532Exercise pulmonary hypertension in asymptomatic severe aortic stenosis


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Abstract

Background: Pulmonary hypertension (PHT) in patients with severe aortic stenosis (AS) is associated with increased morbidity and mortality. Recent studies emphasized the usefulness of exercise stress echocardiography (ESE) in asymptomatic patients with AS. Nevertheless, the additive value of exercise (Ex) PHT in such patients is unexplored. We, therefore, aimed to identify the determinants and impact on outcome of ExPHT in asymptomatic patients with severe AS.Method and results: Asymptomatic patients with severe AS (n=106, aortic valve area<1cm2, 71±8.5 years, 58% of male) and preserved left ventricular (LV) systolic function (LV ejection fraction≥55%) were prospectively referred to ESE. Resting and ExPHT were defined as a systolic pulmonary arterial pressure (SPAP) >50mmHg and >60mmHg, respectively. Ex PHT was more frequent than resting PHT (55% vs. 6%, p<0.0001). Patients with ExPHT were more frequently male (68% vs. 49%, p=0.035), had significant higher mean aortic gradient (47.4±16 vs. 41.7±12mmHg, p=0.04) and longer diastolic filling time (446±177 vs. 372±126ms, p=0.015) than those without ExPHT. There was no other significant difference between these 2 groups with regard to clinical, demographic and echocardiographic data. ExSPAP was correlated with resting aortic mean pressure gradient and peak aortic velocity (r=0.49 and r=0.48, both p=0.01), with LV diastolic filling time (r=0.54, p=0.003) and the Ex-induced changes in E/Ea ratio (r=-0.53, p=0.007). Multivariate logistic regression analysis showed that only Ex-induced changes in E/Ea ratio (p=0.02, β=-0.8±0.3) and resting peak aortic velocity (p=0.007, β=7±2.5) were independently associated with ExSPAP. ExPHT was associated with reduced cardiac event-free survival (27±7% vs. 53±9%, p=0.02). In multivariate Cox proportional hazard model, the independent predictors of events were resting E/Ea ratio (p=0.01), aortic peak velocity (p<0.0001), indexed left atrium area (p=0.005), LV global longitudinal strain (p=0.04) and ExPHT (hazard ratio=1.9, 95% of confidence interval: 1.1-3.5, p=0.04). In addition, when adding Ex-induced changes in aortic mean pressure gradient to the multivariate model, ExPHT remained an independent predictor of reduced cardiac event-free survival (p=0.033).Conclusion: In asymptomatic patients with severe AS, the main determinants of ExPHT are the severity of AS and the Ex-induced changes in LV filling pressure. ExPHT is associated with 2-fold increased risk of cardiac events. These results strongly support the use of ESE in asymptomatic AS.

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