How to manage a patient with a prosthetic heart valve on Warfarin (anticoagulant) therapy who presents with microscopic hematuria (200 red blood cells per high power field) without symptoms?

Management of Microscopic Hematuria in a Patient with Prosthetic Heart Valve on Warfarin

For a patient with a prosthetic heart valve on warfarin who presents with microscopic hematuria (200 RBCs/HPF) without symptoms, continue warfarin therapy while investigating the underlying cause of hematuria, as the risk of thromboembolism outweighs the risk of bleeding in this scenario.

Assessment and Initial Management

• Microscopic hematuria (200 RBCs/HPF) without symptoms in a patient on warfarin requires careful evaluation while maintaining anticoagulation 1
• Check the INR immediately to determine if the patient is within therapeutic range 1
• For mechanical prosthetic valves, the target INR should be:
  • 2.0-3.0 for bileaflet or Medtronic Hall valves in aortic position 1
  • 2.5-3.5 for other disc valves and Starr-Edwards valves in aortic position 1
  • 2.5-3.5 for all mechanical valves in mitral position 1

Evaluation of Hematuria

• Obtain complete urinalysis to assess for infection, proteinuria, and RBC casts 1
• Complete the urine culture as planned to rule out urinary tract infection 1
• Consider renal function tests (BUN, creatinine) to assess for potential renal impairment 2
• If hematuria persists after one week, further evaluation with imaging (renal ultrasound) and possibly urology referral is warranted 1

Anticoagulation Management

• Do not discontinue warfarin therapy for microscopic hematuria without symptoms, as the risk of thromboembolism in prosthetic valve patients outweighs the bleeding risk in this scenario 1
• Bleeding while in the therapeutic INR range often indicates an underlying pathological cause rather than excessive anticoagulation 1
• If INR is above therapeutic range, adjust warfarin dose to achieve target INR but do not discontinue therapy 1

Follow-up Plan

• Re-evaluate the patient in one week as planned 1
• Monitor for:
  • Changes in hematuria (worsening or resolution) 1
  • Development of symptoms (flank pain, visible blood in urine) 2
  • Results of urine culture 1
  • Current INR value 1

Special Considerations and Potential Complications

• If hematuria worsens significantly or becomes symptomatic:

  • Consider imaging studies to rule out renal hematoma, which is a rare but serious complication of anticoagulation 2
  • Temporary reduction of INR to the lower end of the therapeutic range may be considered while maintaining effective anticoagulation 1

• The risk of thromboembolism increases significantly when warfarin is discontinued in patients with prosthetic heart valves 3, 4

  • Thromboembolism risk is 2.3 per 100 patient-years even with proper anticoagulation 4
  • This risk increases to 5.5 per 100 patient-years with non-compliance 4

When to Consider Intervention

• If microscopic hematuria progresses to gross hematuria with clots or hemodynamic instability, hospitalization and temporary interruption of anticoagulation may be necessary 3
• In case of major bleeding requiring temporary discontinuation of warfarin:
  • The risk of thromboembolism remains low for a short period (up to 15 days in one study) 3
  • Resume warfarin as soon as bleeding is controlled 3
  • Consider bridging with heparin if warfarin must be held for more than a few days 1