Imaging-based method to quantify left ventricular diastolic pressures

To establish an imaging-based method to quantify left ventricular (LV) diastolic pressures.

In 115 patients suspected of coronary artery disease, LV pressure was measured by micromanometers and images by echocardiography. LV filling pressure was measured as LV pre-atrial contraction pressure (pre-A P_LV). Based on previous observations, we hypothesized that pre-A P_LV approximates the sum of minimum P_LV and maximum transmitral pressure difference. Parameters used for pressure estimates included LV volumes and strain, left atrial strain, mitral flow velocities, systolic arterial cuff pressure, and body mass index. Minimum P_LV was estimated by predictors identified in a derivative cohort (n = 81). Mitral pressure difference was calculated by a simplified Navier–Stokes equation. Accuracy of estimates of minimum P_LV, pre-A P_LV, and end-diastolic P_LV was investigated in a testing cohort (n = 19). Patient-specific LV diastolic pressure curves were constructed by adjusting a reference curve according to pressure estimates at key diastolic events. There was good agreement between estimated and measured pre-A P_LV: bias 0.0, limits of agreement < 3.1 mmHg (±1.96 SD). Estimated minimum P_LV and end-diastolic P_LV also showed good agreement with measured pressures. Furthermore, there was good agreement between measured and estimated LV diastolic pressure curves, quantified as mean LV diastolic pressure: bias 0.2, limits of agreement < 3.2 mmHg.

The proposed non-invasive method provided estimates of minimum P_LV, pre-A P_LV, and end-diastolic P_LV, each reflecting different features of diastolic function. Additionally, it provided an estimate of the LV diastolic pressure curve. Validation in larger populations with different phenotypes is necessary to determine the validity of the method in clinical practice.