ESSENTIALS OF DIAGNOSIS
Mean PA pressure ≥ 25 mm Hg.
Dyspnea and often cyanosis.
Enlarged pulmonary arteries on chest radiograph.
Elevated JVP and RV heave.
Echocardiography is often diagnostic.
The normal pulmonary bed offers about one-tenth as much resistance to blood flow as the systemic arterial system. Based on the 2019 Sixth World Symposium on Pulmonary Hypertension, the definition of pulmonary hypertension was changed. It was defined by a mean PA pressure of 20 mm Hg with a pulmonary vascular resistance of greater than or equal to 3 Wood units. Three categories were then defined:
Precapillary pulmonary hypertension: mean pulmonary artery pressure greater than 20 mm Hg, PVR greater than or equal to 3.0 Wood units, PCWP less than or equal to 15 mm Hg
Isolated post-capillary pulmonary hypertension: mean pulmonary artery pressure greater than 20 mm Hg, PVR less than 3.0 Wood units, PCWP greater than 15 mm Hg
Combined pre- and post-pulmonary hypertension: mean pulmonary artery pressure greater than 20 mm Hg, PVR greater than or equal to 3.0 Wood units, PCWP greater than 15 mm Hg
The clinical classification of pulmonary hypertension by the Sixth World Symposium on Pulmonary Hypertension is outlined in Table 10–18.
Table 10–18.Updated classification of pulmonary hypertension (PH). ||Download (.pdf) Table 10–18. Updated classification of pulmonary hypertension (PH).
Pulmonary arterial hypertension (PAH)
Drug- and toxin-induced PAH
PAH associated with connective tissue disease, HIV infection, portal hypertension, congenital heart disease, schistosomiasis
PAH long-term responders to calcium channel blockers
PAH with overt features of venous/capillaries (PVOD/PCH) involvement
Persistent PH of the newborn syndrome
PH due to left heart disease
Due to heart failure with preserved LVEF
Due to heart failure with reduced LVEF
Valvular heart disease
Congenital/acquired cardiovascular conditions leading to post-capillary pulmonary hypertension
PH due to lung diseases or hypoxia (or both)
Obstructive lung disease
Restrictive lung disease
Other lung disease with mixed obstructive/restrictive pattern
Hypoxia without lung disease
Developmental lung disorders
PH due to pulmonary artery obstructions
Chronic thromboembolic pulmonary hypertension
Other pulmonary artery obstructions
PH with unclear or multifactorial mechanisms
Systemic and metabolic disorders
Complex congenital heart disease
Group I includes pulmonary arterial hypertension (PAH) related to an underlying pulmonary vasculopathy. It includes the former “primary pulmonary hypertension” under the term “idiopathic pulmonary hypertension” and is defined as pulmonary hypertension and elevated PVR in the absence of other disease of the lungs or heart. Its cause is unknown. About 6–10% have heritable PAH. Clear genetic patterns have been identified that result in a derangement in one or more biologic pathways, and these result in so-called ...