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

BACKGROUND: Previous studies have reported inconsistencies between echocardiographic parameters of severity in aortic valve stenosis (AS). Peak aortic valve velocity (Vmax ) strongly predicts outcome in AS patients. This study was therefore designed to identify the cutoff values of echocardiographic parameters of severity corresponding to a Vmax ≥ 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 Vmax ≥ 3 m/sec obtained from receiver operating characteristic (ROC) curves analysis were 22 mmHg, 1.15 cm(2) , and 0.60 cm(2) /m(2) , respectively. While a cutoff of Vmax ≥ 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 cm(2) /m(2) were related to a Vmax ≥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 Vmax and MPG. The results of this study may serve as safeguard in case of apparent inconsistencies between echocardiographic parameters of severity in NF AS.