Pulmonary Hypertension and Right Heart Failure
Classification and diagnosis
Pulmonary hypertension is classified into five groups: group 1 pulmonary arterial hypertension (PAH), group 2 left heart disease, group 3 lung disease/hypoxia, group 4 chronic thromboembolic disease, and group 5 multifactorial. Echocardiography estimates probability but cannot diagnose. Right heart catheterization is definitive: precapillary PH has mPAP >20 mmHg, PCWP ≤15 mmHg, and PVR >2–3 Wood units; postcapillary PH has PCWP >15 mmHg.
Treatment principles
Group 1 PAH uses risk stratification and combination therapy: endothelin receptor antagonists, PDE5 inhibitors, prostacyclin pathway agents, and riociguat. Vasoreactivity testing identifies the minority who respond to calcium-channel blockers. Group 2 PH is treated by optimizing HF therapy; PAH drugs are not routinely indicated and can precipitate pulmonary edema. Group 4 requires anticoagulation, pulmonary endarterectomy when operable, and riociguat for inoperable disease.
Right heart failure
Manage volume carefully-overdiuresis reduces preload, while fluid loading worsens RV dilation and tricuspid regurgitation. Avoid hypoxia, hypercapnia, and acidosis, which raise PVR. Maintain RV perfusion pressure, often with norepinephrine; inotropes support contractility. Pulmonary vasodilators may worsen systemic hypotension.
Traps
Do not diagnose PH from echo alone. Do not use PAH-specific therapy in group 2 disease without careful evaluation. Distinguish precapillary from postcapillary physiology before treatment.
Worked example
A scleroderma patient with RVSP 55 mmHg on echo undergoes RHC: mPAP 35, PCWP 10, PVR 6 Wood units-group 1 PAH. Start combination therapy and refer to a PH center. Rule of thumb: PCWP ≤15 indicates precapillary; >15 indicates postcapillary.