PATHOPHYS: PAH Flashcards

1
Q

What are the 2 types of pulmonary HTN?

A

Idiopathic Pulmonary HTN

Secondary Pulmonary HTN

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2
Q

What is the definition of PAH?

A

Mean pulmonary arterial pressure >25 mmHg at rest or >30 mmHg with exercise

Mean pulmonary capillary wedge pressure/ Left ventricular end diastolic pressure < 15 mmHg

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3
Q

What does having a

mean pulmonary capillary wedge pressure/ left ventricular end diastolic pressure < 15 mmHg say about the cause of PAH?

A

it indicates that it is due to left heart failure

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4
Q

What is the most common cause of PAH?

A

PVH (pulmonary venous HTN due to LV dysfunction/heart failure)

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5
Q

How can parenchymal lung disease lead to PAH?

A

Hypoxemia leads to pulmonary vasoconstriction which backs up blood into the right heart

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6
Q

What is chronic thromboembolic disease?

A

small emboli occur all the time and there is gradual occlusion of arteries

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7
Q

List the 5 groups of PAH.

A

1) PAH (iPAH, Heritable, HIV-associated, etc)
2) PAH due to heart disease
3) PAH due to lung disease
4) CTEPH
5) PAH due to multifactoral etiology

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8
Q

What is the gene responsible for heritable PAH?

A

BMPR2

bone morphogenetic protein receptor type II

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9
Q

What is the characteristic pathologic sign of PAH?

A

plexiform lesions

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10
Q

What toxins are known to cause PAH?

A

Fen-phen

Aminorex

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11
Q

What 3 factors are associated with pathogenesis of PAH?

A
  • Imbalance of vascular effectors
  • Associated environmental factors
  • Associated genetic abnormalities
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12
Q

What vascular disease is most commonly associated with pulmonary HTN?

A

systemic sclerosis

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13
Q

Why does thrombocytosis lead to PAH?

A

serotonin is released during platelet lysis and it serves as a vasoconstrictor

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14
Q

Why does sickle cell disease lead to PAH?

A

Free heme is a NO scavenger, so there is less vasodilation

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15
Q

In PAH, which vascular mediators are increased and which are decreased?

A
  • Increased TXA2

- Decreased prostacyclin

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16
Q

What is NO and what does it do?

A

Chemical made by nitric oxide synthase in vascular endothelium that promotes vasodilation and inhibits smooth muscle growth

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17
Q

True or false: people with PPH have less nitric oxide synthesis–which is why they have vasoconstriction.

A

True! PPH patients show negligible immunohistochemical staining for nitric oxide synthase

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18
Q

What is endothelin 1? What does it do?

A

Potent vasoconstrictor and mitogen for smooth muscle cells that is produced by the vascular endothelium

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19
Q

What is going on with endothelin 1 in patients with PAH?

A

it localizes to the muscular pulmonary arteries

20
Q

What role does VEGF play in the pathogenesis of PAH?

A

its role is speculative but it is expressed by endothelial cells in plexiform lesions

21
Q

What are serotonin levels like in patients with PAH?

A

plasma serotonin levels are in higher concentrations in PPH patients than average

22
Q

How does Phen-Fen cause PAH?

A

it blocks voltage-gated K+ channels, which makes intracellular K+ go down (so Ca2+ goes in) causing vasoconstriction

23
Q

What is the mean age for PPH diagnosis?

A

36

24
Q

What is the clinical presentation for PPH? What is it commonly mistaken for?

A
Fatigue
Exertional dyspnea
Exertional chest pain
Exertional syncope
Edema
(commonly misdiagnosed as asthma)
25
Q

What are some physical signs of PPH?

A
  • Dyspnea
  • Parasternal heave
  • Palpable P2
  • Widely split S2
26
Q

What would a PFT of a patient with PAH show?

A

Normal FEV1, FVC, and TLC

Reduced DLCO

27
Q

List the tests that should be performed for PAH diagnosis in order?

A

CXR
Echocardiography
V/Q Scanning/CT angiography
Complete right heart catheterizaiton (gold standard)

28
Q

Why do you leave the best test for PAH (complete cardiac catheterizaiton) for last?

A

because it is very invasive

29
Q

What parameter differentiates PAH from PVH?

A

LAP (LVEDP)

30
Q

Why can you not just look at PAP for diagnosis of PAH?

A

Over time, the artery begins to fail (decompensate) due to the constant high pressure, so PAP actually begins to decline. However, PVR and the dyspnea keep getting worse (higher)

31
Q

True or false: vasoreactive patients have a better prognosis than patients without vasoreactivity.

A

TRUE! people who respond to vasodilators have much better prognosis

32
Q

What is “vasoreactivity”?

A

> 20% reduction in PAP and PVR with increased or unchanged CO and minimally reduced systemic blood pressure

33
Q

What is the choice agent for vasoreactivity testing?

A

Nitric oxide (it is better tolerated than the other IV vasodilators)

34
Q

If someone has a positive vasoreactivity test, what does that tell you?

A

they will also respond to CCBs

35
Q

What is riociguat?

A

A new drug that increases cGMP by stimulating guanylate cyclase

36
Q

What are some side effects of epoprostenol?

A

jaw pain
diarrhea
arthralgias

37
Q

How is epoprostenol given?

A

portable IV infusion pump

38
Q

What type of drug is epoprostneol?

A

prostacyclin analog

39
Q

What type of drug is bosentan?

A

endothelin-1 antagonist

40
Q

What are some adverse effects of bosentan?

A

Elevation of serum aminotransferase enzyme levels
Terratogenic
Interaction with other drugs

41
Q

Why are patients with PPH at increased risk for intrapulmonary thrombosis and VTE?

A
  • Sluggish pulmonary blood flow
  • Dilated right heart chambers
  • Venous stasis
  • Sedentary lifestyle
42
Q

What anticoagulant is used for PPH patients?

A

warfarin

43
Q

What is the goal of warfarin anticoagulation?

A

INR of ~2

44
Q

How long do people with PAH typically live?

A

mean is 3 years from diagnosis

45
Q

What echocardiogram findings are associated with poor outcome in PAH?

A
  • Large right atrial size
  • Degree of septal shift during diastole
  • Presence of pericardial effusion
46
Q

What is required to make a definite diagnosis for PAH?

A

High index of suspicion