Severe aortic valve stenosis with low-gradient and preserved ejection fraction: a misclassification issue?

INTRODUCTION AND OBJECTIVES Low-gradient severe aortic stenosis with preserved ejection fraction is a controversial entity. Misclassification of valvulopathy severity could explain the inconsistencies reported in the prognosis of these patients. Planimetry of the aortic area using three-dimensional transesophageal echocardiography could clear up these doubts. The objectives were to assess the agreement between measurements of the valvular aortic area by continuity equation in transthoracic echocardiography and that obtained through planimetry with three-dimensional transesophageal echocardiography in low-gradient severe aortic stenosis patients. METHODS Cross-sectional descriptive study of consecutive patients referred due to severe aortic stenosis. Patients underwent transthoracic echocardiography and three-dimensional transesophageal echocardiography. Paradoxical low-gradient severe aortic stenosis was defined by the presence in the transthoracic echocardiography of aortic valve area<1 cm(2), mean ventricular gradient<40 mmHg, and ejection fraction ≥ 50%. Concordance between the two techniques was evaluated. RESULTS Of 212 consecutive severe aortic stenosis patients evaluated, 63 cases (29.7%) fulfilled the paradoxical low-gradient inclusion criteria. We obtained three-dimensional aortic valve planimetry in 61 (96.8%) of those patients. In 52 patients (85.2%), aortic valve area by transesophageal echocardiography was <1 cm(2). The intraclass correlation coefficient between the two methods was 0.505 (95% confidence interval, 0.290-0.671; P<.001). CONCLUSIONS Paradoxical low-gradient severe aortic stenosis is an actual entity, confirmed in 85% of cases evaluated by three-dimensional transesophageal echocardiography.