Anatomy of the coronary sinus and its clinical significance for retrograde cardioplegia.
OBJECTIVE
To provide an anatomical basis for selecting optimal retrograde cardioplegia technique therefore to improve the effect of the operation.


METHODS
Fifty formalin-fixed adult human cadaveric hearts were collected in this study, and special attention was given to the observation of the coronary sinus tributary drainage and the anatomical relationship between the orifice of the coronary sinus and the atrioventricular nodal artery.


RESULTS
Although the majority of the tributaries drained into the coronary sinus, it was identified in 15 cases that the posterior vein of the left ventricle and in another 2 cases the small cardiac vein (SCV) made their way into the middle cardiac vein (MCV) respectively. In 6 cases MCV solely joined the right atrium, which was joined by SCV only in 1 case. Draining into the coronary sinus as seen in 44 cases, MCV had an opening 3.4+/-1.5 mm away from the orifice of the coronary sinus. In the direction perpendicular to the long axis of the coronary sinus orifice, the anterior and posterior extreme points were 4.9+/-2.5 mm and 9.9+/-4.2 mm respectively, away from the atrioventricular nodal artery, which crossed the long axis of the coronary sinus orifice at an angle of 21.2+/-15.6 degrees. The right atrial wall on both sides of the coronary sinus orifice was of a uniform thickness of 1.1+/-0.2 mm.


CONCLUSIONS
Direct-vision non-balloon-tipped cannulation conforms better to the anatomical features described above. In purse-string suture, however, sufficient care should be taken of the dangerously thin inferior atrial wall and the close relationship between the coronary sinus orifice and the atrioventricular nodal artery. For better cardioprotective effect of retrograde cardioplegia, non-balloon-tipped cannula under direct vision should be adopted with the assistance of antegrade perfusion and, when necessary, additional transfusion via the exotic MCV opening may be used when the opening appears relatively wide.
Liu
Dao-ming
DM
Department of Anatomy, First Military Medical University, Guangzhou 510515, China. leoplus@fimmu.com
Zhang
Fa-hui
FH
Chen
Long
L
Zheng
He-ping
HP
Zhong
Shi-zhen
SZ
D003326:Coronary Circulation / Q000502:physiology; D003331:Coronary Vessels / Q000473:pathology; D004734:Energy Metabolism; D006324:Heart Arrest, Induced; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans