Pulmonary hypertension

Today we discussed pulmonary hypertension (or, we at least had a "tangent"... on it.)
This is an important clinical entitiy to have an approach to both in terms of physical findings and the workup required to determine the etiology. Some considerations:

Defined as mean PA pressure over 25mmHg at rest with mean LA or wedge pressure below 15 (i.e. no LV dysfunction)

May be primary (idiopathic) or secondary.

May occur from disease anywhere in the following circuit:
PA, lungs, PV, LA, MV, LV

1) Pulmonary artery- luminal (PE), mural (PPH), extramural (tumor)
Clinically and patologically indistinguishible from primary pulm HTN are cases associated with the following: anorexigens (diet pills), cocaine, HIV, rheumatologic diseases (esp CREST/scleroderma), portal HTN

2) Lungs- chronic obstructive and restrictive diseases can cause PHTN through hypoxic vasoconstriction. Interstitial lung disease can also cause destructive changes to pulmonary vasculature, leading to PHTN and cor pulmonale.

3) PV- veno-occlusive disease

4) Cardiac- L CHF- usually causes relatively minor PHTN. Mitral stenosis can cause severe PHTN. Shunts (ASD, VSD) cause higher R-sided pressures. Increased PA flows cause changes in PA structure and subsequent reversal of flow (Eisenmenger's)

Clinical features:

Hx: Sx of heart or lung disease, HIV RFs, Sx suggestive of CTD, esp scleroderma, anorexigens, PE symptoms, Fhx (in 5% of pphtn), snoring/OSA, rheumatic heart disease

P: Loud P2, RV lift (L parasternal), R-sided S4, TR murmur (holosystolic, louder on inspiration), edema, high JVP. A murmur of pulmonic insufficiency called the "Graham Steell murmur" is described (early diastolic, decrescendo, increased on inspiration). Look for findings suggestive of secondary causes including scleroderma, HIV, primary lung disease, etc.

Investigations:
ECG- RAE, RVH with strain (i.e. tall R and small S with R/S over 1 in V1)
CXR- enlarged R hilum, dilated PA (over 14mm in females, over16mm in males)
Echo- RVSP (approximaes PA systolic). Should be less than 40.
PFT/ABG
High resolution CT +/- VQ scan
Possible R heart cath to determine pressures directly

Link:
Click here for an excellent JAMA "grand rounds" discussion on pulmonary HTN