EFFECT OF PERIOPERATIVE DILTIAZEM ON MYOCARDIAL-ISCHEMIA AND FUNCTION IN PATIENTS RECEIVING MAMMARY ARTERY GRAFTS

A prospective, randomized study was performed with 66 patients undergoing elective coronary bypass surgery involving internal mammary artery (IMA) grafts to the left anterior descending artery (LAD). Patients received a continuous peri-operative infusion of either diltiazem (0.1 mg. kg(-1) h(-1), n = 32) or nitroglycerin (I mu g. kg(-1) min(-1), n = 34) for 24 It. The aim of this study was to define the effect of the calcium channel blocker diltiazem on peri-opeative ischaemia, arrhythmias and myocardial function in patients receiving arterial bypass grafts by preventing transient vasospasm. The study patients did not differ with respect to pre-operative, operative and haemodynamic data. Patients treated with diltiazem had lower numbers of ventricular premature beats/hour (8.1 +/- 7.8 vs 20.5 +/- 11.2; P < 0.05). The anti-ischaemic efficacy of peri-operative diltiazem in patients receiving IMA grafts significantly reduced the incidence and duration of transient ischaemic events (0 vs 5). Additionally, patients receiving IMA grafts and diltiazem showed significantly lower peak levels of ischaemia-sensitive laboratory parameters, as compared to IMA graft patients receiving only nitroglycerin: CK-MB: 17.3 +/- 7.7 vs 23.5 +/- 11.0, (P < 0.05); MB-M: 29.4 +/- 14.7 vs 43.1 +/- 27.4, (P < 0.05); troponin-T: 0.88 +/- 0.6 vs 1.41 +/- 0.9, (P < 0.05). Postoperative regional systolic function of the anterior (AW) and lateral (LW) left ventricular wall, as assessed by the percent shortening fraction, was significantly improved with a trend to even better improvement in the diltiazem group: 55.1 +/- 14.2 vs pre-operative 37.0 +/- 13.0 (AW) (P < 0.001) and 46.4 +/- 13.0 vs pre-operative 34.0 +/- 13.0 (LW) (P < 0.01) compared to 49.1 +/- 13.0 vs pre-operative 37.3 +/- 12.0 (AW) (P < 0.05) in the nitroglycerin group. The results of our study suggest that diltiazem is efficacious in the prevention of peri-operative myocardial ischaemia in patients undergoing elective coronary bypass operation with TMA grafts.