Why A Post-Op Fatality Is A Wake-Up Call On DVT Prophylaxis

Allen Jacobs DPM FACFAS

The issue of deep vein thrombosis (DVT) prophylaxis remains controversial with reference to foot and ankle surgery. The limited available studies for review suggest that the incidence of DVT and pulmonary embolism (PE) following foot surgery is acceptably low, and that routine prophylaxis is not required. However, many of these same articles suggest that one should consider prophylaxis when several risk factors for DVT or pulmonary embolism (PE) are present.

The controversy is further clouded by the fact that surgical risk factors for DVT/PE and the medical risk factors for DVT/PE are not the same. For example, smoking is reportedly associated with a small decreased risk of DVT/PE in surgical patients.1

In addition, there are factors such as ambulatory surgery (i.e. most forefoot surgery) juxtaposed with procedures that require prolonged immobilization.

The preferred method for prophylaxis also remains unclear. While the American Academy of Orthopaedic Surgeons (AAOS) and some authors endorse aspirin for prophylaxis in bone and joint surgery, others such as the American College of Chest Physicians (AACP) suggest that aspirin is insufficient for DVT prophylaxis.2,3 Immediate post-op ambulation alone is reportedly associated with a 50 percent reduced risk of DVT/PE.

The profession, through the American College of Foot and Ankle Surgeons (ACFAS) or the American Society of Podiatric Surgeons (ASPS), needs to develop a definitive position and distinct recommendations regarding the use of DVT prophylaxis following foot and ankle surgery. I believe the need for such direction is critical.

A recently settled malpractice case, in which I acted as an expert witness, illustrates the need for such a policy. A young woman who was seemingly healthy and not under care for any medical problems died of a PE following a skin biopsy for removal of a localized melanoma of the hallux interphalangeal joint. The patient was taking drospirenone and ethinyl estradiol (Yaz, Bayer Pharmaceuticals) for birth control. We have all seen the commercials on television that Yaz may be associated with DVT/PE.

She also was taking fexofenadine (Allegra D, Sanofi Aventis), which has pseudoephedrine. Days following her skin biopsy, she called her podiatric physician following a brief and self-limited episode of orthopnea and palpitations following the ingestion of an Allegra D and climbing some stairs. One week later, she died of a PE.

The plaintiff's experts, one of whom was a podiatrist from Houston, opined that the patient was a great risk for DVT/PE as she was taking birth control pills. In addition, she had undergone a surgery with an ankle tourniquet (skin biopsy); was immobilized (told to back off on her activity level so as not to disrupt her incision); had a malignancy (the actual melanoma was less than 3 mm and was completely excised); and had undergone lower extremity surgery.

Furthermore, he opined that the standard of care requires that birth control pills be discontinued prior to podiatric surgery, and that he always interdicted the use of birth control pills before any foot surgery. Frankly, this is the opinion that I found personally egregious. The Physicians Desk Reference (PDR) does state that patients should discontinue Yaz prior to elective surgery.

A skin biopsy? Is that what is meant by elective surgery?

I could not find any dermatologist, podiatrist or orthopedic surgeon who ever had a patient cease taking birth control pills for anything, let alone a skin biopsy. Essentially, the woman was taking Yaz and had a PE (a known risk of this medication) following a skin biopsy. Under oath, a podiatric colleague from Houston stated that the defendant should have known that the brief one-time episode of palpitations and orthopnea was not due to the pseudoephedrine in the Allegra D but, in fact, was a sign of DVT/PE in an otherwise healthy patient.

Birth control pills been cited as a factor for increasing the risk for DVT/PE following lower extremity surgery. However, I do not believe for one second that the average podiatrist interdicts the use of birth control pills in the perioperative period.

One practical solution for everyone might be the use of aspirin as prophylaxis as this would be simple and is generally well tolerated. Certainly, two aspirin daily would be preferable to warfarin (Coumadin, Bristol-Myers Squibb), heparin and low molecular weight heparin. There is literature both for and against aspirin for DVT prophylaxis. I suspect that if a patient sustained a PE while on aspirin prophylaxis, my friend from Houston will be there to quote the contrary literature.

You and your patient are always well served to consider, in any clinical situation, the worst pathology which may be present and rule out that pathology. If you even have a twinge that DVT/PE is possible, Doppler evaluation, D-dimer, chest computed tomography (CT) or referral to an emergency room are always appropriate.

We need a defined standard of care supporting or negating the need for DVT prophylaxis from the ACFAS or the ASPS. We need something clear and concise. Without such recommendations, my friend in Houston will continue to make a good deal of money pointing his finger and confabulating a standard of care.

References

1. Mason C. Venous thromboembolism: a chronic illness. J Cardiovasc Nurs 2009 Nov-Dec;24(6 Suppl):S4-7.

2. Johanson NA, Lachiewicz PF, Lieberman JR, et al. Prevention of symptomatic pulmonary embolism in patients undergoing total hip or knee arthroplasty. J Am Acad Orthop Surg 2009 17(3):183-96.

3. Geerts WH, Berggvist D, Pineo GF, et al. Prevention of venous thromboembolism: American College of Chest Physicians Evidence=Based Clinical Practice Guidelines (8th Edition). Chest 2008 Jun; 133 (6 Suppl):381S-453S.

Comments

I could not agree more. A well thought out standard of care for DVT prophylaxsis with specific guidlines in foot is needed for patient protection and to bring us in line with other surgical specialties that have these guidlines in place. Thank you for your comments on this important subect.

Fred Weil DPM

Hello Dr Jacobs,
I was surprised to note your comment that you `could not find any dermatologist etc.`.
In UK in podiatric surgery practice it is routine to undertake a thrombotic risk assessment. Based on a meta-analysis of available data one of our colleagues for whom this has been a special interest for several years developed a matrix type assessment tool for guidance (not an absolute protocol and certainly not an exact science), which takes account of all known factors including type/level of surgery. From this we decide in each case if any thromboprophylaxis is warranted and if so what form it should take. A factor always considered is whether the patient is taking oestrogen, whether in the form of the combined OCP or HRT. Where thrombotic risk is deemed significant and where this includes oestrogen meds we routinely advise the patient to stop the oestrogen pre-op.and if for contraception to adopt alternative methods until recommencement post-op.
Hope this is of interest and if you would like to view the assessment matrix, which I believe most podiatric surgeons in UK have adopted for the last few years, let me have your e-address and i will forward it. Regards

Brian Brown
Consultant Podiatric Surgeon
Sheffield NHS Primary Care Trust, UK

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