Progression of Tricuspid Regurgitation in Patients who Underwent Isolated Mitral Valve Surgery: A Retrospective Observational Study

Introduction

Functional tricuspid regurgitation (TR) is a common accompaniment of left-sided valvular disease, most frequently mitral valve pathology. Chronic haemodynamic overload leads to progressive pulmonary hypertension, right ventricular (RV) dilatation and remodelling, and consequent tricuspid annular dilatation with leaflet malcoaptation [1,2].

Historically, TR was regarded as a secondary lesion expected to resolve spontaneously after correction of the causative mitral lesion. However, a body of evidence accumulated over the past two decades has established that TR may persist or worsen even after technically successful mitral valve surgery [3-5]. Persistent moderate or severe TR is independently associated with right-sided heart failure, reduced exercise capacity, and diminished long-term survival [6].

Contemporary data have identified several determinants of late TR following mitral valve surgery, including preoperative TR severity, the degree of pulmonary arterial hypertension, and tricuspid annular dilatation [7-9]. On the basis of this evidence, current American College of Cardiology/American Heart Association (ACC/AHA) and European Society of Cardiology (ESC) guidelines recommend considering concomitant tricuspid annuloplasty at the time of mitral surgery in patients with moderate TR or with significant annular dilatation (≥40 mm) even in the presence of only mild TR [8,9].

Despite these recommendations, isolated mitral valve surgery without simultaneous tricuspid intervention remains widely practised, particularly in resource-limited settings where reoperation carries substantial risk. A precise understanding of the natural history and predictors of TR progression after isolated mitral surgery is therefore essential to optimise patient selection and postoperative surveillance strategies.

The aim of the present study was to evaluate the trajectory of TR severity following isolated mitral valve surgery in a cohort of predominantly rheumatic patients, and to identify preoperative clinical and echocardiographic predictors associated with TR worsening.

Methods

Study design and setting

This was a single-centre retrospective observational study conducted in the Department of Cardiovascular and Thoracic Surgery at Government Medical College Kozhikode, a tertiary referral hospital in Kerala, India. The study was approved by the Institutional Ethics Committee and was conducted in accordance with the Declaration of Helsinki. Informed consent requirements were waived given the retrospective nature of the study.

Study population

All patients who underwent isolated mitral valve replacement (MVR) or mitral valve repair (MVRep) between January 2019 and December 2022 and who attended scheduled outpatient or valve clinic follow-up were screened for eligibility.

Inclusion criteria: (1) isolated MVR or MVRep with no concomitant cardiac procedure; (2) availability of preoperative and postoperative transthoracic echocardiographic (TTE) data; (3) minimum follow-up of six months. Exclusion criteria: (1) concomitant tricuspid valve surgery; (2) simultaneous coronary artery bypass grafting; (3) concomitant aortic valve surgery; (4) redo mitral valve surgery; (5) congenital heart disease; (6) incomplete echocardiographic records.

A total of 60 patients satisfied the eligibility criteria and constituted the final study cohort.

Surgical technique

All the procedures were performed through a standard median sternotomy under general anaesthesia. Cardiopulmonary bypass was established using ascending aortic and bicaval venous cannulation. Myocardial protection was achieved with antegrade cold blood cardioplegia delivered via the aortic root. The left atrium was accessed through a standard left atriotomy posterior to the interatrial groove (Sondergaard’s plane).

For mitral valve replacement, the native mitral valve was excised with preservation of the posterior leaflet and subvalvar apparatus where feasible. The prosthetic valve annulus was secured using interrupted pledgeted mattress sutures of 2-0 Trubond polyester, placed in an everting or non-everting fashion depending on annular tissue quality. Oxidised regenerated cellulose (Clinicel knitted/fibrillar, Healthium Medtech, India) was used for local haemostasis at bleeding points on the annular, raw epicardial and mediastinal surfaces. The sternotomy closure was done using Trusteel suture and the skin closure was done in layers using Trusynth plus neo suture (Healthium Medtech, India). For mitral valve repair, standard techniques including leaflet resection, chordal transfer, and ring annuloplasty using a flexible or semi-rigid annuloplasty ring were employed as indicated by the intraoperative findings. The left atriotomy was closed with a continuous Trulene 3-0 polypropylene suture. Aortic cross-clamp was released after de-airing manoeuvres, and cardiopulmonary bypass was weaned following confirmation of haemodynamic stability and satisfactory valve function by intraoperative transoesophageal echocardiography.

