Effects on reperfusion injury of adding diltiazem to tepid blood cardioplegia.

Background: Although the present techniques of myocardial preservation for limiting ischemia/reperfusion injury in open heart operations yield excellent results for most patients, certain subgroups of patients with advanced coronary artery disease present a challenge in terms of intraoperative safety.

Methods: In a prospective, randomized, controlled study, we assessed the myocardial protective effects of a total dose of 150 +/- 150 = 300 microg/kg diltiazem added to induction and terminal (reperfusion) doses of tepid blood cardioplegia. We determined the myocardial morphological (ultrastructural) and enzymatic (serum assays for the cardiospecific isoenzyme of creatine kinase [CK-MB]) changes and functional recovery (atrioventricular [AV]-node recovery time and postoperative need for inotropic support) in patients undergoing elective coronary artery bypass operations. The determinations were made with respect to values for control patients, who received the same cardioplegia but without the addition of diltiazem.

Results: The mean isoenzyme CK-MB levels and semiquantitative ultrastructural score values of the diltiazem group were significantly less than those of the control group. Although AV-node recovery time was significantly prolonged (P < .05), this factor did not have major clinical impact.

Conclusions: We concluded that the addition of 150 +/- 150 microg/kg diltiazem to the induction and terminal doses of tepid cardioplegia enhanced myocardial protection in elective aortocoronary bypass surgery in high-risk patients and presented no significant additional operative risk.