Prognostic Value of the Three-Dimensional Right Ventricular Ejection Fraction in Patients With Asymptomatic Aortic Stenosis

Abstract

Background: The right ventricular (RV) function is an important prognostic marker of asymptomatic aortic stenosis (AS). However, previous publications have not addressed the additive value of conventional RV parameters over left heart parameters. Whether three-dimensional echocardiography (3DE)-derived RV ejection fraction (RVEF) has prognostic utility independent of 3DE derived left heart parameters is also unknown. We investigated the prognostic utility of 3DE RVEF in patients with asymptomatic AS. Methods: We retrospectively selected 392 asymptomatic AS patients. RVEF, left ventricular ejection fraction (LVEF) and left atrial volumes (LAVs) were measured using 3DE datasets. We determined the association of those parameters, as well as of aortic valve replacement (AVR), and Charlson's comorbidity index with cardiac events. We also analyzed whether RVEF has incremental value over two-dimensional echocardiography (2DE) RV parameters. Results: During a median follow-up of 27 months, 57 patients developed cardiac events, and 68 patients received AVR. Univariate Cox proportional hazard analysis revealed that RVEF was associated with cardiac events (p < 0.001). Multivariate analysis revealed that RVEF was significantly associated with cardiac events (p < 0.001) even after adjusting for AVR, Charlson's comorbidity index, LVEF, LAV, E/e', and indexed aortic valve area (iAVA). An incremental value of RVEF over left heart parameters was also demonstrated using a nested regression model. Classification and regression-tree analysis selected RVEF first with a cut-off value of 41%. RVEF had incremental value over iAVA, LVEF, and 2DE conventional RV parameters for its association with future outcomes. Conclusions: 3DE RVEF had significant prognostic value even after adjusting for comorbidities, left heart parameters, and conventional 2DE RV parameters in asymptomatic aortic stenosis.

Keywords: 3DE; CART analysis; RVEF; asymptomatic aortic stenosis; prognosis.

Figure 1

Representative 3D RV and LV analyses in a patient with asymptomatic AS who developed a cardiac event. A 74-year-old woman who developed heart failure three months after baseline echocardiography. AS was moderate and LVEF was preserved; however, RVEF was reduced. She also had hypertension, chronic kidney disease, and chronic obstructive pulmonary disease. 3D, three-dimensional; AS, aortic stenosis; ED, end-diastole; ES, end-systole; iAVA, indexed aortic valve area; LV, left ventricular; LVEF, left ventricular ejection fraction; PG, pressure gradient; RV, right ventricular; RVEF, right ventricular ejection fraction.

Figure 2

Receiver-operating characteristic curve analysis for prediction of cardiac events. Comparison of the area under the curve (AUC) of several parameters (black line) and with RVEF added (green line). LAVIn, minimum left atrial volume index; LVEF, left ventricular ejection fraction; PG, pressure gradient; RVEF, right ventricular ejection fraction.

Figure 3

Classification and regression-tree analysis for cardiac events. Blue boxes denote cut-offs, and red boxes describe event rates. 3D, three-dimensional; AVR, aortic valve replacement; LAVIn, minimum left atrial volume index; LVEF, left ventricular ejection fraction; PG, pressure gradient; RVEF, right ventricular ejection fraction.

Figure 4

Kaplan-Meier survival analysis for cardiac events based upon RVEF and LVEF. Kaplan-Meier analysis for cardiac events, according to group, as classified by lower limits of normal LVEF and RVEF. LVEF, left ventricular ejection fraction; RVEF, right ventricular ejection fraction.