Oral session IV240Pulsed Doppler sample volume position in the outflow from the right ventricle does not influence the assessmentn of pressure reflection in the pulmonary circulation241Right ventricular function early after cardiac surgery: compar

摘要

Purpose: The flow profile from the right ventricle is essential for different noninvasive methods that estimate the pulmonary vascular resistance. We have previously proposed a novel method to identify patients with increased pulmonary vascular resistance by assessment of pressure reflection in the pulmonary circulation. The pulmonary pressure reflection is described by three variables based on pulsed Doppler (PWD) from the outflow and continuous Doppler (CWD) in the tricuspid regurgitant jet. Patients with pressure reflection (+PR) have increased pulmonary vascular resistance (>3 Woods units). The aim of this study was to investigate if the PWD sample volume position or the mode (PWD versus CWD) influences the assessment of pressure reflection. Methods. The study population consisted of 48 patients. The PWD sample volume was placed at three different levels: in the right ventricular outflow tract, at the level of the pulmonary valve and in the pulmonary artery. The time intervals from the QRS to valve opening, peak velocity and valve closing were measured. At each location and using the results from CWD we calculated the three variables for pressure reflection and categorized the patients by combining them as either +PR (two of three variables indicating increased pulmonary vascular resistance), without pressure reflection (-PR) or intermediate (neither within the normal range or above the previously defined cut-off levels for pressure reflection). Results. Eleven patients (23%) had pulmonary hypertension (Doppler gradient >40 mmHg). The individual variables related to pressure reflection were influenced by the sample position and mode of registration. The PWD sample volume position did not influence the overall classification of pressure reflection (+PR). At the pulmonary valve the distribution of +PR/intermediate/-PR was 13/9/25, in the right ventricular outflow 13/7/27, in the pulmonary artery 13/14/20 and 12/17/16 using CWD (p = 0.005 compared with the pulmonary valve). Conclusions. The study shows that sample volume position and mode influence the individual variables used to assess pulmonary vascular resistance. However, the overall classification of pulmonary pressure reflection that indicates increased pulmonary vascular resistance was not influenced by PWD sample volume position.