[Non-invasive Doppler echocardiography assessment of right ventricular pressure in patients with ventricular septal...

In patients with VSD right ventricular pressure can be determined noninvasivly by subtracting the VSD-gradient from the systolic blood pressure. Using a stand-alone continuous-wave Doppler the VSD-gradient may be underestimated due to a large angle theta caused by the various VSD locations and the often atypical VSD-jet directions. Therefore Color-Doppler was used to visualize the VSD-jet and to align (angle less than 15 degrees) the continuous-wave Doppler beam. 37 patients, who underwent catheterization were studied. By VSD-jet visualization 3 patients were correctly identified in whom the VSD gradient would have been underestimated due to a large angle 0. They were excluded from this study because of the resulting error. In the remaining 34 patients VSD-gradients up to 105 mmHg were measured. A good correlation was found between the noninvasively an invasively determined right ventricular pressures: r = 0.93; y = 1.06x -2.4. One source of error in this method is the difference between the maximal instantaneous and the peak to peak VSD-gradient. Differences of up to 39 mmHg were found when the maximal instantaneous gradient occurred either very early or very late in systole. In these cases the midsystolic gradient should be used. It is concluded that the presented method is easy to perform and permits a reliable noninvasive estimation of the right ventricular pressure in patients with VSD.