Article Text
Abstract
Introduction Isolated tricuspid valve surgery (TVS) may be associated with high morbidity and mortality. The aim of this study was to investigate the association of preoperative imaging and haemodynamic data derived from echocardiography (ECHO), cardiac magnetic resonance (CMR) and right heart catheterisation (RHC) with postoperative outcomes following TVS.
Methods In a retrospective cohort study, patients who underwent isolated TVS at our institution between 2012 and 2020 were screened and followed up to 1 year. We only included those who had all three tests before surgery: ECHO, CMR and RHC. Patients with congenital heart disease, infective endocarditis and those who underwent concomitant valve or pericardial surgery were excluded. The primary outcome was a composite of mortality and congestive heart failure at 1 year. Time-to-event analyses at 1 year and Cox proportional hazards regression analyses were performed.
Results A total of 60 patients were included (mean age of 60±14 years, 63% women), of whom 67% underwent TV repair. The primary outcome occurred in 16 patients (27%) with a 1-year mortality of 7%. It was associated with ECHO-derived right ventricular (RV) free wall strain and RHC-derived RV systolic and diastolic as well as mean pulmonary pressures. On multivariable Cox regression analysis, only RV systolic and diastolic pressures were significantly associated with the primary outcome at 1 year (HRs=5.9 and 3.4, respectively, p<0.05).
Conclusion Baseline invasive haemodynamic assessment could have a strong association with clinical outcomes and help risk-stratify patients undergoing isolated TVS.
- Tricuspid Valve Insufficiency
- Heart Failure, Systolic
- Echocardiography
- Magnetic Resonance Imaging
- Cardiac Catheterization
Data availability statement
No data are available. The data underlying this article cannot be shared publicly due to exclusivity of the data for the Cleveland Clinic Foundation and for the privacy of individuals who were included in the study.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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- Tricuspid Valve Insufficiency
- Heart Failure, Systolic
- Echocardiography
- Magnetic Resonance Imaging
- Cardiac Catheterization
WHAT IS ALREADY KNOWN ON THIS TOPIC
Isolated tricuspid valve surgery (TVS) is associated with a bad prognosis, and a presurgical risk stratification is an unmet need.
WHAT THIS STUDY ADDS
Haemodynamic parameters rather than imaging modalities are predictive of adverse outcomes following isolated TVS.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
Invasive haemodynamic assessment through right heart catheterisation could be used in identifying high surgical risk patients undergoing isolated TVS.
Introduction
Tricuspid valve regurgitation (TR) is associated with increased mortality despite optimal medical treatment, even in the absence of right ventricular (RV) dysfunction or pulmonary hypertension.1 2 According to current valvular guidelines, a class I indication for tricuspid valve surgery (TVS) is only limited to patients undergoing left-sided surgery.3 Isolated TVS, a class IIa indication in patients with symptomatic right-sided heart failure,4 5 only represents 5%–10% of all TV surgeries.6–8 This is partly related to the relatively high-operative and long-term mortality reported with isolated TVS compared with other valvular surgeries.2 6–8 However, symptoms often occur with advanced stages of TR, and delays in surgical correction might explain the relatively poor outcomes of TVS.8–13 Hence, it is becoming increasingly relevant to better risk-stratify patients with severe TR by identifying preoperative anatomic, functional and haemodynamic parameters that could predict worse clinical outcomes after TVS to help guide timely interventions.3 14
While several diagnostic modalities are currently available to assess the tricuspid valve and right heart function before isolated TVS, the relative prognostic value of such testing remains uncertain. Therefore, we sought to investigate the association of preoperative imaging variables derived from echocardiography (ECHO) and cardiac magnetic resonance (CMR), as well as invasive haemodynamic variables derived from right heart catheterisation (RHC) with outcomes following isolated TVS.
Methods
Study population
We conducted a retrospective cohort study using the Cleveland Clinic database for cardiovascular surgical operations, queried from January 2012 to January 2020 for patients undergoing isolated TVS, defined as TVS without concomitant left-sided valve surgery, and who were followed for at least 1 year. We only included those who had all three tests (ECHO, CMR and RHC) performed before surgery. Patients with congenital heart disease or infective endocarditis and those who underwent concomitant valve or pericardial surgery were excluded (figure 1).
