Evaluation of Left-Right Shunting After Balloon Mitral Valvotomy: A Transoesophageal Echocardiographic Study

The aim of the present study was to assess the incidence and long-term evaluation of left-to-right atrial shunt after balloon mitral valvotomy (BMV). We examined 39 patients, by using transoesophageal echocardiopraphy (TEE). TEE examinaton was performed in 9 of the 39 patients after 1-3 days (I. group), in 10 of the 39 patients after 1-1.5 month (II. group) and the remainder after 4-32 (mean 18) months (last group) after BMV. All first group patients had atrial septal defects (ASD). In the second group, 9 of 10 patients (90 %) showed left-to-right shunts. ASD sizes in this group were smaller than in the first group of patients. In the last group, ASD was detected in 2 of 20 patients (10 %). We obtained minimal left-to-right shunt flow in 5 of 20 patients (25 %) despite an apparently intact atrial septum. By using transthracic echocardiography (TTE), we detected left-to-right shunting in 35 percent of patients showing ASD. Our study suggests that (1) TEE isa more reliable method to obtained left-to-right shunting; (2) ASD size decreases over time and disappears within generally 4-6 months after BMV in most patients.