Data collection

Demographic, clinical, operative, and echocardiographic data were extracted from hospital records. Variables collected included age, sex, aetiology of mitral valve disease, cardiac rhythm, preoperative and follow-up, New York Heart Association (NYHA) functional class, type of surgical procedure (replacement or repair), and prosthetic valve function at follow-up. Data were abstracted by two independent reviewers, with discrepancies resolved by consensus.

Echocardiographic evaluation

All patients underwent TTE using a standard Philips IE33 or equivalent system. Echocardiographic parameters assessed at both preoperative and follow-up evaluations included:

TR Severity: TR was graded semi quantitatively using colour-flow Doppler imaging in accordance with the European Association of Cardiovascular Imaging recommendations on a four-point ordinal scale: Grade 0 (none), Grade 1 (mild), Grade 2 (moderate), Grade 3 (severe) (3).

Tricuspid Annular Diameter: Measured in end-diastole in the apical four-chamber view. Values ≤35 mm were classified as normal; values ≥40 mm were classified as dilated.

Right Ventricular Systolic Function: Assessed using tricuspid annular plane systolic excursion (TAPSE) measured by M-mode echocardiography with the cursor aligned at the tricuspid annulus in the apical four-chamber view. TAPSE < 17 mm was defined as RV systolic dysfunction, consistent with current guideline thresholds.

Pulmonary Artery Systolic Pressure (PASP): Estimated non-invasively by Doppler interrogation of the TR jet, using the modified Bernoulli equation and an assumed right atrial pressure of 5 or 10 mmHg based on inferior vena cava diameter and collapsibility. Pulmonary hypertension was defined as PASP > 40 mmHg.

TR progression was defined as an increase of ≥1 grade in TR severity between the preoperative and follow-up echocardiographic assessments. TR regression was defined as a decrease of ≥1 grade. Patients with unchanged TR grade were classified as stable.

Statistical analysis

Categorical variables are presented as frequencies and percentages; continuous variables are expressed as mean ± standard deviation (SD). Associations between clinical and echocardiographic variables and TR progression were evaluated using the Pearson chi-square test. Fisher's exact test was applied where expected cell frequencies were fewer than five. A two-sided p < 0.05 was considered statistically significant. All analyses were performed using SPSS version 17.0 (IBM Corp., Armonk, NY, USA).

Results

Baseline characteristics

The study cohort comprised 60 patients with a mean age of 48.5 ± 12.3 years (range 24–72 years). Females predominated, constituting 68% (n = 41) of the cohort, reflecting the higher prevalence of rheumatic mitral disease in women in this region. Rheumatic heart disease was the aetiological basis in 78% (n = 47) of cases; the remainder comprised degenerative and other non-rheumatic aetiologies. Atrial fibrillation was present in 38% of patients at the time of surgery. The majority of patients (85%; n = 51) presented in advanced NYHA functional class III or IV preoperatively, underscoring the significant symptomatic burden of the study population. Mitral valve replacement was performed in 80% (n = 48) of patients and mitral valve repair in 20% (n = 12). Mean follow-up duration was 36 ± 18 months (range 6–72 months).

Preoperative and follow-up TR severity

Table 1 summarises preoperative TR grades. At baseline, 25% of patients (n = 15) had no TR, 55% (n = 33) had mild TR, and 20% (n = 12) had moderate-to-severe TR. At follow-up echocardiography (Table 2), TR had resolved or remained absent in 30% (n = 18), was mild in 45% (n = 27), and was moderate-to-severe in 25% (n = 15).