Study variables
Baseline patient characteristics, including demographics, comorbidities, medication use and laboratory data, were obtained from the electronic medical records. The aetiology of TR was determined by a review of the surgical report. Imaging variables were measured by ECHO and CMR, according to guidelines.15 16 For RV longitudinal and free wall strain measurement, we performed an offline analysis of speckle tracking ECHO using Velocity Vector Imaging (V.2.0; Siemens, Erlangen, Germany). The 30-day post-TVS ECHOs were also reviewed to assess the changes in RV dimensions (RV end-diastolic area and diameter and fractional area change (FAC)) following surgery. We defined reverse RV remodelling as a decrease in RV end-diastolic diameter, RV end-diastolic area or an increase in FAC at 30 days. CMR measurements included biventricular size and function and measures of TR severity (regurgitant volume and regurgitant fraction). RHC-derived haemodynamic data included central venous pressure, mean arterial pressure (MAP), RV and pulmonary artery (PA) systolic and diastolic pressures, pulmonary capillary wedge pressure, transpulmonary gradient and cardiac index (CI), and the following variables were calculated:
Cardiac power output=MAP×
Pulmonary effective arterial elastance=
Pulmonary arterial compliance=
Systemic elastance=0.9×
PA pulsatility index=
Study outcome
The primary outcome was a composite of mortality and congestive heart failure (CHF) at 1 year. CHF was defined as New York Heart Association classes III and IV symptoms on routine follow-up or hospitalisation for acute decompensated heart failure requiring diuresis with or without other interventions such as paracentesis and thoracentesis. The surgery date was chosen as the starting point of the observational period. Patients were followed up to 1 year or until developing the primary outcome.
Statistical analysis
Baseline characteristics were compared between study groups using a two-sided Student’s t-test or Kruskal-Wallis test as appropriate for continuous variables and a χ2 analysis of variance (ANOVA) test for categorical variables. Continuous variables are expressed as mean (SD) or median (IQR) and categorical variables as proportions.
The associations of different parameters derived from ECHO, CMR and RHC with the primary outcome were assessed through survival analyses with the Kaplan-Meier non-parametric method. As most included patients were in recent years of the study, we examined these associations at 1-year follow-up. To adjust for differences in baseline characteristics and calculate survival estimates, a multivariable Cox proportional hazard model was employed, and HRs with CI were computed. We adjusted for clinical characteristics using a clinical risk score, a score that has been developed and validated to predict mortality after TVS.17 Neither the Society of Thoracic Surgeons nor the European System for Cardiac Operative Risk Evaluation II has been fully validated for use following TVS. All analyses were done using STATA V.13.0 and R studio (V.1.3.1073).
Results
Of the 775 patients who underwent isolated TVS at our centre (mean age ~47 years, 59% men), and after applying the exclusion criteria, 60 patients (~8%) were finally included. Baseline preoperative characteristics related to the demographics, TR aetiology, surgical details, comorbidities, medications and biochemical data of the study population are presented in table 1. The mean age of the study population was 60±14 years, and 63% were women. Among all study patients, 68% underwent TV repair, with the predominant aetiology being annular dilation (61%) followed by leaflet pathology (cleft, flail, prolapse or torn leaflet; 25%). The most common concomitant procedure performed during surgery was MAZE (33%), followed by epicardial lead placement (5%) and coronary artery bypass grafting (5%). The median follow-up of the study patients was 5.8 months. After 1-year follow-up, 16 (27%) subjects had the primary outcome, with a 1-year mortality of 7%. There were no perioperative mortality or heart failure events. When comparing both groups of patients based on the primary outcome, there was no significant difference in age, gender, type of surgery (repair vs replacement) or baseline medications. However, a higher prevalence of prior stroke (19% vs 2%; p=0.024), atrial fibrillation (81% vs 43% vs; p=0.009) and CHF preoperatively (75% vs 5%; p=0.005), with lower mean levels of serum albumin (3.8 vs 4.1; p=0.045) were observed in patient who had the primary outcome compared with those who did not.
