OPERATIVE TECHNIQUES

Once the decision is made that the tricuspid valve needs to be addressed, a transseptal approach to the mitral valve is utilized. [68 ] Because many patients are predisposed to coagulopathy secondary to hepatic dysfunction and have had previous surgery, aprotinin is used. [69 ]

A median sternotomy incision is made, and heparin is given. The ascending aorta is cannulated, and the caval veins are cannulated directly with angled metal-tip cannulas (DLP, Grand Rapids, Mich.). Cardiopulmonary bypass is established at a flow rate of 2.2 liters/min per m ² at a temperature of 30°C. The heart is arrested using antegrade cold blood cardioplegia. If a long procedure is anticipated, cold blood cardioplegia is also infused retrograde into the coronary sinus. Caval tapes are snugged, an oblique right atriotomy incision is made, and stay sutures are placed on the right atrial wall to arrange exposure (Figure 35-1A) . An incision is started in the posterior portion of the interatrial septum. The incision is extended superiorly, curving anteriorly as the superior portion of the limbus is reached. Bimanual palpation inside and outside the roof of the right atrium allows extension superiorly without exiting the roof of the right atrium. Inferiorly, the incision is carried anteriorly towards and, if necessary, into the coronary sinus. To arrange the exposure of the mitral valve, stay sutures are placed on the cut edge of the septum (Fig. 35-1B) . Retractors are not used because the resulting trauma to the atrioventricular node may produce heart block. Once the mitral valve portion of the procedure has been completed, the patient is rewarmed, high suction is applied to the aortic needle vent to remove air, the aortic cross-clamp is removed, and the septum is closed, usually with a pericardial patch (Fig. 35-1C) . Tricuspid valve repair or replacement is performed with the heart beating.

Three methods of tricuspid valve annuloplasty repair, with modifications, are widely utilized. [70 ] – [86 ] The most common tricuspid annuloplasty currently performed at the Deborah Heart and Lung Center is a bicuspidization-plication repair. For this procedure, one or two pledgeted 0 Prolene (Ethicon, Inc., Somerville, N.J.) sutures are used to obliterate the portion of annulus encompassing the posterior leaflet of the tricuspid valve (Fig. 35-2A,B) . This segment of the tricuspid annulus may be importantly dilated. It also may be useful to place the Puig-Massana-Shiley annuloplasty ring (Shiley, Inc., Irvine, Calif.) to support the repair (Fig. 35-2C,D) . The ring is placed in a supracoronary sinus position to avoid the area of the atrioventricular node. This prosthesis is implanted utilizing a single continuous 3-0 Prolene suture and has the advantage that it is flexible and adjustable. Once the ring is positioned securely, the strings of the ring are tightened, either symmetrically or asymmetrically, to obtain a satisfactory repair. After the device is seated, with the heart beating and the pulmonary artery clamped, competency of the valve is tested by injecting saline into the right ventricular chamber before the adjusting suture is tied.

The DeVega operation can be used in patients with moderately severe annular dilatation. Many modifications of this technique have been reported. [87 ] , [88 ] The procedure is performed utilizing a single, pledgeted 0 Prolene suture (Fig. 35-2A,B) . The suture is started at the commissure between the anterior and septal leaflets. Using both ends, two sequential sutures are taken clockwise through the annulus around the anterior leaflet and down to the commissure between the septal and the posterior leaflets. The suture is then tied so that the portion of the annulus that is plicated is reduced in a circumferential manner. This suture is tightened until it appears that the anterior leaflet is coapting normally. Alternatively, the Carpentier tricuspid valve annuloplasty calibrator can be used, and the suture is tightened until the dimensions of the chosen leaflet sizer are achieved.

The Carpentier ring may be used for more severe degrees of incompetence. The proper size of the ring is determined by measuring the area of the anterior leaflet with a sizer. The ring has a gap at the segment that encompasses the area of the atrioventricular node. The ring is implanted utilizing multiple interrupted, pledgeted 2-0 Ticron (Davis and Geck, Woodbury, Conn.) sutures. Sutures for implanting the Carpentier ring are placed through the annulus and then passed through the annuloplasty ring (Fig. 35-2A,B) . Note that the stitches are placed much wider apart in the tricuspid valve annulus than in the ring. This plicates and effectively imbricates the annulus.

