Clinical outcome predictors in asymptomatic patients with severe aortic stenosis and normal left ventricular systolic function initially managed conservatively: a subanalysis from the AVATAR trial

Introduction

Randomized trials demonstrated that prognosis of asymptomatic patients with severe aortic stenosis (AS) is worse with conservative management compared to early intervention. Among those who are put on conservative management risk stratification is particularly important. Thus, we used data from the AVATAR trial to explore which parameter best predicts worse outcome in asymptomatic patients with severe AS and a normal left ventricular ejection fraction within the group of patients randomized to conservative management.

Method

AVATAR trial randomized total of 157 patients (79 to conservative management) with asymptomatic severe AS and normal LV systolic function to early surgical AVR or conservative management. The primary outcome was major adverse cardiovascular events (MACE: the composite of death, acute myocardial infarction, stroke, or unplanned HF hospitalization). Cox proportional hazards models were used to assess predictors of MACE. Statistical significance was defined as p ˂ 0.05.

Results

The average age was 67 years, 57% were men, and the median Society for Thoracic Surgeons predicted risk of mortality score was 1.7%. Overall median follow-up in survivors was 68 months (IQR 58–79). During the follow up, 36/79 (44%) patients in conservative group underwent aortic valve replacement (AVR) due to AS-related indications.

There was a total of 55 MACEs, 37/79 (46.8%) of them in the conservative treatment group. According to the univariate cox regression analysis brain natriuretic peptide (BNP) was found to be the only independent MACE predictor in patients randomized to conservative management.; Figure 1 The BNP value of 94 pg/ml was identified as the best (cut-off) predictive value for the occurrence of MACE, with a sensitivity 77.8% and a specificity 72.0% (AUC 0.784, p=0.001; Figure 2).

Conclusion

BNP is the best independent outcome predictor in asymptomatic patients with severe AS and a normal LVEF. Risk stratification with this parameter may help in optimal selection of asymptomatic patients considered to be at higher risk and who would additionally benefit from early AVRFigure 2Figure 1