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ATPase: adenosine triphosphatase

BMPR2: bone morphogenetic protein receptor type 2

[Ca2+]cyt: cytosolic free Ca2+ concentration

CCB: calcium channel blocker

COPD: chronic obstructive pulmonary disease

CTEPH: chronic thromboembolic pulmonary hypertension

CYP: cytochrome P450

DAG: diacylglycerol

EC: endothelial cell

ECE: endothelin-converting enzyme

EGF: epidermal growth factor

ERA: endothelin receptor antagonist

ET: endothelin-1

FDA: Food and Drug Administration

HCN: hyperpolarization-activated cyclic nucleotide–gated

HIV: human immunodeficiency virus

HPAP: heritable pulmonary arterial hypertension

HPV: hypoxic pulmonary vasoconstriction

5HT: serotonin

IP3: inositol triphosphate

IPAH: idiopathic pulmonary arterial hypertension

IPR: prostacyclin receptor

LV: left ventricle

mGC: membrane guanylate cyclase

6MWT: six-minute walk testing

NO: nitric oxide

NO2: nitric dioxide

NYHA: New York Heart Association

PA: pulmonary artery

PAEC: pulmonary arterial endothelial cell

PAH: pulmonary arterial hypertension

Pao2: partial pressure of arterial O2

PAOP: pulmonary artery occlusion pressure

PAP: pulmonary arterial pressure

PASMC: pulmonary artery smooth muscle cell

PDE: phosphodiesterase

PDGF: platelet-derived growth factor

PGI2: prostacyclin, prostaglandin I2

PH: pulmonary hypertension

PIP2: phosphatidylinositol 4,5-biphosphate

PKA: protein kinase A

PKG: protein kinase G

PLC: phospholipase C

PVR: pulmonary vascular resistance

RAP: right atrial pressure

ROC: receptor-operated Ca2+ channel

RV: right ventricle

RVF: right ventricular failure

RVH: right ventricular hypertrophy

RVSP: right ventricular systolic pressure

sGC: soluble guanylate cyclase

SR: sarcoplasmic reticulum

SVR: systemic vascular resistance

TKR: tyrosine kinase receptor

TxA2: thromboxane A2

VDCC: voltage-dependent Ca2+ channel

VEGF: vascular endothelial growth factors

VIP: vasoactive intestinal peptide

VSM: vascular smooth muscle


The pulmonary circulation plays a unique and essential role in gas exchange and, in particular, oxygenation of venous blood. It is a low-resistance and low-pressure circulatory system; the mean PAP in a healthy man is about 12 mm Hg. PAP is a function of CO and PVR. PH is defined as the mean PAP of 25 mm Hg or greater at rest. In patients with PH, pressure overload (i.e., increased afterload) places additional stress on the RV, leading to RV dysfunction and hypertrophy, and in some cases right heart failure. Patients present with a range of symptoms, including dyspnea, fatigue, chest pain, and syncope. PH is a complication of many chronic diseases and is estimated to affect as much as 10%–20% of the general population (McLaughlin et al., 2009).

Pulmonary Hypertension Classification

Pulmonary hypertension is a primary disorder of the pulmonary vasculature and a complication of other cardiopulmonary, vascular, and inflammatory diseases. Based on shared pathophysiological and pathological characteristics as well as response to therapies, PH can be classified into five groups (Simonneau et al., 2013):

  1. PAH

  2. PH owing to left heart disease

  3. PH owing to lung diseases or hypoxia

  4. Chronic thromboembolic PH

  5. PH with unclear multifactorial mechanisms

Pulmonary Arterial Hypertension

Pulmonary arterial ...

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