EFFECTS OF CAPTOPRIL ON MYOCARDIAL PROTECTION DURING CARDIOPLEGIA

The study aimed at checking effects exerted by captopril (C) on human myocardial ACE system as well as the role played by tissue ACE inhibit ion in reducing reperfusion damage. A human experimental model was use d during cardioplegia due to aorto-coronary-by-pass (CABG). Fifty-four patients with coronary artery disease affecting 3 vessels having suff ered from acute myocardial infarction anterior (AMI-ant), homogenous a s far as ejection fraction (35-55%), number of grafts (3), clamping ti me, age and sex, were randomised in a double blind experiment, and wer e given captopril of placebo (P). A total of 4 mg/l Captopril was mixe d into the cardioplegic solution with blood according to the method of Buckberg (Buckberg GD. J Thorac Cardiovasc Surg 1987; 93: 127-139). E ight samples (blood/perfusate) were obtained from each patients and no repinephrine (NE), epinephrine (E) were assayed using an HPLC techniqu e. Angiotensin I was assayed by RIA. CK was also assayed (units/ml). B lood/perfusate samples were taken during CABG: (1) pre-pump; (2)pump s ample; (3) pump preclamping; (4) pump preclamping; (4) coronary sinus; (5)coronary sinus sample during reperfusion; (6) coronary sinus durin g warm reperfusion; (7) after clamping sample; (8) after decanulation; Results: Captopril group (29 patients): angiotensin I: (1) 8.15; (2) 7.0; (4) 8.45; (5) 8.93 (6) 8.73; (7) 9.07; (8) 9.40; versus placebo: (1) 7.09, (2) 7.43; (3) 7.80; (4) 9.31; (5) 9.01; (6) 8.35; (7) 8.85; (8) 8.07; ng/ml, probability, not significant. NE: captopril group: (1 ) 359; (2) 404; (3) 333; (4) 296; (5) 263; (6) 216; (7) 310; (8) 337; vs. placebo: (1) 408; (2) 437; (3) 422; (4) 371; (5) 494; (6) 530; (7) 464; (8) 399; pg/ml (P < 0.01). CK, captopril group: (1) 79; (2) 95; (3) 100; (4) 94; (5) 104; (6) 94; (7) 108; (8) 108; vs. placebo: (1) 7 6; (2) 120; (3) 135; (4) 152 (5) 225; (6) 272; (7) 247; (8) 228; units /ml. (P < 0.01). E values showed no significant difference between the two groups. The decrease in NE and CK and increase in angiotensin I i n treated patients as compared with controls suggest some effects exer ted by captopril on ACE-T and its ability of reducing reperfusion dama ge and recommeds its use for heart protection during CABG.