Introduction

Pulmonary arterial hypertension (PAH) represents a heterogeneous group of disorders sharing similar histological abnormalities and pathophysiology. PAH is deÞ ned as a disease characterized by a progressive increase of pulmonary vascular resistance (PVR) and pulmonary artery pressure (PAP), with a normal pulmonary artery wedge pressure (PAWP). These progressive abnormalities can lead to right ventricular failure secondary to increased right ventricular afterload and subsequent decline in right ventricular cardiac output.[1] The median survival from the time of diagnosis in patients with idiopathic pulmonary arterial hypertension (IPAH) before the availability of modern (target) therapy was 2.8 years.

Normal mean PAP (mPAP) is approximately 14 mmHg at rest. In PAH patients, the mPAP is greater than 25 mmHg at rest and/ or 30 mmHg during exercise. Such high pressure is associated with changes in the small blood vessels in the lung, leading to complex pathological sequences that Þ nally result in detrimental outcome.

In the last few years, there have been major improvements in our understanding of the mechanism of the disease and its pathophysiology, which subsequently led to signiÞ cant advances in the diagnostic processes and treatment options, which will be discussed in great details in this guideline.

Epidemiology and Natural History

The true incidence of IPAH is unknown. The rst reported case occurred in 1891, which described a patient who at autopsy showed thickening of the pulmonary artery but no heart or lung disease that might have caused the condition. In 1951, 39 subsequent cases were further reported, and the illness received its name - primary pulmonary hypertension.

The current estimated incidence of IPAH is 1-2 cases per 1 million persons in the general population. However, this is probably an underestimation of the disease, mainly because of under-diagnosing. In the United States, it has been estimated that 300 new cases of IPAH are diagnosed each year; most cases are reported in women between the ages of 21 and 40 years. Indeed, at one time the disease was thought to occur among young women almost exclusively, but recently it has been recognized, however, that men and women in all age ranges can develop IPAH. Apparently, the disease also affects people of all racial and ethnic origins equally.

For the complete information please download the pdf file at the top.