Abstract 11036: Aortic Valve Calcification is Associated With an Increased Risk of Mortality in Patients With Low Flow Low Gradient Moderate Aortic Stenosis

Abstract

Introduction: Aortic Valve Calcification (AVC) measured by computed tomography (C-CT) and Dobutamine stress echocardiography (DSE) are both important when determining AS severity in low flow low gradient (LFLG) AS. It is generally accepted that AS is moderate if aortic mean gradient is <40mmHg on DSE and AVC is not severe. However, recent studies suggest that patients with moderate AS may have a worse outcome than expected when treated medically. Objective: To examine the correlation between AVC and mortality in patients with LFLG moderate AS on both DSE and C-CT when treated medically. Method: 88 Patients with LFLG AS (aortic mean gradient <40 mmHg, aortic valve area <1.0 cm 2 & stroke volume index (SVi) <35ml/m 2 ) and moderate AS on DSE and C-CT were identified from two prospective studies. AVC ratio was calculated as AVC divided by the sex-specific AVC threshold for severity; 2000 AU in males and 1200 AU in females. Results: Optimal threshold of AVC ratio to predict 2-year mortality was 0.68 on ROC-curve (AUC=0.72).Patients were stratified according to AVC ratio: 51 (58%) presented with AVC ratio <0.7 and 37 (42%) with AVC ratio 0.7–1.0. 2 year survival was lower in the latter group (79.5±0.1 vs 46.9±0.1% - Figure 1). Age (78±9 vs 75±11, p=0.32), sex distribution (females 33 vs 41%, p=0.49) and DSE SVi increase (18±24 vs 18±12%, p=0.94) were similar in both groups. Patients with AVC ratio <0.7 presented with higher LVEF (50±15 vs 44±15%, p=0.08) and lower aortic mean gradient at rest (20±7 vs 23±6 mmHg, p=0.01) and during DSE (21±14 vs 29±15 mmHg, p=0.03). In univariate Cox regression AVC ratio >0.7 was associated with mortality: HR 2.91 [1.43-5.9], p=0.003. AVC ratio >0.7 remained associated with mortality after adjustment for LVEF, aortic mean gradient, age and sex: HR 2.66 [1.24-5.7], p=0.012. Especially in patients with reduced LVEF: HR 3.47 [1.49-8.09], p=0.004. Conclusion: In patients with LFLG moderate AS an AVC ratio > 0.7 is associated with increased risk of mid-term mortality.