[Prevention of per-operative myocardial ischemia with continuous nitroglycerin infusion]

Nifedipine reduces the incidence of myocardial infarction and transient ischemia in patients undergoing coronary bypass grafting

A randomized study was performed on 104 patients undergoing elective coronary artery bypass grafting to examine whether the infusion of nifedipine (n = 53) reduces the incidence of perioperative myocardial ischemia and necrosis in the early postoperative period. Continuous hemodynamic and three-channel Holter monitoring was performed for 24 hours and serial assessment of serum enzymes and 12-lead electrocardiography were performed for 36 hours postoperatively. Nifedipine (minimum dose, 10 micrograms/kg/hr for 24 hours) was applied from the onset of extracorporal circulation. The control group (n = 51) received nitroglycerin (minimum dose, 1 micrograms/kg/min for 24 hours). Using the combined analyses of electrocardiography and Holter recordings, myocardial ischemia was defined as being either a transient ischemic event (TIE), transient coronary spasm (TCS), or myocardial infarction (MI). The two groups did not differ with respect to preoperative New York Heart Association classification, age, history of myocardial infarction, extracorporal circulation and aortic cross-clamp time, number of distal anastomoses, or systemic and pulmonary hemodynamics. The incidence of perioperative myocardial ischemia was substantially lower in the nifedipine than in the nitroglycerin group [TIE: three of 53 patients (6%) versus nine of 50 patients (18%), p less than 0.001; MI: two of 53 patients (4%) versus six of 50 patients (12%), p less than 0.001; and TCS: none of 53 patients (0%) versus two of 50 patients (4%), p = NS].(ABSTRACT TRUNCATED AT 250 WORDS)

[Combination of nitroglycerin and vascular loading in abdominal aorta surgery]

Haemodynamic investigations were performed in nine patients during aortic surgery for Leriche's syndrome. Most of these patients had ischaemic heart disease without cardiac failure. Fluid loading was carried out before and during aortic clamping. It was controlled according to the optimal wedge pulmonary pressure determined the day before surgery. Only six of the nine patients receive nitroglycerin (NTG : 0.2 micrograms X kg-1 X min-1) throughout the operation. Before clamping, cardiac index was improved in patients treated with NTG. During clamping, the patients not treated with NTG showed a drop in cardiac index, an increase in peripheral resistance and in left cardiac work. After declamping, there were no haemodynamic differences between the two groups. Two patients not treated with NTG developed azotaemia postoperatively; one patient developed cardiac failure requiring a dopamine perfusion during surgery. In this series, the association of optimal volume loading with a peroperative perfusion of 0.2 micrograms X kg-1 X min-1 NTG gave a good haemodynamic stability.