This week’s Orthopaedic Crossfire® debate was part of the 16th Annual Current Concepts in Joint Replacement® (CCJR) – Spring meeting, which took place in Las Vegas this past May. This week’s topic is “Mobile Pump DVT Prophylaxis: Just Say No to Drugs.” For the proposition is Robert L. Barrack, M.D., Washington University School of Medicine, St. Louis, Missouri. Opposing is Louis M. Kwong, M.D., UCLA Harbor Medical Center, Beverly Hills, California. Moderating is Jay R. Lieberman, M.D., Keck Medical Center of USC, Los Angeles, California.
Dr. Barrack: Forty years ago, Charnley talked about the problem with pulmonary embolism and that being a major concern of surgeons. He had about a 1% incidence with any type of prophylaxis, but it was unacceptably high. He also said all methods of prophylaxis were better than none. So the one thing that we can agree on is, in North America, we have to do something. What we do is still hotly debated.
This is a major public health issue that was identified about 10 years ago. It was actually mandated by CMS [Centers for Medicare and Medicaid Services] that some type of prophylaxis is performed in all hospitalized patients. In the absence of any guidance or recommendation, there was a perception that there were a lot of patients not receiving prophylaxis.
This void was filled by clinical practice guideline committees. The American College of Chest Physicians (ACCP), who are largely not surgeons, convened their conferences and in 2001 they placed all total joint patients in the highest risk category. In ’04 and ’08 these chest physicians did recommend aggressive drugs for all patients, including a relatively high dose of Coumadin, but not aspirin or compression devices for hips.
The endpoint at that point in time was lowering the DVT rate and most of these DVTs were asymptomatic. These were largely drug company studies that happened to use venograms in hope to determine the DVT rate.
In ’07 the AAOS had a major problem with this and they recommended risk stratification. In ’11 and ’14 all the organizations agreed that symptomatic events are important and they recognized all modalities including aspirin and compression devices.
So there are two new developments. There’s interest in newer generation mechanical compression devices and a lot of data and renewed enthusiasm for aspirin.
What’s new in the area of compression devices? Mechanical devices which are portable and have a compliance chip are the only ones that were recommended by the chest physicians based on a Level I study that showed equivalence to Lovenox, with a much lower bleeding rate. Subsequently, in 2014 we published a large national registry study from ten different centers across the United States with more than 3, 000 patients. The level of VTE (0.92%), DVT (0.75%), symptomatic events, PE (0.16%), with no deaths, can’t be beat with any high powered drug that’s available on the market today. Half of these patients got compression devices with aspirin; the other got the compression device alone.
The second big development is reassessment of aspirin for VTE prophylaxis. In a review by Dalury, et al. it was determined that aspirin was as effective, with lower risk of complications. Two recent studies you should be aware of, both in the New England Journal of Medicine, both international studies, on the effectiveness of aspirin to not only lower the risk of recurrent VTE, but also lowering all cause of mortality because of the beneficial effect of lowering the risk of MI [myocardial infarction] and stroke [Beccatini, et al. and Brighton et al.].
Vin Pellegrini, at the 2015 AAOS Annual Meeting, recommended reevaluation of aspirin, perhaps in conjunction with modern mechanical compression. We came to that exact same conclusion five years ago and started looking at the hypothesis that a compression device with aspirin would be as good, and safer, in terms of major complications.
We did a prospective study that has just been concluded. We did risk stratify, most major centers do use drug prophylaxis for high risk patients. The debate is who is high risk. We were conservative at first and included older patients; patients that were obese; and those with a lot of medical co-morbidities. In the second two years, we eliminated age; medical co-morbidities; obesity because other centers had had excellent results including these and our results also encouraged us that we could expand our indications.
The two cohorts were: routine risk patients got a mobile compression device, six weeks aspirin. High risk patients got a compression device only in the hospital—which is two days—and low-dose Coumadin for four weeks. Our outcome measures were perioperative complications, readmissions, and returns to the OR.
We looked at all our patients over a four-year period, 2, 000 hips approximately. Three-fourths of them were in the routine risk category. What we found was, that the efficacy was the same or better and the complication rate was much lower.
We’re now close to over 2, 500, hips and knees, and the compression device with aspirin in 75% of patients is equivalent efficacy with fewer complications.
Our priorities are efficacy and safety; cost effectiveness, which has been shown in one study; and satisfaction. We did a satisfaction survey of over 2, 500 patients and they prefer this over Coumadin with monitoring.
In conclusion, you can use risk stratification and allow us NOT to use aggressive anticoagulation in at least three-fourths of our patients. We found that this approach was superior to the use of Warfarin in high risk patients in terms of complications and the results support this approach. It does have a higher level of patient satisfaction, so I think that aggressive drug prophylaxis should be reserved for a small minority rather than routine use.
Dr. Kwong: We’ve now achieved a relative consensus between the American Academy of Orthopaedic Surgeons (AAOS) and the American College of Chest Physicians with regard to prophylaxis strategies, with regard to venous thromboembolism.
For patients requiring hip and knee replacement, it is recommended that they undergo either treatment with a pharmacologic or a mechanical prophylaxis. Indeed it does not allow recommendation for or against any particular regimen or strategy.
