Starling resistor vs. distensible vessel models for embolic pulmonary hypertension.
We investigated whether the Starling resistor model (Mitzner et al. J. Appl. Physiol. 51: 1065-1071, 1981) or a distensible vessel model (Haworth et al. J. Appl. Physiol. 70: 15-26, 1991) best describes pulmonary vascular pressure-flow (Q) relationships in embolic pulmonary hypertension. Mean pulmonary arterial pressure (Ppa)-Q plots at constant left atrial pressure (Pla) and Ppa-Pla plots at constant Q were investigated in seven dogs before and after 500-micron glass bead pulmonary embolism. Embolization to a mean angiographic obstruction of 78% increased the slope and extrapolated pressure intercept (P(i)) of Ppa-Q plots and increased the inflection point of Ppa-Pla plots, above which an increase in Pla is transmitted to Ppa in a ratio of approximately 1:1. The Starling resistor and the distensible vessel model provided a reasonably good fit to the Ppa-Q and Ppa-Pla coordinates before and after embolism. However, contrary to the prediction of the Starling resistor model, no correlation was found between the inflection point of Ppa-Pla plots and P(i). We therefore conclude that an increased closing pressure is unlikely to contribute to embolic pulmonary hypertension.
Mélot
C
C
Department of Intensive Care, Erasme University Hospital, Brussels, Belgium.
Delcroix
M
M
Closset
J
J
Vanderhoeft
P
P
Lejeune
P
P
Leeman
M
M
Naeije
R
R
D000818:Animals; D001794:Blood Pressure; D005544:Forecasting; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D008955:Models, Cardiovascular; D011652:Pulmonary Circulation; D011655:Pulmonary Embolism / Q000503:physiopathology*