Determination of Inoue Balloon Size by Analysis of Mitral Valve Geometry Using Three-Dimensional Transesophageal Echocardiography in Patients With Mitral Stenosis.

In percutaneous mitral balloon commissurotomy (PMBC) for patients with mitral stenosis (MS), the size of the balloon has traditionally been determined using a crude method based on the patient's height or body surface area. We aimed to evaluate the clinical value of balloon size selection by quantitatively analyzing mitral valve geometry using 3-dimensional (3D) transesophageal echocardiography. In 184 consecutive patients who underwent PMBC, the geometry of the mitral valve annulus was analyzed during mid-diastole, including the measurement of lateral-medial diameters obtained from dedicated 3D software or from analysis using multiplanar reconstruction images. Patients were categorized into 3 groups: those with successful results after PMBC (SU group), those with residual mitral stenosis (MS group), and those with significant MR (MR group). The SU, MS, and MR groups included 110, 50, and 17 patients, respectively. We compared 3 conventional formulas (formulas 1, 2, and 3) based on the patient's height or body surface area, with 2 new formulas derived from data in the SU group: balloon size = 0.0684 × lateral-medial diameters obtained from dedicated 3D software + 24.309 (formula 4) and 0.061 × lateral-medial diameters obtained from analysis using multiplanar reconstruction images + 24.573 (formula 5). Compared with the calculated balloon sizes using formula 4, the inflated balloon sizes were significantly smaller (-0.78 ± 1.02, p <0.001) in the MS group, whereas they were significantly larger (0.56 ± 1.05, p = 0.04) in the MR group. This pattern was also consistent in formula 5. In conclusion, selecting the Inoue balloon inflation size based on the mitral annulus diameter determined by 3D transesophageal echocardiography might be a reasonable approach.