"Reversible" late bioprosthetic aortic valve stenosis with spontaneous recovery

Advantages of bioprosthetic valve replacement in patients with normal sinus rhythm are avoidance of the need for long-term anticoagulation and reduced hemorrhagic accidents. On the other hand, low durability of the valve and a higher re-operation rate are known disadvantages. Bioprosthetic valve thrombosis and related embolism are considered to be rare complications.

This 80-year-old man underwent aortic valve replacement with a 23 mm porcine prosthesis and concomitant single vessel right coronary artery bypass graft with an autogenous vein. Two years after the initial surgery the patient developed progressive dyspnea. Continuous wave doppler echocardiography showed a greatly elevated mean pressure gradient of 48 mmHg and an aortic valve area of 0.45 cm2 compatible with severe aortic stenosis. Two months later prior to the elective repeat aortic valve replacement surgery, a transthoracic echocardiography showed a significantly reduced mean pressure gradient of 19 mmHg and the effective valve area was 1.3 cm2, and the surgery was cancelled.

The authors report a case of "reversible" late porcine aortic valve stenosis with spontaneous resolution, likely due to thrombus formation on the valve leaflets. Spontaneous thrombosis of the Medtronic mosaic porcine aortic bioprosthetic valve may occur in the absence of any identifiable causes.