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The surgical treatment of tricuspid regurgitation (TR) is still the object of debate in terms of its timing and surgical techniques. Particularly in the most recent years, there has been an increasing interest in this field and the series reported by Kim et al 1 provide some important data regarding the preoperative predictors of outcome in patients submitted to tricuspid valve (TV) surgery for primary or secondary severe TR. In this study the great majority of TV surgery was carried out during left-sided valve surgery, reflecting an advanced stage of the disease. A minority of the patients had isolated tricuspid repair or replacement, either for severe primary TR or late tricuspid insufficiency following left-sided valve surgery. Although half of the patients were in New York Heart Association (NYHA) functional class III or IV, hospital mortality was very low. Nevertheless, major complications occurred in 20% of the patients after repair and in 33% of the cases after replacement. Moreover, at a median follow-up time of 63 months, 22.2% of the patients in the repair group and 25% of those in the replacement group died, reflecting the significant complexity of the patients and the advanced stage of their pathology. Predictors of mortality and adverse events were identified. Interestingly the surgical technique (repair vs replacement) and the aetiology of TR (primary vs secondary) had apparently no influence on the outcome. On the other hand, age, gender, NYHA functional class, liver cirrhosis and a number of laboratory markers (haemoglobin, albumin, glomerular filtration rate) were identified as important risk factors for all-cause mortality and for the composite end-point of death, tricuspid reoperation and congestive heart failure. These findings emphasise once more that survival after TV surgery is affected more by preoperative factors like advanced heart failure symptoms, comorbidities and end-organ dysfunction than by the type of surgery or the aetiology of TR. Because of these results, the authors arrived at the conclusion that earlier surgical referral should be recommended in the presence of severe TR before the occurrence of significant laboratory markers of organ failure as those described in this series.
Kim et al have to be congratulated for their efforts. However, some observations can be made regarding their study. In particular it has to be emphasised that to identify predictors of clinical outcome after TV surgery, the authors included in their series primary and secondary TR, first time operations and redo cases, isolated tricuspid surgery as well as multiple concomitant cardiac procedures. The risk of this case mix is that despite all the statistical analysis performed, the potential correlation between preoperative conditions and different outcomes might become more difficult to identify. As a matter of fact, in this study, two distinct groups of patients can be recognised: one group essentially comprises patients with multiple valve disease (typically mitral and/or aortic valve dysfunction) and secondary severe TR, while the second group basically comprises patients with isolated TR (in the form of primary TR or late TR following previous left-sided valve surgery). Although these two groups have been analysed together, they are essentially different and deserve individualised considerations.
Nowadays patients with severe functional TR and left-sided valve dysfunction have become rather uncommon in western countries where mitral surgery, in particular repair, is carried out early in the history of the disease. Nevertheless, when severe TR is demonstrated, it has to be corrected. The type of tricuspid annuloplasty used is not mentioned in the study. Similarly no comparison has been performed in terms of outcomes among the different techniques of repair, although this would have been extremely important information for the clinical implications that the surgical approach does have in terms of survival and rate of recurrence of TR. Many studies have shown that, in severe secondary tricuspid insufficiency, a prosthetic ring annuloplasty represents the most effective and durable method of treatment2–10 providing lower recurrence of significant regurgitation and better long-term and event-free survival up to 15 years after surgery compared with suture annuloplasty (table 1).
