Myocardial preconditioning using adenosine: review and clinical experience.

Adenosine is an endogenous nucleotide and a breakdown product of adenosine triphosphate. Adenosine has been proposed as a mediator of the ischaemic preconditioning phenomenon. Ischaemic reperfusion injury incurred during and following cardiopulmonary bypass contributes to depressed myocardial function after cardiac surgery. It is believed that administering adenosine via the aortic root, immediately following aortic crossclamping as well as just prior to removal of the aortic crossclamp, provides myocardial preconditioning resulting in improved cardiac protection during ischaemic arrest and retarding ischaemic reperfusion injury. A retrospective analysis was done utilizing consecutive patients undergoing coronary artery bypass grafting performed by the same surgeon. Some of the patients received myocardial preconditioning with adenosine. A comparison was made in postoperative cardiac function between patients who underwent myocardial preconditioning and those who did not receive adenosine. Results demonstrate a greater improvement in postoperative cardiac function, when compared to preoperative values, in those patients receiving myocardial preconditioning with adenosine.

The effect of low-dose epsilon-aminocaproic acid on patients following coronary artery bypass surgery.

The effect of low-dose epsilon-aminocaproic acid (EACA) on the postoperative course of 46 patients was studied. Patients undergoing coronary artery bypass grafting were randomly selected in two groups. Group 1 (20 patients) received 5 g EACA upon initiation of cardiopulmonary bypass (CPB). Group 2 (26 patients) received no antifibrinolytic drugs prior to CPB. Neither group received antifibrinolytic drugs after CPB. There was no significant difference between the two groups' blood usage on CPB: 0.65 units in Group 1 and 0.60 units in Group 2. After CPB, blood usage significantly differed: 2.2 +/- 1.7 (SD) units in Group 1 and 3.9 +/- 3.0 units in Group 2 (p = 0.033). Significant difference was also demonstrated in postoperative blood loss in the first 24 hours: 1610 +/- 531 ml in Group 1 versus 2025 +/- 804 ml in Group 2 (p = 0.043). Pre-CPB administration of low-dose EACA significantly decreases blood loss and blood usage in the postoperative period.

Coronary artery bypass grafting in a patient with haemophilia B.

Patients with coagulation disorders present the entire open-heart surgical team with an increased challenge. A patient with a known history of moderately severe Factor IX deficiency (2.4% activity) was evaluated for coronary artery disease. Cardiac catheterization revealed a 99% right coronary artery lesion, a long 99% circumflex lesion and normal left ventricular function. Sextuple coronary artery bypass grafting was performed with the aid of aprotinin and Factor IX transfusions. The patient's platelet count after cardiopulmonary bypass was 65,000/mm3, down from a preoperative level of 172,000/mm3, requiring the transfusion of six units of pooled platelets immediately postoperation. The patient was extubated five and a half hours after arriving in the Intensive Care Unit, and his chest-tube drainage after the first 24 hours was 373 ml. Other than a transient episode of atrial fibrillation on the third postoperative day, the patient had an uneventful postoperative course and was discharged on the sixth postoperative day. With the use of aproptinin and the newer monoclonal antibody-purified Factor IX concentrates that have been developed, many of the added risks of performing open-heart surgery on patients with haemophilia B are greatly reduced if not eliminated.