Indications and Timing of Tricuspid Valve Surgery

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Indications and Timing of Tricuspid Valve Surgery

Because indications for TR surgery differ significantly whether it is performed at the time of left-sided valve surgery, or in isolation, we will discuss them separately.

Isolated Tricuspid Regurgitation Surgery
Recently we have shown that severe (ERO >0.4 cm²), isolated (without significant co-morbidities, structural valve disease, significant PASP elevation by Doppler or overt cardiac cause) TR is associated with excess mortality and morbidity,⁹ thus warranting heightened attention to diagnosis and quantification of TR, and suggesting that it should be treated aggressively. Furthermore, several publications have shown that isolated tricuspid valve surgery can be performed with an acceptable operative mortality if patients undergo surgery before the onset of advanced heart failure symptoms, or severe RV dysfunction.^5,10–12 Based on the recent data the practice has evolved to include more surgical treatment of TR even when it is isolated.¹³ Recent guidelines recommended (Class IIa indication) that isolated tricuspid valve surgery can be performed for patients with symptoms due to severe primary TR, including congestive hepatopathy, preferentially before onset of significant RV dysfunction.^14–16 It should be noted that the optimal timing of isolated tricuspid valve surgery for asymptomatic patients with severe TR is controversial. The US guidelines have suggested a conservative approach that includes serial assessments of RV size and function that may indicate the need for corrective surgery (Class IIb indication) in selected patients with severe TR, continued deterioration of RV and low surgical risk. On the other hand, the European recent guidelines¹⁶ are more specific since they clearly state “Surgery should be considered in asymptomatic or mildly symptomatic patients with severe isolated primary TR and progressive RV dilatation or deterioration of RV function (Class IIa indication).”

Another important and controversial question pertains to whether to re-operate just for severe TR in patients who have undergone previous left-sided valve surgery. Isolated tricuspid valve surgery for severe TR after previous left-sided surgery has historically been performed relatively late in the natural history of the disease, only when patients became severely symptomatic with signs of right heart failure. Because of the delay in surgery, mortality rates for re-operative tricuspid surgery late after left-sided valve surgery have been exceedingly high (10–25 %).^14,15 This high mortality was likely related to the advanced nature of RV failure encountered at the time of the second procedure, residual pulmonary hypertension, LV dysfunction and other valve abnormalities. The sobering results seen with tricuspid valve repair at reoperation inject a note of caution into its performance and may encourage replacement with an ageappropriate (mechanical or biological) prosthesis. Recently, several advanced centers of excellence^17,18 have reported good peri-operative mortality rates (as low as 4 %), and reasonable long-term outcome with tricuspid valve reoperation when performed early and before severe RV dysfunction occurs. Thus, although the US guidelines^15,19 advocate that reoperation for isolated TR may be considered only for persistent symptoms related to TR in patients who have undergone previous left-sided surgery, and the presence of either severe pulmonary hypertension or significant RV dysfunction constitutes a relative contraindication to reoperation, the European guidelines16 are more permissive and recommend surgery in this setting also in asymptomatic patients if there are signs of RV dilatation/dysfunction.

Tricuspid Regurgitation Surgery at the Time of Left-sided Valve Surgery
It is agreed that severe TR of either a primary or functional nature may not predictably improve after treatment of the left-sided valve lesion and reduction of RV after-load.^7,14,15 It is also known that adding tricuspid valve repair during left-sided surgery does not add appreciably to the risks of surgery. Furthermore, it was shown that reoperation for severe, isolated TR after left-sided valve surgery is associated with a peri-operative mortality rate up to 25 %.^14,15 Thus, because of the hazards imposed by reoperation, the unpredictable nature of TR after successful mitral surgery and the simplicity and low morbidity imposed by adding a cerclage stitch or annuloplasty band on the tricuspid annulus during left-sided surgery have influenced decisionmaking in favour of repair of functional TR initially at the time of leftsided valve surgery. The question remains: when to deal with tricuspid correction during left-sided surgery? Left uncorrected at the time of left-sided valve surgery, moderate and even mild degrees of functional TR may progress over time in approximately 25 % of patients and result in reduced long-term functional outcome and survival.^7,20,21 Risk factors for persistence or progression of TR include tricuspid annulus dilatation (>40 mm or 21 mm/m² on transthoracic echocardiogram [TTE], or >70 mm on direct intra-operative inspection), significant RV dysfunction or dilatation, significant tricuspid leaflet tethering, atrial fibrillation or pulmonary hypertension at the time of left-sided valve surgery, rheumatic or functional aetiology of mitral disease or history of right heart failure.^7,20,21 Based on these data the recent guidelines committee has advocated tricuspid valve repair for patients with severe TR (Class I indication), or mild, moderate functional TR at the time of left-sided valve surgery with either tricuspid annular dilatation or prior evidence of right heart failure (Class IIa indication). Furthermore, tricuspid valve repair should be considered (Class IIb indication) in patients with moderate functional TR and pulmonary hypertension at the time of left-sided valve surgery. Nevertheless, not all mitral diseases are similar. In two recent large series from the Mayo Clinic it was shown that in patients who underwent mitral valve repair for isolated degenerative leaflet prolapse that had moderate or less coexistent functional TR at the time of surgery, TR regressed until the third year in the majority of patients following successful and durable degenerative mitral valve repair, irrespective of annular diameter, and only one tricuspid valve repair for severe symptomatic TR was necessary 4.5 years after the initial MV operation.^22,23 On the other hand, 29 % of the patients who had 5-year follow up at that study had at least moderate–severe TR at the end of follow up. Based on these data, the indications for tricuspid repair, at the time of mitral repair for mitral valve prolapsed, continue to be debatable. Some believe that early correction of mitral regurgitation for mitral valve prolapsed, without concomitant tricuspid repair, is reasonable because it may diminish the late occurrence of functional TR,²⁴ while others support a more aggressive approach, requiring tricuspid repair whenever the annulus is dilated, similar to patients with functional, or rheumatic, mitral regurgitation.^7,16