Incidence and predictors of atrial septal defect after percutaneous transvenous mitral commissurotomy - a transesophageal echocardiographic study of 209 cases.

BACKGROUND: The incidence of atrial septal defect (ASD) after percutaneous transvenous mitral commissurotomy (PTMC) ranges from 15.2% to 92% in small studies. AIM: To estimate the incidence of atrial septal defect (ASD) following PTMC and to determine the factors contributing to its development. METHODS: We studied 209 patients with mitral stenosis (MS) undergoing PTMC. Transesophageal echocardiography (TEE) with color Doppler examination was performed to detect ASD. RESULTS: TEE demonstrated ASD in 139 (66.5%) of 209 patients. The mean diameter of the interatrial septal defect detected by TEE was 4.47 ± 1.7 mm. The most common site of septal puncture was the inferior vena caval side of the interatrial septum followed by fossa ovalis. Color flow imaging across the defect showed left to right shunting in all the patients (100%). We examined the relationship of age, Wilkins score, left atrial volumes, the mitral valve orifice area, mitral valve gradient, and the degree of mitral and tricuspid regurgitation between the group that developed ASD and the group without ASD and found that none of these factors predicted the development of ASD. A residual ASD was seen in 11 patients (8.7%) at 6-month follow-up. CONCLUSION: Incidence of residual atrial septal defect immediately following PTMC by TEE color flow Doppler imaging is 66.5%. Surrogate markers of elevated left atrial pressures do not determine the development of atrial septal defect after PTMC. The majority of the defects close spontaneously and a residual defect is observed in 8.7% patients at 6 months.