**2.3 Diagnosis**

To date, transthoracic echocardiography is the gold standard for diagnosis of TR. Current guidelines highlight the importance of a comprehensive evaluation of the TV in order to improve the quality of the diagnosis, but also, the decision-making process, including [20]:

a.TR severy: qualitative, semi-quantitative and quantitative parameters should support the grading of TR.

b.Etiology: primary vs. functional.

c.Mechanism: TVA dilatation, TV leaflet tethering, organic TV disease.

d.Complementary key information:


It should be noted that most of these measurements can be significantly affected by the preload conditions of the patient at the time the study is performed. Therefore, intensive intravenous diuretic therapy should be considered in patients with an over-volume status in order to perform the study in an as close to euvolemic state as possible. In this regard, vena contracta width is becoming one of the most used parameters for TR severy grading given its higher independency from preload conditions. Recently, a 5-degree scheme for grading TR based on the vena contracta and the effective regurgitation orifice area has been suggested pointing out the prognosis addictive significance of massive or torrential TR in patients with huge regurgitant orifices compared to severe TR [21] (**Table 2**). In this regard, patients with massive or torrential TR showed a lower survival, higher cardiovascular mortality and more admissions for heart failure than those with severe TR [22].


#### **Table 2.**

*New classification for grading the severity of TR. VC: vena contracta; EROA: effective regurgitant orifice area; 3D VCA: three-dimensional vena contracta área.*

#### *Percutaneous Treatment of Tricuspid Regurgitation DOI: http://dx.doi.org/10.5772/intechopen.95799*

In addition, right ventricular systolic function assessment is essential when evaluating TR. This has been traditionally addressed by the TAPSE and the fractional area change (FAC). However, recently the RV free wall longitudinal strain (> −23%) has been proposed as an independent risk factor for all-cause mortality and incremental to TAPSE and FAC [23]. In addition, although 3D- echocardiogram could evaluate accurately the RV ejection fraction, cardiac magnetic resonance is still the gold standard method to assess the RV function and volumes.

Together with the development of new percutaneous techniques, advance imaging of TR is also growing, and this evolution will probably contribute to a better understanding of the anatomy and mechanism of this disease. To date, both, transthoracic and, more specifically, transesophageal echocardiography play a key role in the indication of intervention, the selection of candidates for each percutaneous or surgical technique, and as guidance for transcatheter procedures [24]. In the following years, probably the magnetic resonance imaging and computed tomography will provide further insights in this pathology. Furthermore, we expect that all the advances in the field of TV imaging will help to find the optimal timing for intervention, which nowadays is one of the major challenges of this disease.

#### **2.4 Prognosis**

Up to mild TR can be oftenly found in healthy individuals. Moreover, the prevalence of moderate to severe TR has increased in the last years and will probably continue to rise given the expected aging of worldwide population. To date, it is frequently associated with other cardiac disorders and can be found in around 15–40% of patients with AF, HF or severe left-side heart valve disease. The presence of significant TR is associated to an increased mortality in different series and this negative impact on outcomes is related to the severity of the TV insufficiency. In a retrospective study including more than 5000 patients, the survival rates at one year were 92% in patients without TR and 90%, 79% and 64% in those with mild, moderate or severe TR, respectively [25]. Likewise, Chorin et al. analyzed over 33.000 echocardiograms performed in a 5-year period. In this large single center cohort, moderate [HR 1.15, 95% CI 1.02–1.3, p = 0.024] and severe TR (HR 1.43, 95% CI 1.08–1.88, p = 0.011) had a worse prognosis than those with no or minimal TR [26].

Topilsky et al. observed similar findings when analyzed a cohort of 353 patients with isolated TR [27]. They concluded that severe isolated TR was an independent predictor of all-cause mortality and found that an effective regurgitant orifice over 40 mm2 was significantly related to a reduced survival independently of other characteristics. It should be highlighted that adverse prognosis impact of moderate or severe TR has been reported in a wide range of diverse clinical scenarios, such as HF with either preserved or reduced left ventricular ejection fraction, atrial fibrillation without left-side HF or mitral or aortic valve disease. Interestingly, a recent meta-analysis including 70 studies and 32601 patients followed during a mean of over 3 years reported that moderate or severe TR was associated with a two-fold increased mortality risk compared to mild or no TR (RR 1.95, 95% CI 1.75–2.17) [4]. This association remained statistically significant when adjusted for systolic pulmonary artery pressure, RV dysfunction, left ventricular ejection fraction, AF or grade of mitral regurgitation.

#### **2.5 Surgical approach**

Several surgical approaches to treat TR have been suggested in the last decades. Among them, TV repair has been related to superior outcomes compared to TV

replacement [28]. Furthermore, ring annuloplasty offers a consistent reduction in TR in long-term follow up and is nowadays the first line technique in the TV anatomy is suitable [29].

Despite the increasing prevalence of significant TR and its adverse prognosis impact on survival, evidence to date of clinical benefit of open-heart surgery is scarse. Current guidelines in Europe and USA showed a consensual indication for symptomatic primary TR despite medical therapy and for functional TR in patients undergoing left heart valve disease. However, these recommendations have a C level of evidence.

On the contrary, the indication of TV surgery in patients with isolated functional TR is still controversial. Some aspects should be highlighted regarding this issue. First, functional TR is a heterogeneous group including patients at very different stages of TV disease, PH and RV remodeling/function, which might not benefit from the same therapeutical approach. Second, the evaluation of clinical status and its impairment related to TR is oftenly challenging, especially in elderly patients or those with comorbidities. Third, to date, TV surgery has not proven any benefit in hard outcomes compared to conservative management in this population. In this regard, Axtell et al. assessed outcomes in a retrospective cohort of 3276 patients with isolated TR. In this study, there were no differences in survival between patients who received medical versus surgical therapy (HR: 1.34; 95% CI 0.78–2.30; p = 0.288). And four, reported outcomes of isolated TV surgery are poor. Alqahtani et al. recently reviewed trends and outcomes of isolated TV surgery in USA during over a decade [8]. They concluded that isolated repair was associated with high in-hospital mortality (8.1%) and significant rates of permanent pacemaker implantation (10.9%) and new dialysis (4.4%). Morbidity and mortality were even worse among those patients who underwent TV replacement (10.9%, 34.1% and 5.5%, respectively). Similarly, Dreyfus reported an in-hospital mortality of 10% and 19% of major complications during admission in a series of 241 patients who underwent isolated TV surgery in France during a 2 years period [30]. Authors suggested that patients are oftenly referred to late to surgery and that an earlier intervention may improve immediate and possibly midterm outcomes. Nevertheless, this hypothesis has not been proved yet. As a result, in the real-world setting, TV surgery for isolated TR is rarely performed and therefore, most patients are managed conservatively.
