Operative techniques
Both mechanical and bioprosthetic valves have been used for the right-sided valve replacements in CaHD. However, in recent reports, bioprostheses seem to be preferred, as life-expectancy is limited in these patients and warfarin therapy may not be well managed (5).
Aortic cannulation is performed in standard fashion, although inserting the cannula more to the right side of the ascending aorta will improve exposure of the PV. Both venae cavae are snared after separate venous cannulation and commencing CPB. Triple lines for pump suction are utilized and CO2 wound irrigation is started. Basically, both right-sided valves can be replaced on CPB using no or intermittent aortic cross-clamping. In our view, cardioplegic arrest provides better visualization and detailed evaluation of the diseased valves, and more accurate placement of valve sutures. Before starting CPB, the planned incision on the anterior surface of the PA is marked by a felt pen. The order of valve replacement is by surgeon preference, but we generally begin with the PV. We use only antegrade cold blood cardioplegia, every 20 minutes and in large amounts, for optimal protection of the RV. Retrograde cardioplegia may be insufficient in this respect.
Pulmonary valve
An incision is made in the proximal PA and extended backwards across the PV and 3-4 cm into the right ventricular outflow tract (RVOT)(Fig 1A). The PV is exposed by stay-sutures, evaluated and the fibrotic cusps are excised (Fig 1B). A bioprosthetic valve of appropriate size is measured. Pledgeted matress sutures are placed in the annulus, matching the commissures of the prosthesis with the native annular shape (Fig 1C). Approximately one-fourth of the prosthesis is left unanchored with one commissure pointing anteriorly (fig 1D), to enhance RVOT and PA dimensions, as the inserted prosthesis will be seated in a slightly different angle than the native PV. A wide bovine pericardial patch is attached with a running polypropylene suture, starting from the PA corner and continued proximally on both sides. The remaining part of the prosthetic valve is anchored to the patch horizontally, either with a running suture or with additional pledgeted sutures from the sewing ring through the patch. Lastly, the remainder of the patch is sutured to the RVOT incision (Fig 1E,F).
Tricuspid valve
After opening the right atrium (RA), a methodical inspection for and closure of a persistent foramen ovale (PFO) should be performed. The TV is generally fibrotic with retracted non-mobile leaflets and a narrowing of the valve opening. A prosthetic valve of the largest possible size should be implanted. Some authors advocate resection of the anterior and posterior leaflets, while leaving the septal leaflet intact with chords. We routinely keep all leaflets, making multiple incisions from the free edge to the annular plane and leaving the chordal attachments intact to preserve tricuspid annular and RV synchrony (Fig 2A,B,C). This technique widens the valve sufficiently and allows for an adequately sized prosthesis. Occasionally, a thickened chord clearly retracting the valve may have to be cut. We use atrially pledgeted sutures for anchoring the valve, passing the needles through the annulus and the body of the leaflets (Fig 2D). Caution is advised, as the annulus is frail, and deep bites in the posterior leaflet area may compromise the right coronary artery. We prefer pericardial bioprosthetic valves with a softer sewing ring, which fit better and can be tied in more gently without ripping the annular tissue. The valve should be oriented with one commissure towards the corner of the native anteroseptal commissure and another valve commissure towards the posteroseptal commissure.
Aortic and mitral valves
In very few CaHD patients, the aortic or mitral valves are severely regurgitant in addition to the dysfunctional right-sided valves and must be addressed with standard bioprosthetic AVR and/or MVR concomitantly. Repair of the mitral and aortic valves have also been reported. In our experience, carefully selected patients can tolerate and benefit even from quadruple valve replacement (11Albåge A, Alström U, Forsblad J, Welin S. Quadruple Bioprosthetic Valve Replacement in a Patient With Severe Carcinoid Heart Disease. JACC: Case Reports Vol 2, Issue 2, Feb 2020. DOI: 10.1016/j.jaccas.2019.11.030).