Value of Speckle Tracking Echocardiography Combined with Stress Echocardiography in Predicting Surgical Outcome of Severe Aortic Regurgitation with Markedly Reduced Left Ventricular Function

Abstract

Background: Predicting outcomes of surgical aortic valve replacement (AVR) in patients with chronic severe aortic regurgitation (AR) and markedly reduced left ventricular (LV) function remains a challenge. This study aimed to explore the preoperative echocardiographic index that could predict the recovery of LV systolic function after surgery in patients with chronic severe AR and reduced left ventricular ejection fraction (LVEF).

Methods: The study group consisted of 50 patients diagnosed with chronic severe AR ( $>$ 6 months) and significantly reduced LVEF (18~35%, average 26.2 $\pm$ 5.3%). Low-dose dobutamine stress echocardiography (DSE) was performed before surgery. Only patients with an absolute increase in LVEF $\ge$ 8% during DSE were referred for surgical AVR. During following up (over six months to one year after surgery), the patients were divided into two groups by postoperative LVEF ( $>$ or $\le$ 40%). DSE- and speckle tracking echocardiography (STE)-derived LV functional parameters were compared between groups to identify predictors of post-operative improvement in LVEF.

Results: A total of 38 patients underwent AVR. One patient died before discharge. Post-surgical LV size and LVEF improved markedly after surgery in all patients (n = 37). Pre-surgical LV end-systolic diameter, baseline global longitudinal strain (GLS) and peak GLS were better in the group with LVEF $>$ 40% (n = 18; p $<$ 0.05, t test). Baseline GLS and peak GLS correlated moderately with post-surgery LVEF (R = -0.581, p $<$ 0.001; R = -0.596, p $<$ 0.001; respectively). Logistic regression analysis demonstrated baseline GLS and peak GLS were the independent predictors of post-surgery improvement of LVEF. Peak GLS had the highest prediction value (area under the curve = 0.895, sensitivity and specificity: 89.5% and 77.8%, respectively), with a cutoff value of -9.4%.

Conclusions: This study shows that STE combined with DSE can provide sensitive quantitative indices for predicting improvement of LV systolic function after AVR in patients with chronic severe AR and significantly decreased LVEF.

Keywords: LVEF; aortic regurgitation; left ventricular systolic function; longitudinal strain; speckle tracking echocardiography; stress echocardiography.

Fig. 1.

Representative example of LV volume analyzed through triplane Simpson method, with subsequent calculation of LVEF. LV, left ventricular; LVEF, left ventricular ejection fraction.

Fig. 2.

Representative example of the LV GLS measurement based on 2D echocardiography by offline analysis software EchoPAC. LV, left ventricular; GLS, global longitudinal strain; 2D, two-dimensional.

Fig. 3.

The experimental flow chart. AR, aortic regurgitation; LVEF, left ventricular ejection fraction; DSE, Dobutamine stress echocardiography; 2D-STE, two-dimensional speckle tracking echocardiographic; LV, left ventricular; CR, contraction reserve; AVR, aortic valve replacement.

Fig. 4.

The ROC curves for predicting marked recovery of LV contractive function (follow-up LVEF $\mathrm{>}$40%). Baseline GLS showed AUC = 0.868, sensitivity and specificity were 89.5% and 72.2%, respectively. Peak GLS showed the highest AUC = 0.895, sensitivity and specificity were 89.5% and 77.8%, respectively. ROC, receiver-operating characteristic; LV, left ventricular; LVEF, left ventricular ejection fraction; GLS, global longitudinal strain; AUC, area under the curve; LVEDD, left ventricular end-diastolic diameter; LVESD, left ventricular end-systolic diameter.