Spontaneous resolution of percutaneous balloon mitral commissurotomy‐related mitral regurgitation

Abstract

The incidence of increased mitral regurgitation after percutaneous balloon mitral commissurotomy has been reported to range from 11% to 44%; however, only 3-1 1% of patients experience a deterioration by 2 2 severity grades [l]. The majority are due to small changes (i.e., worsening by one severity grade only). Given the longstanding pulmonary hypertension commonly present in these patients, mitral regurgitation is often well tolerated acutely. Furthermore, unlike the situation with severe mitral stenosis, the availability of reasonable medical therapy for mitral regurgitation (e.g., afterload reduction and diuresis) makes longer-term tolerance of this lesion possible.The natural history of iatrogenic mitral regurgitation has been a source of concern in the interventional community. In a group with procedure-related mitral regurgitation, Roth et al.[2] reported an improvement of one severity grade in 53% of those who underwent catheterization a mean of 9 months after the commissurotomy. More recent data from Reyes et al. [3] suggest that although 13 patients out of 30 had moderate or severe mitral regurgitation 1 week after commissurotomy, only 5 of these patients had persistent moderate or severe disease at 3 years. In our own cohort of 2 14 percutaneous balloon mitral commissurotomy patients at Duke University Medical Center, we have had similar instances of patients who have improved one severity grade over 3 months to 3 years of follow-up, but we have not seen any cases as dramatic as the one reported by Kannan and Jeyamalar [4] in this issue of the Journal.Putative mechanisms of balloon-related regurgitation are varied [l-71. Trauma to the mitral leaflets can be inflicted by the guidewire used with the non-Inoue technique, especially if the wire is placed out the left ventricle to the aorta and the large left ventricular loop is lost. This tends to put direct pressure on the anterior mitral leaflet. Trauma from the balloon itself can come about either because the balloon is oversized relative to the receptacle annulus, because the balloon is malpositioned, or simply because the valve morphology is unfavorable.An overly large balloon can result in excessive commissural splitting, annular stretching, or even annular tearing. To avoid this possibility, we endeavor to size the mitral annulus in multiple echocardiographic views prior to the catheterization, and we temper these measurements with a height-based nomogram for balloon size. Multivariable analysis has suggested that the ratio of balloon dilation diameter to body size has predictive value for iatrogenic mitral regurgitation [2]. Furthermore, we begin with modest balloon inflations and cautiously increase balloon volume with each inflation, stopping when either an adequate result is seen or maximal inflation is achieved. We are also careful to note whether commissural fusion is asymmetric by observing the mitral morphology in the short axis view (i.e., the one used for planimetry). If there is no commissural fusion along the lateral aspects of the leaf...