Comment
Atrial septal aneurysms are rare, but the range of their prevalence is due to variations in ASA diagnostic criteria, materials, methods, diagnostic equipment, study populations and recognition by echographers.1 These aneurysms are often associated with other cardiac anomalies such as an intraarterial shunt, atrial septal defect type II, PFO, valvular prolapse, etc.2Complications of ASA include cerebrovascular events, arrhythmia and pulmonary hypertension. Even among these, candidates for surgical repair of ASA and reports about the surgery of ASA are very rare. Stroke is one of the worst complications of ASA. Mattioli et al. reported that ASA is the only potential cardiac source of embolism detected by transesophageal echocardiography in patients aged < 45 years.3 Cabanes et al. reported that PFO and ASA are significantly associated with stroke in adults aged < 55 years.4 On the other hand, Shinohara et al. described a thrombus attached to the left side of an atrial septal aneurysm that disappeared under anticoagulation therapy, but the aneurysm was eventually excised and repaired with an atrial patch because of risk of recurrent thrombus and a need for lifelong anticoagulation therapy.5 The thrombus that was attached to the left side of the ASA pouch in our patient disappeared with anticoagulation therapy. However, we identified a PFO next to the ASA during surgery. Because our patient was at risk for cardiogenic embolism with intraatrial thrombi and PFO, we decided on surgical management of the ASA. Interatrial shunts are similar complications of ASA, and their prevalence is 54.4% – 77%. One risk of cardiogenic embolism with ASA is the intraatrial shunt.2,6 Although holes were not found in the atrial septal wall of our patient, pathological and macroscopic findings showed that parts of wall were so thin that rupture seemed imminent. The cause of the interatrial shunt in our patient remains obscure, but it might have been due rupture of the weakened atrial septal wall due to long-term bulging and stretching. Atrial tachyarrhythmias are also complications of ASA, with a prevalence of 18% – 25%.1,2,7 The cause of arrhythmias in patients with ASA is not clear, but cardiac abnormalities might be responsible, such as hypertension, atrial enlargement, systolic dysfunction, or valvular prolapse.1 Although atrial tachyarrhythmias in patients with ASA are not a risk for cardiac embolism per se, ASA does confer thromboembolic potential, and long-term anticoagulant therapy is indicated for patients with ASA and a history of embolic events.2,6The incidence of mitral valve prolapse associated with ASA is 12% – 20.5%,1,2,7,8 and the cause is also unclear. Mitral valve prolapse and ASA might have a similar pathological basis, namely, a connective disorder involving fibrous cardiac tissue1. The connective tissue of an ostium primum atrial septal defect can become defective, especially when patients have myxomatous degeneration of the mitral valve. As a result, a weakened atria1 septum might lead to outpouching of the atrial septal wall4. Taking into consideration these factors, echocardiography did not reveal mitral valve prolapse or regurgitation in our patient, but our patient has a potential risk of a mitral valve prolapse.