Technique of percutaneous transvenous mitral commissurotomy using the Inoue balloon catheter

Percutaneous transvenous mitral commissurotomy (PTMC) with the Inoue balloon has had increasing use internationally since its introduction in 1984. This device was designed specifically for mitral commissurotomy and differs substantially from conventional large diameter peripheral arterial or valvuloplasty balloon catheters. It is constructed of two layers of latex with a nylon mesh in between. The latex is extremely compliant, whereas the nylon mesh limits the maximum inflated diameter of the balloon and also gives it a unique shape and set of inflation characteristics. The balloon inflates in three stages. The front half inflates first, creating the appearance of a balloon flotation catheter. The proximal half of the balloon inflates next, creating an hourglass shape. When straddling across the valve, this allows self-positioning of the balloon. Finally, the center portion inflates, resulting in commissurotomy. The technique of commissurotomy involves introducing the balloon into the left atrium over a guidewire and then passing it into the left ventricle with the distal portion of the balloon inflated in a manner analogous to crossing the tricuspid valve with a pulmonary artery flotation catheter. Thus a guidewire is not used to enter the left ventricle with this technique. Increasing inflation volumes allow a single balloon catheter to be inflated to a variety of sizes, allowing stepwise dilatation of the mitral valve in a manner analogous to coronary angioplasty. This report describes the performance of this technique in detail, with practical approaches to many common problems encountered during PTMC.