title: Alteration of right ventricular-pulmonary vascular coupling in a porcine model of progressive pressure overloading.
abstract: In acute pulmonary embolism, right ventricular (RV) failure may result from exceeding myocardial contractile resources with respect to the state of vascular afterload. We investigated the adaptation of RV performance in a porcine model of progressive pulmonary embolism. Twelve anesthetized pigs were randomly divided into two groups: gradual pulmonary arterial pressure increases by three injections of autologous blood clot (n=6) or sham-operated controls (n=6). Right ventricular pressure-volume (PV) loops were recorded using a conductance catheter. Right ventricular contractility was estimated by the slope of the end-systolic PV relationship (Ees). After load was referred to as pulmonary arterial elastance (Ea) and assessed using a four-element Windkessel model. Right ventricular-arterial coupling (Ees/Ea) and efficiency of energy transfer (from PV area to external mechanical work [stroke work]) were assessed at baseline and every 30 min for 4 h. Ea increased progressively after embolization, from 0.26+/-0.04 to 2.2+/-0.7 mmHg mL(-1) (P<0.05). Ees increased from 1.01+/-0.07 to 2.35+/-0.27 mmHg mL(-1) (P<0.05) after the first two injections but failed to increase any further. As a result, Ees/Ea initially decreased to values associated with optimal SW, but the last injection was responsible for Ees/Ea values less than 1, decreased stroke volume, and RV dilation. Stroke work/PV area consistently decreased with each injection from 79%+/-3% to 39%+/-11% (P<0.05). In response to gradual increases in afterload, RV contractility reserve was recruited to a point of optimal coupling but submaximal efficiency. Further afterload increases led to RV-vascular uncoupling and failure.
authors: Hemodynamic Research Laboratory (Hemoliege), Liege University, Belgium. a.ghuysen@chu.ulg.ac.be
authors: Alexandre
authors: A
authors: Ghuysen
authors: Bernard
authors: B
authors: Lambermont
authors: Philippe
authors: P
authors: Kolh
authors: Vincent
authors: V
authors: Tchana-Sato
authors: David
authors: D
authors: Magis
authors: Paul
authors: P
authors: Gerard
authors: Véronique
authors: V
authors: Mommens
authors: Nathalie
authors: N
authors: Janssen
authors: Thomas
authors: T
authors: Desaive
authors: Vincent
authors: V
authors: D'Orio
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004617:Embolism / Q000473:pathology / Q000503:physiopathology*; D006439:Hemodynamics; D008168:Lung / Q000098:blood supply*; D011652:Pulmonary Circulation; D011897:Random Allocation; D013552:Swine; D018497:Ventricular Dysfunction, Right