If secondary TR is less than severe, the diameter of the tricuspid annulus rather than the grade of regurgitation (which is highly subjective and variable) should be the criterion to indicate the need for concomitant TV repair at the time of mitral valve (MV) surgery.11 Compelling data are now available showing that, if the tricuspid annulus is dilated and is not corrected at the time of mitral valve surgery, it is very likely that significant late TR will occur. For that reason, the 2012 European Guidelines on valvular heart disease recommend tricuspid annuloplasty even in presence of mild TR, whenever the tricuspid annulus is 40 mm or larger.11–13
The second group of patients included in the series reported by Kim et al is basically represented by those with isolated TR in the form of either primary TR or late TR following left-sided valve surgery. Surgical indications in this subgroup can be more challenging due to the presence of a variable degree of right ventricular dysfunction and pulmonary vascular disease caused by long-standing tricuspid insufficiency. The dilatation of the tricuspid annulus is usually associated to the important tethering of the tricuspid leaflet secondary to advanced remodelling of the right ventricle. In such circumstances, an isolated annuloplasty is often unable to restore a durable competence of the TV and additional procedures have been proposed, including the augmentation of the anterior leaflet with a pericardial patch. Although preliminary results with this approach are encouraging, more data and longer follow-up are necessary to prove its long-term effectiveness. Most patients are still treated with TV replacement, possibly on a beating heart and with complete preservation of the valvular and subvalvular apparatus. In order to minimise early failure and recurrence of regurgitation, the choice between tricuspid repair and replacement, therefore, has to be made according to the stage of the disease. After systematic measurement of the dimensions of the tricuspid annulus and the degree of tethering of the tricuspid leaflets, a ring annuloplasty should be performed in the presence of isolated annular dilatation. Conversely, when severe annular dilatation and leaflet tethering are present, pericardial patch augmentation of the anterior leaflet or replacement of the TV should be considered.
In patients belonging to this second group, hospital mortality is usually higher, particularly in those with late TR after previous mitral surgery, and late outcome is often disappointing. Surprisingly, this was not the case in the series described by Kim et al, where previous cardiac surgery (late TR following previous mitral/aortic surgery) was not identified as a predictor of poor outcome and did not even reach a p value <0.2 to be included in the multivariate analysis. The small number of such cases (65/449, 14.5%) within the overall study population can possibly explain the results of the statistical analysis performed.
In many published series, the preoperative condition of the right ventricle and the severity of secondary renal and hepatic impairment are the major factors limiting survival in this subgroup of patients.14 Typically patients with severe TR after MV surgery are managed medically for a long time and are referred to surgery only when they develop severe incapacitating symptoms of right heart failure and organ dysfunction. At this stage, surgery is associated with high mortality and morbidity. This perpetuates the notion that surgical treatment of TR, following left-sided valve surgery, is a high-risk procedure, which further delays the surgical referral and increases the reluctance to operate on these patients. Since late surgical referral explains most of the unfavourable outcomes reported, the only way to interrupt this vicious circle is earlier surgical indication. Patients submitted to left-sided valve surgery should have a close follow-up and, if significant TR develops, early surgical treatment should be recommended before the occurrence of right ventricular dysfunction. Besides conventional echocardiography, tissue Doppler imaging, three-dimensional echocardiography, MRI, cardiac CT and new Doppler indexes might prove useful in the future to better define the ideal timing of surgery. In terms of surgical timing, the study by Kim et al gives an important contribution providing data which demonstrate the role of preoperative clinical conditions and laboratory markers in the selection and risk stratification of the surgical candidates. On the basis of their results they suggest a more aggressive surgical approach in patients with severe TR. This attitude is certainly appropriate and has already been implemented, at least in part, in the new 2012 European guidelines on the management of valvular heart disease. The previously recommended ‘symptoms-guided’ surgical referral has been significantly modified in the new guidelines, which state that surgical intervention should now be considered in patients with severe primary TR or persistent/recurrent severe TR after left-sided valve surgery if signs of progressive right ventricular (RV) dilatation or dysfunction are detected, even in asymptomatic patients. Delaying surgery in the above mentioned circumstances is likely to result in irreversible RV damage, organ failure and poor results. The data reported by Kim et al further support the above mentioned strategy and provide useful information to guide clinicians and surgeons in the challenging effort of determining the correct timing of surgical indication in severe TR, particularly in patients with no or mild symptoms.
Contributors OA and MDB wrote the editorial together.
Competing interests None.
Provenance and peer review Commissioned; internally peer reviewed.
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