title: Pulmonary artery acceleration time in identifying pulmonary hypertension patients with raised pulmonary vascular resistance.
abstract: BACKGROUND
  In patients with pulmonary hypertension (PH), ascertaining raised vascular resistance as a cause is a clinical objective, for which various Doppler-based measurements have been proposed, but with modest accuracy. We hypothesize that pulmonary acceleration time (PAcT) and the ratio of PAcT/peak pulmonary artery systolic pressure (PASP) reflect better the extent of the vascular resistance, compared with other available methods, and can differentiate accurately between pre- and post-capillary PH.
  
  
  RESULTS
  We investigated 56 patients (mean age 61 ± 13 years, 23 males) in a simultaneous echocardiography and right heart catheterization (RHC) study. Based on the RHC, pulmonary vascular resistance (PVR), and pulmonary capillary wedge pressure (PCWP), patients were divided into four groups: Group 1 = normal PVR [<3 WU (Wood units)] and PCWP (<12 mmHg), Group 2 = raised PVR but normal PCWP, Group 3 = raised PVR and PCWP; and Group 4 = normal PVR but raised PCWP. We used spectral Doppler to measure PAcT (corrected for heart rate) and to estimate PASP (peak tricuspid regurgitation pressure drop + estimated right atrial pressure of 7 mmHg). We also tested other available methods for assessing PVR. There were small age differences between patient groups but no age difference between Groups 2 and 4. PAcT and PAcT/PASP were both significantly (P = 0.008) reduced in Groups 2 and 3 compared with Groups 1 and 4. PAcT ≤90 had an 84% sensitivity and an 85% specificity in identifying patients with PVR ≥3 WU with a positive and a negative predictive value of 88% and 81%, respectively. The non-linear relationship between PVR and PAcT gave a quadratic r = 0.61, P < 0.001. ROC curve analysis showed PAcT having the best accuracy (83%) in detecting a PVR ≥3 WU.
  
  
  CONCLUSIONS
  PAcT <90 ms can serve as a strong non-invasive predictor of PVR >3 WU, which could differentiate patients with pre- and post-capillary PH.
authors.affiliation: Department of Cardiology, Umeå University, Umeå, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Tossavainen
authors.forename: Stefan
authors.initials: S
authors.lastname: Söderberg
authors.forename: Christer
authors.initials: C
authors.lastname: Grönlund
authors.forename: Manuel
authors.initials: M
authors.lastname: Gonzalez
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Henein
authors.forename: Per
authors.initials: P
authors.lastname: Lindqvist
mesh_terms: D000054:Acceleration; D001783:Blood Flow Velocity; D006328:Cardiac Catheterization; D015897:Comorbidity; D004452:Echocardiography; D005260:Female; D006334:Heart Function Tests; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D011669:Pulmonary Wedge Pressure / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology*
keywords: Doppler echocardiography; Pulmonary acceleration time; Pulmonary vascular resistance