CONTROLLED LIMB REPERFUSION TO REDUCE LOC AL AND SYSTEMIC COMPLICATIONS AFTER PROLONGED ISCHEMIA - AN EXPERIMENTAL-STUDY ON HOGS

Our previous studies in isolated rat hindlimbs using crystalloid perfu sion solutions have shown that control of the initial reperfusion redu ces postischemic complications. However, no experimental study has bee n undertaken to evaluate the concept of controlled limb reperfusion ex perimentally in an in-vivo blood-perfused model and to assess the loca l as well as systemic effects of normal blood reperfusion and controll ed limb reperfusion. Of twenty pigs undergoing preparation of the infr arenal aorta and iliac arteries, six were observed for 7.5 hours and s erved as controls. Fourteen other pigs underwent 6 hours of complete i nfrarenal occlusion. Thereafter, embolectomy was simulated in 8 pigs b y removing the aortic clamp and establishing normal blood reperfusion at systemic pressure. In 6 other pigs, control of the composition of t he reperfusate and control of the conditions of reperfusion was done d uring the first 30 min, followed by normal blood reperfusion. Six hour s of infrarenal aortic occlusion lead to a severe decrease in high ene rgy phosphates and muscle temperature and a slight increase in creatin e kinase (CK) and potassium in the systemic circulation. Normal blood reperfusion resulted in severe reperfusion injury: massive edema devel oped (80.6 % vs. 76.6 %, p < 0.0009), the tissue showed a marked decre ase in oxygen consumption (7.3 +/- 1.1 vs. 14.3 +/- 2.5 mt O-2/100 g/m in, p < 0.02), glucose consumption (0.19 +/- 0.06 vs. 0.51 +/- 0.03 mg /100 g/min, p < 0.06), tissue ATP (18.3 +/- 1.9 vs. 36.1 +/- 0.9 mu mo l/g protein, p < 0.000001), total adenine nucleotides (26.3 +/- 2.6 vs . 45.8 +/- 1.5 mu mol/g protein, p < 0.00001), muscle pH (5.9 +/- 0.1 vs. 7.3 +/- 0.1, p < 0.000006) and total calcium in the femoral vein ( 2.1 +/- 0.1 vs. 2.7 +/- 0.1 mmol/L, p < 0.002). Furthermore, a massive increase was seen in CK concentration (12,743 +/- 2,562 vs. 513 +/- 8 0 U/L, p < 0.0003), potassium (7.9 +/- 0.3 vs. 4.4 +/- 0.2 mmol/ L, p < 0.000001) and muscle rigidity (60 +/- 11 vs. 122 +/- 1 degrees, p < 0.00008). In sharp contrast, initial treatment of the ischemic skeleta l muscle by controlled limb reperfusion resulted in normal water conte nt (77.6 +/- 0.4 vs. 76.8 +/- 0.3 %), oxygen consumption (13.2 +/- 1.6 vs. 14.9 +/- 3.2 mL O-2/100 g/min), glucose consumption (0.58 +/- 0.1 8 vs. 0.46 +/- 0.11 mg/100 g/min), flow (5.4 +/- 1.1 vs. 4.6 +/- 0.5 m L/100 g/min) and muscle rigidity (106 +/- 4 vs. 122 +/- 1 degrees). Fu rthermore, controlled limb reperfusion resulted in higher total adenin e nucleotides content (78 % vs. 57 % of control), less tissue acidosis (6.6 +/- 0.2 vs. 5.9 +/- 0.1, p < 0.002), severely reduced CK release (2,618 +/- 702 vs. 12,743 +/- 2,562, p < 0.02) and potassium release (5.1 +/- 0.3 vs. 7.9 +/- 0.3 mmol/L, p < 0.0002) as compared to normal blood reperfusion. In conclusion this study shows that 6 hours of acu te infrarenal aortic occlusion will result in a severe reperfusion inj ury (postischemic syndrome) if normal blood at systemic pressure is gi ven in the initial reperfusion phase. In contrast, initial treatment o f the ischemic skeletal muscle by controlled limb reperfusion reduces the metabolic, functional and biochemical alterations.