title: Usefulness of the right ventricular systolic to diastolic duration ratio to predict functional capacity and survival in children with pulmonary arterial hypertension.
abstract: The objective of this study was to investigate the systolic to diastolic duration ratio (S:D ratio) in children with pulmonary arterial hypertension (PAH) and its association with right ventricular (RV) performance, hemodynamics, 6-minute walk test, clinical outcomes, and survival. We reviewed 503 serial echocardiograms in 47 children with PAH (mean pulmonary artery pressure >or=25 mm Hg) and compared the S:D ratio, assessed from Doppler flow of tricuspid valve regurgitation, to that in 47 age-matched controls. We reviewed echocardiograms, catheterization data, 6-minute walk tests, clinical data, lung transplantation, and death and used univariate linear regression models with a maximum likelihood algorithm for parameter estimation to investigate associations between S:D ratio and RV function, hemodynamics, functional capacity, and clinical outcomes. The S:D ratio was significantly higher in patients than in controls (1.38 +/- 0.61 vs 0.72 +/- 0.16, p <0.001). A higher S:D ratio was associated with worse echocardiographic RV fractional area of change, worse catheterization hemodynamics, shorter 6-minute walk distance, and worse clinical outcomes independent of pulmonary resistance or pressures. An increase of 0.1 in the S:D ratio was associated with a 13% increase in yearly risk for lung transplantation or death (hazard ratio 1.13, p <0.001). An S:D ratio 1.00 to 1.40 was associated with a moderate risk and an S:D ratio >1.40 was associated with a high risk of a negative outcome. In conclusion, in children with PAH, an increased S:D ratio is temporally associated with worse RV function, hemodynamics, exercise capability, clinical status, and survival.
authors.affiliation: Division of Pediatric Cardiology, The Labatt Family Heart Center, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Jaime
authors.initials: J
authors.lastname: Alkon
authors.forename: Tilman
authors.initials: T
authors.lastname: Humpl
authors.forename: Cedric
authors.initials: C
authors.lastname: Manlhiot
authors.forename: Brian W
authors.initials: BW
authors.lastname: McCrindle
authors.forename: Janette T
authors.initials: JT
authors.lastname: Reyes
authors.forename: Mark K
authors.initials: MK
authors.lastname: Friedberg
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003971:Diastole; D015150:Echocardiography, Doppler; D005080:Exercise Test; D005260:Female; D006439:Hemodynamics; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D011237:Predictive Value of Tests; D012129:Respiratory Function Tests; D016019:Survival Analysis; D013599:Systole; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging / Q000503:physiopathology; D055815:Young Adult