The incidence of primary tricuspid valve annuloplasty that requires immediate secondary tricuspid valve replacement (TVR) is low. Only 4 patients (2.2 percent) in the Deborah experience of 179 tricuspid valve replacements had immediate tricuspid valve replacement for failed repairs. [48 ] These data imply that TVR was overutilized, but this notion is difficult to assess, either retrospectively or prospectively.

In an earlier study, logistic regression analysis identified preoperative variables associated with tricuspid valve replacement. These preoperative criteria included increasing jugular venous distension ( p = 0.04), increasing preoperative angiographic severity of tricuspid valve incompetence ( p = 0.008), a previous cardiac operation ( p = 0.05), and the presence of tricuspid valve stenosis ( p = 0.02). [48 ]

In addition to uncertainty and controversy regarding when TVR is required, there is also disagreement as to which prosthesis is suitable in the tricuspid position. Isolated reports of stent-mounted and unstented homograft valves indicate satisfactory early-phase results. [89 ] – [92 ] Although an earlier Deborah report indicated satisfactory results in 154 patients with tricuspid bioprostheses, [93 ] we currently use a St. Jude Medical valve (St. Jude Medical, Inc., Minneapolis, Minn.), particularly if mechanical valves are to be implanted simultaneously in the left side of the heart. [94 ] – [97 ] These patients require anticoagulation, but in a large series of patients with multivalvular disease, Coumadin actually conferred a survival advantage ( p < 0.001). [48 ]

For tricuspid valve replacement, the native tricuspid valve leaflets are left in situ. Multiple interrupted, pledgeted 0 Ticron sutures are placed through the leading edge of the tricuspid valve leaflets starting at the 9 o'clock and working posteriorly in a counterclockwise direction to the 3 o'clock position. Sutures are placed through leaflet tissue and then immediately through the sewing ring of the valve. This avoids injury to the bundle of His and atrioventricular node. Once this part of the suture line has been completed, suture ends are tagged and the needles trimmed. The anterior part of the suture line is completed working in a clockwise direction, placing sutures from 9 o'clock to 3 o'clock. Again, sutures are placed through the leaflet and then immediately through the sewing ring. The St. Jude valve is implanted in an antianatomic orientation. [98 ] The valve is seated, and the sutures are tied (Fig. 35-5A,B) .

There are advantages to leaving the tricuspid valve leaflets in place. This method avoids trauma to the atrioventricular node and His bundle. Maintenance of subvalvular structures may better preserve right ventricular geometry and improve mechanical function of the right ventricle, as occurs with the left ventricle when subvalvular structures are left in place during mitral valve replacement. [99 ]

The surgical technique for tricuspid valve replacement is modified in the presence of Ebstein's malformation. [100 ] , [101 ] Repair may be attempted with the goal of restoring the configuration of the atrioventricular valve orifice (Fig. 35-6A—C) . However, if the septal leaflet is attenuated or adherent to the right ventricular endocardium, the valve should be replaced. In this situation, an interatrial communication is frequently present. The atrial septal defect is closed using a pericardial patch, and the prosthetic valve is implanted in the supracoronary sinus position using multiple interrupted, pledgeted 0 Ticron sutures. The inferior part of the suture line often traverses the atrial septal defect patch. Sutures are placed in the same sequence used for straightforward tricuspid valve replacement. Although using a bileaflet valve appears to run the risk of leaflet impingement against the atrial free wall near the coronary sinus, once the valve has been seated and the sutures tied, the atrial wall falls away from the area of the valve sewing ring and the mechanical valve leaflets have free movement (Fig. 35-7A,B) .

In some patients with necrosis of a portion of the tricuspid valve due to active or chronic infective endocarditis, it is possible to debride the necrotic portion of the valve leaflet and perform pericardial patch reconstruction. [102 ] – [105 ] However, several authors recommend excision of infected leaflets in drug addicts to avoid early or late reinfection, associated with resumption of intravenous drug abuse. [105 ] – [109 ] Secondary valvular replacement can be performed at a later date once the endocarditis resolves and if the drug addict is rehabilitated. [110 ] – [113 ] However, this recommendation is controversial because some patients may not tolerate acute, massive tricuspid incompetence. [114 ] A stented homograft valve or a bioprosthesis can be implanted primarily as an alternative to valvectomy. [115 ] , [116 ] Implantation of a mechanical prosthesis in the tricuspid position in a drug-addicted patient is contraindicated because of the inability to comply with anticoagulation. The Deborah experience with isolated tricuspid valvulectomy for tricuspid infective endocarditis is described later.