It is recognized that mechanical compression is effective in decreasing the risk of DVT after total joint replacement as a result of its local mechanical, as well as systemic humoral effects. It has been long viewed as being an ideal modality in our patients at high risk for bleeding. We do also recognize that the effectiveness of any strategy, whether pharmacologic or mechanical, is dependent on patient compliance.
There are a number of reasons patients may not be compliant with the use of mechanical prophylaxis. Some patients don’t tolerate the noise generated by the motor or the pump. Others may develop a skin rash or irritation. Some patients find wearing the sleeves to be uncomfortable because of warmth or a variety of other complaints. Some patients find it cumbersome to use. All the devices have undergone an evolution that requires sleeve application which may be difficult in patients with limited hip or knee motion. Some devices have hoses. And the mobility of the patient is limited by the six-hour battery life. And while these have been studied for up to two weeks, we recognize that some of our patients after hip replacement surgery can be at risk for up to five weeks.
A randomized control trial was conducted with regard to the mobile compression device and low molecular weight heparin in hip replacement patients [Colwell et al., 2010]. We don’t have data regarding knee replacement patients. And the same exclusions with regards to patients undergoing revision, bilateral procedures, prior history of DVT or PE, prior surgery. So we don’t know the performance in terms of safety and efficacy under those circumstances. People were treated for up to 10 days, but the hospital length of stay was 2-10 days.
They demonstrated good compliance at 83%, but no reported compliance between in- versus out-patient use. Patients in the compression group were allowed to use aspirin and it should be noted that this study was powered for the safety assessment and was underpowered with regard to efficacy. So efficacy, again, not really known.
What other scientific evidence is there? Warwick et al.’s work comparing foot pumps versus low molecular weight heparin in hip replacement. Finding no difference between the two in terms of efficacy and safety, but again, underpowered. Paiement et al.’s work looking at pneumatic compression foot pumps versus Warfarin, also in hip replacement, identifying also no difference with regard to bleeding or efficacy, but again, underpowered.
Are there contraindications? We don’t know how this performs in our high risk patients with prior history of VTE, and perhaps we should use this with caution in patients with severe peripheral vascular disease or any compromise in peripheral circulation and profusion. Our most recent recommendations from the AAOS is that our patients undergoing hip or knee replacement with prior VTE should receive both mechanical and pharmacologic. And it’s clear from the data that there is no single strategy that is best for all patients.
In summary, it’s clear that mechanical compression and mobile devices serve a valuable clinical option in VTE prophylaxis. Chemoprophylaxis continues to represent our standard of care. And we know there is no single strategy that’s shown to be best. It is our responsibility as treating physicians to determine what is best for our patient regarding their benefits versus risks, as well as the ease of use and patient compliance.
Moderator Lieberman: I just want to make one point as clarification for everybody. In the last ACCP guideline, they really didn’t make recommendations. What they did was they said there were certain number of agents, which basically included every agent that is available today, that were better than no prophylaxis at all. That’s the difference in recommending particular agents. So we have to remember that.
Robert, I think everybody is interested in using aspirin and certainly they’re interested in these mobile compression devices. They’re attractive, they may be easier to use. What about the compliance issue? One of the major concerns that you would have is if the patient didn’t keep the device on when they’re at home, then they would not be getting any prophylaxis at all and, particularly in the United States, that could put you at medical legal risk. Any tricks that you guys have to increase compliance?
Dr. Barrack: They’re counseled on the importance of this and the reason the ACCP recommended this device is because it had a monitoring chip, and we’ve used it in thousands of patients and we published the compliance and it’s close to 20 hours. It’s rare that 95% of patients are over 18 hours.
Moderator Lieberman: Louis, I think the biggest issue with the newer anticoagulants is that they actually work, so they cause bleeding and that’s obviously very important to orthopedic surgeons. You want to comment on how they should be used?
Dr. Kwong: Safety and bleeding, absolutely, is the primary concern of most surgeons. Surgeons probably worry more about the bleeding complications with the pharmacologic agents than the disease itself. The timing of the first dose is very important. It’s important not to administer too early. With greater deformity, revision, more dissection—we induce a lot of surgical trauma and primary hemostasis may not be achieved until the following morning. So it’s important to recognize that and delay the administration of the first dose.
Moderator Lieberman: I think the biggest problem that we have is this risk stratification. I think everybody should be asking their patients if they’ve had a prior history of VTE or DVT because those are the patients that are higher risk. We just completed a large database study with over 50, 000-something patients with Craig Della Valle and Jay Parvizi and it turned out that age was important. Patients over 70 had an increased risk.
Dr. Barrack: I agree. A prior history is number 1. If they have three first-degree relatives that died of PEs, we’re going to treat them; hypercoagulable conditions; if they have active malignancy; and if they are going to immobile after surgery. Those are the biggies.
Dr. Kwong: I think this is critical point. It’s a point that we do talk to our patients. We get the history and education and information is most valuable thing we provide for our patients.
Moderator Lieberman: I think that one final point is look at the patient. The patient that’s going to be immobile, you did a big revision on, that’s different than a routine primary hip replacement, knee replacement, that’s getting out of bed the same day. I want to thank the speakers for a terrific job and we want to thank you for your attention.
Please visit www.CCJR.com to register for the 2016 CCJR Spring Meeting, May 22 – 25 in Las Vegas.
