BALLOON DIAMETER OF THE INOUE BALLOON CATHETER DURING PERCUTANEOUS TRANSVENOUS MITRAL COMMISSUROTOMY - CLINICAL AND EXPERIMENTAL-STUDY

To determine adequate and effective balloon diameters of the Inoue balloon catheter, we reviewed clinical results and characteristics of the Inoue balloon catheter, especially the relationship between the intra-balloon pressure and the balloon diameter, experimentally and clinically, in 46 patients with mitral stenosis undergoing percutaneous transvenous mitral commissurotomy (PTMC). Mitral valve area increased from 1.1 +/- 0.3 to 2.1 +/- 0.3 cm2 in all patients after PTMC. Based on balloon diameter settings, mitral valve area increased from 1.3 +/- 0.4 to 2.3 +/- 0.5 cm2 in patients treated with a balloon setting greater than 26 mm diameter, from 1.1 +/- 0.3 to 2.0 +/- 0.5 cm2 in patients with a balloon setting at 26 mm in diameter, and from 1.1 +/- 0.4 to 1.7 +/- 0.4 cm2 in those treated with a balloon setting less than 26 mm in diameter, with an increase in mitral valve area of 1.0 +/- 0.6, 0.9 +/- 0.4, and 0.7 +/- 0.2 cm2, respectively. There was a significant difference between the increase in mitral valve area at a setting of 26 mm in diameter and that observed at a setting less than 26 mm in diameter. We next investigated differences between balloon diameter settings and actual balloon diameters measured from cineangiograms at maximum balloon inflation. The ratio of actual balloon diameter to a setting diameter of less than 26 mm was smaller than that of 26 mm. To evaluate the reason for the difference, we investigated the relationship between intra-balloon pressure and balloon diameter. In the prototype Inoue balloon catheter, intra-balloon pressure increases from 1.0 kg/cm2 at 20 mm in diameter to 2.2 kg/cm2 at 30 mm in diameter at atmospheric pressure. In conclusion, the increase in mitral valve area was inadequate when the balloon was less than 26 mm in diameter because of inadequate intra-balloon pressure. We, therefore, recommend a balloon size set above 26 mm to obtain adequate intra-balloon pressure when using the Inoue balloon catheter.