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

A prospective, randomized study was performed with 66 patients undergo ing elective coronary bypass surgery involving internal mammary artery (IMA) grafts to the left anterior descending artery (LAD). Patients r eceived 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, arrhyth mias and myocardial function in patients receiving arterial bypass gra fts by preventing transient vasospasm. The study patients did not diff er with respect to pre-operative, operative and haemodynamic data. Pat ients treated with diltiazem had lower numbers of ventricular prematur e beats/hour (8.1 +/- 7.8 vs 20.5 +/- 11.2; P < 0.05). The anti-ischae mic efficacy of peri-operative diltiazem in patients receiving IMA gra fts significantly reduced the incidence and duration of transient isch aemic events (0 vs 5). Additionally, patients receiving IMA grafts and diltiazem showed significantly lower peak levels of ischaemia-sensiti ve 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 func tion of the anterior (AW) and lateral (LW) left ventricular wall, as a ssessed 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 nitrogly cerin group. The results of our study suggest that diltiazem is effica cious in the prevention of peri-operative myocardial ischaemia in pati ents undergoing elective coronary bypass operation with TMA grafts.