title: Comparison between acute hypoxia-induced and mechanically-induced pulmonary artery hypertension on the hemodynamics, myocardial contractility and regional blood flow in dogs.
abstract: Two groups of eight anesthetized dogs with pulmonary artery hypertension (PAH) were compared. PAH was induced by submitting one group (HP) to hypoxia (FiO2 range: 6-10%) and the other group (ME) to microemboli through glass microbead injection into the pulmonary circulation. Hypoxia-induced PAH was moderate (PAP: +65%; PVR: +152%) contrasting with marked PAH after microbead injection (PAP: +190%; PVR: +389%). For similar effects on left ventricular contractility (LV dP/dt max and segmental myocardial shortening), heart rate and systemic vascular resistance, left ventricular end-diastolic pressure showed significant differences between the two groups (HP group: +75%, ME group: -9%), and so did left ventricular end-diastolic length (HP: +9%, ME: -11%). Thus, contrary to the injection of microbeads, hypoxia did not give rise to any pulmonary barrier, and consequently the changes in cardiac output (HP: +19%, ME: -15%) and hepatic blood flow (HP: +383%, ME: -77%) were significantly different. Hypoxia, and not microbead injection, was responsible for systemic hypertension (MAP: +34% and -4%, respectively). The microbead model resulted in a significantly higher PVR/SVR ratio compared to the hypoxic model (HP: 0.14, ME: 0.41). Hypoxia increased left and right myocardial blood flows whereas microbead injection affected only right ventricular blood flow, leading to significantly different RV/LV endocardial perfusion ratios (HP: +10%, ME: +98%). We conclude that microbead-induced PAH is more appropriate than hypoxia-induced PAH for hemodynamic and pharmacological studies.
authors.affiliation: Département d'Anesthésie Réanimation, Hôpital Cardiovasculaire et Pneumologique Louis Pradel, Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: Girard
authors.forename: J M
authors.initials: JM
authors.lastname: Fargnoli
authors.forename: P
authors.initials: P
authors.lastname: Fourie
authors.forename: B
authors.initials: B
authors.lastname: Maitrasse
authors.forename: C C
authors.initials: CC
authors.lastname: Arvieux
mesh_terms: D000208:Acute Disease; D000818:Animals; D003326:Coronary Circulation / Q000502:physiology; D004285:Dogs; D006439:Hemodynamics / Q000502:physiology*; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology*; D009200:Myocardial Contraction / Q000502:physiology*; D011651:Pulmonary Artery / Q000502:physiology; D011655:Pulmonary Embolism / Q000503:physiopathology*; D012039:Regional Blood Flow / Q000502:physiology; D013152:Splanchnic Circulation / Q000502:physiology