Right Ventricular Function and Prognosis in Patients with Low-Flow, Low-Gradient Severe Aortic Stenosis

Abstract

Background: Patients with low left ventricular ejection fractions and low-flow, low-gradient aortic stenosis (AS) represent a challenging cohort with high morbidity and mortality. The prevalence and clinical impact of right ventricular dysfunction (RVD) on risk stratification and prognosis in these patients is unknown.

Methods: A retrospective analysis was performed of 65 patients with low-flow, low-gradient AS who underwent low-dose dobutamine stress echocardiography to determine AS severity and to ascertain flow reserve status (≥20% stroke volume increase). Clinical, demographic, and imaging data were prospectively collected. Per guidelines, RVD was defined as tricuspid annular plane systolic excursion < 16 mm in the apical four-chamber view and measured at baseline. Cox proportional hazards modeling was used to risk-adjust comparisons for the end point of all-cause mortality.

Results: The mean age was 74 ± 9 years, the mean left ventricular ejection fraction was 29 ± 10%, the mean indexed aortic valve (AV) area was 0.49 ± 0.1 cm(2)/m(2), and the mean AV gradient 22 ± 7 mm Hg. RVD was present in 37 patients (57% of the study cohort). After a median follow-up period of 13 months (interquartile range, 5-30 months), there were 29 AV replacements and 30 deaths. The presence of RVD (hazard ratio, 2.86; 95% CI, 1.21-6.75; P = .02) was an independent risk factor associated with all-cause mortality despite many adjustments for potential clinical and echocardiographic confounders such as AV replacement, Society of Thoracic Surgeons Predicted Risk of Mortality score, severity of tricuspid regurgitation, and left ventricular global longitudinal strain.

Conclusions: Baseline RVD is prevalent in patients with low-flow, low-gradient AS undergoing dobutamine stress echocardiography. Quantification of right ventricular systolic function in these complex patients provides important prognostic value and risk stratification adjunctive to Society of Thoracic Surgeons Predicted Risk of Mortality score and should be incorporated into the decision-making process.

Keywords: Low-flow, low-gradient aortic stenosis; Prognosis; Right ventricular function.