HPH in Chronic Hypoxic Lung Disease Flashcards
What are two mechanisms of PH in COPD?
Structural changes directly caused by disease
Hypoxic Pulmonary hpertension
What are 2 structural changes caused by COPD?
Destruction of vascular bed
Obstruction of vascular lumen
Why was it thought that remodelling was dominant in PH/
Return to normal PO2 does not immediately restore PAP
Normal PO2 returns PAP to baseline as remodelling regresses
Vasodilators do not restore PAP
What did a study show about vascular remodelling?
Remodelling was not inwards -> rat lumens were the size between hypoxic and normoxic
What does activity of ROCK induce?
Activity of ROCK inhibits MLCP and causes contraction
What is contraction also caused by?
Globular actin turns into fibrillar actin
How does ROCK cause actin contraction?
Maintains depolymerization of G-actin into F-actin
Which system does Rho kinase play a greater role in?
Pulmonary vascular smooth muscle
Does blocking Ca2+ reduce PVR?
No
What happens if a Rho kinase inhibitor at a selective conc. is induced?
Reduce PVR in chronic hypoxic lung
What does Rho kinase inhibitors show?
PH is not only due to remodeling
there is a vasoconstriction element
What happens if you gave enough of a Rho kinase inhibitor?
Acute reversal of PH to nearly zero
What are 2 risks of vasodilator therapy?
Worsening of hypoxemia
Systemic hypotension
What does NO/ NO agents cause?
Reduce mPAP
delivery of oxygen to systemic organs increase
V/Q mismatch
Which is a better route for vasodilator administration?
Inhaled route