Tables 2 and 3 compare the baseline ECHO-derived, CMR-derived and RHC-derived data between the two groups. The median interval between all three preoperative modalities and surgery date was 25 days (IQR 5–68). According to the effective regurgitant orifice area classification of TR severity,18 23% of the population had severe, 6% massive and 69% torrential TR. Patients with the primary outcome had significantly worse apical RV strain (−8.3 vs −14.0; p=0.007). On the other hand, none of the variables measured on CMR were significantly different among the two groups. When looking at the haemodynamic data, the two groups had similar left-sided pressures; yet those who had the primary outcome had significantly higher right-sided pressures. Specifically, they had higher RV systolic (42.2 vs 32.8 mm Hg ; p=0.009), diastolic pulmonary pressure (21.5 vs 15.9 mm Hg, p=0.024) and mean PA pressure (30.8 vs 22.2 mm Hg; p=0.006). Table 4 shows the association of changes in RV dimensions at 30 days with the primary outcome. The majority of patients had signs of reverse RV remodelling evidenced by a decrease in RV end-diastolic area and diameter (70% and 78%, respectively), while 43% had an increase in FAC at 30 days. Although patients who did not have the primary outcome had a higher prevalence of reverse RV remodelling and a lower prevalence of significant (≥moderate) TR at 30 days, there was no significant difference between the two groups in terms of changes in RV dimensions or significant TR. Patients who had the primary outcome had higher prevalence of increased FAC compared with those who did not have the primary outcome (79% vs 42%, p=0.02). Only 12 subjects had follow-up ECHOs at 6 months and 10 subjects had follow-up ECHOs at 1 year, so we did not include results on RV remodelling beyond 30 days.
Regarding our time-to-event analyses, there was a significant difference at 1 year in the time to primary outcome based on RHC data (figure 2). Subjects with higher RV diastolic (log-rank p=0.02) and RV systolic pressures (log-rank p=0.01), as well as higher mean PA pressure (log-rank p=0.03), had a significantly higher likelihood of CHF and death at 1 year. Stratifying, according to RV free wall and global longitudinal strains, showed no difference in the likelihood of having the primary outcome at 5 months (online supplemental figure 1). In the multivariable-adjusted Cox regression analyses, only patients with baseline RV systolic pressure greater than 40 mm Hg (HR=3.64, 95% CI: 1.12 to 15.5; p=0.026) and RV diastolic pressure greater than 10 mm Hg (HR=3.18, 95% CI: 1.02 to 9.97; p=0.036) had a higher risk of having the primary outcome at 1 year (table 5). Among those who had an echocardiogram at 30 days (n=50), only 7 patients had ≥moderate TR. Compared with those who did not develop ≥moderate TR at 30 days, those who did have a higher risk of having the primary outcome (HR=4.7, 95% CI: 1.76 to 13.0; p=0.002) (data not shown).
Supplemental material
Discussion
To our knowledge, this is the first study to simultaneously explore the prognostic value of anatomic and functional variables, as assessed by ECHO, CMR and invasive haemodynamic data obtained by RHC in patients undergoing isolated TVS. The main finding from our study is that right-sided pressures, rather than anatomic and functional parameters, are the factors associated with clinical outcomes after isolated TVS (figure 2). Specifically, elevated RV systolic and diastolic pressure preoperatively are the only factors associated with the primary outcome at 1 year on multivariable-adjusted Cox regression analyses.
Although severe TR is largely undertreated, its grim clinical implications have been increasingly recognised.19 ECHO remains the cornerstone of TV and RV assessment. However, its prognostic impact remains uncertain. Although some studies show that preoperative and intraoperative ECHO-derived LV function20 and RV dimensions10 21 may be associated with outcomes following TVS, most of these are limited by their small sample size and selection bias. Other larger-scale studies failed to show the predictive value of RV size. In a prospective analysis of 1292 patients with significant secondary TR, RV dilation (based on tricuspid annulus≥40 mm) was not associated with long-term survival.22 Similarly, qualitative measures of moderate–severe RV dilation were not associated with mortality after surgical TV replacement in a retrospective analysis of 189 patients with severe TR.23 In both of these studies, measures of RV systolic function were the only significant predictors of mortality after TVS. Notably, in the study by Topilsky et al, the only predictor of mortality was the right index of myocardial performance, which is strongly correlated with right heart haemodynamics.24
We previously showed at our institution that TVS has the potential in reversing RV remodelling and improving RV function,25 yet this study shows that reverse RV remodelling at 30 days was not associated with clinical outcomes. On the other hand, RV free wall strain has emerged as a valuable tool and has been previously shown to be an independent predictor of outcomes after isolated TVS.26 27 Similarly, in our study, RV global and RV free wall strains were the only ECHO parameters that were significantly different between the two study groups; however, their association with outcomes on time-to-event analysis was not statistically significant. Our study may be underpowered to detect a significant association of RV strain parameters given borderline p values from the survival analysis.
