The Functional Significance of Paradoxical€Low-Gradient Aortic€Valve€Stenosis

Fro Gr PIS (Dr Eu thi Ma OBJECTIVES The goal of this study was to determine the functional impact of paradoxical low-gradient aortic stenosis (PLGAS) and clarify whether the relevance of the valvular obstruction is related to baseline flow. BACKGROUND Establishing the significance of PLGAS is particularly challenging. METHODS Twenty symptomatic patients (77 6 years of age; 17 female subjects) with PLGAS (mean gradient 28 6 mm Hg; aortic valve area 0.8 0.1 cm; ejection fraction 66 7%) underwent cardiopulmonary exercise testing combined with right-heart catheterization and Doppler echocardiographic measurements. RESULTS Aortic valve area increased by 84 23% (p < 0.001) and, in 70% of subjects, it reached values >1.0 cm at peak exercise. Stroke volume index and blood pressure increased by 83 56% and 26 16%, respectively (both p < 0.0001). Peak oxygen consumption inversely correlated with the rate of increase in pulmonary capillary wedge pressure (PCWP) (PCWP slope: R 1⁄4 –0.61; p 1⁄4 0.004). In turn, the PCWP slope was determined by changes in the valvular and vascular load but not by the rest of the indices of aortic stenosis. The functional impact of PLGAS was also not related to baseline flow. Agreement between Doppler echocardiography and the Fick technique was good up to intermediate workload. CONCLUSIONS In symptomatic patients with PLGAS, the capacity to dynamically reduce vascular and valvular loads determines the effect of exercise on PCWP, which, in turn, conditions the functional status. A critically fixed valvular obstruction may not be the main mechanism of functional impairment in a large proportion of patients with PLGAS. Exercise echocardiography is suitable to study the dynamics of PLGAS. (J Am Coll Cardiol Img 2017;10:29–39) © 2017 by the American College of Cardiology Foundation. A lmost one-third of patients with aortic stenosis (AS) and normal left ventricular (LV) ejection fraction are considered to have severe AS based on aortic valve area (AVA) (<1 cm and <0.6 cm/m of body surface area), but their m the Department of Cardiology, Hospital General Universitario Greg egorio Marañón, and Facultad de Medicina, Universidad Complutense de 09/02602, PIS012/02878, and RD12/0042 (Red de Investigación Cardiova . Pérez del Villar) from the Instituto de Salud Carlos III, Ministerio de E ropean Regional Development Fund. The authors have reported that the s paper to disclose. nuscript received September 28, 2015; revised manuscript received Febru pressure gradients are below cutoff values considered to identify severity. This condition is designated paradoxical low-gradient aortic stenosis (PLGAS) (1). Although it has been recommended to further distinguish low-flow PLGAS from normal-flow PLGAS (2), orio Marañón, Instituto de Investigación Sanitaria Madrid, Spain. This study was supported by grants scular), FI11/00700 (Dr. Espinosa), and CM12/00273 conomía y Competitividad, Spain, and by the EU– y have no relationships relevant to the contents of ary 29, 2016, accepted March 3, 2016. TABLE 1 Clinical and Echocardiographic Data at Enrollment Age, yrs 77 6 Female 17 (85) Body surface area, m 1.7 0.2 Body mass index, kg/m 29 4 Systolic cuff blood pressure, mm Hg 137 11 Diastolic cuff blood pressure, mm Hg 68 13 Echocardiographic data Aortic valve mean pressure gradient, mm Hg 27 5 Aortic valve area, cm 0.75 0.10 Aortic valve area index, cm/m 0.46 0.08 ABBR EV I A T I ON S