Pulmonary Hypertension Flashcards
In people PH is defined as a PAP of or above XXXX
> 25 mm Hg
Postcapillary PH is defined as increased PAP + a PWP of above XXXX.
15 mm Hg
How does LHD lead to PH?
LHD causes volume overload of the LA –> will increase pulmonary venous pressure
initially should be without increase in pulmonary vascular resistance, but increased pressure can cause remodelling and constriction –> postcapillary can cause secondary precapillary PH
What are the 3 cardiovascular changes that can lead to PH?
- increased pulmonary blood flow (e.g., congenital shunt)
- increased pulmonary vascular resistance (e.g., PTE, pulmonary fibrosis, heart worm, etc.)
- increased pulmonary venous pressure (LHD)
Explain how you can extrapolate an approximate systolic PAP from an echocardiogram
with the modified Bernoullie equation
measure tricuspid valve regurgitation velocity (TRV)
Pressur gradient = 4 x TRV ^2
TRV in m/s
ideally for systolic PAP estimate need RA pressure, but no validated method to measure this on echo in SA, so this is ignored
What are factors besides PH that can influences and alter TRV?
pulmonary or tricuspid stenosis
RV function, pericardial restain
poor patient cooperation
labored brathing
What echocardiographic measurement can be used to estimate mean or diastolic PAP?
Pulmonary regurgitation jet velocity –> Mean PAP
add RA pressure –> diastolic PAP
List 4 changes to the ventricles that are indicative of PH
RV hypertrophy (dilation/eccentric or wall hypertrophy/concentratic)
ventricular septal flattening
LV underfilling/decreased size (not in LHD-induced PH)
RV systolic dysfunction
Name 4 changes to the PA on echo, indicative of PH
- PA enlargement PA:Ao > 1
- Peak early diastolic PR velocity > 2.5 m/s
- Right pulmonary artery distensibility < 30%
- lower RV outflow time, systolic notching of the doppler RV outflow
Name 2 changes to the RA and CVC on echo indicative of PH
RA enlargement
CVC enlargement
In addition to PH echo changes, what must be present on echo to identify LHD-PH?
- unequivocal LA enlargement
- signs of LHD (LV dysfunction or MV or AV disease)
List the 6 categories of PH classifications
Pulmonary hypertension
Vascular Occlusive disease
Left-heart disease
Respiratory disease
PTE
Parasites
Mxed
Fill in the blanks
What triscuspid regurgitation pressure gradient cutoff indicates at least moderate PH
> 46 mm Hg
What 2 breeds are predisposed to PH from interstitial lung disease?
West Highland White Terrier
Pekingese
What cardiac auscultation abnormalities may be heard with PH?
- right systolic murmur (TR)
- diastolic murmur if severe PH
- split second heart sound - takes longer to eject
Fill in the gaps
List 5 changes to thoracic radiographs indicative of PH
- tortuous/blunted/dilated pulmonary arteries
- Pulmonary trunk bulging
- assymmetric radiolycent lung fields on VD/DV
- patchy diffuse alveolar infiltrates
- R-sided cardiac enlargement
List 7 clinical changes indicative of HW disease
- hyperbilirubinemia
- Resp distress
- Coughing
- Exercise intolerance
- Ascites
- anemia
- collapse
Name 3 clinical changes indicative of Angiostrongylus disease
CNS signs
respiratory signs
bleeding diathesis
Name 8 risk factors (i.e. diseases) for PTE development
- IMHA
- PLN
- PLE
- heartworm disease
- hyperadrenocorticism
- sepsis
- neoplasia
- DIC
What are the 3 pathways leading to pulmonary arterial vasoconstriction?
- nitric oxide
- endothelin
- prostacycline
Name an alternative PDE5-i to sildenafil that has a longer half-life. Which medication is superior in clinical efficacy and outcome?
tadalafil
no difference in superiority of outcome
Explain the recommendations for PDE5-i administration in PH class 1d1
1d1 - congenital shunt
if left-to-right shunt –> occlusion is recommended and PDE5-i is not expected to make as much of a difference
if right-to-left –> initial PDE5-i therapy is thought to stabilize patient, may even reverse some shunt and may reduce risk of shunt occlusion