CMR is considered the gold standard in RV size and function assessment and has been increasingly used in valvular assessment. Data on the role of CMR before TVS are scarce. RV ejection fraction,28 RV mass index29 and TR severity by CMR30 have been shown to play a potential prognostic role, but none of the studies also included ECHO and RHC data. In our study, none of the imaging-derived parameters, whether by ECHO or CMR, were associated with the primary outcome following isolated TVS. This could be related to our patient population, which only included patients with severe symptomatic TR at a relatively advanced stage of the disease. Moreover, RV functional assessment by CMR might be affected by an increase in preload and in afterload, which is typical in severe TR patients.
Interestingly, and among a myriad of preoperative imaging and haemodynamic variables that we included, only right-sided pressures derived by RHC were associated with the primary outcomes. When studied in isolation, the value of invasive haemodynamic assessment in predicting outcomes following TV interventions31 32 has been previously explored. Similar to our findings, elevated right-sided pressures preoperatively,12 32 or postoperatively33 appear to be associated with adverse outcomes following TVS. Also, preoperative ECHO-based estimates of haemodynamic parameters have been shown to have prognostic value in patients undergoing TVS.22 24 34 35 Our study adds to the literature by showing that invasive haemodynamic data rather than imaging-derived anatomic or functional data provide the most prognostic value in patients undergoing TVS. It is important to note that while RHC-derived RV systolic pressure was associated with the study’s outcome, RVSP calculated by ECHO was not different between those who did and did not have the primary outcome. This is might be due to intraobserver/interobserver variability in the measurement of RVSP, a parameter that can challenge to accurately assess in many patients.
Furthermore, from a practical standpoint, identifying patients with a higher risk of worse clinical outcomes following TVS could allow for the more widespread use of novel transcatheter tricuspid valve interventions (TTVI). Several TTVI technologies targeting different structures of the tricuspid valve apparatus are currently available.36 For example, edge-to-edge repair using the TriClip system (Abbott Vascular, Santa Clara, California, USA), which effectively bridge the septal and one of the mural leaflets together is a valid alternative.37 Also, multiple devices targeting the annulus have been developed. For instance, the Cardioband system (Edwards Lifesciences, Irvine, California, USA) is a direct annuloplasty device.38 Transcutaneous TV replacement technologies are also being investigated with numerous available systems like the Lux-Valve (Ningbo Jenscare Biotechnology, Ningbo, China) or the Evoque valve (Edwards Lifesciences, Irvine, California, USA).39 40 Finally, the TricValve system (Products & Features GmbH, Vienna, Austria) that consists of two self-expanding biological valves that are implanted percutaneously into the superior and inferior vena cavae without disturbing the native tricuspid valve is a breakthrough system intended for patients with severely symptomatic TR and right heart failure with limited treatment alternatives.41
Several study limitations are worth noting. First, this was a single-centre retrospective study, and therefore, the analysis was subject to inherent biases, including ascertainment and selection bias, according to data availability from all three modalities. The centre experience with isolated TVS and its preoperative assessment using several modalities might not be generalisable to routine care of TR patients. Thus, these novel findings should be further validated in prospective clinical trials. The study is also subject to common limitations of observational design, where causality cannot be established. Significant loss to follow-up and relatively small sample size at follow-up beyond 1 year did not allow for longer-term survival analyses and might have not revealed significant associations of previously reported predictors of outcomes after TVS such as CMR-based parameters and speckle strain parameters. Moreover, the low event rates of the primary endpoints prohibited more extensive multivariable-adjusted regression analyses.
Conclusion
Routine use of preoperative invasive haemodynamic assessment could potentially have an important role in the risk stratification of patients undergoing isolated TVS. Our study shows that data derived from RHC, specifically RV systolic and diastolic pressures, rather than Echo and CMR-derived anatomical and functional data, are associated with postoperative mortality and CHF following isolated TVS.
Supplemental material
Data availability statement
No data are available. The data underlying this article cannot be shared publicly due to exclusivity of the data for the Cleveland Clinic Foundation and for the privacy of individuals who were included in the study.
Ethics statements
Patient consent for publication
Ethics approval
This study was approved by the Cleveland Clinic Institutional Review Board (#19-711, approved on 27 June 2019). Written informed consent was waived owing to the retrospective study design.
Acknowledgments
This paper was presented as an abstract at the ACC22 conference.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
EH and HL are joint first authors.
Twitter @habib_layoun, @kassisMD
Contributors EH, HL and SCH conceived and designed the study. EH, HL, JH, OAH and SCH collected, analysed and interpreted the data. EH, HL, JK, NK and SCH drafted and critically revised the manuscript. PCC, MH, AM, SDF, BG, HE, SU, GP, SK and SCH supervised the study. HL and SCH are responsible for the overall content and serve as guarantors. All authors read and approved the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.