RESUMEN
We describe our surgical treatment in a patient with subvalvular aortic stenosis due to pannus formation beneath a monocusp mechanical valve. In this case, transvalvular removal of subvalvular pannus using a CUSA (Cavitron ultrasonic surgical aspirator) was performed successfully. A 77-year-old woman underwent aortic valve replacement with a monocusp tilting-disk mechanical valve (Björk-Shiley, 23 mm) 30 years previously. Reoperation for severe aortic stenosis due to calcified subvalvular pannus formation was required. Intraoperative findings revealed no limitation of leaflet motion of the valve but presence of left ventricular outflow tract obstruction caused by subvalvular pannus formation under the major orifice of the prosthesis. Because of difficulty of exposure of the prosthetic valve due to severely calcified valsalva sinus wall, simple re-do aortic valve replacement seemed to be almost impossible. Therefore, we tried transvalvular removal of the pannus. A scalpel could not be applied due to severe calcification of the pannus. Then we used CUSA and removed the pannus successfully. Finally, subvalvular stenosis (LVOTO) was ameliorated and a decrease of trans-aortic valve velocity was recognized. She is doing well without recurrence 1.5 years after the surgery.