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Literature Review

Impact of Right Ventricular Dysfunction and Tricuspid Regurgitation on Outcomes in Patients Undergoing Transcatheter Aortic Valve Replacement

Schwartz LA, Rozenbaum Z, Ghantous E, et al. J Am Soc Echocardiogr. 2017;30(1):36–46.

Reviewers: Brenton Alexander, MD1; Dalia Banks, MD FASE1

  1. Department of Anesthesiology, University of California, San Diego
Background

Transcatheter aortic valve replacement (TAVR) is becoming increasingly common not only in patients with severe aortic stenosis who are unable to tolerate the risks of a traditional surgical approach, but also in patients with fewer preoperative risk factors.1 Various comorbidities need to be addressed to best determine who would benefit most from the less invasive approach. In patients with aortic stenosis (AS), tricuspid regurgitation (TR) is considered to be a manifestation of right ventricular (RV) failure, enlargement, pulmonary hypertension, or atrial fibrillation. It is unknown if TR dysfunction should prompt more invasive surgical correction or if a less invasive approach is still warranted. Therefore, the authors specifically addressed the association between RV dysfunction, TR severity, and other comorbidities on outcomes following TAVR. Additionally, they reported the association between changes in TR following TAVR and the resulting outcomes.

Methods

Five hundred sixty-four consecutive patients with severe symptomatic native AS (aortic valve area < 1 cm2) underwent TAVR at the authors’ hospital. All patients were considered high risk for valve surgery by their institutional heart team. Clinical details were prospectively recorded but retrospectively analyzed for all patients at baseline, 1-month, 6-month, and yearly clinical assessments. Echocardiographic data were recorded at baseline and 6 months after TAVR. They excluded patients who had incomplete preprocedural echocardiographic data, leaving 519 TAVR patients (92%) to be included in the study. The study end points included all-cause mortality and a combined cardiac outcome, including death and heart failure hospitalization (see original text for definition of heart failure hospitalization).

Apart from RV qualitative grading, RV function was evaluated by tricuspid annular plane systolic excursion (TAPSE), RV end-systolic area, fractional area change (FAC), and myocardial performance index (Tei index). TR severity was determined by an integrative, semiquantitative approach as recommended by the American Society of Echocardiography.

Please refer to the original text for complete statistical analyses. They included students’ t-test, Wilcoxon rank sum test, chi-squared, Fisher exact test, univariate analyses, and multivariate analyses. P value < .05 was deemed significant and most of the discussed results were concluded utilizing multivariate Cox proportional-hazards models with the predefined end points (time to death and time to combined cardiac event).

Results

The prevalence of moderate or greater TR was 11% (44 patients with moderate TR and 15 with severe TR). Patients with moderate or severe TR had significantly more clinical and physiologic comorbidities than those without.

Multivariate analysis demonstrated that preoperative systolic pulmonary artery pressure (P= .0006) and annular diameter (P= .008) were the only independent correlates of TR grade (r2=80.4, P<.0001 for the model). Interestingly, in a multivariate Cox hazard analysis adjusted for comorbidities, TR was not associated with mortality when adjusted for European System for Cardiac Operative Risk Evaluation score (P=.3), systolic pulmonary pressure, gender, presence of atrial fibrillation, or pacemaker (P=.20), emphasizing the link among TR grade, advanced clinical stage, and adverse outcome. RV dysfunction was associated with higher mortality irrespective of TR grade.

Qualitative measures of RV size or function and parameters estimating radial contraction (FAC) were not associated with outcome. Alternatively, TAPSE was associated with mortality (HR, 0.92; 95% confidence interval [CI], 0.87–0.97;P=.006) in unadjusted analysis and remained a significant factor associated with death even when adjusted for clinical parameters (age, gender, pacemaker, atrial fibrillation), hemodynamic parameters (stroke volume, pulmonary pressure, diastolic dysfunction), or TR grade.

In patients with significant TR before TAVR, TR grade improved on average after the procedure, and in patients with baseline moderate or greater TR, survival was better in those who improved compared with those who did not. Improvement in TR was associated with reduced mortality (HR, 0.31; 95% CI, 0.1–0.86;I= .02) in unadjusted analysis and when adjusted for age, atrial fibrillation, gender, pacemaker, or TAPSE.

Conclusion

There are several major takeaway points from this article. Firstly, TR in association with severe AS is common (11.3%) and frequently progressive despite TAVR, although it is not an independent factor associated with outcomes and should not be considered an obstacle for the success of TAVR. Additionally, quantitative RV function is a stronger driver of adverse outcomes, rather than qualitative RV function or simply TR, and is the key for proper risk stratification in these patients. Finally, the persistence of significant TR after TAVR may be associated with poor outcomes.

Comments

As briefly discussed in this paper, it is important to note that the results here are quite different from another recently published study with a similar objective.2 This prior study, which was a subgroup analysis of the widely referenced PARTNER trial, demonstrated that TR, and not RV functionality, was most associated with mortality. It is important to note that these two studies cannot be directly compared, as the starting morbidity was lower in the present study and may therefore favor different predictive factors. Lastly, only 59 patients in the present study had moderate to severe tricuspid regurgitation, which could have led to underpowered results.

References
  1. Thyregod HG, Steinbruchel DA, Ihlemann N, et al. Transcatheter versus surgical aortic valve replacement in patients with severe aortic valve stenosis: 1-year results from the all-comers NOTION randomized clinical trial. J Am Coll Cardiol. 2015;65(20):2184–2194.
  2. Lindman BR, Maniar HS, Jaber WA, et al. Effect of tricuspid regurgitation and the right heart on survival after transcatheter aortic valve replacement: insights from the Placement of Aortic Transcatheter Valves II inoperable cohort. Circ Cardiovasc Interv. 2015;8(4).

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