title: Dobutamine stress echocardiography for the assessment of pressure-flow relationships of the pulmonary circulation.
abstract: BACKGROUND
  Stress testing of the pulmonary circulation (via increasing pulmonary blood flow) can reveal abnormal mean pulmonary artery pressure-cardiac output (mPpa-Q) responses, which may facilitate early diagnosis of pulmonary vascular disease. We investigated the application of dobutamine stress echocardiography (DSE) for the noninvasive assessment of mPpa-Q relationships.
  
  
  METHODS
  DSE using an incremental dose protocol (≤ 20 μg/kg/min) was performed in 38 subjects (16 patients with pulmonary arterial hypertension [PAH] and 22 healthy control subjects). An additional 22 healthy control subjects underwent exercise stress echocardiography as a comparator group. Multipoint mPpa-Q plots were analyzed, and the pulmonary vascular distensibility coefficient α was calculated.
  
  
  RESULTS
  DSE was feasible and informative in 93% of subjects. The average dobutamine-induced mPpa-Q slope was 1.1 ± 0.7 mm Hg/L/min in healthy control subjects and 5.1 ± 2.5 mm Hg/L/min in patients with PAH (P < .001). The dobutamine-induced α was markedly reduced in patients with PAH (0.003 ± 0.001 mm Hg vs 0.02 ± 0.01 mm Hg in control subjects, P < .001). When exercise and dobutamine stress were compared in healthy control subjects, the exercise-induced mPpa-Q slope was modestly higher (1.6 ± 0.7 mm Hg/L/min, P = .03 vs dobutamine). In patients with PAH, lower functional class status was associated with lower dobutamine-induced mPpa-Q slopes (P = .014), but not with resting total pulmonary vascular resistance.
  
  
  CONCLUSIONS
  Noninvasive assessment of mPpa-Q relationships is feasible with dobutamine stress. DSE may potentially be a useful noninvasive technique for stress testing of the pulmonary vasculature.
authors.affiliation: Discipline of Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia. Electronic address: edmundmtlau@gmail.com.
authors.forename: Edmund M T
authors.initials: EMT
authors.lastname: Lau
authors.affiliation: Department of Pathophysiology, Free University of Brussels, Brussels, Belgium.
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Vanderpool
authors.affiliation: Discipline of Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia.
authors.forename: Preeti
authors.initials: P
authors.lastname: Choudhary
authors.affiliation: Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia.
authors.forename: Lisa R
authors.initials: LR
authors.lastname: Simmons
authors.affiliation: Discipline of Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia.
authors.forename: Tamera J
authors.initials: TJ
authors.lastname: Corte
authors.affiliation: Department of Cardiology, Second University of Naples, Naples, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Argiento
authors.affiliation: Department of Cardiology, Second University of Naples, Naples, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: D'Alto
authors.affiliation: Department of Pathophysiology, Free University of Brussels, Brussels, Belgium.
authors.forename: Robert
authors.initials: R
authors.lastname: Naeije
authors.affiliation: Discipline of Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia.
authors.forename: David S
authors.initials: DS
authors.lastname: Celermajer
mesh_terms: D000328:Adult; D000368:Aged; D002316:Cardiotonic Agents; D004280:Dobutamine; D025401:Echocardiography, Stress / Q000379:methods*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011652:Pulmonary Circulation / Q000502:physiology*; D014655:Vascular Resistance / Q000502:physiology*
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine