Cardiovascular Journal of Africa: Vol 32 No 5 (SEPTEMBER/OCTOBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 5, September/October 2021 AFRICA 285 attached to the annulus, and the annulus maintained a good shape without expanding. After incision of the bioprosthetic valve, we were surprised to found that, while the native posterior and septal leaflets were connected to the chordae tendineae and in a normal state, the native anterior leaflet, preserved in the previous operation, was adhering tightly to the bioprosthetic valve leaflets (Fig. 2). The leaflets of the bioprosthetic valve maintained good plasticity, but were restricted from closing by the native anterior tricuspid leaflet. The anterior leaflet of the bioprosthetic valve did not meet with the other two (Fig. 3), causing severe tricuspid regurgitation. The bioprosthetic valve was therefore removed and most of the native tricuspid valve leaflets were excised, keeping only a small portion of the native leaflet, which was plicated to the annulus. The bioprosthetic valve was replaced with a new mechanical prosthetic valve (31-mm St Jude Medical prosthesis), according to the patient’s own choice before the re-operation, and the heart and sternotomy were successfully sutured closed. The patient recovered well. Transthoracic echocardiography showed good functioning of the new tricuspid mechanical prosthesis. Discussion Preservation of the subvalvular apparatus and creating valve– ventricular interaction has been advocated in the past decades, causing this to become a routine procedure in TVR operation. It maintains better right heart function and has a lower probability of myocardial rupture. 3 However, the phenomenon of bioprosthetic valve regurgitation in this case alerted us to the fact that stubbornly preserving the native leaflets may cause restrictive motion and early dysfunction of the prosthetic valve, which can lead to re-operation. Since the first operation was performed at another hospital, we could only guess why the native tricuspid valve leaflet had adhered to the bioprosthetic valve. The patient may have suffered from pulmonary hypertension after the first operation, which would have caused the native anterior leaflet to come into contact with the bioprosthetic valve and eventually fuse. Prosthetic valve regurgitation induced by preserving the native valve leaflets is not rare in the left heart system. Tomoki et al . 4 reported a similar case of the aortic valve, in which the left coronary leaflet of the bioprosthetic valve had attached and fused to the wall of the sinus of Valsalva, causing deformation of the valve leaflet and a commissural gap between the left and right coronary leaflets. They hold the view that a mismatch of the prosthesis size was the main reason for aortic regurgitation in that case. This was not so in our case because the same size prosthesis (both 31 mm) was used in both operations, and we observed the tricuspid annulus to be in good shape with no expansion. Some cases may need a second TVR due to thrombosis in the prosthetic valve, 5 however anticoagulant therapy was routinely performed in our case and ultrasonic cardiography carried out in the third and 12th month after the first operation had revealed the bioprosthesis was functioning well. Conclusion The experience from this case indicates that preserving the subvalvular apparatus may hamper the motion of the prosthetic valve. However one need not abandon the valve-preserving principle. The decision to keep or remove the native tricuspid valve during TVR depends on its morphology. If the individual morphological features of the native tricuspid valve and right ventricular structure are in good shape, the subvalvular Fig. 3. The bioprosthetic posterior and septal leaflets main- tained good plasticity. The anterior leaflet was curled and did not close with the other two leaflets, forming a commissural gap between the leaflets. No calcified plaque or defect was found in the bioprosthesis. Fig. 2. The native anterior leaflet adhered tightly to the bioprosthesis. BAL: bioprosthetic tricuspid anterior leaflet; JAP: junction of native anterior and posterior leaflet; JAS: junction of native anterior and septal leaf- let; NAL: native tricuspid anterior leaflet.