How much septal-lateral mitral annular reduction do you get with new ischemic/functional mitral regurgitation annuloplasty rings?

Objective: Disproportionate reduction of the mitral septal-lateral annular dimension is the goal in the surgical treatment of ischemic or functional mitral regurgitation and avoids the need for ring "downsizing.'' How much the new annuloplasty rings designed for patients with ischemic/functional mitral regurgitation reduce annular septal-lateral dimension, however, is proprietary information and debated. Methods: Outer and inner septal-lateral and commissure-commissure diameters of all available sizes of Edwards GeoForm, Edwards IMR ETlogix (both Edwards Lifesciences, Irvine, Calif), St Jude Medical Rigid Saddle Annuloplasty Ring (St Jude Medical, Inc, St Paul, Minn), and Medtronic Profile 3D (Medtronic, Minneapolis, Minn) annuloplasty rings with and without the fabric covering were measured with electronic calipers. These rings were compared with a Carpentier-Edwards Physio ring (Edwards Lifesciences) to assess the relative amount of septal-lateral and commissure-commissure dimension change. Average fractional changes (% +/- 1 standard deviation) versus the Physio ring were calculated. Results: The GeoForm provided the greatest outer septal-lateral reduction relative to Physio ring (-24% +/- 2%), followed by the IMR ETlogix (-9% +/- 2%) and Profile 3D (-8% +/- 5%). The septal-lateral diameter of the Rigid Saddle Annuloplasty Ring was similar to that of the Physio ring (+1% +/- 3%). Although commissure-commissure outer diameters of the IMR ETlogix, Rigid Saddle Annuloplasty Ring, and Profile 3D were similar to that of the Physio ring (0% +/- 2%, +4% +/- 3%, and +3% +/- 4%, respectively), the GeoForm had a larger commissure commissure dimension (+12% +/- 2%). The inner diameter septal-lateral reductions were even more pronounced. Conclusions: Relative to the Physio ring, the GeoForm has the most outer and inner septal-lateral reduction but larger commissure-commissure dimension; the IMR ETlogix and Profile 3D provide a moderate degree of septal lateral reduction without affecting commissure-commissure dimension, and Rigid Saddle Annuloplasty Ring septal-lateral and commissure-commissure diameters are similar to those of the Physio ring. Knowing the degree of disproportionate septal-lateral downsizing inherent in each ring type will help guide surgical decision making. (J Thorac Cardiovasc Surg 2010;140:117-21)