THE EFFECT OF ARTERIAL RECONSTRUCTION ON THE NATURAL-HISTORY OF DIABETIC NEUROPATHY

Objective: To determine whether reversal of hypoxia slows the progress ion of neuropathy. Design: Cohort study with a mean follow-up of 19.2 months. Setting: Institutional and private hospital. Patients: A volun teer sample of 55 patients with diabetes (mean age, 62 years; range, 3 0-74 years; mean duration of diabetes, 21 years; range, 1-57 years) re quiring lower-extremity arterial bypass. Twenty-one successfully treat ed patients were reexamined at the conclusion of the study. Neuropathy and hypoxia were assessed the day before the operation and during the follow-up visit. Intervention: Lower-extremity arterial reconstructio n. Main Outcome Measures: Peroneal nerve conduction velocity and trans cutaneous oxygen tension. Results: In the leg operated on, the peronea l nerve conduction velocity remained unchanged during the follow-up pe riod (preoperative, mean [+/-SD] 35.79+/-6.02 vs postoperative 35.33+/ -7.51 m/s; P>.05), but deteriorated in the leg not operated on (36.68/-6.22 vs 33.64+/-7.30 m/s; P<.05, Wilcoxon signed rank test). Transcu taneous oxygen tension increased in the revascularized extremity (mean [+/-SD] 40.62+/-24.76 vs 66.73+/-14.89 mm Hg) but remained unchanged in the leg not operated on (56.76+/-17.07 vs 62.00+/-15.66 mm Hg; P>.0 5). Of the entire cohort, 5 patients died during the study period. Gra ft occlusion occurred in 10 (17%) of 59 extremities. Subset analysis d isclosed that the preoperative transcutaneous oxygen tension was signi ficantly higher in the successfully revascularized extremities (41.98/-23.58 vs 24.10+/-21.50 mm Hg; P<.001). Conclusions: Reversal of hypo xia halts the progression of diabetic neuropathy, lending further supp ort to the role of hypoxia in the pathogenesis of nerve destruction in diabetes mellitus. Preoperative transcutaneous oxygen tension is lowe r in patients with bypass failure, but the severity of neuropathy does not affect the outcome of the operation.