Chronic thromboembolic and pulmonary arterial hypertension share acute vasoreactivity properties.
BACKGROUND
Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are the major classes of pulmonary hypertensive disorders according to the World Health Organization; both lead to right heart failure and death. A better understanding of disease mechanisms has led to the suggestion that the thromboembolic and nonthromboembolic types of pulmonary hypertension may share pathophysiologic features. We therefore compared acute vasoreactivity and proximal pulmonary artery compliance in patients with PAH and CTEPH during the initial diagnostic heart catheterization.


METHODS
Right heart catheterization using a flow-directed Swan-Ganz catheter was performed in patients with CTEPH (n = 22) and PAH (n = 35). Pulmonary hemodynamics were assessed at baseline, during the inhalation of 40 ppm of nitric oxide, and 30 min after the inhalation of 10 mug of iloprost. To assess the proximal pulmonary artery compliance, the pulse pressure (PP) [systolic-diastolic pressure] and the fractional PP (PPf) [divided by the mean pressure] were calculated.


RESULTS
Both vasodilators produced similar hemodynamic improvement, and the difference between CTEPH and PAH was not significant. The baseline PP and PPf did not vary between the two groups.


CONCLUSIONS
Patients with PAH and CTEPH show similar acute vasoreactivity to inhaled nitric oxide and iloprost, and have similar pulmonary artery compliance. These findings support the presence of some shared pathophysiologic pathways in both disorders and may lead to therapeutic implications in patients with inoperable CTEPH.
Ulrich
Silvia
S
Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, University Hospital of Zurich, Raemistrasse 100, 8091 Zurich, Switzerland. ulris@bluewin.ch
Fischler
Manuel
M
Speich
Rudolf
R
Popov
Vladimir
V
Maggiorini
Marco
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001993:Bronchodilator Agents / Q000494:pharmacology; D006328:Cardiac Catheterization / Q000379:methods; D002908:Chronic Disease; D003187:Compliance; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000145:classification / Q000503:physiopathology*; D016285:Iloprost / Q000494:pharmacology; D008168:Lung / Q000098:blood supply / Q000503:physiopathology; D008875:Middle Aged; D009569:Nitric Oxide / Q000494:pharmacology; D011651:Pulmonary Artery / Q000187:drug effects / Q000503:physiopathology*; D011655:Pulmonary Embolism / Q000503:physiopathology*; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology; D014944:World Health Organization
D001993:Bronchodilator Agents; D014665:Vasodilator Agents; D009569:Nitric Oxide; D016285:Iloprost