Relationship between Cutoff Values of Peak Aortic Valve Velocity and Those of Other Doppler Echocardiographic Parameters of Severity in Patients with Aortic Stenosis and Normal Flow

Abstract

Background: Previous studies have reported inconsistencies between echocardiographic parameters of severity in aortic valve stenosis (AS). Peak aortic valve velocity (V_max) strongly predicts outcome in AS patients. This study was therefore designed to identify the cutoff values of echocardiographic parameters of severity corresponding to a V_max ≥ 3 m/sec, ≥4 m/sec, 5 m/sec, or 5.50 m/sec in a large cohort of patients with normal flow (NF) AS. Methods and Results: We retrospectively reviewed the echocardiograms of 528 consecutive patients with normal flow (NF) AS, left ventricular (LV) ejection fraction ≥0.50, and NF (stroke volume index > 35 mL/m²). The values of mean pressure gradient (MPG), aortic valve area (AVA), and indexed aortic valve area (IAVA) corresponding to V_max ≥ 3 m/sec obtained from receiver operating characteristic (ROC) curves analysis were 22 mmHg, 1.15 cm², and 0.60 cm²/m², respectively. While a cutoff of V_max ≥ 4 m/sec to define severe AS was consistent with a value of 39 mmHg for MPG, corresponding values for AVA and IAVA of 0.90 cm² and 0.48 cm²/m², respectively, were substantially different from those recommended in current guidelines. MPG ≥60 and 65 mmHg, AVA ≤0.76 and ≤0.68 cm², and IAVA ≤0.41 and ≤0.35 cm²/m² were related to a V_max ≥5 and ≥5.5 m/sec (very severe AS), respectively. Conclusions: Guidelines recommended cutoff values for AVA and IAVA are not consistent with those of V_max and MPG. The results of this study may serve as safeguard in case of apparent inconsistencies between echocardiographic parameters of severity in NF AS.