TR outcome trajectory

Table 3 delineates TR progression, stability, and regression. Overall, TR progressed in 28% of patients (n = 17), remained stable in 52% (n = 31), and regressed in 20% (n = 12). Of note, among those with preoperative moderate-to-severe TR (n = 12), 67% demonstrated persistent or worsening TR at follow-up.

Predictors of TR progression

Three preoperative variables were significantly associated with postoperative TR progression (Table 4). Preoperative moderate TR was the strongest predictor (p = 0.02). Pulmonary hypertension (PASP > 40 mmHg) was significantly associated with TR worsening (p = 0.04). Tricuspid annular dilatation ≥40 mm was likewise a significant predictor (p = 0.03). Age, sex, cardiac rhythm, and surgical procedure type did not reach statistical significance as predictors of TR progression in this cohort.

Right ventricular function

Mean TAPSE across the cohort was 17.2 ± 3.8 mm. RV systolic dysfunction (TAPSE < 17 mm) was identified in 42% of patients (n = 25), indicating a substantial burden of subclinical RV impairment in this population, even among those with apparently stable TR.

Functional outcomes

Postoperative NYHA functional class improved substantially across the cohort (Table 5). The proportion of patients in NYHA class I or II increased from 15% (n = 9) preoperatively to 92% (n = 55) at follow-up, while the proportion in class III or IV fell from 85% (n = 51) to 8% (n = 5). This improvement was statistically significant (p < 0.001).

Grading adapted from Lancellotti et al.,(2013) [3].

TR, tricuspid regurgitation.

TR, tricuspid regurgitation.

TR, tricuspid regurgitation.

TR, tricuspid regurgitation; PASP, pulmonary artery systolic pressure.

NYHA, New York Heart Association. p < 0.001 (chi-square test).

Discussion

The principal finding of the present study is that TR progressed in approximately one-quarter to one-third of patients (28%) following isolated mitral valve surgery over a medium-term follow-up period. This observation reinforces the growing recognition that functional TR does not reliably resolve after correction of the primary mitral lesion and that a significant minority of patients may experience ongoing tricuspid valve deterioration in the postoperative period.

The traditional paradigm held that TR secondary to mitral valve disease would regress once the haemodynamic burden imposed by mitral pathology was relieved. Matsunaga and Duran [5] challenged this assumption in a landmark study demonstrating TR progression rates of up to 74% at 10 years after mitral surgery in patients with preoperative TR. Subsequent reports by Dreyfus et al.,[9] and Matsuyama et al.,[2] confirmed that even mild preoperative TR may worsen postoperatively, particularly in the presence of annular dilatation. The 28% progression rate observed in the present cohort, though lower than some historical series, is consistent with studies in rheumatic populations from similar geographic settings, where the pathological substrate of chronic rheumatic inflammation may limit regression.

Three variables emerged as independent predictors of TR progression in our analysis: preoperative moderate TR, pulmonary hypertension, and tricuspid annular dilatation ≥40 mm. These findings align with current mechanistic understanding. Tricuspid annular dilatation results from chronic RV pressure and volume overload and represents geometric distortion that may be irreversible even after relief of pulmonary hypertension following mitral correction [9]. Preoperative TR severity likely reflects the degree of established annular and subvalvar distortion. Pulmonary hypertension exerts sustained afterload on the right ventricle, perpetuating RV remodelling even when mitral haemodynamics improve postoperatively [7].

The finding that 42% of patients exhibited RV systolic dysfunction by TAPSE criteria is clinically significant. RV dysfunction at the time of follow-up may reflect the combined effects of preoperative pressure overload, intraoperative RV ischaemia, and ongoing TR-mediated volume overload. Low TAPSE is an established independent predictor of adverse outcomes in patients with valvular heart disease and has been associated with increased morbidity and mortality after cardiac surgery [3]. Although the present study was not powered to assess outcomes by TAPSE category, the high prevalence of RV dysfunction in this cohort warrants prospective investigation.

