title: Feasibility of generating hemodynamic pressure curves from noninvasive Doppler echocardiographic signals.
abstract: OBJECTIVE
  This study was designed to determine the feasibility of Doppler generation of accurate, complete right ventricular and pulmonary artery pressure curves in patients with Doppler-measurable tricuspid and pulmonary regurgitation.
  
  
  BACKGROUND
  Doppler-derived flow velocities have been used to assess right ventricular systolic pressure; pulmonary artery systolic, diastolic and mean pressures, and left ventricular systolic and diastolic pressures. Instantaneous gradient across any area of discrete narrowing is accurately derived using the simplified Bernoulli equation (4V2). Invasive catheterization is currently the only means of generating intracardiac pressure curves. Noninvasively derived pressure curves using Doppler echocardiography would be a considerable advance in the assessment of normal and pathologic cardiac hemodynamics.
  
  
  METHODS
  Right ventricular and pulmonary artery pressure curves were generated in 18 of 22 patients with measurable tricuspid and pulmonary valve regurgitation using superimposition of Doppler-measured tricuspid and pulmonary valve blood flow velocities on an assumed right atrial pressure. Doppler-measured right ventricular and pulmonary artery pressure curves were compared with simultaneous catheterization-measured curves.
  
  
  RESULTS
  Doppler-derived pulmonary artery systolic pressure (Doppler PAP) correlated with simultaneous catheter-measured pulmonary artery pressure (Cath PAP) by the equation Doppler PAP = 0.92(Cath PAP) + 4.5, r = 0.98. Other Doppler-derived pressure measurements that correlated at near identity with the catheterization-measured corresponding measurement include Doppler-derived pulmonary artery mean pressure (Doppler mean PAP) [Doppler mean PAP = 0.85(Cath mean PAP) + 2.6, r = 0.97], and Doppler-derived right ventricular pressure (Doppler RVP) [Doppler RVP = 0.84(Cath measured RVP) + 7.9, r = 0.98]. Doppler-derived pulmonary, artery diastolic pressure (Doppler PAP diast) did not correspond as well in this study [Doppler PAP diast = 0.45(Cath PAP diast) + 6.6, r = 0.83].
  
  
  CONCLUSIONS
  Clinically usable right ventricular and pulmonary artery pressure curves can be derived by superimposing Doppler-measured tricuspid and pulmonary valve blood flow velocities in patients with tricuspid and pulmonary valve regurgitation.
authors.affiliation: Department of Pediatrics, Indiana University, Indianapolis.
authors.forename: G
authors.initials: G
authors.lastname: Ensing
authors.forename: J
authors.initials: J
authors.lastname: Seward
authors.forename: R
authors.initials: R
authors.lastname: Darragh
authors.forename: R
authors.initials: R
authors.lastname: Caldwell
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D006328:Cardiac Catheterization; D002648:Child; D015150:Echocardiography, Doppler; D005240:Feasibility Studies; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D011651:Pulmonary Artery / Q000503:physiopathology; D011664:Pulmonary Valve / Q000503:physiopathology; D011665:Pulmonary Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted; D014261:Tricuspid Valve / Q000503:physiopathology; D014262:Tricuspid Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016278:Ventricular Function, Right / Q000502:physiology