Clinical significance of small left-to-right shunts after percutaneous mitral valvuloplasty

Abstract Left-to-right shunt after percutaneous mitral valvuloplasty was evaluated by contrast echocardiography in 29 patients at 24 hours and at 1, 3, 6, and 9 months after the procedure. The patients were divided into two groups: in group A (13 patients) the double-balloon technique was used; in group B (16 patients) the Inoue single-balloon technique was used. The two groups were comparable in terms of age, gender, and mitral valve area before and after percutaneous mitral valvuloplasty. A left-to-right shunt was detected in all patients 24 hours after the procedure. At 1 month follow-up the shunt was present in 12 patients of group A (92%) and in 13 of group B (81%) with a statistically significant difference (p < 0.001). At 3 months the values were 7 (54%) in group A and 6 (37.5%) in group B (p < 0.05); at 6 months the values were 3 (23%) in group A and 3 (19%) in group B (NS). At 9 months a left-to-right shunt was no longer detectable in any of the patients in either group. The disappearance of the shunt could be related to a healing process of the atrial septal injury that occurs within a few months after percutaneous mitral valvuloplasty. This process seems to be more rapid in group B patients, probably because of the smaller lesion that is produced in the atrial septum by the passage of the Inoue balloon.