Right Ventricular Adaptation, Tricuspid Regurgitation, and Clinical Outcomes: A Close Bond.

Patients with significant tricuspid regurgitation (TR) represent a large burden and incur excess mortality and considerable undertreatment. The realization of this ominous situation has led to a recent explosion of studies and articles related both to tricuspid valve structural interventions and to efforts to reappraise the etiology and classification of TR. We are indeed aware that TR can be classified as primary, secondary (atrial vs ventricular), and cardiovascular implantable electronic device related. We are also aware that a notable percentage of patients who have undergone left-sided heart surgery will develop significant TR in their life span. The exact prediction of patients at risk for this complication is being investigated, but an important study published recently highlights that early tricuspid valve repair at the time of mitral surgery, even before severe TR has developed, is beneficial for long-term outcomes.

Broadening Indications of Tricuspid Interventions

There has been growing evidence that tricuspid structural interventions have a large variety of applications. For example, Roth et al described the procedure of tricuspid valve edge-to-edge repair in heart transplant recipients, who incur high perioperative risk and may thereby have favorable 2-year outcomes. Another example is, in pregnancy, the potential for tricuspid valve-in-valve procedures to save both mother and fetus from further complications.

Careful Planning = Successful Outcomes

The task of the imager is to guide clinical decision making (patient selection and interventional timing) and the intervention for a successful procedure. Careful preplanning yields improved outcomes.

Despite the current progress provided by careful evaluation of tricuspid valve anatomy with transthoracic and transesophageal echocardiography, thus yielding TR etiology, severity, and classification, we should not neglect right ventricular (RV) remodeling assessment. Furthermore, although we already have echocardiographic tools to diagnose elevated pulmonary pressures, it is paramount also to identify parameters that are prognostic of an unfavorable outcome, particularly in patients with pulmonary hypertension (Figure 1).

Figure 1

Echocardiographic Indices Proven to Have Diagnostic or Prognostic Value in Predicting Raised Pulmonary Pressures

3D = 3-dimensional; FAC = fractional area change; IVRT = isovolumic relaxation time; MPI = myocardial performance index; RA = right atrial; RV = right ventricular; RVOT AT = right ventricular outflow tract acceleration time; RVSP = right ventricular systolic pressure; TAPSE = tricuspid annular plane systolic excursion; TR = tricuspid regurgitation.

Right-sided heart catheterization remains the gold standard for identification and characterization of pulmonary hypertension, but Doppler echocardiographic characteristics may shed light onto adaptive and maladaptive RV remodeling. A maladaptive RV response to excess preload or afterload will likely lead to recurrent TR after annuloplasty and may considerably increase the risks of surgical and transcatheter interventions (Figure 2). Moreover, maladaptive RV remodeling or advanced RV dysfunction may help to identify an end-stage situation where even a successful intervention with TR reduction could be futile.

Figure 2

Adaptive and Maladaptive RV Remodeling

PVR = pulmonary vascular resistance; RHC = right-sided heart catheterization; RAP = right atrial pressure; RV = right ventricle and right ventricular; other abbreviations as in Figure 1. Heart image reproduced from https://www.istockphoto.com/.

Furthermore, in RV remodeling characterization, computed tomography, but most importantly cardiac magnetic resonance, may contribute to accurate RV volume and ejection fraction assessment, as well as determining the degree of RV fibrosis, depending the clinical context.

What Does the Future Hold?

The purpose of this Editors’ Page is not to list all interventions or the latest trials, but rather to focus on a few thoughts about careful planning and better characterization of RV remodeling.

A potentially important step forward in terms of sensitivity and specificity was published in JACC: Case Reports by Van den Enden et al, who described biventricular pressure-volume loop monitoring and invasive cardiomechanics during transcatheter tricuspid valve repair. Invasive pressure-volume loop analysis allows direct monitoring of changing ventricular mechanics during structural heart interventions. Invasive hemodynamics combined with echocardiographic indices will undoubtedly provide insights into the determinants of successful structural, particularly tricuspid valve interventions.

As a hope for the future, it would be of utmost interest to obtain long-term clinical outcomes in relation to these imaging and hemodynamic indices.

Funding Support and Author Disclosures

Dr Taramasso has consulted for or received consulting fees from Abbott, Edwards Lifesciences, Boston Scientific, Shenqi Medical, CoreMedic, 4tech, Simulands, MTEx, Cardiovalve, and MEDIRA. Dr Enriquez-Sarano has consulted for Cryolife, Edwards Lifesciences, ChemImage, and HighLife. Dr Grapsa has reported that she has no relationships relevant to the contents of this paper to disclose.