Pulmonary hypertension (PH) refers to elevated pulmonary arterial pressure (PAP) and is commonly defined as a mean PAP ≥ 25 mmHg. The presence of PH does not indicate any specific pathological or physiological cause. This distinction is underestimated, leading to confusion in clinical practice and the medical literature. The prognosis of PH is predicted by the underlying cause, pathophysiology, and the interaction between the right heart and pulmonary circulation. The degree of PAP elevation itself is not the primary cause of the adverse effects of PH, and reducing PAP is not the goal of treatment. This contrasts with systemic hypertension, where high pressure itself causes many subsequent events such as chronic kidney disease and stroke, with treatment aimed directly at lowering systemic blood pressure. PH is common in adults with congenital heart disease (CHD). Nearly 6% of adults with coronary heart disease are diagnosed with PH; this subset of patients is at higher risk of hospitalization and death.1 More than one-third of complex hospitalizations for ACHD in the United States involve a diagnosis of PH.2 The epidemiology of PH associated with Congenital heart disease (PH-CHD), however, is poorly defined, with data based on widely disparate diagnostic techniques and definitions (detailed below). More importantly, PH is often confused with pulmonary arterial hypertension (PAH), which refers to PH characterized by elevated PVR but normal pulmonary venous pressure (Table 1). Although PH-CHD is stereotypically attributed to high PVR (eg, Eisenmenger syndrome), elevated pulmonary venous pressure, pulmonary disease, chronic thromboembolism, and extrinsic compression of pulmonary vascular structures are all contributors. currents. Therefore,...... middle of article ......ks citedLowe BS, Therrien J, Ionescu-Ittu R, Pilote L, Martucci G, Marelli AJ. The diagnosis of pulmonary hypertension in the adult population with congenital heart disease impacts outcomes. J Am Coll Cardiol. 2011;58:538-546.2. Opotowsky AR, Siddiqi OK, Webb GD. Trends in hospitalizations among adults with congenital heart disease in the United States J Am Coll Cardiol. 2009;54:460-467.3. Simonneau G, Gatzoulis MA, Adatia I, Celermajer D, Denton C, Ghofrani A, Gomez Sanchez MA, Krishna Kumar R, Landzberg M, Machado RF, Olschewski H, Robbins IM, Souza R. Updated clinical classification of hypertension pulmonary. J Am Coll Cardiol. 2013;62:D34-41.4. Wood P. Pulmonary hypertension with special reference to the vasoconstrictor factor. Brother Heart J. 1958;20:557-570.5. Wood P. Eisenmenger syndrome or pulmonary hypertension with reversed central shunt. I. Fr. Med J.. 1958;2:701-709.