Flashcards in Clinical Pulmonary HTN Deck (23):
When does a pt have clinical pulmonary HTN?
mean pulmonary arterial pressure is greater than 25 mm Hg at rest.
*mean arterial pressure= SPAP + (2DPAP/3)
What are some causes of pulmonary HTN?
- connective tissue disease (scleroderma, RA, SLE)
- pulmonary veno-occlusive disease
- portal HTN
- sickle cell
**** What are the 5 groupings of the WHO classification for diagnosis of pulmonary HTN?
1. vascular problems alone= proliferation of intima and media (idiopathic/primary; BMPR2 association).
2. left heart disease= systolic dysfunction, diastolic dysfunction, or valvular disease.
3. lung disease= COPD, interstitial lung disease, restrictive disease, sleep disorders, high elevations...
4. unresolved clots
5. everything else= myeloproliferative disorders, splenectomy, sarcoidosis, neurofibromatosis, vasculitis...
**** What are the 3 main processes of pulmonary HTN pathophysiology?
1. increase in vasoconstrictors (endothelin-1, thromboxance A2, and serotonin) and decrease in vasodilators (prostacyclin, NO, vasoactive peptide).
2. smooth muscle and endothelial cell proliferation (VEGF, endothelin-1, and serotonin).
3. in situ thrombosis (increased thomboxane A2, serotonin, and plasminogen activator inhibitor-1).
**** So what are the important mediators and therapeutic targets?
- DECREASED prostacyclin (so we want to increase this)
- INCREASED endothelin 1 (so we want to decrease this)
- DECREASED NO (se we we want to increase this)
How do pts with pulmonary HTN present clinically?
- dyspnea, exertional syncope due to hypoxia and decreased CO, exertional chest pain due to right ventricular ischemia, hemoptysis, peripheral edema from right-sided CHF, and abdominal fullness.
What will you find on physical exam?
- pertinent findings include prominent pulmonic heart sound.
- right-sided S4
- pulmonary artery "tap and flow" murmur
- Graham Steell murmur of pulmonary regurg
- tricuspid regurg
- digital clubbing
- increased JVD
- peripheral edema
What DX studies should we consider?
CXR, EKG, echo, PFTs, CT chest, V/Q scan, sleep oximetry/nocturnal polysomnogram, cardiac cath, ANAHIV, LFTs, CVC, 6 min walk test
** What will you see on CXR?
dilatation and pruning of pulmonary arteries and/or enlargement of the right atrium and ventricle
** What will you see on EKG?
- right axis deviation= QRS in lead I is predominantly negative.
- RBBB= rabbit ears in V1, V2
- right atrial enlargement= large p wave in lead II
- right ventricular hypertrophy= large R wave in V1
** What will you see on echocardiogram?
- increased right ventricular systolic pressure (estimated from TR jet).
- bowing of septum toward left ventricle
- you can also see tricuspid and/or pulmonic regurg with doppler
**** For what reason and what grouping are PFTs useful?
to prove lung disease as a cause of pulmonary HTN (group 3)!!
** What is cardiac catheterization?
float a balloon directed catheter through a central line, through the heart and out into the pulmonary artery. This allows us to measure the right atrial pressure, right ventricular pressure, and the pulmonary artery pressure directly. We can also measure the left heart pressures using the pulmonary capillary wedge pressure (less than 15 excludes pulmonary venous hypertension).
**** What do we do after making the diagnosis of pulmonary HTN?
1. look at echo to see if it is due to left sided heart disease.
2. if not look at echo to see if it's congenital
3. if not consider CT disease or HIV infection by ordering sed rates and serology.
4. if not do V/Q scan to see if its chronic PE
5. if V/Q scan is suspicious, do an angiogram
6. if V/Q is normal, consider intrinsic parenchymal disease or some state of hypoxia hypoxia.
7. then look at CT scan, PFTs and blood gases
8. if all of these are normal, you are left with idiopathic pulmonary HTN
9. do 6 min walk test to monitor pt's status
10. do pulmonary wedge pressure to document specific pressures.
How do we treat, overall?
- prevent and reverse the vasoactive imbalance and vascular remodeling.
- prevent RV failure
- treat underlying cause of pulmonary HTN
**** How do we treat based on groupings?
- group 1= prostanoids, endothelin receptor antagonists, PDEIs, and calcium channel blockers (Nifedipine).
- group 2= treat the heart disease
- group 3= treat the respiratory illness and utilize supplemental O2.
- group 4= anticoagulation to dissolve the clots and surgical thromboendarterectomy if you don't get clot resolution. Riociguat= new drug that may be considered
- group 5= treat that underlying illness
What are the supportive therapies?
- dobutamine and inhaled NO
How do we test to see if a pt should be placed on a calcium channel blocker?
acute vasoreactivity test= inhaled NO, adenosine, or prostacyclin. If you lower the pulmonary artery pressure using this, then go ahead and put the pt on Nifedipine.
What are the other vasodilators besides calcium channel blockers that can be considered?
- IV prostacyclin= decreases platelet aggregation and smooth muscle proliferation
- prostacyclin analogues (ex. inhaled iloprosat, subcutaneous treprostinil, or oral beraprost)= easier to take and no central venous catheter side effects.
- endothelin-1 antagonists (ex. bosentan or ambrisentan), but contraindicated in liver disease.
- PDEIs (ex. sildenifil)= increase cGMP leading to increased NO and vasodilation.
- Riociguat (new drug)= stimulates NO receptor
What procedure can be done for refractory pulmonary HTN?
- balloon atrial septostomy= creation of R to left shunt (however will worsen hypoxia).
- lung transplant
** How do we know what drugs to pick?
based on NY heart association class:
- class 1 (asymptomatic)
- class 2 (asymptomatic at rest but symptomatic with physical activity)
- class 3 (asymptomatic at rest but symptomatic with less-than-ordinary effort)
- class 4 (symptomatic at rest)
**** What treatment option do we pick based on the NY heart association class?
- class 2= Nifedipine if vasoreactive; PDEI or ERA if not vasoreactive.
- class 3= Nifedipine if vasoreactive; PDEI, ERA or prostanoids if not vasoreactive.
- class 4= parenteral prostanoids or combination therapy early if RV dysfunction; PDEI, ERA or prostanoids otherwise