Pulmonary Vascular Disease Flashcards
why is pulmonary circulation low pressure?
right ventricle generates less pressure than the left
vessels are thin-walled and distensible
the adult pulmonary circulation is _____ flow, _____ pressure, and _____ resistance
high
low
low
where does the bronchial artery come from?
systemic aorta
what is venous drainage from the bronchial circulation?
bronchial veins to right atrium and partly pulmonary veins to left atrium
what does nitric oxide produced by pulmonary endothelial cells mediate?
vascular relaxation
arachidonic acid metabolites thromboxane A2 and LTC4 and D4 are ________________________________________________
potent vasoconstrictors and increase pulmonary vascular resistance
what is the primary determinant of pulmonary vascular resistance?
PAO2
what are some vasoactive agents that are metabolized by pulmonary endothelial cells before they are delivered to general circulation?
polypeptides
biogenic amines
arachidonic acid metabolites
what leads to cardiogenic pulmonary edema?
inadequate left ventricular function
capillary hydrostatic pressure increases
what does altered permeability due to epithelial or endothelial cell injury and loss of barrier integrity lead to?
non-cardiogenic pulmonary edema
ALI/ARDS
what are some chronic changes that can lead from reversible vasoconstriction to persistent pulmonary hypertension?
hyperbaric oxygen
chronic endotoxemia
monocrotaline
cattle pastured at high altitude develop:
pulmonary arterial hypertension
congestive heart failure
edema involving thorax, abdomen, and subcutaneous tissue of brisket forelimbs and abdomen
what is equine exercise-induced pulmonary hemorrhage (EIPH) characterized by?
pulmonary hypertension
alveolar edema
pulmonary capillary rupture
intra-alveolar hemorrhage
what do repeated bouts of EIPH result in?
fibrosis and sustained pulmonary inflammation
where does bleeding occur in exercise-induced pulmonary hemorrhage?
caudo-dorsal lungs
what is pulmonary thromboembolism (PTE)?
obstruction of pulmonary vessel by a thrombus that may have formed locally or translocation of a thrombus from elsewhere
why is a large thrombus obstructing obstructing in a major pulmonary artery a bad thing?
increases dead space and disrupts V/Q ratio
increased flow to non-obstructed areas alters V/Q and results in hypoxemia, which induces vasoconstriction
concurrent bronchoconstriction can lead to airway collapse and alveolar collapse
what organism is most commonly involved in bovine septic thromboembolism (caudal vena cava thrombosis)?
Fusobacterium necrophorum
gram negative pleomorphic rod and normal inhabitant of GI tract
what leads to right ventricular dilation and hypertrophy (cor pulmonale)?
chronic pulmonary hypertension
what is the normal systolic pressure of the pulmonary circulation?
25mmHg
when does resistance in the pulmonary circulation increase?
when lungs are inflated to very high volumes
what does the bronchial circulation provide blood for?
cells in walls of trachea and airways
vascular bundles
nerves
lymph nodes
visceral pleura
what do PGI2 and PAF do with vascular supply?
vasodilate
what mediates hypoxic vasoconstriction?
sensor at level of smooth muscle cells mitochondria and Ca influx
LTC4 and D4
oxygen radicals or peroxide may also act as mediators through control of transmembrane Ca flux
what are some growth factors that pulmonary endothelial cells synthesize and release when perturbed?
platelet-derived growth factor
epidermal growth factor
heparin-like growth inhibitory factor
why does altered permeability of endothelial barriers occur?
epithelial or endothelial cell injury and loss of barrier integrity
ALI/ARDS or non-cardiogenic pulmonary edema
what pathologic changes occur when reversible vasoconstriction leads to persistent pulmonary hypertension?
thickening of medial smooth muscle
extension of smooth muscle distally to normally non-muscular arteries
narrowing and occlusion of distal arteries
what does bovine brisket disease develop as a sequelae to?
hypoxic pulmonary vasoconstriction
chronic pulmonary hypertension with vascular remodeling
how is equine exercise-induced pulmonary hemorrhage (EIPH) diagnosed?
observation of epistaxis
endoscopy followed by transtracheal aspiration
bronchoalveolar lavage to obtain a cytology sample to detect hemosiderophages
where does equine exercise-induced pulmonary hemorrhage occur?
caudo-dorsal lungs
what is the treatment and prevention for equine exercise-induced pulmonary hemorrhage?
diuretics
nasal dilator strips
inhaled nitric oxide leads to more severe bleeding (but reduces pulmonary artery pressure)
what signs are associated with pulmonary thromboembolism?
hypoxemia
hyperventilation
dyspnea
what develops after septic emboli from hepatic abscesses metabolize to the lungs?
pulmonary arteritis and aneurysms develop
aneurysms may rupture: fatal pulmonary hemorrhage
what stage of Dirofilariasis larvae cause lesions?
5th
what are the two types of lesions that develop during canine Dirofilariasis?
intimal proliferation due to effects of live parasites
thrombosis due to dead parasites
why does pulmonary hypertension occur with canine Dirofilariasis?
intravascular proliferative lesions
inflammatory-mediated vasoconstriction
decreased endothelial nitric oxide production
