Aortic Prosthesis Re-Replacement due to Concealed Stenosing Subvalvular Pannus Ring

Introduction

We admitted a 50-year-old female patient, 16 years after mechanical aortic and mitral valve replacement, because of an extraordinarily high transvalvular gradient (92/48 mmHg) and increasing clinical symptoms. The symptoms (dyspnea, atypical chest pain) were present for almost two years and worsening. The patient initially did not consent to a redo operation, due to fear of complications, and physicians did not urge her further, since no cause could be identified by ECG, echocardiography or angiography. However, the progressive transvalvular gradient and worsening symptoms led to the patient finally consenting to the redo procedure.

The preoperative echocardiography revealed a high mean pressure gradient of 74 mmHg over the aortic valve. The prosthesis itself did not exhibit signs of malfunctioning, and leaflet motion seemed to be undisturbed. Due to the echo effects (“ultrasonographic shadow”) of the mechanical prosthesis, there was no clear evidence of subaortic stenosis and pannus formation. In fact, the causative etiology for the patient's high transvalvular gradient could not be identified. We performed the elective reoperation under standard extracorporeal circulation. The old mechanical prosthesis - a 21-mm SJM - was excised.

Following removal of the prosthesis, we observed a severe extraordinary circumferential stenosis of the subaortic lumen ([Fig. 1 A]). This ring had a rigid and calcified consistency and had a diameter of 8 mm. We excised the ring in toto, thereby enlarging the outflow tract to sufficient size. We implanted a SJM 21-mm prosthesis again. After the operation, the patient recovered quickly and uneventfully.

Fig. 1 A and B A A massive subvalvular ring stenosis was observed after removing the aortic valve prosthesis (white arrows). B The subaortic ring stenosis with a rigid consistency (pannus formation) and a diameter of 8 mm was excised in toto

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