Pulmonary Hypertension (PH)
PH is defined as mPAP > 20 mmHg + PVR ≥ 2 Woods Units.
Hemodynamic Definitions
| Group | mPAP | PVR (Woods Units) | PCWP | Causes |
|---|---|---|---|---|
| Isolated pre-capillary | >20 | ≥2 | ≤15 | PAH, PH from lung disease, CTEPH, unclear/multifactorial |
| Isolated post-capillary | >20 | <2 | >15 | Left heart disease, unclear/multifactorial |
| Mixed pre and post-capillary | >20 | ≥2 | >15 | Left heart disease, unclear/multifactorial |
PVR = (mPAP - PCWP)/CO (in Dynes) Woods Units = Dynes/80
- PH defined as mPAP > 20 mmHg
- old definition: PVR > 3 Woods units, now >2 Woods units (2022)
- Normal mPAP is 14 +/- 3 mmHg in normal populations.
- Pre- vs post-capillary: breakpoint PCWP is 15 mmHg.
Classification of PH
Group 1
Vasodilator responder patients (low %) typically have very severe disease, but have remarkable clinical and hemodynamic response to high dose CCB (nifedipine) with significant prognostic implications.
Group 1 PAH is a disease (mostly) of vascular proliferation and obliteration, rather than (rarely) vasoconstriction. I.e. it is a vasculopathy driven by underlying condition.
Group 2
Increased LA pressures, increases pulm venous pressures, and in genetically predisposed individuals leads to increased pulmonary pressures and congestion.
Diagnosis of PH
Consider screening for CTEPH for patients with (1) moderate to severe PH/RV dysfunction with heart/lung disease, (2) or no heart/lung disease confirmed.
