Pulmonary Vascular Disease - Pulmonary HTN

Question 1

What’s a simple definition of pulmonary hypertension?

Answer 1

High blood pressure within the pulmonary vascular bed.

Question 2

Ohm’s law solved for resistance?

Answer 2

Resistance = Pressure / Flow

Question 3

Equation for Pulmonary Vascular Resistance (PVR)? (with cardiac catheterization values)

Answer 3

PVR = (mean PA pressure - mean PCW pressure) / CO

Question 4

Does preload have a greater effect on the LV or on the RV stroke work?

Answer 4

The LV stroke work is more dependent on preload.

Question 5

Does afterload have a greater negative effect on the LV or on the RV stroke volume?

Answer 5

The RV really can’t deal with afterload - stroke volume rapidly drops off with increasing afterloads.

Question 6

How are normal pulmonary arteries different from normal systemic arteries?

Answer 6

Systemic arteries deal with high pressures and are highly muscularized.
Pulmonary arteries deal with low pressures and are normally only minimally muscularized.

Question 7

How do the arteries change in pulmonary arterial hypertension (PAH)?

Answer 7

Concentric intimal thickening / “plexogenic” changes.

plexogenic means… vessels start to branch… not important

Question 8

Pulmonary hypertension is defined by a mean pulmonary pressure of what?

Answer 8

> 25 mmHg (ish)

Question 9

3 pathophysiologic mechanisms of pulmonary HTN?

etiologies?

Answer 9

Increased flow. (chronic anemia, liver dis., L->R shunt… etc)
Elevation of outflow pressure. (left HF)
Increased PVR. (PAH, instrinsic lung dis., PE)

Question 10

5 clinical classifications of pulmonary HTN (WHO groups)?

-apparently important-

Answer 10

PAH (WHO Group 1).
Pulmonary HTN associated with L. heart dis. (2)
Pulmonary HTN with lung dis. and/or hypoxemia. (3)
Pulmonary HTN due to chronic thromboembolic dis. (4)
Miscellaneous and/or multifactorial. (5)

Question 11

Progression of PAH, starting with increased PVR? (6 steps)

Answer 11

Increased PVR.
Increased RV afterload. (recall RV can’t handle it)
Reduced RV ejection (CO) and pulm blood flow.
RV hypertrophy and/or dilation.
RV failure.
Death.

Question 12

Why don’t we normally have increased PA pressure with exertion? (when CO will normally be increased)
How does this vary in PAH?

Answer 12

Thought there is increased flow, our capillary beds have reserve volume to vasodilate and accomodate it.

If pt has PAH, PA pressure will increase markedly with exertion.

Question 13

Normal pulmonary capillary wedge pressure (PCWP)? -estimate of LA pressure.

Answer 13

< 15 mmHg

Question 14

Definition of increased PVR? (in Wood units)

Answer 14

> 3 Wood units

Question 15

4 classifications of PAH?

Which are the 2 most common?

Answer 15

Idiopathic PAH (IPAH)
Heritable PAH (HPAH)
Drugs and toxins
Associated with _____ PAH (APAH)

IPAH and APAH are most common.

Question 16

5 examples of diseases / pathophysiologies with which APAH is… associated?

Answer 16

Collagen vascular disease.
Congenital L->R shunt.
Portal HTN.
HIV infection.
Schistosomiasis.
...and others.

Question 17

7 risk factors (from history) for PAH? - lots of overlap with the APAH causes,

Answer 17

Family history.
Connective tissue disease.
Congenital heart disease (esp L->R shunt).
Portal HTN.
History of DVT/PE.
Environmental/drug factors.
HIV.

Question 18

What drug might actually be responsible for a lot of “idiopathic” PAH?

Answer 18

Methamphetamine.

from a study at one center where 30% of IPAH pts had used meth

Question 19

Symptoms of PAH? (are they caused by the PAH itself?)

Answer 19

All related to inability to increase CO on demand.
Dyspnea, fatigue, pre-syncope, cough, chest discomfort, edema.
(these symptoms are often misinterpreted as being caused by something else)

Question 20

5 physical exam findings associated with Pulmonary HTN?

Answer 20

Loud P2.
RV lift.
Systolic murmur (tricuspid regurg.)
Diastolic murmur (pulmonary regurg.)
RV S4.

Question 21

5 physical exam findings consistent with presence of RV failure?

Answer 21

JVD with V wave.
RV S3.
Hepatomegaly.
Edema.
Ascites.

Question 22

5 aspects of general medical management of PAH?

Answer 22

Oxygen.
Diuretics (esp. spironolactone).
Digoxin (if RV failing).
Warfarin.
Lifestyle adjustments.

Question 23

Important lifestyle adjustments for PAH?

Answer 23

Avoiding stimulants and decongestants.
Low-salt diet, possibly fluid restriction.
Exercise.
Stress reduction.
Avoiding pregnancy.

Question 24

Should pregnancy and PAH mix?

Answer 24

No. Never. Not even if she really wants a baby. Adoption’s great.
(the mortality rate is 30%ish, which is unacceptable)

Question 25

Prostacyclin -do you want it or not want it if you have PAH?

Answer 25

You want prostacyclin. PAH is associated with a prostacyclin deficiency (leading to increased cell proliferation, thrombosis, vasoconstriction, and inflammation)

Question 26

Endothelin is important in causing PAH?

Answer 26

Endothelin causes vasoconstriction, but other things too.

Question 27

3 targets of current specific therapies for PAH?

Answer 27

Give back prostacyclin.
Antagonize endothelin.
Increase NO (with NO, or PDE-5 inhibitor).