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Comparison between acute hypoxia‐induced and mechanically‐induced pulmonary artery hypertension on the hemodynamics, myocardial contractility and regional blood flow in dogs
Author(s) -
Girard C.,
Fargnoli JM,
Fourie P.,
Maitrasse B.,
Arvieux CC
Publication year - 1995
Publication title -
fundamental and clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 73
eISSN - 1472-8206
pISSN - 0767-3981
DOI - 10.1111/j.1472-8206.1995.tb00533.x
Subject(s) - contractility , hypoxia (environmental) , medicine , cardiology , hemodynamics , pulmonary artery , vascular resistance , pulmonary hypertension , microbead (research) , blood flow , cardiac output , chemistry , oxygen , biochemistry , organic chemistry
Summary— 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.