Moeller, J E

Abstract Background Dobutamine stress echocardiography (DSE) is recommended to distinguish between true-severe and pseudo-severe aortic stenosis (AS) in patients with low flow low-gradients and left ventricular ejection fraction (LVEF) <50%. However, DSE has mostly been tested in the setting of LVEF<35%. Purpose The purpose of this study was to examine the diagnostic accuracy of DSE according to aortic valve calcification (AVC) score, in patents with low-flow, low-gradient AS across a wide range of LVEF. Methods Patients with aortic mean gradient <40 mmHg, aortic valve area (AVA) <1.0 cm2, and stroke volume index (SVi) ≤35 mL/m2 undergoing DSE were identified from three prospectively collected patient cohorts, and stratified according to LVEF; <35%, 35-50% and >50%. Severe AS was defined as AVC score ≥2000 AU among men, and ≥1200 AU for women. Recommendation for severe AS according to DSE, are an AVA <1.0 cm2 combined with an aortic mean gradient ≥40 mmHg or peak velocity ≥4 m/s. Receiver operating characteristic curves for DSE-derived AVA, mean gradient and Vmax were used to identify optimal cut-off points for each LVEF subgroup. Results Of the 221 patients included in the study, 78 (35%) presented with LVEF <35%, 67 (30%) with LVEF 35-50%, and 76 (34%) with LVEF >50%. Baseline characteristics are presented in the table. Based on AVC, severe AS was present in 102 (46%) of patients. Using recommended thresholds for severe AS for AVC and DSE, led to a sensitivity of 49%, a specificity of 84% and an accuracy of 67% for DSE for all patients with LVEF <50%, but with significant heterogeneity between groups figure. AVA performed rather uniformly across LVEF subgroups; (AUC =0.68 vs 0.62 vs 0.54, p=0.36) LVEF<35%, LVEF 35-50%, LVEF>50% respectively and displayed a rather uniform optimal cut-off (1.0 cm2 vs 0.9 cm2 vs 0.8 cm2). However, mean gradient and Vmax during DSE, both showed significantly diagnostic heterogeneity across LVEF groups (AUC= 0.90 vs 0.67 vs 0.65, p=<0.001 and AUC= 0.90 vs 0.66 vs 0.60, p=<0.001) with different optimal thresholds (30 mmHg & 3.8 m/s, 45 mmHg & 4.3 m/s and 37mmHg & 4 m/s, LVEF<35%, LVEF 35-50%, LVEF>50%, respectively). Conclusion Our study shows, that the association between DSE gradients and AS severity assessed by AVC demonstrates important heterogeneity depending on LVEF. While DSE had the highest accuracy in patients with LVEF<35% both patients with LVEF 35-50%, and patients with LVEF>50% showed significantly less concordance between DSE and AVC.

Abstract Background Patient-worn accelerometer is increasingly used in patients with heart failure and reduced ejection fraction (HFrEF) to assess daily activity and and as surrogate endpoint. We examined the association between cardiac physiology and daily activity by patient-worn accelerometer recordings in stable HFrEF patients. Methods In this descriptive study, physical average daily accelerometer units (PADA) and total average daily accelerometer unit (TADA) were assessed by a accelerometer recordings. Sixty three stable ambulatory patients with HFrEF, mainly men (92%), mean age 58±10 years, and ejection-fraction 26±4% underwent hemodynamic exercise testing, and accelerometry (Table 1). Patients were divided by PADA in a low and high activity level groups based on counts per minute physical activity. Results Patients in the low activity group were older and more frequently treated with diuretics. At rest, the low activity group was characterized by a lower cardiac index (CI) (2.2±0.4 vs. 2.4±0.4 l/min/m2, p=0.01), Stroke volume (SV) (70±19 vs. 81±17 ml, p=0.02) but not pulmonary capillary wedge pressure (PCWP) (12±5 vs. 11±5 mmHg, p=0.3) (Figure 1). Low activity group reached a lower CI (4.8±1.7 vs. 6.6±1.7 l/min/m2, p<0.001) and SV (94±32 vs. 121±29 ml, p<0.001), but not in PCWP (31±12 vs. 27±8 mmHg, p=0.2) or arterial-venous O2 content difference (A-VO2 diff) (13.00±2.32 vs. 12.96±1.65 ml O2/dl, p=0.9) at peak exercise. The attenuated increase was associated with attenuated increase in SV rther than increase in heart rate (42±23 vs. 52±21 bpm, p=0.07). Finally, CI at peak exercise was the only independent variable associated with PADA after adjusting for age, gender, and BMI (p<0.0001). The PADA and TADA were associated to functional assessments using Kansas City Cardiomyopathy Questionnaire, but not with New York Heart Association class or N-terminal pro brain natriuretic peptide (NT-proBNP) (Table 1). Conclusion Accelerometer-assessed activity in patients with HFrEF are associated with impairments in LV performance, SV reserve and cardiac output during exercise, to a greater extent than changes in arterial-venous O2 content difference or pulmonary vascular pressures. Accelerometer data may provide information about the functional status that we do not nessecary find in the widely used tools in both research and daily clinical practice. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): This work was supported by the Danish Heart Foundation [grant numbers 17-R116-A7714-22076, 18-R124-A8573-22107]; Steno Diabetes Center Odense, Denmark [grant number 3363] and A.P. Møller Foundation for the Advancement of Medical Science [grant number 17-L-0339]. Table 1. Baseline and regression analysisFigure 1. Change in PCWP and CI by exercise