A Single Centre Five-Year Retrospective Case Study Analysing Risk Factors Of Secondary Tricuspid Regurgitation Progression And Surgical Outcomes Of Primary And Redo Tricuspid Valve Surgery
J Singh, M Mg Ly, D Wolfers, Z Akhunji, H Wolfenden, P Grant
J Singh, M Mg Ly, D Wolfers, Z Akhunji, H Wolfenden, P Grant. A Single Centre Five-Year Retrospective Case Study Analysing Risk Factors Of Secondary Tricuspid Regurgitation Progression And Surgical Outcomes Of Primary And Redo Tricuspid Valve Surgery. The Internet Journal of Thoracic and Cardiovascular Surgery. 2021 Volume 22 Number 1.
Background: Delayed Tricuspid regurgitation after isolated mitral surgery is associated with decreased exercise tolerance and poor quality of life. Many of these patients undergo re-operative Tricuspid valve surgery with poor prognosis. This study aims to identify independent predictor of late TR progression and surgical outcomes of primary and late secondary tricuspid valve surgery after concomitant left heart surgery.
Method: 250 patients (208 Primary / 42 Redo for Late Secondary TR) who underwent Tricuspid valve surgery along with left sided valve surgery from January 2014 to March 2019 were retrospectively registered in the study. Isolated Tricuspid valve surgeries and Redo tricuspid valve surgeries were excluded from the study. We analysed the predictors of delayed TR progression and surgical outcomes of Primary and Late Secondary Tricuspid valve surgery (28 repair Vs 14 replacement) requiring Redo surgeries.
Result: The operative mortality rate in Primary tricuspid valve surgery was 4.8% (10/208) while 16.66% (7/42) in Redo tricuspid valve surgery. High systolic Pulmonary artery pressure, Atrial fibrillation and Enlarged Left atrial diameter are independent risk factors of Secondary TR progression requiring Redo tricuspid valve surgeries.
Cross clamp time was 130 ± 60 min in Repair group compared to 115 ± 55 min in Redo Replacement group. Mortality was higher in Redo Replacement group 28.57 %( 4/14 ) compared to Repair group 10.71%( 3/28)..
Factors related to early mortality were Emergency surgery, New York Heart Association (NYHA) class III & IV, severe TR, left ventricle ejection fraction less than 0.40 and postoperative low cardiac output state. Postoperative complications included reoperation for bleeding, renal failure requiring dialysis, prolonged ICU / ventilatory support needing tracheostomy and pacemaker for heart block.
Conclusion: It’s quite obvious that despite good left heart surgery, TR doesn’t go away or get better overtime. Severe TR is an independent predictor of long term mortality. Patients with NYHA class III/IV symptoms had significantly poor outcomes. Increased pulmonary artery pressure, permanent atrial fibrillation are important risk factors of TR progression. Concomitant Tricuspid valve surgery at the time of left heart surgery should be considered in cases where risk of TR progression is high or dilated tricuspid annulus.
To improve outcomes of Tricuspid valve surgery whether Primary or Redo surgeries for secondary late TR progression, timely referral is very important prior to development of end- organ damage.
The incidence of tricuspid regurgitation associated with left valvular disease is quite significant, ranging from 6 to 30 %. The most common association is with mitral valve but also related to aortic valve pathology. The tricuspid regurgitation is called ‘functional’ due to annular dilatation secondary to pulmonary hypertension and RV dilatation.
The approach that surgical treatment of left heart disease would correct the problem of right side is redundant now and tricuspid regurgitation is treated more aggressively. Patients who develop severe TR after left sided heart surgery have higher mortality rate, poor quality of life and reduced exercise tolerance.
Patients with late onset secondary TR progression after correction of left sided heart surgery need serial follow-up to ascertain redo surgery before the development of severe RV dysfunction. Timely referral is important before the onset of end organ damage. 
METHOD & OBSERVATION
The study included retrospective analysis of all patients (n=250) who underwent primary tricuspid valve surgery (n=208) along with left sided heart surgery or late for the secondary TR (n=42) appeared after left sided heart surgery without Tricuspid procedure. Preoperative and postoperative 2D Echo data was compared to Echocardiographic findings at the time of Redo surgery.
