0111: Prognostic impact of global left ventricular hemodynamic afterload in severe aortic stenosis with preserved ejection fraction: a cardiac catheterization-based study

Abstract

The global left ventricular (LV) hemodynamic afterload as assessed by valvulo arterial impedance (Zva), may be an independent predictor of mortality in patients with severe aortic stenosis (AS) and preserved LV ejection fraction (LVEF). However, its quantification using echocardiography may be subject to error measurement. The aim of this study is to determine the prevalence and impact on long-term survival of high Zva, purposely measured by cardiac catheterization. 768 patients with preserved LVEF (>50%) and severe AS (valve area ≤1cm²) underwent cardiac catheterization. Zva was derived from catheterization data and calculated using validated formula. Zva was considered high when >5 mmHg/ ml/m 2 . Overall, high Zva was found in 42% of all AS patients. Patients with high Zva were significantly older (p<0.0001), and more often female (p< 0.0001), they had significantly smaller aortic valve area (p<0.0001), higher mean gradient (p=0.001), lower indexed stroke volume (p<0.0001) and cardiac output (p<0.0001), significantly higher LVED filling pressures (p=0.03), systolic pulmonary artery pressure (p=0.0005), higher capillary wedge pressure(p=0.006), reduced systemic arterial compliance (p<0.0001), but higher systemic vascular resistances(p<0.0001). Ten-year survival was significantly reduced in patients with higher Zva (50±5%) as compared to those with lower Zva (67±3%; p=0.01). After adjustment for all other risk factors, Zva was independently associated with reduced long-term survival (hazard ratio [HR] =1.12 95% CI: 1.009-1.22; p=0.03). Of interest, high Zva remains associated with reduced survival as compared to low Zva, in patients with normal LV stroke volume, but was no longer significant in low flow patients (>60mL: 49±8vs. 69±4%, p=0.012; ≤60mL: 49±7 vs. 53±13%, p=0.96). In this large cardiac catheterization-based study, high Zva estimated invasively is frequent in patients with severe AS, and appears as a robust and independent predictor of survival.