Tricuspid Regurgitation Uncommon After Surgery for Ischemic Mitral Regurgitation But Tied to Cardiac Events
Key findings
- This analysis pooled data from two multicenter randomized trials in which 492 patients underwent surgery for moderate or severe ischemic mitral valve regurgitation (IMR) without treatment of nonsevere tricuspid regurgitation (TR)
- Two years after IMR surgery, the incidence of TR progression (6%) and the incidence of moderate or severe TR (11.5%) were lower than expected based on previously published retrospective data
- Predictors of moderate or severe TR at two years were baseline TR grade, concomitant surgical ablation of atrial fibrillation and baseline annular dimension; however, baseline tricuspid annular dilation alone performed poorly for predicting TR progression or moderate/severe TR
- Both TR progression and moderate or severe TR at two years were significantly associated with postoperative MR recurrence and presence of a permanent pacemaker, as well as high rates of major adverse cardiac events during follow-up
- Efforts to reduce or avoid postoperative TR in patients with IMR are still warranted, but decision-making about concomitant tricuspid valve repair should not be based routinely on tricuspid annular dimension alone
How and when tricuspid regurgitation (TR) should be treated during mitral valve surgery is a matter of continuing debate. An ongoing randomized trial is investigating in patients with primary mitral regurgitation (MR), but the results won't be applicable to ischemic MR (IMR). A very different pathophysiologic entity, IMR is caused by heart failure due to ischemic heart disease.
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To investigate the prevalence and significance of TR after IMR surgery, Judy Hung, MD, director of the Echocardiography Lab in the Corrigan Minehan Heart Center at Massachusetts General Hospital, and Philippe Bertrand, MD, PhD, clinical and research fellow, and colleagues in the Cardiothoracic Surgical Trials Network (CSTN) pooled data from two multicenter randomized trials. The results, reported in the Journal of the American College of Cardiology, show a rate of TR progression after IMR surgery several times smaller than previously reported in retrospective studies, but found that TR had a substantial impact on the risk of cardiac events.
Study Methods
The CSTN previously reported two-year results from:
- A trial of surgery for severe IMR, published in The New England Journal of Medicine, in which 251 patients were randomly assigned to MV replacement or repair
- A trial of surgery for moderate IMR, published in the same journal, in which 301 patients were randomly assigned to coronary artery bypass grafting (CABG) plus MV repair or CABG alone
Concomitant tricuspid valve repair was left to the discretion of the surgeon, and 492 patients (92%) did not have that intervention. Echocardiography, including dedicated tricuspid valve assessment, was performed at prespecified time points and analyzed by an independent central laboratory.
The new analysis assessed outcomes for the 492 patients in whom nonsevere TR was left untreated.
Postoperative TR
Progression of TR was defined as the composite of the following within two years after randomization: the presence of severe TR, reoperation for TR, or TR progression from baseline by two grades. TR progression occurred in 20 patients (6%).
A separate measure, the incidence of moderate or severe TR within two years, was 11.5%.
Predictors of Postoperative TR
In multivariable analysis, independent, significant predictors of moderate or severe TR at two years were:
- Baseline TR grade (OR, 2.51 for mild vs. none/trace; 6.66 for moderate vs. none/trace)
- Concomitant surgical ablation of atrial fibrillation (OR, 3.44)
- Tricuspid annular index (mm per m2 of body surface area) (OR, 1.17)
Tricuspid annular dilation as defined by the American Heart Association/American College of Cardiology (≥40 mm or 21 mm/m2) correlated with baseline TR severity, confirming its utility for determining TR severity at the time of surgery. However, when considered alone it performed poorly for predicting TR progression or moderate/severe TR, even when higher cutoffs were tested.
IMR Recurrence and Pacemaker/ICD Leads
The presence of moderate/severe TR at two years was higher in patients with IMR recurrence (20% vs. 9%; P=0.02) or a permanent pacemaker or implantable cardioverter-defibrillator (19% vs. 9%; P=0.01).
Clinical Outcomes
Major adverse clinical events (MACE) were defined as the composite of the following within two years: increase of at least one New York Heart Association functional class, hospitalization for heart failure, revision MV surgery or stroke. Significant results were:
Of the 20 patients with TR progression
- 55% had MACE (P<0.003 compared with patients without TR progression)
- 45% were hospitalized for heart failure (P=0.002)
Of the 37 patients who developed moderate/severe TR at 2 years
- 38% had MACE (P=0.04)
- 19% had an increase of ≥1 NYHA class (P=0.03)
- 27% were hospitalized for heart failure (P=0.05)
Recommendations for Surgeons
Despite a lower than anticipated incidence of TR progression and prevalence of moderate/severe TR at two years, this study reveals a substantial clinical impact of TR progression after IMR surgery. Efforts to reduce or avoid postoperative TR in patients with IMR are still warranted.
However, decision-making about concomitant tricuspid valve repair should not be based routinely on tricuspid annular dimension alone. The other factors to consider are TR grade at baseline and whether surgical ablation of atrial fibrillation is being performed.
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