Ischemic mitral valve prolapse

Abstract

Ischemic mitral prolapse (IMP) is a pathologic entity encountered in about one-third among the patients undergoing surgery for ischemic mitral regurgitation (IMR). IMP is generally the result of a papillary muscle injury consequent to myocardial, but the recent literature is progressively unveiling a more complex pathogenesis. The mechanisms underlying its development regards the impairment of one or more components of the mitral apparatus, which comprises the annulus, the chordae tendineae, the papillary muscle and the left ventricular wall. IMP is not only a disorder of valvular function, but also entails coexistent aspects of a geometric disturbance of the mitral valve configuration and of the left ventricular function and dimension and a correct understanding of all these aspects is crucial to guide and tailor the correct therapeutic strategy to be adopted. Localization of prolapse, anatomic features of the prolapsed leaflets and the subvalvular apparatus should be carefully evaluated as also constituting the major determinants defining patient's outcomes. This review will summarize our current understanding of the pathophysiology and clinical evidence on IMP with a particular focus on the surgical treatment.

Biomechanics raises solution to avoid geometric mitral valve configuration abnormalities in ischemic mitral regurgitation

“…Conversely, the biomechanical consequences of PMPM ischemia are more eloquent because of its deep location in the left ventricle wall translating into a higher stress. Moreover, PMPM is perfused by either the right coronary or the circumflex artery, dramatically increasing its sensitivity to ischemia [reported in 91% of the cases in our patients (4,5)]. Relationship between biomechanical behaviour and PM microcirculation is confirmed by the observed segmental distribution and a well-identified arterial trunk, named Kugel's artery that perforates the PM from base to apex (7).…”

“…Subsequent biomechanical investigation stressed the central role of coronary blood flow distribution in the PMs as well as its different mechanical performance due to deep location in left ventricular wall (7). There is general consensus about a difference of coronary vascular distribution in the two PM with evidence of a more scarce vascularization of the PMPM among persons with a IMR [about 91% in our series (4,5)]. The evidence discussed here comes from several observational and randomized clinical study of surgical treatment of IMR suggesting that the spectrum of patients with severe impairment of right coronary blood flow distribution and inferior wall motion abnormalities is higher in IMR (2,8-10).…”

“…The evidence discussed here comes from several observational and randomized clinical study of surgical treatment of IMR suggesting that the spectrum of patients with severe impairment of right coronary blood flow distribution and inferior wall motion abnormalities is higher in IMR (2,8-10). Anterior lateral PM and all the segment of ventricular wall are rarely affected because of the perfusion provided by both the left anterior descending coronary artery and diagonal branch (4). In preliminary biomechanic studies evidence of nonhomogeneous tension exerted by the chordae located in ALPM and PMPM has been provided suggesting a different distribution of dynamic stress-strain occurring at the level of PMs (11).…”

“…Another recently recommended option in the context of surgical repair of IMR is an adjunctive subvalvular procedure in combination to standard undersizing mitral anuloplasty (3,4,9).…”

Papillary muscle approximation in mitral valve repair for secondary MR

“…In type III, IV or V approximation is performed with a 4 mm Gore-Tex tube (W-L Gore and Associated, Flagstaff, Ariz) encircling the bodies of PMPM and ALPM. In the presence of two independent heads, both PMPM are approximated to minimize mitral valve tenting (26). In the relocation technique the ALPM and PMPM are fixed to the anterior and posterior trigones, respectively (20).…”