Reply

Abstract

We would like to thank Dr Nappi1Nappi F. A geometric approach to ischemic mitral regurgitation: evaluating the evidence of valve distortion (letter).Ann Thorac Surg. 2020; 109: 982Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar sincerely for his insightful comment on our paper.2Harmel E. Pausch J. Gross T. et al.Standardized subannular repair improves outcomes in type IIIB functional mitral regurgitation.Ann Thorac Surg. 2019; 108: 1783-1792Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar We are aware of the extensive work published by Dr Nappi’s group on the pathophysiology and treatment of ischemic mitral regurgitation (IMR). We highly respect his comment and share his point of view in many ways. IMR as a sequel of ischemic myocardial injury indicates left ventricular (LV) disease (ie, ventricular secondary mitral regurgitation) that is associated with papillary muscle dysfunction.3Nappi F. Carotenuto A.R. Avtaar Singh S.S. Mihos C. Fraldi M. Euler’s elastica-based biomechanics of the papillary muscle approximation in ischemic mitral valve regurgitation: a simple 2D analytical model.Materials (Basel). 2019; 12: E1518Crossref PubMed Scopus (9) Google Scholar From this point of view, subannular repair by papillary muscle relocation could be the preferred treatment in patients with IMR.1Nappi F. A geometric approach to ischemic mitral regurgitation: evaluating the evidence of valve distortion (letter).Ann Thorac Surg. 2020; 109: 982Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar Nonetheless, IMR treatment is a complex and multifaceted topic that clearly mandates a comprehensive heart team approach. In the setting of acute ischemia, expeditious target vessel revascularization significantly limits the region of infarction and myocardial scar formation and may thereby reverse acute papillary muscle dysfunction.4Nishino S. Watanabe N. Kimura T. et al.The course of ischemic mitral regurgitation in acute myocardial infarction after primary percutaneous coronary intervention: from emergency room to long-term follow-up.Circ Cardiovasc Imaging. 2016; 9e004841Crossref PubMed Scopus (25) Google Scholar Furthermore, the occurrence of significant IMR in the setting of acute myocardial infarction is frequently a surrogate for an extensive infarction area often accompanied by cardiogenic shock and acute heart failure.5Mentias A. Raza M.Q. Barakat A.F. et al.Prognostic significance of ischemic mitral regurgitation on outcomes in acute ST-elevation myocardial infarction managed by primary percutaneous coronary intervention.Am J Cardiol. 2017; 119: 20-26Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar Surgical risk is high in this clinical scenario, and rescue percutaneous coronary intervention, with or without mechanical circulatory support, could be a lifesaving procedure. Moreover, manipulation of acutely infarcted papillary muscles may be dangerous and has at least a theoretical risk of papillary muscle rupture. In the chronic phase of ischemic IMR, ongoing LV remodeling results in apicolateral displacement of papillary muscles. The decision-making process for isolated revascularization vs revascularization and mitral valve repair with a subannular procedure must consider regional and global LV fibrosis. Magnetic resonance imaging–based analysis of (1) regional scar transmurality in the target vessel area and (2) the extent of diffuse LV fibrosis, quantified by extracellular volume and T1 mapping, plays a crucial role in the decision-making algorithm, as clearly demonstrated by the previous CTSNet trial (Surgical Interventions for Moderate Ischemic Mitral Regurgitation).6Michler R.E. Smith P.K. Parides M.K. et al.Two-year outcomes of surgical treatment of moderate ischemic mitral regurgitation.N Engl J Med. 2016; 374: 1932-1941Crossref PubMed Scopus (264) Google Scholar Finally, decision making in favor of subannular repair vs isolated annuloplasty in IMR should include a thorough analysis of mitral valve tenting severity, as indicated by a tenting area greater than 2.5 to 3.0 cm2 and, more recently, by tenting volume. Considering the given complexity while tailoring IMR treatment to an individual patient, a dedicated heart team approach seems to be most reasonable. A Geometric Approach to Ischemic Mitral Regurgitation: Evaluating the Evidence of Valve DistortionThe Annals of Thoracic SurgeryVol. 109Issue 3PreviewI congratulate Dr Harmel and colleagues for their interesting report on ischemic mitral regurgitation that was treated using a standardized subannular repair.1 In this study, the use of subannular repair was associated with a significantly lower risk of mitral regurgitation recurrence, decreased residual leaflet tenting and significantly improved 1-year outcome as compared with the use of annuloplasty alone. We recognize three phases that respond differently to the interventions. Full-Text PDF