Quadrangular resection of the tricuspid valve.

Quadrangular resection is the gold standard technique for correction of the posterior leaflet prolapse in mitral valve disease. Prompted by the idea that the anterior leaflet of the tricuspid valve corresponds to the posterior leaflet of the mitral valve in its structure and function, we conducted a quadrangular resection of the anterior leaflet of the tricuspid valve in a case of tricuspid endocarditis. Tricuspid regurgitation was well corrected, and the durability of the repair was proven by the patient's freedom from cardiac events for the following 8 years.

CASE REPORT

A 58-year-old male presented with progressive dyspnea of insidious onset that he had for a month. On echocardiographic examination, the right heart was markedly enlarged, and large, freely moving vegetation was seen on the tricuspid valve with severe tricuspid regurgitation (Fig. 1). The blood cultures were negative. On follow-up echocardiography of two week intervals, tricuspid regurgitation was persistent, but the vegetation disappeared. New patch infiltrations developed in both of the lung fields suggesting septic emboli from the vegetations.

Fig. 1

(A) Initial echocardiographic findings showing a huge vegetation (arrow) and (B) massive tricuspid regurgitation.

The patient underwent surgery after 6 weeks of antibiotic treatment. Median sternotomy was performed, and the operation was carried out under standard hypothermic cardiopulmonary bypass and cardioplegic arrest. When exploring the tricuspid valve from a right atriotomy, the septal and posterior leaflets were intact but a significant area of the anterior leaflet had destructed including all the chordae arising from the anterior papillary muscle. When meticulous trimming of the destructed valve leaflet was completed, we realized that the appearance of the surgical field was very similar to the one seen in a quadrangular resection. Based on the idea that the anterior leaflet of the tricuspid valve is similar to the posterior leaflet of the mitral valve in its structure and function, we reapproximated and sewed-up each of the remaining leaflet remnants to the annulus, which is commonly performed in quadrangular resection of mitral valve repair (Fig. 2). Instead of applying a valve ring, we performed De Vega annuloplasty (Fig. 3). The valve became completely competent after the repair based on a saline loading test. The patient's postoperative recovery was event-free. The congestive heart failure rapidly resolved, and he remained symptomless for the following 8 years. Tricuspid regurgitation was trivial on a late echocardiogram performed eight years after the operation.

Fig. 2

(A) Operative view of the tricuspid valve showing a large defect of the anterior leaflet before and (B) after partial reapproximation.

Fig. 3

(A) Schematic drawings of the operative procedure showing leaflet reapproximation and (B) De Vega annuloplasty.

DISCUSSION

Tricuspid valve is frequently compared to mitral valve due to their structural and functional similarities [1]. With the ventricular septum as a symmetry plane, the anterior leaflet of the mitral valve corresponds to the septal leaflet of the tricuspid valve. The component of the posterior leaflet is divided into the anterior and posterior leaflet due to the geometrical difference of the right ventricle bearing an acute margin. Based on this theoretical background, we applied the quadrangular resection technique to the anterior leaflet of the tricuspid in a case of tricuspid valve endocarditis, and the feasibility of the technique in the context of mitral valve repair is addressed in this report.

The tricuspid and mitral valve in humans share common anatomical and functional characteristics, with the D-shaped annulus and a skirt of the leaflet tissue divisible into two functional units [2]. From their animal study, Victor et al. [3] reported that the two valves were symmetrical in design across the septum. The anterior leaflet of the tricuspid valve acts as the anatomical counterpart of the posterior leaflet of the mitral valve, and both of the leaflets are largely suspended from a round contractile part of the annulus and the free wall of the ventricle. They also asserted that, as both mural leaflets were suspended by curved contractile segments of the annulus, the presence of the cleft was essential for the smooth operations allowing them to constrict the orifice during systole, yet open widely during diastole. Particularly, because the tricuspid valve operates in the region of the acute margin of the heart, a major cleft is required, and thus, dividing the leaflets into an anterior and posterior one.

Quadrangular resection is regarded as one of the established techniques for repair of the posterior leaflet prolapse in degenerative mitral valve disease [4]. Although the durability of this simple technique has been proven, with more than 30 years of predictable results since Carpentier et al.'s first report [5], it is rarely applied in tricuspid valve disease, which is most often secondary to the elevated right ventricle and pulmonary artery pressure from left heart valve disease. Additionally, the tricuspid surgery has been limited to simple annuloplasty in most cases [1].

In this particular case of tricuspid valve endocarditis, the surgical findings reminded us of quadrangular resection, prompting us to carry out reapproximation of the remaining leaflets and annular plication with the rationale that the anterior leaflet of the tricuspid valve corresponds to the posterior leaflet of the mitral valve. Although the result was quite satisfactory, we were unable to find a suitable case to repeat the procedure in the following years for above mentioned reasons. However, this case showed that the concept of quadrangular resection might be extended to the anterior leaflet of the tricuspid valve and can be applied in carefully selected cases such as a valve endocarditis with severely destructed leaflet and/or mandating leaflet resection.