The effect of naftidrofuryl on transcutaneous oxygen tension during a treadmill test in patients with peripheral arterial occlusive disease

Tissue hypoxaemia can be evaluated by the noninvasive method of transcutaneous oxygen tension (tcpO2) measurement in patients with peripheral arterial occlusive disease (PAOD). The effects of naftidrofuryl (Praxilene) on exercise-induced tissue ischaemia was objectively assessed by continuously measuring the tcpO2 in 30 patients during three treadmill tests over a 3-month period in a randomized double-blind, placebo controlled, parallel group study. To be included in the study, the tcpO2 and total walking distance had to be stable during the washout period (D-15-D0). The area under the tcpO2 curves was scanned and automatically calculated after identification of baseline and the end of the treadmill test. The treadmill test on D30 and D90 was terminated at a similar walking distance to that obtained on D0. On D0 both groups were comparable (p = 0.22). The area under the curve (AUC) reduced significantly in the naftidrofuryl group between D0 and D30 (p < 0.001) and D0 and D90 (p < 0.001). However, no significant tcpO2 AUC reduction was found in the placebo group (D0-D30, p = 0.58; D0-D90, p = 0.50). This was confirmed by calculation of the percentage of patients whose percentage change in the AUC on D90 was higher than the upper limit of the 90% confidence interval, calculated from the percentage change over the washout period. Of the 15 patients receiving natfidrofuryl, 66.6% exceeded this upper limit, compared with only 7% of patients receiving placebo (p = 0.0017). This study shows that naftidrofuryl has a protective effect on exercise-induced tissue ischaemia as measured by the tcpO2 AUC in PAOD stage II patients.