[Left ventricular distribution of retrograde cardioplegia. Should the interventricular posterior vein be occluded in the coronary sinus?].

Retrograde cardioplegia is still controversial due to the heterogeneous left ventricular flow distribution particularly in the posterior wall. The purpose of this study was to compare retrograde flow distribution delivered through the coronary sinus with two types of cannula. Fifty two patients were prospectively randomized to receive cold blood retrograde cardioplegia with manual inflating long balloon prototype cannula (group I, 26 patients) or with manual inflating short balloon cannula (group II, 26 patients). Left ventricular distribution of the cardioplegic solution was assessed by monitoring the left ventricular wall temperatures (anterior and posterior). The cardioplegic retrograde infusion was stopped as the anterior wall temperature reached 15 degrees C. In group I, 91% of the patients had identical cooling in the anterior and posterior wall of the left ventricle, versus 19% in group II (p < 0.05). The mean temperature difference between anterior and posterior wall was 0.5 degrees C (standard deviation = 1.7) in group I versus 8 degrees C (standard deviation = 4.1) in group II (alpha < 0.05). The cannula with the long balloon allows a better left ventricular distribution of the cardioplegia flow than the short one because it occludes the interventricularis posterior vein in the coronary sinus.