Authors: (Nicolas Brozzi, Eric E. Roselli, and Jose L. Navia)
Abstract: Tricuspid valve pathology has a prevalence of 0.8% in the United States of America, significantly less than mitral valve pathology that may be present in up to 2,4% of patients . Most patients with tricuspid valve disease are asymptomatic and receive medical treatment upon development of symptoms, Only 8000 patients receive surgical treatment of the tricuspid valve every year .
Tricuspid valve anatomy and function are most frequently affected by pathologic processes that involve other structures of the heart. Historically, most tricuspid valve pathology in adult patients was considered secondary to left heart valve disease leading to changes in right ventricular dimensions and function. It was assumed that tricuspid valve function would improve after treatment of the original left-sided pathology . This concept has been modified after recent studies reported that tricuspid valve pathology persists, and in many cases progresses even after adequate treatment of left heart valve pathology [4, 5]. Treatment of tricuspid valve disease concomitant with left side heart valve disease can improve functional results and long term survival of these patients.
Independent of the etiology of tricuspid valve disease, the indication for surgical treatment is based on the degree of hemodynamic compromise generated by valvular dysfunction. Surgical treatment of tricuspid valve disease has been shown to be associated with increased mortality, but it is most frequently performed simultaneously to the surgical treatment of left side valvular disease, and as such may be a marker for more advanced bi-ventricular dysfunction [6, 7]. However, the surgical correction of tricuspid valve disease has also been shown to improve postoperative recovery and offers clinical and survival benefits to patients with multiple valve disease.
Persistence of tricuspid valve pathology with progressive dysfunction of the right ventricle represents a negative prognostic factor that affects the quality of life and survival of patients. Those patients that require cardiac reoperations for progression of tricuspid valve pathology generally present late in the course of disease after years of medical treatment and are at high risk for surgical mortality .
Patients with severe right ventricular dysfunction are especially vulnerable to the fluid shifts and other hydrodynamic sequelae of open heart surgery. This is particularly true for patients requiring reoperations with the potential for associated bleeding and transfusions. These patients are expected to reap the most benefit from a less invasive approach.
Transcatheter valve intervention is a less invasive approach to treating valvular heart diseases. Transcatheter replacement of both the pulmonary and aortic valves have been shown to be safe, and many devices have been implanted in the last decade [9, 10].
A decade has passed since the initial reports of transcatheter valve implants for aortic valve stenosis. Early clinical trials have shown good results in high-risk patients and it‘s approval for commercial use in the U.S. is expected to result in a 5 fold increase of their application over the following 3-5 years. Recently, the attention has focused on the development of transcatheter techniques for atrioventricular valves [11, 12].
Several transcatheter approaches have been employed to repair the mitral valve in humans as well, including a clip that can bring the free edge of the leaflets together to increase leaflet coaptation, and a band that can be implanted inside the coronary sinus to correct the dilatation of the mitral valve annulus [13, 14]. Several groups have made significant progress toward the development of valves that can be implanted percutaneously in the mitral position, but the experience is limited to feasibility animal studies.
In contrast to the increased attention paid to the other valves, reported experience for the treatment of tricuspid valve insufficiency to date has been limited mostly to animal models with percutaneous implant of stented valves . The initial experiences look promising, but several challenges will need to be resolved before the transcatheter approach becomes an available option for clinical practice.
This chapter will review the anatomic characteristics and functional dynamics of the tricuspid valve, the current therapeutic options, the pioneering experiences with transcatheter valve implantation, and the potential and limitations for development of catheter-based therapies in the future.