title: Validation of the isovolumetric relaxation time for the estimation of pulmonary systolic arterial blood pressure in chronic pulmonary hypertension.
abstract: OBJECTIVE
  Transthoracic echocardiography is a useful technique for non-invasive detection of pulmonary arterial systolic pressure (PASP). Isovolumic relaxation time (IVRT) measured by Doppler tissue imaging (DTI) is a sensitive measurement of changes in pulmonary vasculature. Our aim was to validate IVRT in the echocardiographic assessment of pulmonary hypertension (PH) patients.
  
  
  RESULTS
  We studied 196 PH patients (67% women, mean age 51.8 ± 16.6 years, mean PASP: 81 ± 24 mmHg) and 37 consecutive age- and sex-matched controls (58% women, mean age 44.7 ± 16.4 years, mean PASP 27.7 ± 5.5 mmHg). The estimation of PASP was derived from tricuspid regurgitation velocity according to the Bernoulli equation. The measurement of IVRT was calculated using pulsed tissue Doppler. In the PH group and in the healthy volunteers group (P < 0.0001), the average IVRT was 113.4 ± 28.5 ms [95% confidence interval (CI): 109-117] and 41 ± 12.5 ms (95% CI: 37-45), respectively. We found a strong correlation between IVRT and systolic pulmonary pressure in the PH group (r = 0.52, P < 0.0001) and a cut-off of 75 ms showed a sensitivity and specificity of 94% and 97%, respectively, for the prediction of elevated PASP.
  
  
  CONCLUSIONS
  The determination of IVRT by DTI is a simple and reproducible method that correlates well with PASP. It is, therefore, a parameter to consider in the echocardiographic assessment of patients with PH, and may be particularly important when the tricuspid Doppler signal is poor.
authors.affiliation: Department of Cardiovascular Sciences, Hammersmith Hospital, Imperial College NHS Trust, Du Cane Road, London W12 0HS, UK. ines.cabrita05@imperial.ac.uk
authors.forename: Inês
authors.initials: I
authors.lastname: Zimbarra Cabrita
authors.forename: Cristina
authors.initials: C
authors.lastname: Ruísanchez
authors.forename: Julia
authors.initials: J
authors.lastname: Grapsa
authors.forename: David
authors.initials: D
authors.lastname: Dawson
authors.forename: Bernard
authors.initials: B
authors.lastname: North
authors.forename: Fausto J
authors.initials: FJ
authors.lastname: Pinto
authors.forename: J Simon R
authors.initials: JS
authors.lastname: Gibbs
authors.forename: Petros
authors.initials: P
authors.lastname: Nihoyannopoulos
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001794:Blood Pressure; D016022:Case-Control Studies; D002908:Chronic Disease; D015150:Echocardiography, Doppler / Q000379:methods; D018619:Echocardiography, Doppler, Pulsed; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011669:Pulmonary Wedge Pressure; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume; D014261:Tricuspid Valve / Q000503:physiopathology; D016278:Ventricular Function, Right