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Spatial relationship of coronary sinus-great cardiac vein with adjoining anatomic structures: a key element in predicting the success of percutaneous transvenous mitral annuloplasty.

BACKGROUND AND AIM OF THE STUDY
Knowledge of the anatomy of the coronary venous system and its relationship with the mitral valve annulus (MVA) and coronary arteries is a key element to successful percutaneous transvenous mitral annuloplasty (PTMA) device implantation for treating patients with severe mitral regurgitation.


METHODS
The spatial relationship of the coronary sinus-great cardiac vein (CS-GCV) with the MVA, left circumflex coronary artery (LCx) and its branches was examined in 120 formalin-fixed adult human cadaveric hearts.


RESULTS
During the initial part of its journey, the CS-GCV was seen to course along and parallel to the plane of the MVA in 109 cases (90.8%), and to cross the MVA obliquely in 11 cases (9.2%). The LCx crossed deep or superficial to the CS-GCV at a discrete point in 98 cases (81.6%) and in eight cases (6.6%), respectively. In two cases (1.6%), the LCx was overlapped by the CS-GCV for an average length of 3.5 +/- 0.7 cm, and in five cases (4.1%) it lay superficial to the CS-GCV for an average length of 3.1 +/- 1.0 cm. In the remaining seven cases (5.8%), the artery did not accompany the CS-GCV along the MVA. Obtuse marginal arteries and the ramus intermedius were seen coursing deep to the CS-GCV in 40 cases (33.3%) and 33 cases (27.5%), respectively.


CONCLUSION
The study results showed that the CS-GCV crosses the annulus obliquely in 9.2% of cases, and hence might affect the efficiency of PTMA. Similarly, positioning of the annuloplasty device in the CS-GCV in cases where the LCx and its branches lay deep to the vein may result in an impingement of the arteries, leading to ischemia.