In This Article
- There are no high-quality data about venous thromboembolism in patients with COVID-19. Most, but not all, available publications point to an increased risk compared to other hospitalized patients
- COVID-19 patients are also at risk of bleeding, but the rate of major bleeding and clinically minor relevant bleeding occurring is still being determined
- To assist clinicians facing this conundrum, Mass General has developed an algorithm for prophylactic anticoagulation in COVID-19 patients and offers guidance about therapeutic anticoagulation
- Recurrent line clotting has been anecdotally reported, for which Mass General recommends recommends escalating anticoagulation and using anti–factor Xa to monitor unfractionated heparin; if clotting continues, transition to a direct thrombin inhibitor
- Presently there are insufficient data to support universal use of VTE chemoprophylaxis after hospital discharge, but expected immobility might be a major consideration in individualized decision-making
For reasons unknown, patients hospitalized for COVID-19 appear to be at high risk of acute venous thromboembolism (VTE).
Ido Weinberg, MD, vascular medicine specialist in the Fireman Vascular Center, Annemarie Fogerty, MD, clinical director of the Center for Hematology at the Mass General Cancer Center, and Kenneth Rosenfield, MD, section head for Vascular Medicine and Intervention at Massachusetts General Hospital, reviewed this clinical conundrum and explained the hospital's current approach in a Division of Cardiology grand rounds presentation on April 22, 2020.
Dearth of Data
There are no high-quality data about VTE and bleeding in patients with COVID-19.
As of April 21, 2020, at Mass General, dozens of patients with confirmed or suspected COVID-19 who were imaged for VTE had deep vein thrombosis (DVT), pulmonary embolism (PE) or both.
Earlier in the month the percentage of all COVID-19 patients who had VTE was calculated as 3.5%, and a 393-patient case series from New York City published in the New England Journal of Medicine gives a figure of 3.3%. Similar rates have historically been seen among critically ill patients.
The only evidence for use of thrombolytics is a case series of three patients who only had transient improvement with tissue plasminogen activator, as published in the Journal of Trauma and Acute Care Surgery. Ongoing trials with this agent are examining its effect on ARDS and not VTE.
Additional Elements of Complexity
The team notes the following complexities:
- D-dimer elevation is very common in COVID-19 and has poor positive predictive value for VTE in this population especially (however, negative D-dimer has good negative predictive value)
- The usual risk scores (e.g., Wells, sPESI) may not apply
- Worsening hypoxia, a hallmark of COVID-19, can be challenging to differentiate from PE, especially because of higher thresholds for diagnostic testing due to concerns about contaminating equipment and exposing staff to infection
VTE Prophylaxis at Mass General
Pursuant to a new algorithm, all patients hospitalized at Mass General for COVID-19 receive enoxaparin routinely except in cases of:
- Active hemorrhage or platelets <25,000/mL — mechanical compression
- Current or prior heparin-induced thrombocytopenia — fondaparinux and hematology consult
- Creatinine clearance <30 mL/min — unfractionated heparin (UFH)
- ICU care — individualized decision-making
Treatment of VTE
There is no agreement about how to manage VTE in COVID-19, but some guidance is offered:
- Strongly consider immediately starting anticoagulation for presumed PE, even if imaging confirmation is delayed or unavailable
- Point-of-care ultrasound and lower-extremity duplex ultrasound may guide the diagnosis and therapy of suspected VTE
- For hemodynamically unstable or high-risk patients, fibrinolysis is still the preferred initial therapy; however, optimal agents and dosages are unclear
- Invasive procedures (catheter-directed lysis or thromboaspiration, surgery) are appropriate for confirmed COVID-negative (and some COVID-positive) patients if they do not threaten the availability of limited resources
- For patients with suspected PE or threatening VTE, multidisciplinary consults via videoconference are essential to optimize outcomes and conserve resources
There have been many anecdotal reports of line clotting outside systemic VTE or arterial thrombosis. For recurrent line clotting, Mass General recommends escalating anticoagulation to full intensity and using anti–factor Xa to monitor UFH. If clotting continues, transition to a direct thrombin inhibitor.
Presently there are insufficient data to support universal VTE chemoprophylaxis after hospital discharge. VTE chemoprophylaxis should be considered if a discharge is to a skilled nursing or rehabilitation facility, substantial immobility is anticipated at home or the patient has a strong risk factor for VTE such as active cancer or had prior VTE.
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