Insight into the dynamics of the coronary sinus/great cardiac vein and the mitral annulus: implications for percutaneous mitral annuloplasty techniques.

BACKGROUND Implantation of devices into the coronary sinus (CS)/great cardiac vein (GCV) to reshape the mitral annulus (MA) is being investigated, despite these structures not being within the same plane and coronary arteries frequently traversing between them. Furthermore, dynamic changes in their relationship have never been studied. We analyzed the CS/GCV dimensions and its relationship with the MA and the coronary arteries. METHODS AND RESULTS Of 390 consecutive computed tomography angiographies reviewed, 56 met the inclusion criteria. Mean age of the patients was 68.9 + or - 13.1 years (26.8% men). The dimensions of the CS/GCV and the distance between this structure and the MA were measured at 10 different spatial points along the CS/GCV trajectory and at 3 different time points along the cardiac cycle (phases 0%, 40%, and 75% of the RR interval) by using curved multiplanar reconstruction technique. The CS/GCV was larger in phase 40% than in phase 75% and was smallest in phase 0% (P<0.001). The distance between the CS/GCV and the MA was longest in phase 40% and shortest in phase 0% (P=0.013). The diameter of the MA was measured in oblique 2- and 4-chamber reconstructions, being largest in phase 0% and smallest in phase 40% (P=0.019). A coronary artery traversed between the CS/GCV and the MA in 85.7% of the patients. CONCLUSIONS This study demonstrated dynamic changes in the relationship between the CS/GCV and the MA and also that coronary arteries frequently traverse between both structures. Whether these findings are of clinical relevance for patients undergoing percutaneous mitral annuloplasty needs to be prospectively evaluated.