Letter by Messas et al Regarding Article, “Initial Results of Posterior Leaflet Extension for Severe Type IIIb Ischemic Mitral Regurgitation”
To the Editor:
In their recent article in Circulation, De Varennes et al1 proposed to test the efficacy of posterior leaflet extension with remodeling annuloplasty on 44 patients with type IIIb ischemic mitral regurgitation (MR). In their introduction, the authors explain that most often ischemic MR mechanism is complex, “and the resulting MR jet is composed of a central and posteriorly directed jet of regurgitation (Carpentier type I and III).” In the discussion, the authors further explain that, “The net result (of the complex mechanism of ischemic MR) is a complex interplay of regurgitant jets with central (type I) jet principally resulting from the annular dilatation and the posterior-directed ones (type IIIb) principally resulting from the posterior displacement of the posteromedial papillary muscle (PM).”
Because the authors cited the Carpentier classification in their title, introduction, inclusion criteria, and discussion, we feel obliged to make the following comment. Carpentier is a functional classification describing leaflet motion during MR.2 In type I, there is normal leaflet motion, and lesions are most often annular dilatation or endocarditis. In type III, there is abnormal leaflet motion with restriction of leaflet motion only in systole for type IIIb and also in diastole for type IIIa. So, by definition, we cannot have a type IIIb and a type I at the same time and for the same MR case. The leaflet motion must be normal or abnormal (restricted in our case).
Jet localization is not always linked to the type of dysfunction classification: MR central jet can be produced by the displacement of symmetrical PMs without significant mitral annulus dilatation.3 According to Carpentier, one who wants to describe MR has to define 3 items: pathogenesis (eg, rheumatic or degenerative disease), lesion (eg, annulus dilatation, PM rupture), and dysfunction (as defined earlier).
Surgeons are trying to restore dysfunction, not the pathogenesis or lesion. Therefore, in the case of ischemic MR, the mechanism most often involved is type IIIb of the posterior and anterior leaflet (with the seagull sign), which can be associated with left ventricular remodeling and annulus dilatation (classified as “lesion” and not “dysfunction”). We hope that this comment will offer better insight into the Carpentier classification and point clinicians toward a better approach to MR evaluation using the 3 items (pathogenesis, lesion, and dysfunction) to get the best cure for their patients.