Clinical relevance of tricuspid regurgitation and its management

Abstract

Tricuspid regurgitation (TR) is very common and is often found in patients with left-sided heart valve disease. Tricuspid annuloplasty (TA) is currently recommended for the treatment of significant TR. However, long-term survival benefit has not been established due to the high prevalence of postoperative residual TR and mortality. Accurate assessment of TR severity and detailed preoperative and postoperative risk evaluation are thus essential to identify high-risk patients and improve clinical outcome. The aim of the present thesis is to assess clinical relevance of TR and its management. Chapter 2 evaluated the relationship between TR severity and detailed echocardiography parameters and liver stiffness in 131 patients with TR secondary to left-sided heart valve disease. Results showed that patients with severe TR had increased liver stiffness and higher prevalence of liver cirrhosis compared with those with mild-moderate TR. Further, the degree of TR, right atrial pressure and inferior vena cava (IVC) diameter were independently associated with elevated liver stiffness. Importantly, the presence of ≥0.4cm2 effective regurgitant orifice of TR and >2.15cm IVC diameter may predict the presence of liver cirrhosis in patients with TR. Chapter 3 assessed the clinical prognostic value of two modified Model for End-stage Liver Disease (MELD) scores in 394 patients undergoing TA. Results demonstrated that patients with severe TR had higher percentage of hepatorenal dysfunction than those with mild-moderate TR. Preoperative MELD-XI and MELD-Albumin scores were independently associated with adverse outcome. Significant improvement of hepatorenal function at 1-year post-operation was noted in patients who had no adverse events but not in those who experienced adverse outcome. Chapter 4 evaluated the prognostic role of red blood cell distribution width (RDW) in 172 patients who underwent concomitant TA during left-sided valve surgery. Results showed that preoperative RDW was independently associated with adverse events. Importantly, an RDW measurement ≥15.2% predicted 1-year adverse outcome with high negative predictive value (94.4%). Further, preoperative right ventricular end-diastolic area was closely associated with RDW. Chapter 5 assessed the incidence of acute kidney injury (AKI) and its impact on clinical outcomes in 339 patients undergoing TA. Results demonstrated that the incidence of AKI, defined using RIFLE, AKIN and KDIGO criteria was 57%, 52% and 53% respectively. For short-term outcome, AKI defined by all three scoring systems was independently associated with major adverse cardiovascular events (MACE) and mortality. For outcome beyond 30 days, AKI by all three criteria was associated with MACE and heart failure; only AKI by AKIN and KDIGO, but not RIFLE, was independently associated with mortality. Besides having higher incidence of AKI, pulmonary systolic artery pressure may remain high in patients underwent TA. Chapter 6 found that residual pulmonary hypertension (PHT) occurred in 43% of patients who underwent TA. Preoperative larger right ventricular geometry and tricuspid valve tethering area, and significant TR were associated with residual PHT. Importantly, the presence of mild residual PHT had a 4.9-fold risk and significant residual PHT had an 8.7-fold risk of adverse events compared with no residual PHT.