Die pathophysiologischen und -biologischen grundlagen der pulmonal-arteriellen hypertonie bei angeborenen Herzfehlern

Pulmonary arterial hypertension (PAH) is still an important cause of morbidity and mortality, and is commonly associated with congenital heart disease (CHD). The prevalence of PAH-CHD has fallen in developed countries over recent years and the number of patients surviving into adulthood has increased markedly. The vast majority of PAH-CHD patients present with congenital cardiac shunts. Patients with uncorrected cardiac defects with primary left-to-right shunting are at risk of developing PAH, owing to the increased shear stress and circumferential wall stretch induced by increased pulmonary blood flow, and sometimes also with an increased pulmonary artery pressure load, which leads to endothelial dysfunction and progressive vascular remodeling and thereby to increased pulmonary vascular resistance. The most advanced form of PAH-CHD is Eisenmenger's syndrome which is characterized by a reversal of the shunt and cyanosis. The anatomical, pathological and structural abnormalities occurring in the pulmonary circulation of these patients are similar to those observed in other forms of pulmonary arterial hypertension. PAH results in increased pressure load to the right heart and a chronic adaptive hypertrophic response to increased right ventricular afterload, which may lead to right ventricular dysfunction and failure. Therefore the right ventricular function is an important determinant of the long-term prognosis of patients with PAH-CHD.