Intro4u2u

Despite half-century of experience in heart valve reconstruction, the tricuspid valve has been a “second class structure” for cardiac surgery. More than 20 years ago, the high incidence of tricuspid disease in our population, encouraged us to attempt to clarify the indications for repair, particularly in patients with functional tricuspid incompetence (1). Since functional tricuspid insufficiency always reflects some degree of right ventricular failure with elevated pulmonary resistance, or significant volume overload, we concluded that mild and moderate tricuspid incompetence can be surgically ignored only when the pulmonary resistance will predictably be reduced. However, the experience has demonstrated this beneficial postoperative event is not always well anticipated. On the other hand, some patients with postoperative low pulmonary vascular resistance continue with functional tricuspid insufficiency, because they do not recover the ability of the tricuspid valve annulus to shorten in systole.

Nowadays, with more than 900 functional tricuspid valve repaired at our Institution, it is time to analyse the state of the art of this commonly forgotten valve pathology. Current articles and meeting presentations on the functional tricuspid valve insufficiency are scarce and still asking the same type of questions: Should it be repaired? (2), What should be done? (3), Which should be the criteria for surgical repair? (4).

Functional tricuspid regurgitation is not a rare entity, since more than 25% of mitral valve insufficiency is associated with some degree of tricuspid dilatation with normal valve structures. This entity is often unrecognised, being only apparent during periods of increased preload or afterload. Dilatation of the annulus, involving the annular area supporting the anterior and posterior leaflets, is the only pathological finding at surgery. It is not always clear whether a functional tricuspid insufficiency, which may be expected to disappear or to improve, will remain and progressively increase the right ventricular cardiomyopathy, pulmonary hypertension, and chronic systemic venous hypertension, contributing to a poor outcome. One-third of symptomatic patients with an ignored functional tricuspid valve insufficiency, at the time of left side valves surgery, are referring to hospital for isolated tricuspid valve reoperation.

A better understanding of the natural history of the functional tricuspid incompetence and the progress made in transesophageal echocardiography has significantly contributed to clarify the indications and the limits for tricuspid valve repair. However, preoperative echo based on tricuspid valve grading at rest does not compare well with tricuspid dilatation found at surgery. Under general anesthesia, intraoperative echocardiography is not very useful to quantify the tricuspid regurgitation in order to indicate valve repair or to assure valve competence after correction.

Different methods and rules are used to indicate valve repair in the presence of functional tricuspid insufficiency. The indications were based on the clinical, echocardiography, and surgical findings. Moderate and severe tricuspid regurgitation should be repaired since it has been widely demonstrated that in those patients, tricuspid annuloplasty provides better symptomatic results and may improve survival. Further reoperation for isolated tricuspid valve repair after prior left heart valve surgery are also prevented. Dreyfus et al (2) recommend to examine the valve at the time of mitral valve surgery and to repair the tricuspid annulus if it is significantly dilated to more than twice normal (greater than 70 mm between the antero-septal and postero-septal commissures). Colombo et al. (5) surgically treated the tricuspid insufficiency when the indexed annulus dimension in more than 21 mm/m², been effective in term of clinical improvement and of late functional results.

Double venous cannulation is used in patients with mitral valve disease, and we always open the right atrium to inspect the tricuspid valve when pre- or per-operative echocardiography demonstrate a significant (moderate or severe) tricuspid regurgitation, in the presence of right atrial or ventricular dilatation, and in cases of high pulmonary artery systolic pressure.

Thirty years ago after the De Vega annuloplasty was described (6), this simple selective remodelling of the tricuspid annulus with a double suture at the anterior and posterior area continues as the most popular reconstructive surgical technique for significant functional tricuspid insufficiency. We have used a modified De Vega annuloplasty using interrupted pledgeted supported sutures. This segmental tricuspid annuloplasty (7) avoids tearing of the suture from the tricuspid annulus, “guitar string valve incompetence”, which leads to failure of De Vega annuloplasty early after surgery.

In our experience, multivariate analysis in a recent group 230 patients with functional tricuspid insufficiency demonstrates that the independent risk factors for tricuspid valve reoperation were the presence of residual tricuspid valve incompetence (OR: 3.25), pulmonary artery systolic pressure > 55 mmHg (OR:2.5) or ignored functional tricuspid insufficiency. Recently, Bhudia SK et al (8) from Cleveland Clinic has reported their experience with tricuspid valve repair in 790 patients, and they concluded that tricuspid valve annuloplasty did not consistently eliminate severe functional regurgitation and they identified as risk factors for repair failure the preoperative TR grade, poor left ventricular function, and repair type other than the Carpentier ring annuloplasty. These findings were not found in other important series, previously described.

In patients with severely dilated tricuspid annulus, we prefer a flexible ring annuloplasty to prevent the repair failure, allowing the physiological dynamic changes in the annular size and shape, and preventing the potential for future enlargement of the annulus. Controversy of whether a rigid or a flexible annuloplasty ring is better for tricuspid valve annuloplasty is still opened. The fact that a deformable (flexible) ring does not restore the physiological shape of the annulus and thus requires overcorrection resulting in a high incidence of residual tricuspid stenosis was not true in our experience.

Modern cardiac reconstructive surgery should pay more attention to a frequently forgotten valve pathology, which is killing many of our patients.