The Validation of Non-Invasive Pressure-Volume Loop Indices in Severe Aortic Stenosis

BackgroundStudies utilizing invasive pressure-volume loops offer valuable insights into left ventricular (LV) contractility, yet their availability remains limited. Conversely, non-invasive indices are accessible and reproducible; however, their validation in aortic stenosis (AS) is lacking. We sought to validate the non-invasive indices of PVL studies in a group of symptomatic severe AS. MethodsWe recruited patients with symptomatic severe AS admitted for trans-catheter aortic valve replacement (TAVR) to undergo invasive PVL studies. Non-invasive PVL indices were measured with three-dimensional (3D) echocardiography with a pre-specified protocol. The agreement between invasive and non-invasive calculation methods were assessed. ResultsEleven patients (11) were recruited for this pilot study. The non-invasive end-systolic pressure-volume relationship (ESPVR) Kellys method (Ees(sb) = 0.9 x systolic blood pressure/end-systolic volume (ESV)) had the best agreement with invasive ESPVR (limits of agreement - 1.7 to 2.1 with a percentage error of 24%, one sample T-test p =0.504). Systolic blood pressure, as measured by the brachial blood pressure cuff, had the best agreement with end-systolic pressure in severe aortic stenosis (limits of agreement -60 to 60 with a percentage error of 3%, one sample T-test p =0.959). ConclusionMeasurement of the single-beat estimate of ventricular elastance (Ees(sb)) is possible in patients with severe aortic stenosis. Kellys method (Ees(sb) = 0.9 x SBP /ESV) has the best agreement with the invasive measurement of left ventricular elastance (Ees). Systolic blood pressure, as measured by the brachial blood pressure cuff, has the best agreement with end-systolic pressure in severe aortic stenosis.