Balloon mitral valvotomy: Comparison between antegrade Inoue and retrograde non-transseptal techniques

Abstract

Aims. The results of percutaneous mitral valvotomy performed by the antegrade transseptal method using the Inoue balloon (n = 1000; group 1) and by the retrograde non-transseptal technique using a polyethylene balloon (n = 100; group 2) were compared in a retrospective, non-randomized study. Methods and results. Both the groups were similar with respect to baseline characteristics. The success rate was 95% in group 1 and 93% in group 2. There was a significant increase in mitral valve area estimated by Gorlin's equation (Group 1: from 0.8 ± 0.5 to 2.1 ± 0.8 cm2; Group 2: from 0.8 ± 0.3 to 1.9 ± 0.8 cm2, both P < 0.001) and by Doppler echocardiography using the pressure half-time method (Group 1: from 0.9 ± 0.4 to 2.2 ± 0.6 cm2; Group 2: from 0.9 ± 0.3 to 2.0 ± 0.7 cm2, both P < 0.001). However, the calculated immediate post-valvotomy mitral valve area was larger with the Inoue technique (2.1 ± 0.8 vs 1.9 ± 0.8 cm2; P < 0.02). Results were considered optimal when the mitral valve area increased to ≤ 1.5 cm2, the percentage increase was ≤ 50, and mitral regurgitation was ≤ 2/4. Out of the total successful procedures, optimal results were obtained in 95% patients in Group 1 and 94% in Group 2. Incidence of significant mitral regurgitation (≤ grade 3/4) was similar in two groups (Group 1: 4% vs Group 2: 5%, P = ns). A significant left to right atrial shunt (Qp/Qs ≤ 1.5:1) in 2.5% and tamponade in 2% of cases occurred exclusively with the Inoue technique, while conduction disturbances, such as transient (< 24 h) left bundle branch block (28%) and complete heart block (2%,) were noted with the retrograde technique (Group 2). Local complications were significantly higher in Group 2 (3% vs 0.5%, P < 0.01). The procedure time with the Inoue technique was shorter than with the retrograde (Group 1: 15 ± 8, range 10 to 35 min; Group 2: 22 ± 14, range 15 to 45 min, P = 0.05). Echocardiographic follow-up at 1 year showed no significant difference in mitral valve area between the two groups (Group 1 (n = 300): 1.8 ± 0.8 vs Group 2 (n = 60): 1.9 ± 0.9 cm2; P = 0.3). Conclusions. Balloon mitral valvotomy using the Inoue balloon and the retrograde non-transseptal technique results in significant immediate haemodynamic and symptomatic improvement. The Inoue technique achieved a larger immediate post-valvotomy mitral valve area, but the difference was not apparent at 1 year follow-up. Incidence of significant mitral regurgitation was similar with both the techniques: however, local complications occurred more frequently with the retrograde technique. Both techniques may complement each other in technically difficult cases.