Adenosine reduces postbypass transfusion requirements in humans after heart surgery

The objective of this study was to determine the effect, if any, of adenosine blood cardioplegia on blood component usage after heart surgery.

The most common cause of nonsurgical postcardiopulmonary bypass bleeding is platelet dysfunction. For this reason, pharmacologic agents are under investigation in an effort to reduce the need for transfusion in this setting.

A posthoc analysis of blood product usage was performed in data obtained from a Phase I, single center, open label, randomized study performed in 63 patients. The trial was designed to test the safety and tolerance of adenosine when added to blood cardioplegia in increasing doses to enhance myocardial protection. The database provided information regarding the effect of adenosine cardioplegia on venous plasma adenosine concentrations, the amount of platelets, fresh frozen plasma and packed erythrocytes used, and the association between the adenosine dose and postoperative thoracic drainage.

The postoperative thoracic drainage at 6 hours, 24 hours, and at the time of chest tube removal in the high-dose adenosine cardioplegia group was 68%, 76%, and 75% of the placebo and low-dose adenosine cardioplegia group (p < 0.05). The highest dose of adenosine studied increased baseline adenosine venous plasma levels 360-fold, from 0.17 +/- 0.09 mumol/L to 42.30 +/- 11.20 mumol/L (p < 0.05). This marked increase was associated with a 68%, 56%, and 58% reduction in platelet, fresh frozen plasma, and packed erythrocyte usage, respectively (p < 0.05).

In addition to enhancing the heart's tolerance to ischemia, adenosine-supplemented cardioplegic solution also may reduce bleeding after cardiopulmonary bypass.