Left ventricular dilatation in patients with significant aortic regurgitation: association with mortality

Abstract

Abstract Background In aortic regurgitation (AR), left ventricular (LV) dilatation occurs as a response to volume and pressure overload. Current guidelines recommend the use of LV end-systolic diameter index (LVESDi) to give indication for intervention, but recent studies suggested that volumetric measures may be more accurate in identifying LV remodeling in AR as compared to linear dimensions. Purpose To characterize LV dilatation in patients with significant AR (≥moderate), based on linear and volumetric dimensions, and to determine their prognostic value. Methods A total of 1070 patients (56 ± 18 years,65% male) were included. Cut-off values of 20 mm/m2 for LVESDi and 45 ml/m2 for end-systolic volume index (LVESVi) were used to identify the following LV remodeling patterns: No-significant LV dilatation (N=485), when both LVESDi and LVESVi were below the cut-off values; Discordant LV dilatation (N=279) if only one positive criterion was present; and Concordant LV dilatation (N=306) when both LVESDi and LVESVi were enlarged (Figure 1). The primary endpoint was all-cause mortality. Results Baseline characteristics differed across the 3 LV dilatation groups. Compared to patients with no-significant or discordant LV dilatation, those with concordant LV dilatation were more likely to be men, had a lower prevalence of systemic arterial hypertension and were more symptomatic. Concerning the echocardiographic characteristics, patients with concordant LV dilatation showed more severe AR, worse LV systolic function and larger left atrial volumes compared to the other two LV dilatation groups. During a median follow-up of 89 (IQR,54-132) months, 168 (16%) patients died and 484 (45%) underwent aortic valve surgery (AVS). Patients with concordant LV dilatation had worse 10-year survival (72%) compared to the groups (Figure 2), but benefited more from AVS based on a landmark analysis (p=0.001). In multivariable analysis, a significant association with the risk of all-cause mortality was observed for the presence of discordant (HR 1.645, 95%CI 1.077-2.513;p=0.021) or concordant LV dilatation (HR 2.695, 95% CI 1.710 to 4.249;p<0.001) after adjusting for the variables significant in the univariate analysis such as, age, male gender, NYHA class III-IV, AVS as a time-dependent covariate and LV ejection fraction (LVEF) ≤55%. Moreover, the addition of LV dilatation groups to a basal model including the above mentioned clinical and echocardiographic variables led to a significant increase in the predictivity of the model (Chi-square difference=21.1,p<0.001). Conclusion In patients with significant AR, LV dilatation detected by linear and/or volumetric measures was independently associated with increased mortality. Combining both methods for assessment of LV remodeling may improve risk stratification of these patients.