The substantial improvement in NYHA functional class observed postoperatively (from 85% in class III/IV preoperatively to 8% at follow-up) confirms the overall haemodynamic benefit of mitral valve surgery and is consistent with published literature [6]. However, it is important to recognise that symptomatic improvement does not necessarily reflect freedom from adverse remodelling. Patients with progressive TR may remain asymptomatic for prolonged periods before decompensating with overt right-sided heart failure, at which point reoperation carries markedly elevated risk [6].

The current ACC/AHA and ESC guidelines advocate concomitant tricuspid repair at the time of mitral surgery in patients with moderate or greater TR, or with annular dilatation ≥40 mm even with mild TR [8,9]. The findings of the present study lend further empirical support to these recommendations, demonstrating that all three guideline-endorsed risk factors - TR severity, pulmonary hypertension, and annular dilatation — were significantly predictive of late TR progression in an independent cohort. Nevertheless, application of these guidelines in resource-constrained settings requires careful individual risk–benefit analysis, since concomitant tricuspid procedures prolong operative time and cardiopulmonary bypass duration.

The findings also underscore the importance of structured postoperative echocardiographic surveillance. Identification of progressive TR at an earlier, less symptomatic stage may provide a window for catheter-based or surgical tricuspid intervention before irreversible RV dysfunction is established. Emerging transcatheter tricuspid technologies offer a promising future avenue for high-risk patients who are not candidates for redo surgery [8].

Limitations

Several limitations must be acknowledged. The retrospective single-centre design introduces inherent selection bias and limits the generalisability of the findings. The sample size of 60 patients, while adequate for chi-square analyses, restricts the statistical power to detect modest associations and precludes multivariate regression modelling. Echocardiographic follow-up was performed at a single postoperative timepoint rather than serially, so the trajectory of TR change over time cannot be characterised. TR grading by colour Doppler is inherently semi-quantitative and subject to inter-observer variability; quantitative Doppler parameters such as effective regurgitant orifice area and vena contracta were not systematically recorded. The study also does not include survival analysis or long-term clinical outcome data, which would be necessary to determine the prognostic impact of TR progression in this cohort. Prospective multicentre studies with standardised echocardiographic protocols and longer follow-up are required to validate and extend these observations.

Conclusion

Tricuspid regurgitation may persist or progress in a clinically significant proportion of patients following isolated mitral valve surgery. In the present cohort, nearly 28% of patients exhibited TR worsening at medium-term follow-up. Preoperative TR severity, pulmonary hypertension, and tricuspid annular dilatation ≥40 mm were significant and independently consistent predictors of TR progression. Rigorous preoperative echocardiographic assessment of tricuspid annular dimensions, TR grade, and pulmonary haemodynamics is essential to guide the decision for concomitant tricuspid intervention at the time of mitral surgery. Regular postoperative echocardiographic surveillance is recommended to facilitate timely detection and management of progressive TR before irreversible right ventricular dysfunction ensues.

Declarations

Ethics approval and consent to participate

This study was approved by the Institutional Ethics Committee of Government Medical College Kozhikode. All procedures were conducted in accordance with the Declaration of Helsinki. Informed consent requirements were waived due to the retrospective nature of data collection.

Availability of data and materials

The datasets used and analysed during the current study are available from the corresponding author on reasonable request.

Competing interests

The authors declare that they have no competing interests.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Authors’ contributions

TCP: study conception, data collection, manuscript drafting, final approval, study design, critical revision of manuscript. AA: data analysis, literature review, manuscript revision. RS: supervision, critical revision, final approval. All authors read and approved the final manuscript.

Acknowledgements

The authors wish to thank the nursing and echocardiography staff of Government Medical College Kozhikode for their contributions to patient care and data acquisition.