title: Pulmonary artery diastolic pressure gradient as an indicator of severity of illness in patients with pulmonary hypertension related to left-sided heart disease.
abstract: BACKGROUND
  Pulmonary hypertension (PH) due to left-sided heart disease (Group 2 PH) is most commonly due to passive backward transmission of elevated left-sided heart pressures. A subgroup of these patients develop pulmonary artery remodeling, resulting in systolic and mean pulmonary artery pressures that are 'reactive' or 'out of proportion' to the elevated left-sided heart pressures. These patients have historically been identified by a transpulmonary gradient (TPG) > 12 mmHg. However, since diastolic pulmonary artery pressures are less susceptible to changes in pulmonary blood flow, a diastolic pulmonary gradient (DPG) ⩾ 7 mmHg may be a superior indicator of worse clinical function and prognosis.
  
  
  METHODS
  Based on measurements from a right-heart catheterization (RHC) database (Baylor College of Medicine, Houston, TX, USA), comparisons of several clinical parameters were made among three Group 2 PH patients: normal TPG and DPG (Group 2A), elevated TPG and normal DPG (Group 2B), and elevated TPG and DPG (Group 2C).
  
  
  RESULTS
  Among 173 RHCs, 39 were found to have Group 2 PH. Among these 39 cases, 10 (32%), 13 (32%), and 16 (36%) cases were categorized into Groups 2A, 2B, and 2C, respectively. Group 2C patients had significantly worse 6-min walk distance (308 ± 69 m) than Group 2A (425 ± 81 m) and Group 2B (350 ± 103 m) (p = 0.038). There was no significant difference in cardiac output, cardiac index, and right atrial pressure among the three subgroups.
  
  
  CONCLUSIONS
  Among patients with Group 2 PH, elevated DPG proved to be a more specific indicator of worse functional status than the historically used TPG. International guidelines and protocols for performing RHC for the assessment and diagnosis of PH should include the measurement of DPG.
authors.affiliation: Division of Pulmonary-Critical Care Medicine, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Howard
authors.affiliation: Division of Pulmonary-Critical Care Medicine, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Kapil
authors.initials: K
authors.lastname: Rangajhavala
authors.affiliation: Associate Professor of Medicine, Director, Baylor Pulmonary Hypertension Program, Pulmonary-Critical Care Medicine, Baylor College of Medicine, Houston, TX 77030, USA safdar@bcm.edu.
authors.forename: Zeenat
authors.initials: Z
authors.lastname: Safdar
mesh_terms: D000328:Adult; D000368:Aged; D062186:Arterial Pressure; D006328:Cardiac Catheterization; D003971:Diastole; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006304:Health Status; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000503:physiopathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D066253:Vascular Remodeling; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D016277:Ventricular Function, Left; D017725:Ventricular Pressure
keywords: diastolic pulmonary gradient; pulmonary hypertension left-sided heart disease; transpulmonary gradient