johanson NA, Lachiewicz PF, Lieberman JR, Lotke PA, Parvizi J, Pellegrini V, Stringer TA, Tornetta P 3rd, Haralson RH 3rd, Watters WC 3rd. Prevention of symptomatic pulmonary embolism in patients undergoing total hip or knee arthroplasty. J Am Acad Orthop Surg. 2009;17;183-96.17183
2009
[PubMed]
Aspirin Is Enough
By Arlen D. Hanssen, MD
Aspirin (acetylsalicylic acid) has been used as a method of chemoprophylaxis following total joint replacement for decades. When used within a multimodal approach as prophylaxis for venous thromboembolism in patients undergoing total joint arthroplasty, aspirin continues to be an excellent choice for many surgeons because it is safe, inexpensive, tolerated by most patients, and does not require monitoring1. The primary reason for the use of chemoprophylaxis should be the risk of pulmonary embolism or death, not deep venous thrombosis, and aspirin compares favorably with other anticoagulants when these end points are considered.
Aspirin does not complicate the practice patterns of anesthesiologists and, unlike other anticoagulants, is not associated with higher neuraxial-bleeding complication rates2. Given preoperatively, aspirin helps prevent platelet aggregation during the operative and immediate postoperative time period, whereas chemoprophylaxis agents require a designated postoperative time delay. Low-dose aspirin, unlike other agents, allows for the concomitant use of nonsteroidal medications postoperatively. The use of aspirin has been associated with a low prevalence of the wound-healing problems, hematomas, and other serious bleeding complications that have been associated with use of more potent anticoagulants.
Venous thromboembolic events after total knee replacement and total hip replacement have been reduced over the past decade, for a variety of reasons. These include early mobilization, more efficient and less traumatic surgical procedures, use of pneumatic compression devices, better pain management allowing early mobilization, use of regional anesthesia, and the now-routine use of a variety of chemoprophylaxis agents in a multimodal approach toward the prevention of venous thromboembolism. Many surgeons continue to believe that, after assessing the patient's risk for venous thromboembolism, aspirin remains the safest option for the majority of their patients who are undergoing total joint replacement. Choosing a chemoprophylaxis method is a classic risk-versus-benefit analysis because any reduction in the prevalence of deep venous thrombosis will be offset by an increased prevalence of bleeding events. Bleeding concerns are often considered to be minor by other medical specialists who recommend chemoprophylaxis protocols for total joint replacement3.
Furthermore, the data regarding successful chemoprophylaxis regimens for venous thromboembolism have come from prospective randomized drug trials that enrolled only healthy patients with no history of deep venous thrombosis. A history of deep venous thrombosis is most likely not an accurate marker for the risk of embolic disease after total joint replacement, as no association has been demonstrated between the presence of deep venous thrombosis and subsequent symptomatic or fatal pulmonary embolism after total joint replacement. Primary questions include whether aspirin is as effective when judged against the prevalence of fatal pulmonary embolism, nonfatal pulmonary embolism, and symptomatic deep venous thrombosis in the first six weeks after total joint replacement. Most large clinical trials that demonstrate a reduction in deep venous thrombosis are not designed to determine clinical outcomes and the impact of deep venous thrombosis or adverse events associated with the use of anticoagulation in patients after total joint replacement.
No analysis has been made regarding the final result in patients who have substantial bleeding, minor bleeding, wound-healing problems, medical complications, or thrombotic events. Additionally, the concept of using the end points of all causes of mortality and clinical functional outcomes when judging a chosen chemoprophylactic method seems to be a rational consideration for future investigation. In conclusion, aspirin in combination with contemporary practice protocols for total joint replacement may be all that is required for a safe and effective chemoprophylaxis regimen to prevent venous thromboembolism in the majority of patients who undergo total joint replacement.
Dorr LD, Gendelman V, Maheshwari AV, Boutary M, Wan Z, Long WT. Multimodal thromboprophylaxis for total hip and knee arthroplasty based on risk assessment. J Bone Joint Surg Am.2007;89:2648-57.892648
2007
[PubMed][CrossRef]
Mantilla CB, Horlocker TT, Schroeder DR, Berry DJ, Brown DL. Risk factors for clinically relevant pulmonary embolism and deep venous thrombosis in patients undergoing primary hip or knee arthroplasty. Anesthesiology.2003;99:552-60.99552
2003
[CrossRef]
Sharrock NE, Gonzalez Della Valle A, Go G, Lyman S, Salvati EA. Potent anticoagulants are associated with a higher all-cause mortality rate after hip and knee arthroplasty. Clin Orthop Relat Res.2008;466:714-21.466714
2008
[CrossRef]
Low-Molecular-Weight Heparin: The Latest Facts
By Henry D. Clarke, MD
Background
Without prophylaxis, venous thromboembolic events may occur in 40% to 85% of patients who undergo hip and knee replacement1. Of greater concern is the risk of symptomatic and fatal pulmonary embolism. Without prophylaxis, the overall rates of pulmonary embolism and fatal pulmonary embolism have been reported to be in the range of 1% to 28% and 0.1% to 2.0%, respectively1. Prophylaxis with a variety of chemical and mechanical agents has been shown to reduce the occurrence of all venous thromboembolic events, and, consequently, it has become the standard of care for patients undergoing major orthopaedic surgery. A survey of members of the American Association of Hip and Knee Surgeons showed that 100% use some form of prophylaxis2. However, controversy still surrounds the most suitable modalities. Trade-offs in efficacy, the prevalence of bleeding events, patient convenience, and cost issues exist with all modalities. Low-molecular-weight heparin is one option.
