Pretreatment of human myocardium with adenosine

While the role of adenosine pretreatment in animals has been well established, the role in humans has been controversial. We performed this prospective, randomized study to find out the usefulness of adenosine pretreatment in humans.

Twenty patients undergoing coronary artery bypass surgery for severe triple vessel disease and left ventricular dysfunction (ejection fraction<35%) formed the study population. The adenosine group (n=10) received adenosine infusion (200 microg/kg) before aortic cross-clamp. The control group (n=10) received only normal saline injection. Cardiac function indices were assessed post-operatively.

In the adenosine group there was a significant increase in cardiac output in the post-operative period from 3.46+/-1.06 to 4.46+/-0.92 l/min (P<<0.05). The cardiac index increased significantly in the adenosine group from 1.97+/-0.43 to 2.54+/-0.5 l/min per m2 (P<<0.05) and even when compared with the control group this increase was significant (adenosine group vs. control group, P=0.03). Systemic vascular resistance fell from 1898.8+/-558.4 to 1134.9+/-530.7 dyne/s per cm(-5) (P<<0.05) in the adenosine group. The pulmonary artery wedge pressure fell significantly in the adenosine group from 11.1+/-5.0 to 7.2+/-2.6 mmHg (P<<0.05). Patients in the adenosine group maintained a lesser increase in resting heart rate post-operatively (96.1+/-13.4 to 114.1+/-18.7 beats/min) (P=0.7), as compared to the control group where the increase in the heart rate was significant (77.1+/-8.3 to 109.7+/-14.9 beats/min) (P<<0.05). In the adenosine group only one patient (10%) had a raised creatine phosphokinase (MB) level at 12 h post-operatively as compared to three patients (30%) in the control group (P<0.05).

Adenosine pretreatment appears to protect against reperfusion injury in human hearts and thus results in improved post-operative haemodynamics.