[Effects of a nucleotide-nucleoside mixture on ischemic muscle metabolism in patients with stage II peripheral arterial occlusive disease. MR spectroscopic and biochemical analytic results].

In order to assess the acute metabolic effects of an intra-arterial infusion of nucleotide-nucleoside-mixture (NNM), 31P-mr-spectroscopy at the site of m. gastrocnemius and metabolite determinations from blood of the femoral artery and vein were carried out in 10 patients with PAOD stage II during ergometric calf exercise to the claudication pain limit. The spectroscopic measurements revealed a greater exercise-induced fall of PCr and a higher increase of Pi in calf muscles during supply of NNM compared with control ergometry. Post-exercise recovery of PCr was distinctly delayed during infusion of NNM. The anaerobic production of energy, however, was sufficient to maintain the ATP concentration to the same extent as under control ergometry. On the other hand, intramuscular lactate acidosis developed to a lower degree with NNM infusion than without NNM. A reduced muscular release of lactate, pyruvate, ammonia and alanine followed from the evaluation of the arteriovenous balance of these metabolites in the femoral vessels indicating a favourable global metabolic effect of NNM infusion in the extremity. The apparent contradiction in the spectroscopic and analytic-biochemical findings can be explained by local blood shunts induced by maximum vasodilation. Noninvasive mr-spectroscopy allows to detect directly and continuously the metabolic impact of ischemia in the calf muscles afflicted by arterial occlusion, whereas the metabolite concentrations in femoral blood are altered by afflux from non-ischemic areas. The known clinical benefit of frequently repeated intra-arterial infusions of NNM is thought to be due to an expansion of collateral circulation and to a favourable influence on endothelial functions.