While the majority of patients who underwent Redo Tricuspid valve surgery were having mild TR and Tricuspid annulus less than 4 cm at the time of primary left sided surgery, late onset secondary TR seems to have progressed. Important predictors of late TR progression are high systolic PA pressure (54±14.7), atrial fibrillation (n=30) and enlarged left atrium diameter (49 ± 6.8 mm).
The age group of patients who underwent primary surgery was less (54 ± 15.2 years)
compared to Redo group (62 ± 8years). The majority of patients in the redo group were in NYHA class III & IV (39/42 ) with 38.09 % patients having LV ejection fraction < 40 %. Incidence of infective endocarditis is comparable in both group while 30.9 % patients are having renal dysfunction.
While 11.9 % percent patient in the redo group had pre-op inotropic requirements, almost 14.28% patients presented in shock in the redo group. 10 patients had emergency surgery (23.81%) in the redo group compared to 13.85% patients in the primary group. 30 days mortality was 4.8% in primary group compared to 16.66% (7/42) in the redo group.
28 patients underwent tricuspid valve repair in the redo group while 14 patients had Tricuspid valve replacement. Clamp time was higher in the repair group 130±60 min vs 115 ±55 min.
Intubation period was higher for the replacement group. 6/14 patients stayed in the ICU for more than five days. Operative mortality was higher in the replacement group (28.57% vs 10.71%)
35.71% patients in the redo replacement group were in low cardiac output state post-operatively. Almost (6/14) 42.85 % patient required dialysis for renal failure.
Incidence of stroke was comparable in both group (7.14%). Reoperation for bleeding was similar in both groups. Prolonged intubation in redo replacement meant more number of patients (35.71%) acquiring hospital acquired pneumonia.
The concomitant correction of functional tricuspid regurgitation secondary to left heart disease remains underused and an associated functional tricuspid regurgitation typically reveals a delayed correction of left-sided heart disease.
Secondary dilatation of the tricuspid annulus is present in vast number of patients with left heart disease, even in the absence of TR. This is a progressive disease that does not always resolve after the correction of left sided lesion . Due to high mortality involved with Redo surgeries, many recommend medical treatment and delayed referral for surgery until right heart failure becomes refractory to medication.
The factors related to high mortality in redo surgery are high functional class, severe RV failure and dimensions, low Ejection Fraction, elevated pulmonary artery pressure, all of which are progressive. Association between atrial fibrillation and progression of TR in native valve or repaired valve is well demonstrated in many studies including ours. An early referral for surgery will drastically reduce the mortality in this clinical subset. 
Transthoracic Echo allows good assessment of RV diameters and functions in patients with TR. However it has limitations given the complex morphology of RV and most parameters are influenced by load conditions. The severity of TR, the degree of RV dysfunction, a tenting area > 1.63 sq. cm and depth of tethering >0.76 are good indicators of Tricuspid valve needing surgery. Cardiovascular MR is a good tool in the assessment of the LV and RV volumes and EF, considered independent predictors of residual TR post-surgery. 
The high mortality associated with Tricuspid valve replacement in redo group could be due to large rigid prosthesis inserted into a deformable, low –pressure right ventricular cavity could lead to progressive right ventricular dysfunction. Despite more TR in the repair group during follow up, reoperation rates and functional class were similar.
The extended Intensive care stay with prolonged ventilation is associated with reduced survival in this study. It could be a reflection of patients with underlying lung disease or reflection of patients with pulmonary hypertension. On a similar note prolonged bypass time and postoperative low cardiac output syndrome are associated with reduced survival, a reflection of severity of underlying cardiac disease. 
We demonstrated that patients with NYHA Class III/IV had significantly poor outcomes. To improve outcomes, timely referral before end organ damages is very important. Surgical correction of TR at the time of primary surgery should be pursued more aggressively if patient is in Chronic AF, increased pulmonary artery pressure with dilated tricuspid annulus.
It’s quite obvious that despite good left heart surgery, TR doesn’t go away or get better overtime.