Significant Prognostic Value of Acute Preload Stress Echocardiography Using Leg-Positive Pressure Maneuver for Patients With Symptomatic Severe Aortic Stenosis Awaiting Aortic Valve Intervention

Abstract

Background:Although aortic valve intervention is recommended for virtually all symptomatic patients with aortic stenosis (AS), how urgently the intervention should be performed remains controversial. The aim of this study was thus to determine whether the preload reserve in response to leg-positive pressure (LPP) maneuver could serve for decision-making for AS patients awaiting aortic valve intervention.

Methods and Results:Sixty-eight patients with symptomatic AS, who were referred for aortic valve intervention, were recruited. Stroke volume (SV) was assessed by means of pulsed-wave Doppler, and the ratio between transmitral E wave and mitral annular velocity (e’) was calculated to estimate ventricular filling pressure. While waiting for intervention, 11 patients experienced preoperative cardiac events. During acute preload stress, forward SV for patients without cardiac events increased significantly (from 43±9 to 49±10 mL/m², P<0.01) along with a minimal change in filling pressure (E/e’: from 20±8 to 21±9, NS). For patients with cardiac events, the Frank-Starling mechanism was significantly impaired (SVi: from 40±9 to 38±7 mL/m², NS), while filling pressure increased to the critical level (E/e’: from 24±8 to 31±8, P<0.001). Both the patients without flow reserve (∆SVi <4.5 mL/m²) and those without diastolic reserve (∆E/e’ ≥2.9) exhibited significantly worse event-free survival than the others (P<0.05, respectively).

Conclusions:Assessment of preload reserve during LPP stress could facilitate risk stratification of patients with severe AS waiting for aortic valve intervention.