Mitral regurgitation detected during the intraoperative period after atrial septal defect closure: a case report

Atrial septal defect (ASD) is a congenital cardiac defect often diagnosed in adult patients. Mitral regurgitation (MR) observed in ASD patients mostly improves after ASD closure. However, a subset of adult ASD patients present new-onset MR or aggravation of preexisting MR after ASD closure. Intraoperative MR aggravation after surgical ASD closure is a rare occurrence which has not been reported in the literature to date. A 54-year-old woman was referred to our center due to large secundum ASD with a diameter of 17 mm which was incidentally detected on pre-operative echocardiography at a local clinic. Surgical repair of ASD under mini-thoracotomy was performed. After completion of the operation, intra-operative transesophageal echocardiography showed newly developed Grade II MR which subsequently deteriorated to severe level on postoperative day 3. Because the patient was asymptomatic, we decided to observe closely and treat conservatively with diuretics. Thereafter, echocardiography was evaluated on postoperative day 10 and MR disappeared to trivial level. Intraoperative MR aggravation is a rare complication following ASD closure. The possibility of MR aggravation should be evaluated in all ASD patients prior to surgery. This case highlights the importance of mitral leaflet examination after ASD closure for early detection of MR.