Atrial septal defect is the most common type of hole in the heart encountered in adults. In many cases, the patients do not have any symptoms or difficulties. Are there any studies to show that there is an advantage of closing such defects (either surgically or using devices inserted through the skin) when incidentally found in adults? Does closure improves longevity or reduces future heart-related illnesses? Thanks for your insight.
While not all patients with an atrial septal defect experience, complications, but it can be beneficial to surgically repair the defect to prevent future complications that could occur.
Sometimes children with an atrial septal defect will not need surgery as the defect may close itself, but if the hole is large and is determined to be likely to cause problems as an adult, the doctor will usually recommend surgery to prevent possible future complications. This does not really answer your question, though, as you specifically ask about atrial septal defects in adults.
By the time they are adults, patients with an atrial septal are likely to start showing symptoms, unless the hole is very small (smaller than 5 millimeters). Studies on patients who have begun to show symptoms show that it is generally beneficial to close the atrial septal defect and can improve the life span in adults and help to prevent further complications, especially in younger patients, usually those younger than 25, while the symptoms may still be nearly non-existent. Even though the closure is not as beneficial to older patients, it is still usually recommended when there are symptoms.1, 2, 3
Though the results shown from those studies mentioned above, it can be reasoned that closing an atrial septal defect in a patient in which the defect was found incidentally can be beneficial. Having a very small defect will not typically cause the symptoms associated with atrial septal defects and usually a doctor will not recommend surgical closure of the defect. If a larger defect is found incidentally and any symptoms have yet to occur, then it would be logical to the hole closed. This will help prevent the complications that could occur later in your life and is likely to increase your overall life-quality and lengthen your lifespan.
Agree with @michaelpri regarding some of the timing considerations and the overall sense of factors affecting whether closure is necessary.
As to how ASDs cause harm, the usual effect is one of blood shunting from the left heart to the right heart through the ASD. Over time, this increases the filling volumes of the right heart and can lead to right heart failure as the right heart is pumping some excess volume of blood in a circuit from the right heart to the left atrium, back to the right atrium via the ASD and, ultimately, back to the right ventricle again. In this fashion, left ventricular filling can also be decreased, but generally no penalty on systemic circulation occurs, except in extreme cases.
Asymptomatic patients may have a closure depending on the size of the ASD and its specific location. There are studies underway to better understand when to close ASDs.
Konstantidides, et al. A Comparison of Surgical and Medical Therapy for Atrial Septal Defect N Engl J Med 1995; 333:469-473.
See also an editorial challenging the methodology of the above study:
C. Ward and R.A. Henderson. Correspondence. N Engl J Med 1996; 334:56-57