A novel “proximal first” Inoue balloon catheter for retrograde aortic valvuloplasty: Initial case report

The Inoue balloon, invented for percutaneous transseptal mitral commissurotomy for mitral stenosis, is initially dilated in the distal portion and then the proximal portion, forming an hourglass shape that stabilizes the balloon at the mitral valve orifice with a pulling action. The device has been successfully applied to antegrade aortic valvuloplasty; the hourglass shape stabilizes the balloon across the aortic valve without rapid ventricular pacing. Subsequently, an Inoue balloon was developed for retrograde aortic valvuloplasty using the same design as the antegrade balloon. The hourglass-shaped balloon, however, has difficulty maintaining stability across the aortic valve because the distal portion of the balloon, which inflates first, directly receives systolic pressure from the left ventricle. A novel Inoue balloon was invented to overcome this issue by altering the manner of inflation: the proximal portion inflates first, followed by the distal portion. Theoretically, the proximal portion, which initially inflates just above the aortic valve, remains secure across the valve by applying a pressing force that counteracts the systolic forward pressure. Furthermore, a radiopaque marker is placed at the center of the balloon to enable rapid and precise balloon adjustment. We present a case involving a 65-year-old female hemodialysis patient with severe symptomatic aortic stenosis who we successfully treated with balloon aortic valvuloplasty using the novel Inoue balloon followed by transcatheter aortic valve implantation. The present case demonstrates the feasibility and effectiveness of the novel "proximal first" Inoue balloon for retrograde balloon aortic valvuloplasty for severe aortic stenosis.