Invited Commentary

Abstract

It is generally recognized that mitral regurgitation (MR) improves after aortic valve replacement for aortic stenosis. In this important study by Waisbren and colleagues [1Waisbren EC, Stevens L-M, Avery EG, Picard MH, Vlahakes GJ, Agnihotri AK. Changes in mitral regurgitation after replacement of the stenotic aortic valve. Ann Thorac Surg 2008;86:56–63.Google Scholar], the management of mild to moderate MR in patients with severe aortic stenosis is clarified. Intraoperative transesophageal echocardiography (TEE) is known to underestimate MR. By including preoperative and late postoperative transthoracic echocardiography (TTE) this report provides much needed insight into the perioperative relationships between TTE and TEE. Although the initial postoperative MR improvement was impressive, this improvement diminished during the mean 2-year follow-up. When compared with preoperative TTE, late TTE studies were largely unchanged. Importantly, none of the patients progressed to severe MR. Vena contracta width (VCW) was used as the sole measure of MR grade. The VCW is a direct anatomic measurement and is therefore less likely to be influenced by varying inotropic and loading conditions as compared to jet area, proximal iso-velocity surface area (PISA) or similar Doppler measurements. Given that this is a retrospective study, selection of VCW as the single measurement was completely appropriate. However, contemporary evaluation continues to improve and is worthy of mention. Three-dimensional echocardiography has resulted in important MR quantification advancements. Vena contracta area (VCA) and planimetry from three-dimensional echocardiography are also direct anatomic measurements. Like VCW, they are load-independent. However unlike VCW, which assumes a circular or elliptical regurgitant orifice, VCA and planimetry directly measure the regurgitant orifice surface area and thereby substantially improve accuracy. In practice, an integrated approach including VCW, various Doppler measurements, VCA, and planimetry is considered optimal. Additional direct anatomic measurements associated with myopathic or “functional” MR have also been demonstrated to be useful. These include coaptive characteristics, tenting area, and closing angles, all of which can be predictive of late postoperative mitral function. Details of the echocardiographic analysis are delineated in an excellent article from Quebec, Canada, by Magne and colleagues [2Magne J. Pibarot P. Dagenais F. Hachicha Z. Dumesnil J.G. Sénéchal M. Preoperative posterior leaflet angle accurately predicts outcome after restrictive mitral valve annuloplasty for ishemic mitral regurgitation.Circulation. 2007; 115: 782-791Crossref PubMed Scopus (221) Google Scholar]. We consider these direct anatomic measurements to be mandatory prior to mitral repair. In summary, the authors have addressed an important management dilemma. A subgroup analysis, which includes TTE data, gives important insight into intermediate-term mitral function. The limitations of intraoperative TEE are acknowledged and appropriately addressed. This study supports their conclusion that a conservative, selective approach to mitral intervention is appropriate in patients presenting for correction of aortic stenosis with concomitant mild to moderate mitral regurgitation. The authors are to be congratulated on their excellent work. Changes in Mitral Regurgitation After Replacement of the Stenotic Aortic ValveThe Annals of Thoracic SurgeryVol. 86Issue 1PreviewConcomitant mitral regurgitation (MR) is frequently seen in patients undergoing aortic valve replacement (AVR) for aortic stenosis. This study was undertaken to characterize the magnitude of MR in these patients and identify factors associated with significant postoperative change. Full-Text PDF