Low-Molecular-Weight Heparin
The low-molecular-weight heparins have gained in popularity as a prophylaxis for deep venous thrombosis. They have gained in popularity not only because of their well-documented bioavailability but also the failure to require routine monitoring of clotting indices. The efficacy of low-molecular-weight heparins is well documented. After total knee arthroplasty, the total rate of deep venous thrombosis, on the basis of the pooled data from six randomized studies in which low-molecular-weight heparin was compared with warfarin, was 33% for patients who received low-molecular-weight heparin compared with 48% for patients who received warfarin. Similarly, the total rate of proximal deep venous thrombosis was 7.1% for patients who received low-molecular-weight heparin compared with 10.4% for patients who received warfarin. However, the use of low-molecular-weight heparin was associated with a higher bleeding rate than that associated with the use of warfarin, and major bleeding complications occurred in a greater percentage of patients (4.5%) who received low-molecular-weight heparin than in those who received warfarin (2.7%) (p = 0.02)1. Also, cost for the medication remains relatively high.
Conclusions
Prophylaxis after hip and knee replacement has become the standard of care and includes a variety of modalities. The optimal protocol depends on numerous factors; however, it appears that, in general, a trade-off exists between prevention of venous thromboembolism and an increased risk of major bleeding. Therefore, each surgeon must consider the risks and benefits.
Clinical Relevance
Due to the high rate of venous thromboembolism following hip and knee arthroplasty, prophylaxis for deep venous thrombosis has become the standard of care. The use of low-molecular-weight heparin remains an option.
Geerts WH, Bergqvist D, Pineo GF, Heit JA, Samama CM, Lassen MR, Colwell CW; American College of Chest Physicians. Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest.2008;133(6 Suppl):381S-453S.133381S
2008
[PubMed][CrossRef]
Mesko JW, Brand RA, Iorio R, Gradisar I, Heekin R, Leighton R, Thornberry R. Venous thromboembolic disease management patterns in total hip arthroplasty and total knee arthroplasty patients: a survey of the AAHKS membership. J Arthroplasty.2001;16:679-88.16679
2001
[CrossRef]
Warfarin: What Is Our Goal?
By Vincent D. Pellegrini Jr., MD
Background
Venous thromboembolism remains the most common cause of hospital readmission and death after total joint arthroplasty1. We sought to define the role of routine screening for deep venous thrombosis and the efficacy of extended low-intensity (international normalized ratio, 2.0) warfarin prophylaxis to prevent thromboembolism after total hip and knee arthroplasty.
Methods
The study was conducted at three university teaching hospitals from 1984 through 2003; 3293 patients undergoing total hip2 (n = 1972 patients) or knee3 (n = 1321 patients) arthroplasty were enrolled. Screening contrast venography performed before discharge was the basis for ongoing anticoagulation therapy. For the duration of the study, patients with negative results on venography received no outpatient anticoagulation. From 1984 through 1992, patients not completing venography were discharged without further anticoagulation; from 1993 through 2003, patients without venography received low-intensity warfarin (international normalized ratio, 2.0) for six weeks after the operation. Patients with documented venous thromboembolism received standard therapy. All deaths and readmissions for deep venous thrombosis, pulmonary embolism, and bleeding were audited six months postoperatively.
Results
Extended warfarin prophylaxis reduced the overall readmission rate for venous thromboembolism (two [0.2%] of 844 patients who received warfarin compared with thirty-eight [1.6%] of 2449 patients who did not; p = 0.0015) and eliminated readmission for pulmonary embolism (zero of 844 patients who received warfarin compared with seventeen [0.7%] of 2449 patients who did not; p = 0.01) after total hip and knee arthroplasty2,3. Four patients (three who underwent hip arthroplasty and one who underwent knee arthroplasty) sustained a fatal pulmonary embolism; all had had negative results on venography and had received no warfarin after discharge. Readmission occurred in twenty-four (1.8%) of the 1357 patients who had negative results on venography and had received no further anticoagulation after discharge as compared with two (0.2%) of the 844 patients who completed a six-week course of warfarin (p = 0.0007). Three bleeding events (in three [0.1%] of the 3293 patients) resulted in one death and two reoperations.
Conclusions
Extended low-intensity (international normalized ratio, 2.0) warfarin prophylaxis reduces readmission rates associated with all thromboembolic events (p = 0.0015) and pulmonary embolism (p = 0.01) after total hip and knee arthroplasty, with a low rate (0.1%) of clinically meaningful bleeding events.
Clinical Relevance
When compared with newer, more intensive anticoagulants, low-intensity warfarin represents a therapeutic compromise that effectively prevents thromboembolic events while accepting a clinically insignificant residual rate of deep venous thrombosis in return for less bleeding.
Pellegrini VD Jr. Warfarin prophylaxis for orthopaedic venous thromboembolic disease. Instr Course Lect.2002;51:491-8.51491
2002
[PubMed]
Pellegrini VD Jr, Donaldson CT, Farber DC, Lehman EB, Evarts CM. Prevention of readmission for venous thromboembolic disease after total hip arthroplasty. Clin Orthop Relat Res.2005;441:56-62.44156
2005
[CrossRef]
Pellegrini VD Jr, Donaldson CT, Farber DC, Lehman EB, Evarts CM. Prevention of readmission for venous thromboembolism after total knee arthroplasty. Clin Orthop Relat Res.2006;452:21-7.45221
2006
[CrossRef]