How to treat a 58-year-old male with symptomatic COVID-19, who is 4 months post open heart surgery, with questionable bypass graft patency, hypertension, type 2 diabetes, and impaired renal function, on Xarelto (rivaroxaban) for anticoagulation?

Treatment of Symptomatic COVID-19 in a High-Risk Post-Cardiac Surgery Patient

Continue Xarelto (rivaroxaban) unchanged and add supportive care with antiviral therapy (nirmatrelvir/ritonavir or remdesivir) for this symptomatic COVID-19 patient with multiple cardiovascular risk factors. 1, 2

Anticoagulation Management

Continue rivaroxaban at the current dose without modification. 1

• The American College of Chest Physicians guidelines explicitly recommend that patients hospitalized with COVID-19 who are taking anticoagulant therapy for an underlying medical condition (such as post-cardiac surgery thromboprophylaxis) should continue this treatment unless significant bleeding or other contraindications develop 1

• For outpatients with symptomatic COVID-19 already on therapeutic anticoagulation, continuation of existing therapy is preferred over switching or intensifying anticoagulation 1

• Do not add prophylactic-dose anticoagulation on top of therapeutic rivaroxaban - this patient is already therapeutically anticoagulated 1

• The ACTION trial demonstrated that therapeutic anticoagulation with rivaroxaban in hospitalized COVID-19 patients did not improve outcomes and increased bleeding risk (8% vs 2%) compared to prophylactic dosing 3

Antiviral Therapy Selection

Prioritize nirmatrelvir/ritonavir (Paxlovid) as first-line antiviral therapy if no contraindications exist. 2

• This patient qualifies as high-risk given: age 58, hypertension, type 2 diabetes, recent cardiac surgery, and impaired renal function 2, 4

• Critical drug interaction concern: The ritonavir component in Paxlovid significantly increases rivaroxaban levels through CYP3A4 inhibition 1

Alternative Antiviral Options (in order of preference):

1. Remdesivir - No significant drug interactions with rivaroxaban; appropriate for hospitalized or high-risk outpatients 2, 5

2. Molnupiravir - Oral alternative without ritonavir component, though less effective than Paxlovid 2, 5

3. Monoclonal antibodies - If available and active against circulating variants 2

Antiplatelet Therapy Considerations

Do not initiate antiplatelet therapy unless there is a specific indication (prior ACS, stent, or stroke). 1

• The guidelines state that antiplatelet therapy alone should not be used for prevention of thromboembolism in COVID-19 patients 1

• If this patient has a history of CABG with prior ACS requiring dual antiplatelet therapy (DAPT), continue the antiplatelet therapy unchanged 1

• If on DAPT plus therapeutic rivaroxaban, individualize the decision on continuing antiplatelet therapy based on bleeding risk, though this carries substantial bleeding risk 1

Supportive Care Measures

Implement standard COVID-19 supportive care protocols: 2

• Oxygen supplementation to maintain SpO2 >90-96% 2

• Monitor for respiratory deterioration given cardiovascular comorbidities 2

• Careful fluid management (critical in post-cardiac surgery patients) 2

• Monitor for co-infections or superinfections 2

Monitoring Requirements

Check the following before and during treatment: 1

• Platelet count 1
• Coagulation parameters (PT/INR, aPTT) 1
• Liver function tests 1
• Renal function (especially important given impaired baseline renal function and rivaroxaban dosing) 1, 6
• Blood glucose control (diabetes management during acute illness) 4

Risk Stratification

This patient has multiple high-risk features for severe COVID-19: 4

• Type 2 diabetes confers a 5.26-fold increased risk of mortality and is the dominant risk factor 4
• Hypertension combined with diabetes increases mortality risk 3.02-fold 4
• Recent cardiac surgery (4 months post-CABG) places him at risk for cardiovascular complications 1
• Impaired renal function affects drug clearance and bleeding risk 1

Critical Pitfalls to Avoid

Do not switch from rivaroxaban to heparin unless the patient requires hospitalization in the ICU. 1

• Switching to LMWH or UFH should only be considered in hospitalized patients with COVID-19 due to potential drug-drug interactions with antivirals or instability of anticoagulation parameters 1

Do not use therapeutic-dose anticoagulation for COVID-19 thromboprophylaxis in patients already on therapeutic anticoagulation. 3

• The PREVENT-HD trial showed no benefit of rivaroxaban 10 mg for thromboprophylaxis in outpatients with COVID-19 7

Monitor closely for bleeding complications given the combination of therapeutic anticoagulation, acute illness, and potential need for additional antithrombotic therapy 8

• Major bleeding risk with rivaroxaban in acute illness settings ranges from 0.3-1.0% 8

Disposition Planning

If hospitalization becomes necessary: 1

• Continue rivaroxaban unless bleeding complications develop 1
• Consider switching to LMWH if drug interactions with antivirals become problematic 1
• If requiring ICU-level care, individualize anticoagulation strategy based on bleeding versus thrombotic risk 1

For post-discharge thromboprophylaxis (if hospitalized): 9

• The MICHELLE trial demonstrated that rivaroxaban 10 mg daily for 35 days post-discharge reduced thrombotic events (3% vs 9%) without increased bleeding in high-risk COVID-19 patients 9
• However, this patient is already on therapeutic rivaroxaban, so extended prophylaxis is not applicable 9