# Pulmonary Hypertension

PVR = (mPAP - PCWP) / CO.   (V=IR)

rearranges to: 

mPAP = (PVR * CO) + PCWP  <= increase each leads to mPAP (exercise, anemia for CO) 

Definition: pHTN = 21+ mmHg

1. PAH: PVR over 3.0, PCWP under 15. iPAH (idiopathic), aPAH (associated: SSC, HIV, asd/vsd, etc), hPAH (heritable)
2. L Heart: PCWP over 15. Echo hints - large atria, diastolic dysfxn
3. Lung dz: co-occuring with ILD, COPD, OSA/OHS, etc. 
4. CTEPH
5. Grab bag that we don't understand (e.g. sarcoid) 

"pHTN by echo" to avoid implication that a formal workup has been done to split into a WHO group. 

####Shunt
Left to right: R Heart cath can be used to measure oxygen step up between chambers (if more than 7-8% increase, signficant) 

Right to left: echo bubble study measures. 

Important to differentiate: PFO is a 1-way valve and will not allow left to right shunting

###Treatments

beneficial for iPAH +/- CTEPH that is nonsurgical. 3 pathways: 

1. NO (Nitric Oxide) - all oral - viagra, riocigual. 
2. Endothelin - all oral - macitentan, ambrisentan
3. Prostacyclin - oral/inh/iv/sq - e.g. flolan