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Fitting a round plug in a crescent‐shaped hole: The percutaneous approach to paravalvular leaks

The paper by Kuehl et al. in this issue of Catheterization and Cardiovascular Interventions highlights a procedure that has become a staple in only a very small number of structural heart intervention programs around the world. The procedure actually dates back far longer than the authors credit. Lock and coworkers at Children’s Hospital in Boston experimented with percutaneous paravalvular leak closure as early as 1987 utilizing primarily a double umbrella device [1]. Their efforts were at first limited to prosthetic valves in the aortic position but by the mid-1990s a similar approach was being used for prosthetic mitral paravalvular leak closure as well. The latter is technically far more challenging primarily because of difficulties in accessing the fenestration, which has proved ultimately unsuccessful in an important minority of cases or required such long duration that concern has been raised about radiation burns in some cases [2]. Median fluoroscopy times in the range of an hour or occasionally far longer are common [3]. Because there are frequently multiple fenestrations, or the fenestrations are primarily crescent-shaped rather than round, the devices that have been used, primarily patent ductus arteriosus plugs, vascular plugs, or septal defect closure devices (all off label uses), have left a significant number of residual leaks behind. The need for a second plug is common as is the need for repeat procedures to achieve significant improvement. A host of complications have been reported relating to (a) transseptal puncture, (b) interference with the free movement of the mitral valve leaflets, (c) embolization of air or thrombus, and (d) device embolization. The reported success rates (variably defined, but generally considered to be a diminution of the leak without need for heart surgery) have varied from 30% to 80%, with device embolization, stroke and death all occurring in a small but significant number of patients. Historically, the long-term outcomes, likely influenced by the significant comorbidities that rendered these patients relatively inoperable, have been poor, with 3 month mortality of 25% [4] and 1 year mortality up to 90% [2]. Nevertheless, several improvements in technology have made this procedure more appealing, albeit with some caveats. Access to the fenestration from the left atrium has been improved by equipment developed for electrophysiology, in particular the Agilis 8.5F guiding catheter (St. Jude Medical, St. Paul, MN). Placed transseptally, and used in combination with one or two catheters inside the sheath, it allows an approach to even the most challenging sites (though not necessarily successful crossing), in particular the posterior and medial surface of the mitral ring. Use of the Inoue wire (Toray Medical, Houston, TX) , designed for balloon mitral valvuloplasty, allows for atraumatic advancement of hardware into the left atrium. The Amplatzer duct occluder (AGA Medical, Plymouth, MN) has been the most commonly used plug, although a variety of septal defect occluders and some coils have been employed as well. The Amplatzer Vascular Plug is occasionally helpful, since it does not have a retention skirt, and is therefore unlikely to interfere with the valve leaflets themselves. It does, however, not contain the fabric integral to the ductus device; whether or not this is an issue in paravalvular leak closure is uncertain. In my experience, the possibility of interfering with valve leaflets does require great vigilance. This is most likely to be important, in order of decreasing risk, with single leaflet valves similar to the Bjork-Shiley, then with bileaflet valves such as in the case report in this issue, and finally least likely to occur with tissue valves. Early warning signs are the obvious (if looked for) change in mechanical valve leaflet excursion, readily noted on fluoroscopy, and in addition, the appearance of ‘‘smoke’’ (spontaneous