CONCOR, an Initiative Towards a National Registry and DNA-bank of Patients with Congenital Heart Disease in the Netherlands: Rationale, Design, and First Results

Introduction: Survival of patients with congenital heart disease has dramatically improved after surgical repair became available 40 years ago. Instead of a mortality of 85% during childhood following the natural course, over 85% of these infants are now expected to reach adulthood. However, data on long-term outcome is scarce due to the lack of large, national registries. Moreover, little is known about the genetic basis of congenital heart defects. In 2000, the Interuniversity Cardiology Institute of the Netherlands and the Netherlands Heart Foundation have taken the initiative to develop a national registry and DNA-bank of patients with congenital heart disease in the Netherlands named CONCOR.

Objectives: The aims of the CONCOR project are to facilitate investigation of the prevalence and long-term outcome of specific congenital heart defects and their treatment, to develop an efficient organisational structure for the improvement of healthcare for patients with congenital heart disease, and to allow investigation of the molecular basis of congenital heart defects.

Methods: After informed consent, research nurses enter data of participating patients into the CONCOR database using a web application. Data is transferred over the Internet via a secure connection. About 20 ml blood is withdrawn from the patient, and the DNA is isolated and stored. From each participating patient family history on congenital heart disease is obtained.

Results: Within two and a half years more than 4200 patients have agreed to participate. More than 99% of the patients that were asked have given their consent to participate in CONCOR. From 60% of these patients DNA has already been obtained. Mean age of the patients included is 34 years; more than 85% of the patients are younger than 45 years. Late complications occur frequently and the incidence increases with advancing age. 18% of the patients are known with supraventricular or ventricular arrhythmias. 2% of the included patients suffered a cerebrovascular accident, 139 (3%) had endocarditis. 6% of the patients has pulmonary hypertension or Eisenmenger syndrome. More than 15% of the patients reported an affected family member with congenital heart disease in the first, second, or third degree. 6% has an affected first-degree relative, and 4% a second-degree relative. Already 10 research projects have started using the CONCOR data and DNA.

Conclusion: The population of patients with congenital heart disease is young and rapidly growing. Late complications occur frequently and the incidence increases with advances age. The CONCOR registry and DNA-bank facilitates research on prevalence and long-term outcome and allows investigation of the molecular basis of congenital heart disease.