Prevalence and incidence of pulmonary arterial hypertension (PAH) in congenital heart disease (CHD) in Belgium; developing detection methods of preclinical PAH; and influencing clinical outcome by early treatment of pulmonary vascular disease.

Pulmonary arterial hypertension (PAH) in patients with congenital heart disease (CHD) implicates considerable morbidity and mortality. Through the unique Belgian Registry on Adult CHD, we first want to identify the prevalence and incidence of PAH in CHD. Also predictors of the development of PAH and long-term outcome will be defined.
 
Secondly, we would like to track these CHD patients who were discharged from follow-up in the past, but still prone to develop PAH later in life. Based on local database analysis, we identified around 1000 unreported patients, who might impact substantially the true prevalence and incidence of PAH.
 
Our research group showed earlier that, although pulmonary artery pressures seem to be normal at rest after late atrial septal defect closure, an abnormal increase in pulmonary vascular resistance during exercise is found. We hypothesize that patients who present with such mild pulmonary vascular disease may develop PAH and have impaired prognosis. We aim to develop an early detection method of PAH and want to investigate whether selective pulmonary vasodilators may alter outcome of these patients.

Lastly, in collaboration with the Centre for Human Genetics, we aim to look for a genetic link between CHD patients and the development of PAH. Remarkably, some patients develop PAH and others do not. Therefore, we believe that not only hemodynamic, but also genetic factors determine this clinical variability. Genetic screening could then be used as an additional detection tool for PAH in a preclinical stage, with new opportunities for prevention or early treatment.
 
Our research hypothesis:
We believe that the combination of environmental risk factors and a genetic predisposition leads to the development of early PVD (detectable by bicycle stress echocardiography). This early PVD may evolve to morphometric changes of the right heart and/or PAH development, and in the longer run to complications as arrhythmias and right heart failure. Early detection and treatment of pulmonary vascular disease could neutralize or at least slow down this pathophysiological process and perhaps prevent the development of PAH and its associated morbidity and mortality.