title: Residual pulmonary vasodilative reserve predicts outcome in idiopathic pulmonary hypertension.
abstract: OBJECTIVE
  Idiopathic pulmonary arterial hypertension (IPAH) remains a devastating and incurable, albeit treatable condition. Treatment response is not uniform and parameters that help to anticipate a rather benign or a malignant course of the disease are warranted. Acute pulmonary vasoreactivity testing during right heart catheterisation is recommended to identify a minority of patients with IPAH with sustained response to calcium channel blocker therapy. This study aimed to evaluate the prognostic significance of a residual pulmonary vasodilative reserve in patients with IPAH not meeting current vasoresponder criteria.
  
  
  METHODS
  Observational right heart catheter study in 66 (n=66) patients with IPAH not meeting current vasoresponse criteria. Pulmonary vasodilative reserve was assessed by inhalation of 5 µg iloprost-aerosol.
  
  
  RESULTS
  Sixty-six (n=66) of 72 (n=72) patients with IPAH did not meet current definition criteria assessed during vasodilator testing to assess pulmonary vasodilatory reserve. In those, iloprost-aerosol caused a reduction of mean pulmonary artery pressure (Δ pulmonary artery pressure-11.4%; p<0.001) and increased cardiac output (Δ cardiac output +16.7%; p<0.001), resulting in a reduction of pulmonary vascular resistance (Δ pulmonary vascular resistance-25%; p<0.001). The magnitude of this response was pronounced in surviving patients. A pulmonary vascular resistance reduction of ≥30% turned out to predict outcome in patients with IPAH.
  
  
  CONCLUSIONS
  Residual pulmonary vasodilative reserve during acute vasodilator testing is of prognostic relevance in patients with IPAH not meeting current definitions of acute vasoreactivity. Therefore vasoreactivity testing holds more information than currently used.
authors.affiliation: Department Internal Medicine II, Neuwittelsbach Academic Hospital Ludwig Maximilians University, Munich, Germany Department of Internal Medicine V, Ludwig Maximilians University, Klinikum Grosshadern, Munich, Germany.
authors.forename: Hanno H
authors.initials: HH
authors.lastname: Leuchte
authors.affiliation: Department of Internal Medicine V, Ludwig Maximilians University, Klinikum Grosshadern, Munich, Germany.
authors.forename: Carlos
authors.initials: C
authors.lastname: Baezner
authors.affiliation: Department Internal Medicine II, Neuwittelsbach Academic Hospital Ludwig Maximilians University, Munich, Germany Department of Internal Medicine V, Ludwig Maximilians University, Klinikum Grosshadern, Munich, Germany.
authors.forename: Rainer A
authors.initials: RA
authors.lastname: Baumgartner
authors.affiliation: Department of Internal Medicine V, Ludwig Maximilians University, Klinikum Grosshadern, Munich, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Muehling
authors.affiliation: Department of Internal Medicine V, Ludwig Maximilians University, Klinikum Grosshadern, Munich, Germany.
authors.forename: Claus
authors.initials: C
authors.lastname: Neurohr
authors.affiliation: Department of Internal Medicine V, Ludwig Maximilians University, Klinikum Grosshadern, Munich, Germany.
authors.forename: Juergen
authors.initials: J
authors.lastname: Behr
mesh_terms: D002121:Calcium Channel Blockers / Q000627:therapeutic use; D006328:Cardiac Catheterization; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D016285:Iloprost; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D014655:Vascular Resistance / Q000502:physiology*; D014665:Vasodilator Agents
chemical_list: D002121:Calcium Channel Blockers; D014665:Vasodilator Agents; D016285:Iloprost