Lec 33 Pulmonary Hypertension Flashcards Preview

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Flashcards in Lec 33 Pulmonary Hypertension Deck (36)
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What types of vessels in pulm vasculatrue have most resistance?

small vasculature = arterioles and venules


What is flow/resistance of pulm circulation?

high flow
low resistance


What is capacitance of pulm circulation?

high capacitance to accommodate increased CO


What are the major causes of pulmonary hypertension?

- left heart disease
- chronic thrombotic or embolic disease
- parenchymal lung disease or chronic hypoxemia
- miscellaneous --> sarcoidosis
- pulmonary arterial hypertension


What is the most common cause of pulmonary hypertension?

left heart disease


What are the major causes of pulmonary arterial hypertension?

- idiopathic = primary pulmonary hypertension
- heritable
- drug/toxin induced
- associated w/ other disease
- persistant plum HTN of newborn


What is general definition of pulmonary hypertension?

resting mean pulm arterial pressure > 25 mmHg


What is general definition of pulmonary arterial HTN?

resting mean PAP > 25 AND
- PCWP/LAP/LVEDP < 15 mmHg
- pulmonary arteriolar resistance > 3 woods units


What 3 vascular changes happen in PAH?

- vasoconstriction
- smooth muscle and endothelial cell proliferation
- thrombosis in situ


What is effect of vascular remodeling in PAH?

decrease flow
increase resistance


What are plexiform lesions?

hallmark of advanced pulmonary HTN

proliferation of cells that compromise lumen of small pulmonary artery


What are the mechanisms leading to PAH?

- homeostatic imbalance of vascular effectors [vasoconstors, prothrombotic, mitogenic factors]

- environmental



What is role of prostacyclin and thromboxane A2 in PAH?

prostacyclin = vasodilator, inhibits platelet activation

TXA2 = vasoconstrictor, platelet agonist

in PAH levels of TXA2 > > prostacyclin


What is role of serotonin in PAH?

- vasoconstrictor
- promotes smooth muscle cell hypertrophy
- elevated in PAH
- impaired serotonin reuptake in PAH patients


What is role of Endothelin 1 in PAH?

- potent vasoconstrictor, stimulates smooth muscle cell proliferation

increased in PAH


What is role of NO in PAH?

- vasodilator, inhibits smooth cell proliferation

- endothelial isoform of NO synthase decreased in pts with PAH


What is role of hypoxia in PAH?

- in systemic circulation --> hypoxia induces vasodilation

- in pulm beds --> induces vasoconstriction [to improve V/Q mismatch]

chronic hypoxia --> structural remodeling, SMC proliferation


What is role of anorexigens in PAH?

- linked to higher risk for PAH
- fen-phen


What is role of CNS stimulants in PAH?

cocaine/methamphetamines cause medial hypertrophy of pulm arteries


What is role of TFG-B in PAH?

- bone morphogenetic protein receptor type 2 [BMPR2]

modulates growth of vascular cells
mutant --> lose control, extra growth

incomplete penetrance --> may be necessary but insufficient to cause disease


What genetic pathways predispose to PAH?

- TFG-B mutation
- serotonergic path mutation


What is role of serotonergic path in PAH development?

variant gene expression of serotonin receptor --> increase serotonin dependent vascular remodeling


WHat is theory of cause of PAH?

causes multiple hits to get the disease

risk factors + genetic predispostion + cell dysfunction + inflammation


What happens in presymptomatic/compensated PAH?

higher PAP pressure but able to compensate

CO ok


What happens in symptomatic/decompensating PAH?

RV facing consequences of years of pressure --> weakens --> CO starts to drop and RAP rises

manifests as fatigue, lower extremity edema, elevated neck veins


What happens in declining/decompensated PAH?

CO way down
RAP way up
pulm artery pressure reaches inflection point and starts to go down = sign of how poor your RV is function you can't even get fluid into pulm vasculature

eventually get RV failure


What is prognosis of PAH?

3 year survival 60%


What are symptoms of PAH?

- dyspnea
- fatigue
- chest pain
- syncope
- palpitations
- edma


What are physical findings in PAH?

- elevated jugular venous distension
- tricuspid regurg due to increase pulm artery P
- accentuated S2
- S3 gallop
- peripheral edema
- hepatomegaly, pulsatile liver, ascites


What doe you see on EKG with PAH?

- not sensitive enough to be a screening tool

- RV hypertrophy = big V1 QRS; big S in V5/6
- R axis deviation = I down; aVF up
- R atrium enlarged = big P wave in II, III, aVF


What do you see on CT with PAH?

- enlarged central pulm arteries
- reduced caliber of peripheral vessels


What diagnostic workup for PAH?

- do clinical exam
- look for sings of RV or RA enlargement or increased pressure

primary screening = do echo

rule out other common causes of pulm HTN

if you see high pressure on pulm arteries --> confirm with invasive cath lab measurement of pressures


What should you screen for if you think PAH?

- screen for thromboembolic disease
- work up for infectious disease or connective tissue disorder
- screen for chronic lung disease


What is treatment for PAH?

- give ox --> maintain saO2 > 90%
- routine vaccinations
- give diuretics carefully for volume overload symptoms
- maybe digitalis
- warfarin b/c of prothrombotic state of PAH

can give vasoactive agents


What should you avoid in PAH

- avoid vasoconstrictors --> nicotine, sympathomimetics
- avoid deep valsalva
- avoid pregnancy


How does phosphodiesterase 5 inhibitor help in pAH?

prevents breakdown of cGMP --> get vasodilitory effects of NO