title: Echocardiographic assessment of raised pulmonary vascular resistance: application to diagnosis and follow-up of pulmonary hypertension.
abstract: OBJECTIVE
  To optimise an echocardiographic estimation of pulmonary vascular resistance (PVR(e)) for diagnosis and follow-up of pulmonary hypertension (PHT).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Tertiary referral centre.
  
  
  METHODS
  Patients undergoing right heart catheterisation and echocardiography for assessment of suspected PHT.
  
  
  METHODS
  PVR(e) ([tricuspid regurgitation velocity ×10/(right ventricular outflow tract velocity-time integral+0.16) and invasive PVR(i) ((mean pulmonary artery systolic pressure-wedge pressure)/cardiac output) were compared in 72 patients. Other echo data included right ventricular systolic pressure (RVSP), estimated right atrial pressure, and E/e' ratio. Difference between PVR(e) and PVR(i) at various levels of PVR was sought using Bland-Altman analysis. Corrected PVR(c) ((RVSP-E/e')/RVOT(VTI)) (RVOT, RV outflow time; VTI, velocity time integral) was developed in the training group and tested in a separate validation group of 42 patients with established PHT.
  
  
  RESULTS
  PVR(e)>2.0 had high sensitivity (93%) and specificity (91%) for recognition of PVR(i)>2.0, and PVR(c) provided similar sensitivities and specificities. PVR(e) and PVR(i) correlated well (r=0.77, p<0.01), but PVR(e) underestimated marked elevation of PVR(i)-a trend avoided by PVR(c). PVR(c) and PVR(e) were tested against PVR(i) in a separate validation group (n=42). The mean difference between PVR(e) and PVR(i) exceeded that between PVR(c) and PVR(i) (2.8±2.7 vs 0.8±3.0 Wood units; p<0.001). A drop in PVR(i) by at least one SD occurred in 10 patients over 6 months; this was detected in one patient by PVR(e) and eight patients by PVR(c) (p=0.002).
  
  
  CONCLUSIONS
  PVR(e) distinguishes normal from abnormal PVR(i) but underestimates high PVR(i). PVR(c) identifies the severity of PHT and may be used to assess treatment response.
authors.affiliation: School of Medicine, The University of Queensland, Australia.
authors.forename: Arun
authors.initials: A
authors.lastname: Dahiya
authors.forename: William
authors.initials: W
authors.lastname: Vollbon
authors.forename: Christine
authors.initials: C
authors.lastname: Jellis
authors.forename: David
authors.initials: D
authors.lastname: Prior
authors.forename: Sudhir
authors.initials: S
authors.lastname: Wahi
authors.forename: Thomas
authors.initials: T
authors.lastname: Marwick
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D003430:Cross-Sectional Studies; D042241:Early Diagnosis; D004452:Echocardiography / Q000592:standards*; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology