A 55-year-old accountant with a history of hypertension and duodenal ulceration presents with tearing interscapular back pain and a new early diastolic murmur. Aortic dissection involving the aortic root and disrupting the aortic valve is confirmed on CT scan. The patient undergoes urgent operative intervention with replacement of the aortic root with a Dacron graft and replacement of the valve with a metallic prosthesis. After excellent postoperative recovery, he returns for a follow-up appointment complaining of increasing lethargy, exertional dyspnoea and palpitations. His medication includes warfarin, methyldopa, nifedipine and ranitidine. Physical examination reveals a small haematoma related to his sternal scar, sinus tachycardia, an ejection systolic murmur and pale mucous membranes. Investigations:
Hb 5.7 g/dl 13.5 - 17.5 g/dl
WCC 12.0 × 10 /l 4 - 11 x 10 /l
PLT 486 × 10 /l 150 - 400 x 10 /l
MCV 69 fl 76 - 98 fl
ESR 27 mm/h 0-10 mm in the 1 hour
Direct Coombs test Negative
Faecal occult blood Negative
Serum transferrin-receptor assay Increased
Fibrin degradation products Increased
What is the most likely diagnosis?
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Fragmentation of erythrocytes on a prosthetic valve is an unusual complication of valve replacement, but doesn’t necessarily imply haemodynamic dysfunction of the valve. It tends to manifest as low-grade iron deficiency anaemia but occasionally causes a clinically important anaemia. The increased fibrin degradation products also fit with the possibility of valve haemolysis.
The negative faecal occult blood test makes this a less likely diagnosis.
A negative Coombs test excludes autoimmune haemolysis (which in this case could have been related to methlydopa treatment).
The negative faecal occult blood test, and INR of 3.3 (target 2–3), make this a less likely diagnosis.
This patient’s significant anaemia and increased fibrin degradation products make valve haemolysis a more likely diagnosis than valve dysfunction.