Echocardiographic assessment of raised pulmonary vascular resistance: application to diagnosis and follow-up of pulmonary hypertension

Heart. 2010 Dec;96(24):2005-9. doi: 10.1136/hrt.2010.204834.

Abstract

Objective: To optimise an echocardiographic estimation of pulmonary vascular resistance (PVR(e)) for diagnosis and follow-up of pulmonary hypertension (PHT).

Design: Cross-sectional study.

Setting: Tertiary referral centre.

Patients: 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).

Conclusion: 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.

Publication types

  • Evaluation Study
  • Validation Study

MeSH terms

  • Adult
  • Aged
  • Blood Flow Velocity / physiology
  • Cross-Sectional Studies
  • Early Diagnosis
  • Echocardiography / standards*
  • Female
  • Humans
  • Hypertension, Pulmonary / diagnostic imaging*
  • Hypertension, Pulmonary / physiopathology
  • Male
  • Middle Aged
  • Sensitivity and Specificity
  • Stroke Volume / physiology
  • Vascular Resistance / physiology*
  • Ventricular Function, Left / physiology