Flashcards in Twenty Nine Deck (18):
What is PVR like compared to SVR? What happens in hypoxia?
In keeping with these low pressures,
the walls of the pulmonary artery and its branches are
contain relatively little smooth muscle
Lungs accept whole cardiac output as PVR
resistance is only one-tenth that of the systemic
circulation in normal conditions
PVR increases with alveolar hypoxia because of
constriction of small pulmonary arteries
How is pulmonary hypertension clinically defined? What are the 5 different groups?
Mean pulmonary-artery pressure of more than 25
mm Hg at rest
Pulmonary arterial hypertension (PAH)
Pulmonary venous hypertension due to left heart disease
Pulmonary hypertension owing to lung diseases and/or
Chronic thromboembolic Pulmonary hypertension (CTEPH)
Pulmonary hypertension with unclear multifactorial
How is group I hemodynamically defined?
Mean pulmonary artery pressure(mPAP) > 25 mm Hg
Pulmonary Artery Wedge Pressure (PCWP) ≤ 15 mm Hg
Pulmonary Vascular Resistance (PVR) > 3 Wood units
What are the pathological changes in PAH?
Medial hypertrophy Intimal thickening
What is a genetic mutation associated with PAH? How does the genetic association work?
Mutations in bone morphogenetic protein type II
receptor (BMPR2) or activin receptor-like kinase-1
(ALK-1 are emerging as determinants of severity of
Mutations in BMPR2 have been reported in
more than 70% of subjects with 1 or more
affected relatives (heritable PAH)
Without any genetic component, even initiators of pulmonary hypertension won't do much, but with the mutation, an individual will be much more reactive to the initiators.
What are various vascular mediators of PAH? Why are these significant?
decreased NO, decreased PGI2, Increased endothelin
They are what the drugs target.
What are some presenting symptoms of PAH? How is the diagnosis of IPAH made? What will be seen on Xray? What is the best tool for screening for PAH? What is the gold standard for diagnosing PAH?
IPAH is by exclusion
Enlarged pulmonary arteries
Screening with echocardiogram/doppler is the best tool for screening
Estimates the RA-RV pressure gradient
- measures the tricuspid systolic peak velocity (TR)
Using a modified Bernoulli equation
Right heart catheterization (RHC) is the gold standard.
What are the 4 functional classes of PAH?
I=no physical limitations
II=Feel symptoms in ordinary physical activities
III=feel symptoms in less than ordinary phys. activities
IV=Signs of RV damage, feel symptoms at rest.
What recommendations are there in PAH concerning diuretics? Cardiac glycosides? Pregnancy?
symptomatic and clinical benefits in the treatment of
right heart failure
In recent RCTs with new treatments, approximately
50% to 70% of patients were treated with diuretics
Digoxin incr. CO in IPAH
Efficacy not known
Should be avoided, or termination recommended. Level of Evidence: Good; Net Benefit: Substantial; Grade of
We will need larger series before the general recommendation to avoid pregnancy in all patients with PAH is reconsidered
When is anticoag recommended in PAH? Explain?
Recommended in patients with
PAH due to anorexigens
In situ microscopic thrombosis
RV failure venous stasis at increased risk for PE
Improved survival with oral anticoagulation in IPAH
When are calcium channel blockers recommended? Explain?
Useful in the following situations –
1. Absence of R heart failure
2. Demonstration of acute vasoreactivity
Smooth muscle hypertrophy
Contribute to the pathogenesis
Should oxygen be given in PAH? Explain.
Supplemental oxygen should be used as
necessary to maintain oxygen saturations
at > 90% at all times
If hypoxemia is severe investigate for Right to Left shunt due to the reopening of a PFO
worsens pulmonary hypertension by vasoconstriction
Contributes to the development and/or progression of PAH
What medications target the NO pathway in treating PAH?
Phosphodiesterase type 5 inhibitors (PDE5) inhibitors
Soluble guanylate cyclase stimulators( sGC
Riociguat – oral
What medications target the PGI2 pathway in treating PAH?
Epoprostenol - IV
Trepoprostinil – IV, subcutaneous, inhaled and oral
Iloprost – inhaled
Beraprost- oral . Approved in Japan.
What medications target the endothelin pathway in treating PAH?
Endothelin Receptor Antagonists
When is lung transplantation recommended for PAH? How is it done?
The advent of disease targeted therapy for severe PAH
has reduced and delayed patients referral for lung
Important option for those who fail medical therapy
and remain in WHO-FC III or IV
SINGLE LUNG TRANSPLANTATION
What is BAS? When should it be performed? What does it accomplish? How should it be performed?
Balloon Atrial Septostomy (BAS)
The creation of an interatrial right-to-left shunt can
decompress the right heart chambers, and increase left
ventricle pre-load and cardiac output
BAS should be regarded as a palliative or bridging
To be performed only by centers with experience in the