Intraperitoneal metabolic consequences of supraceliac aortic balloon occlusion in an experimental animal study using microdialysis.

BACKGROUND: To investigate the effects of supraceliac aortic balloon occlusion (ABO) and superior mesenteric artery (SMA) occlusion on abdominal visceral metabolism in an animal model using intraperitoneal microdialysis (IPM) and laser Doppler flowmetry. METHODS: A total of 9 pigs were subjected to ABO and 7 animals were subjected to SMA occlusion for 1 hour followed by 3 hours of reperfusion. Seven animals served as controls. Hemodynamic data, arterial blood samples, urinary output, and intestinal mucosal blood flow (IBF) were followed hourly. Intraperitoneal (i.p) glucose, glycerol, lactate, and pyruvate concentrations and lactate-to-pyruvate (l/p) ratio were measured using IPM. RESULTS: Compared with the baseline, ABO reduced IBF by 76% and decreased urinary output. SMA occlusion reduced IBF by 75% without affecting urinary output. ABO increased the i.p l/p ratio from 18 at baseline, peaking at 46 in early reperfusion. SMA occlusion and reperfusion tended to increase the i.p l/p ratio, peaking at 36 in early reperfusion. ABO increased the i.p glycerol concentration from 87 µM at baseline to 579 µM after 3 hours of reperfusion. SMA occlusion and reperfusion increased the i.p glycerol concentration but to a lesser degree. CONCLUSIONS: Supraceliac ABO caused severe hemodynamic, renal, and systemic metabolic disturbances compared with SMA occlusion, most likely because of the more extensive ischemia-reperfusion injury. The intra-abdominal metabolism, measured by microdialysis, was affected by both ABO and SMA occlusion but the most severe disturbances were caused by ABO. The i.p l/p ratios and the glycerol concentrations increased during ischemia and reperfusion and may serve as markers of these events and indicate anaerobic metabolism and cell damages respectively.

Extracellular purine metabolism in blood vessels (Part II): Activity of ecto-enzymes in blood vessels of patients with abdominal aortic aneurysm.

Both platelet aggregation and high blood pressure are associated with development of atherosclerosis. Among other factors that modulate platelet aggregation and blood pressure, extracellular purines (e-purines) influence these processes via purinoceptors P1 and P2 for which they are natural ligands. We hypothesized that ecto-enzymes such as nucleoside triphosphate diphosphohydrolases (NTPDases), adenylate kinase, 5'-nucleotidase, and adenosine deaminase that regulate the level of e-purines may be involved in the development of atherosclerosis. The enzymatic assays were performed either on the fragments of human abdominal aortas obtained after death or on abdominal aneurysm samples collected during surgery. The substrates and products such as adenine nucleosides and nucleotides were analyzed using reverse phase high-performance liquid chromatography (HPLC) method. Here, we estimated and demonstrated the activities of these ecto-enzymes in the patients with atherosclerosis or atherosclerosis-like diseases such as abdominal aneurysm, myocardial infarction, or Leriche syndrome (LS) with worse thrombosis of extremities. In particular, we noticed reduction in activity of NTPDase1(app), NTPDase2(app), ecto-adenylate kinase( app), and ecto-adenosine deaminase(app); however, ecto-5'-nucleotidase(app) that hydrolyzed e-adenosine monophosphate (e-AMP) into e-adenosine did not show any significant changes. This led us to suggest that alteration of the activity of examined ecto-enzymes is responsible for the development of atherosclerosis or atherosclerosis-like diseases.

Intraoperative continuous hemofiltration for metabolic management in acute aortoiliac occlusion.

Acute aortoiliac occlusion, or Leriche's syndrome, carries a risk of the development of severe ischemia-reperfusion injury, characterized by electrolyte and acid-base balance disturbances. These injuries are often fatal, because of the rapid deterioration of multiple organ systems. We present a case in which we intraoperatively and postoperatively treated hyperkalemia and metabolic acidosis by high-volume, continuous, veno-venous hemofiltration, which is a recently developed form of continuous renal replacement therapy.