Andersons pediatric cardiology 1468

FIG 55.11 Different inflation stages of the Inoue balloon in percutaneous mitral balloon valvuloplasty (Courtesy Magdi Yacoub Foundation, Aswan Heart Center.) The double-balloon technique was introduced a few years after the Inoue technique and involves crossing the valve with two wires over which two regular balloons are advanced across the valve.68 This technique has the advantage of being cheaper—an important factor to consider in resource-poor settings—and enables the use of a smaller vascular access, which might be advantageous in small patients and can result in slightly larger valve area However, this technique is more time-consuming, more technically challenging, and carries an increased risk of LV perforation compared with the Inoue technique The multitrack system utilizes the same concept as that of the double-balloon technique but with a combination of over-the-wire and rapid exchange of balloons, enabling the use of a single guidewire and hence simplifying the procedure.69 The metallic valvutome, inspired by the surgical Tubbs dilator, was introduced in 1995.70 It consists of a metallic dilator made of stainless steel screwed onto the distal end of a catheter The distal half of the dilator consists of two hemicylindric bars that can be opened out in parallel by a lever-arm system The opening of these two bars leads to separation of the commissures This innovation might be very appealing from a cost perspective, as the entire system is sterilizable; however, limited outcome data and complexity have limited its widespread adoption Table 55.3 summarizes the key features of these various techniques Table 55.3 Comparison of Different Percutaneous Mitral Valvuloplasty Techniques Double Balloon Multitrack System 1985 2004 Non– BalloonBased Metallic Valvutome 1995 ++ + + +++ (+) perforation ++ (+) perforation +++ (+) perforation Technically easier than double balloon (only one wire needed) Resterilizable $$$ $ Balloon-Based Inoue Balloon Year 1982 introduced Use +++ (penetrance) Complexity ++ Complications Mortality: 0%–3% Tamponade: 0%–4% Embolism: 0%–3% Severe MR: 1%–4.6% Failure: 1%– 15% Advantages Lower risk of LV perforation Relatively easy Cost $$$$ Slightly larger valve area compared to Inoue Smaller sheath required $$ MR, Mitral regurgitation Complications and Outcomes The main complications of the percutaneous approach are cardiac tamponade, severe MR, systemic embolism, and failure to achieve an acceptable MV area (defined as >1 cm2/m2 body surface area) (see Table 55.3) The mid- and longterm outcomes of PMBV have been evaluated in a number of studies showing favorable results compared with closed and open commissurotomy Event-free survival (alive and without MV replacement, repair, or redo PMBV) rates at 10 years vary from 56% to 90% in different series, with patients with Wilkins scores at or below 8 having significantly better outcomes Older age, previous surgical commissurotomy, severity of MR before and after the procedure, and high pulmonary artery pressure are additional independent predictors of adverse outcomes.71 Percutaneous Management of Aortic Stenosis Significant rheumatic aortic stenosis is rare in young patients There are therefore very limited data on percutaneous aortic balloon valvuloplasty in young patients with rheumatic aortic stenosis Although aortic balloon valvuloplasty may have an important role in treating infants and children with severe congenital aortic stenosis, this is probably limited to critically ill patients, or as a bridge to open heart surgery in those with rheumatic aortic stenosis