Percutaneous Mitral Annuloplasty

Abstract

Background-To allow performance of "stand-alone" mitral annuloplasty with minimal invasiveness, percutaneous techniques consisting of delivery into the coronary sinus (CS) of devices intended to shrink the mitral valve annulus have recently been tested in animal models. These techniques exploit the anatomic proximity of the CS and mitral valve annulus in ovine or dogs. Knowledge of a detailed anatomic relationship between the CS, coronary arteries, and mitral valve annulus in humans is essential to define the safety and efficacy of percutaneous techniques in clinical practice. We sought to determine the qualitative and quantitative anatomic relationships between CS and surrounding structures in human hearts. Methods and Results-The distance from the CS to the mitral valve annulus and the relationship between the CS and surrounding structures were studied in 61 excised cadaveric human hearts. Maximal distance from the CS to the mitral valve annulus was found to be up to 19 mm (mean, 9.7Ϯ3.2 mm). A diagonal or ramus branch, main circumflex artery, or its branches were located between anterior interventricular vein/CS and the mitral valve annulus in 16.4% and 63.9% of cases, respectively. Conclusions-Surgical anatomy suggests that in humans the CS is located behind the left atrial wall at a significant distance from the mitral valve annulus. Percutaneous mitral annuloplasty devices probably shrink the mitral valve annulus only by an indirect traction mediated by the left atrial wall; a theoretical risk of compressing coronary artery branches exists. Chronic studies are needed to address this problem and to determine long-term efficacy of such methods. (Circulation. 2006;114:377-380.)

Anatomical variants of left circumflex artery, coronary sinus and mitral valve can determine safety of percutaneous mitral annuloplasty

“…In 2006 Maselli et al [11] published the results of an anatomical study of the human CS in relation to the MV and coronary arteries in 61 excised cadaveric human hearts. They found that the LCx lies between the CS and the MV annulus in 63.9% -in our study it was 74.6%.…”

Optimal visualization of heart vessels before percutaneous mitral annuloplasty

“…For example Maselli et al [17], examined the hearts of 61 patients who had died of non-cardiological causes.…”

Innovations in Therapies for Heart Valve Disease

“…In an anatomical study of normal cadaveric hearts, Maselli et al reported that the coronary sinus was not in proximity of the mitral annulus in most humans, but was vertically away from it, running along the left atrial surface. 63- 65 In a more recent study, Plass et al also reported high variability in the angle between the coronary sinus and the mitral annulus, with a significant proportion of patients presenting with an oblique orientation of the sinus. 66 This oblique orientation of the coronary sinus not only reduces the ability of the inserted device to induce reduction in the septal lateral dimension of the mitral annulus, but also causes compression of the circumflex artery.…”

“…66 This oblique orientation of the coronary sinus not only reduces the ability of the inserted device to induce reduction in the septal lateral dimension of the mitral annulus, but also causes compression of the circumflex artery. 65 Additionally, the mitral annulus is a dynamic structure with a sphincteric motion involving complex translational and rotational components, and interaction of the mitral annulus with the coronary sinus through the cardiac cycle might govern the efficiency of these devices that are designed for a more static environment. These anatomical constraints will not only induce high variability in patient outcomes using the same device, but might also fail in a variety of ways due to complexity in the mechanical loading in each patient, complicating the design specifications and safety testing protocols for such devices.…”