Here’s how readers responded to a You Make the Call question about the appropriate length of anticoagulation for a provoked DVT.
Disclaimer: ASH does not recommend or endorse any specific tests, physicians, products, procedures, or opinions, and disclaims any representation, warranty, or guaranty as to the same. Reliance on any information provided in this article is solely at your own risk.
I am a pediatric hematologist, but I see many young adult and adolescent patients. I agree with 6 months for a provoked extensive PE. I would tend to treat for 6 months for an anatomic-based DVT (as seen in May Thurner, Paget-Schroetter, and superior vena cava syndromes), especially if stenting is done to prevent recurrence. In general, I recommend 3 months of anticoagulation for all provoked VTE with resolution of the primary risk factors. A provoked thigh DVT that has significantly improved or resolved in 3 months would be no different. I routinely use only 3 months of anticoagulation if the risk factors have resolved.
Gary Woods, MD
Multiple studies have shown similar risk of VTE recurrence with 3 months of treatment compared with 6-12 months of treatment. If the purpose is to complete “active treatment” for a provoked VTE, 3 months of anticoagulation is sufficient.
Ming Lim, MB BChir, MSCR
Salt Lake City, UT
I would treat an unprovoked DVT for 6 months. Consider maintaining prophylaxis indefinitely according to site and morbidity of patient.
William Caceres, MD
Rio Piedras, Puerto Rico
I treat provoked lower-extremity DVTs for 3 months unless there is a large clot burden. I apply the same principle with PE; the idea being that proximal or distal, it’s all part of the same process and thus can be treated in a similar fashion.
Lara Zuberi, MBBS (Lara)
Since we have at least 4 trials that show that 3 vs. 6 months have comparable efficacy, I tend to give 3 months. The question, then, is 3 months vs. extended or indefinite anticoagulation. The situations with the highest probability of recurrence are 2nd or subsequent VTE, or cancer. The situations with the lowest risk are surgery, hormonal exposure that has ceased (pregnancy, birth control pill, testosterone use), and distal and small DVT. Thus, extended/indefinite for the former group (if acceptable to patient and provider), 3 months for the latter. In summary: acute treatment when risk was eliminated vs. acute treatment and risk reduction when risk is not eliminated. The thrombus size or its lung migration play almost no role in this framework.
Julio Hajdenberg, MD
I might give 6 months of anticoagulation for provoked VTE in patients with known thrombophilia.
Cristina Pascual, MD
I would treat for 6 months.
Ganesh Shivlingrao Jaishetwar, MD
I think 3 months is adequate, as long as signs and symptoms (warmth, tenderness, and swelling) abate. I would also look for normalization of D-dimer.
Muhammad Shurafa, MD
Grosse Pointe Park, MI
For a provoked DVT in the thigh, I would like to find out whether the provocation is a minor transient risk factor or a major transient risk factor. If it is a major one, I am comfortable stopping anticoagulation by the 3rd month. If it is a minor one [that might not fully account for the thrombotic risk], I would be cautious doing so. At the end of the 3rd month, before stopping anticoagulation, I would do D-dimer and venous Doppler testing. If the D-dimer level is high and post-thrombotic syndrome is present, I would continue anticoagulation for 6 months.
Saifudeen Abdulrahman, MBBS, MD, MRCP
I would conduct repeat Doppler and D-dimer tests to decide when to stop anticoagulation.
Ruben A. Saez, MD (Ruben)
While my default position is to anticoagulate for a minimum of 6 months for a thigh DVT, there are always two parties involved, and if the patient is keen on stopping therapy, then I do an ultrasound and D-dimer at 3 months. If the DVT has resolved and D-dimer is normal, and the patient wishes to stop, then I concur. If there is residual thrombus scar tissue, then I encourage continued anticoagulation to 6 months and repeat the ultrasound primarily as a baseline for future events. In the Australian context, cost is not a big issue, so it largely reflects the choice of the patient, and we do have the option of continued full-dose or half-dose rivaroxaban or apixaban.
Patrick Anthony Carroll, MBBS
For an unprovoked proximal DVT, I would give 6 months of anticoagulation. For a provoked proximal DVT, I would give 3 months of anticoagulation, then conduct a Doppler ultrasound scan. If it’s not fully resolved at that point, I would continue anticoagulation for another 3 months. I would also perform a D-dimer test at 3 months and, if elevated, continue anticoagulation for a total of 6 months.
Muhammad Gohar Maqbool, MBBS, MRCP
For truly provoked DVT, I feel comfortable with 3 months of anticoagulation, even if it’s a proximal DVT.
Marc Lalancette, MD, FRCP (Marc)
I feel it is quite difficult to make a clear distinction between provoked and unprovoked VTE. A VTE after orthopedic surgery (hip/knee) can be considered “strongly provoked,” while a VTE after an ordinary long-haul flight or occurring under ethinylestradiol-containing contraception is only “mildly provoked,” and therefore may have a substantial “idiopathic pathogenesis.” The more “clearly provoked” with transient provoking factor, the more it may be justified to anticoagulate for a shorter period of time.
Bernhard Lämmle, MD
I agree with your assessment of 3 months of anticoagulation for a calf DVT and 6 months for a proximal DVT or PE.
Satvir Singh, MD
I would recommend 3 months of anticoagulation for both provoked and unprovoked DVT.
Michel E. Kuzur, MD
For a patient with provoked DVT, we have the evidence from the EINSTEIN CHOICE and AMPLIFY-EXT trials that 3-6 months of anticoagulation is not enough. (Even the ASPIRE and WARFASA trials support the same idea.) If we strictly follow the criteria of the trials, then we should do an extended anticoagulation for at least 12 months after completing the 3-6 months of anticoagulation. These trials tested patients who received 6-12 months of full-dose anticoagulation. For an unprovoked event, the risk of recurrence is even higher, especially if the factor cannot be modified (as in the case of anti-phospholipid antibody syndrome, genetic mutations, etc.). Although guidelines do not support extended anticoagulation after a first event, it would be a hard decision to stop the anticoagulation. In the era of direct oral anticoagulants (DOACs), it is a little easier to administer anticoagulation reliably and safely. With the availability of coagulation factor Xa [recombinant], inactivated-zhzo, reversing anticoagulation effects from DOACs is also a good backup.
Ankit Mangla, MD
I find this area very ambiguous. If it is a young patient with a major risk factor as a provocation and no other complicating comorbidities, such as cancer, and the DVT involves the lower extremity, I feel comfortable giving 3 months of anticoagulation. However, if there is any doubt about the provoking factor, or if this is PE, I err on the side of 6 months or longer. Managing an unprovoked DVT is a dilemma. Guidelines seem to suggest the use of indefinite anticoagulation, and some studies would suggest a maintenance dose of a new oral anticoagulant for 1-2 years.
Anisa Hassan, MD
I would give 6 months of anticoagulation for extensive PE and extensive DVT above the knee.
Daryl Roitman, MD, FRCPC