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).