Pulmonary Arterial Hypertension Flashcards
Normal right ventricle pressure
<25
Normal PA pressure
14
Equation for pulmonary artery pressure
P = CO*Pulmonary vascular resistance + PLA
Resistance/compliance of pulmonary vascular system
Less muscle and elastin than in systmeic vessels, so low resistance, high compliance. Capillary recruitment helps
Pressure definition of pulmonary hypertension
mean PA>25mmhg
5 WHO groups
1: Pulmonary arterial hypertension (BMPR or associated with CTD HIV congential heart disease)
2: Left heart disease
3: Lung disease causing hypoxia (COPD/ILD)
4: thromboembolic
5: misc
Vascular pathology of PAH
Plexiform lesions, in situ thombosis, medial hypertrophy
BMPR2
Mutation can lead to PAH
Other things that can cause PAH
CTD’S, Congenital heart diseases
Idiopathic pulmonary arterial hypertension mortality?
Can live for 2.8 years
Is RV like a weak LV?
No, morphologically different and embryologically different. RV is more compliant.
Will RV fail when exposed to increased afterload?
Yes super easily.
Why do pHTN patients decompensate so rapidly.
Vicious cycle. You can intuit this. Cardiogenic shock occurs eventually
Symptoms of phtn
dyspnea fatigue chest pain, palpitations. all due to low perfusion. Then also ascites and peripheral edema
Physical exam
RV heave, split S2, loud P2, TR due to left ventricular dilitation
Are there rales in PAH?
No! Occurs before capillaries so no transudate.
Right heart cath to diagnose must show
PCWP<15 for who I, III, IV.
Natural history of PHTN
CO drops, PAP and RAP increase, PVR increases too
Final stage pulmonary artery pressure decreases dramatically due to right heart not being able to pump into it anymore.
How to decrease RV afterload
Give CCBs, prostacyclin derivatives, No derivatives, PDE inhibitors. Endothelin receptor antagonists
Use of CCBs in pulmonary HTN
Use dihydropyridines. Cause PA vasodilation but only if positive vasoreactivity test
Vasoreactivity test
Give short acting vasodilator. If mPAP decreases by more than 10, then CCbs will work. Not many people are vasoresponders
Prostanoids
Prostaglandin derivates that cause increase in cAMP.
Three examples of prostanoids
Epoprostanol, treprostinil, iloprost
Epoprostanol
Is prostacyclin, given by 2 dedicated IVs just incase one fails. Only pulmonary HTN medication with proven survival benefit.
Endothelin receptor antagonists
Want a drug that blocks A but not B because B is implicated in endothelin clearance. Drugs include bosentan, abrisentan, macitentan.
PDE5 inhibitors
Increase cGMP by preventing its breakdown. Sildenafil,
Riociguat
Stimulator of GC, increases cGMP
Problem with PA vasodilators
Decrease SVR and can cause hypotension, also abrupt withdrawal can cause PA hypertension!
Biggest problem, can worsten V/Q matching because will dilate the vessels around shitty alveoli.They also can increase pulmonary capillary pressure causing pulmonary edema
Why do PA vasodilators worsten VQ matching
Because they dilate the vessels around shitty alveoli
