The role of strict metabolic control by insulin infusion on fibrinolytic profile during an acute coronary event in diabetic patients

Background: Many clinical and laboratory observations give support to the h ypothesis that strict metabolic control by insulin infusion during acute co ronary events may improve the ischemic damage and prognosis. Hypothesis: We investigated the impact of intensive insulin treatment on fi brinolytic parameters during an acute ischemic myocardial event (unstable a ngina or acute myocardial infarction) in patients with type 2 diabetes mell itus. Methods: The study group consisted of 48 type 2 diabetic patients, of whom 24 were randomized to conventional therapy plus intensive insulin treatment (Group 1) and 24 to conventional therapy only (Group 2). The two groups we re comparable according to gender, age, body mass index, waist:hip ratio, d uration of diabetes, previous antidiabetic treatment, type of ischemic even ts, concomitant therapy, and the classic risk factors for coronary disease. Insulin-treated patients were excluded from the study. Plasma levels of fi brinogen, tissue plasminogen activator (t-PA), and plasminogen activator in hibitor-1 (PAI-1) were measured on admission and discharge. Fibrinogen (fib r) was measured using the photometric method. PAI-1 and t-PA were measured by enzyme-linked immunosorbent assays. Results. T-PA increased in both groups during hospitalization (t-PA(admissi on) vs. t-PA(discharge): Group 1: 15.42 +/- 4.4 ng.ml(-1) vs. 21.2 +/- 5.74 ng.ml(-1), p = 0.000037; Group 2: 14.47 +/- 6.31 ng.ml(-1) vs. 19.18 +/- 6 .88 ng.l(-1), p = 0.001). On the other hand, fibr and PAI-1 levels increase d remarkably in controls (Group 2, fibr(admission) vs. fibr(discharge): 2.9 8 +/- 1.04 g.l(-1) vs. 3.59 +/- 1.01 g.l(-1), p = 0.002, and PAI-1(admissio n) vs. PAI-1(discharge): 30.6 +/- 17.34 ng.ml(-1) vs. 40.62 +/- 23.48 ng.ml (-1), p = 0.003). This finding was not observed in the intensive insulin tr eatment group (Group 1, fibr(admission) vs fibr(discharge): 2.87 +/- 0.73 g .l(-1) vs. 2.67 +/- 0.72 g.l(-1), p = 0.101, and PAI- 1(admission) vs. PAI- 1(discharge): 30.75 +/- 15.81 ng.ml(-1) vs. 27.75 +/- 6.43 ng.ml(-1), p = 0 .484). Conclusion: Intensive insulin treatment during an acute coronary event impr oves fibrinolytic profile in patients with diabetes mellitus. This is a pos sible mechanism for the reduced short- and long-term mortality in diabetic patients treated with intensive insulin treatment protocol.