Holes in the heart are among the most frequent congenital heart defects. They occur most frequently between the heart chambers and between the atria. Likewise, it is rarely the case that the prenatal connection between the aorta and the pulmonary artery, the so-called ductus arteriosus, does not close properly after birth. Heart defects that are mild by comparison feature so-called shunts, that is, passageways in the heart, that allow for greater amounts of blood than usual to flow across the lung at once.

Such passageways are able to be closed easily today. Usually, the patients are “heart-healthy” and show a normal exercise capacity after the corrective intervention. However, regular medical follow-up remains necessary also after successful correction. This was able to be demonstrated in a recent study of the National Register for Congenital Heart Defects.

How Does Pulmonary Hypertension Develop?

Pulmonary hypertension is a rare, life-threatening disease. It can be caused by congenital holes in the heart, among others. Between five and ten percent of affected patients are estimated to develop pulmonary hypertension in the course of their life. They face an increased risk of premature death. This risk is known to be significantly higher in cases of uncorrected atrial septal defect (ASD), ventricular septal defect (VSD) or patent ductus arteriosus (PDA), as compared to corrected defects. Corrective treatment at a young age prevents the stronger blood flow from causing lasting damage to the tender vessels, thus preventing a lasting increase of the blood pressure in the pulmonary circulation.

Risk despite Correction

Does closure avert the risk? Scientists assume that an increased risk remains also after corrective treatment. According to a Dutch study, it is at around seven percent. A more extensive study investigating this matter is still pending, however. What would the findings in a nationwide long-term observation based on regular examination visits be in the investigated patient group? This research gap has now been closed by a research team led by pediatric cardiologist Astrid Lammers at the University Hospital of Münster.

Long-term Course was Investigated in 825 Patients

By providing donated data of more than 55,000 participants, the National Register served as the research basis. The research team analyzed the data of 825 patients aged 16 years and older who were born with a hole in the heart that had been treated via catheter intervention or surgery during childhood. Patients with other heart defects or genetically caused diseases were deliberately excluded. In just over half of the included patients (52 percent), a hole in the septum between the atria had been closed, 41 percent had a hole in the septum between the two heart chambers and seven percent had a patent ductus arteriosus.

A Rare Sequela, but not Harmless by Far

This was the result: Contrary to what was previously assumed, pulmonary hypertension occurs significantly less frequently in this patient group. Only three percent of the patients developed pulmonary hypertension as a secondary disease. However, the risk increases over life. In this connection, the age of patients at the time of corrective treatment also plays a role. The older a patient is at the time of the corrective treatment for the congenital heart defect, the higher the likelihood is of developing the said secondary disease. In addition, pulmonary hypertension leads to more severe symptoms and an increased risk of premature death with increasing age. “We therefore strongly recommend lifelong specialized cardiology follow-up for the patients in question in order to allow for an early diagnosis of the pulmonary hypertension and for initiating appropriate treatment,” Astrid Lammers states, summarizing the recommendation of the scientists involved in the study.

The study was funded by Actelion.