Percutaneous transluminal angioplasty (PTA) provokes a huge trauma to the arterial wall and potentially liberates fragments of atherosclerotic material that may impair the microcirculation downstream. Incidence and clinical relevance of such embolisms are not known. This study was aimed at investigating the changes of the skin microcirculation in patients with peripheral arterial occlusive disease undergoing PTA of the lower limbs. Pedal transcutaneous oxygen tension (tcpO2) and nailfold skin microcirculation were measured in 21 patients with disabling peripheral arterial occlusive disease before and after PTA. Sixteen matched patients undergoing arteriography alone were used as controls. The skin microcirculation was investigated at the nailfold of the great toe by the combination of laser Doppler fluxmetry and dynamic capillaroscopy. PTA was successful in all patients. The tcpO2 decreased immediately after PTA (delta tcpO2 = -5 mm Hg; p < 0.004), whereas it tended to increase (delta tcpO2 = 1 mm Hg; NS) following arteriography as compared with baseline values. By contrast, blood flow increased in both groups, predominantly for the total circulation in the PTA group and for nutritional circulation (p < 0.0017) in the arteriography group, respectively. Consequently, the 'nutritional index', i.e., the index of nutritional versus total microcirculation, was decreased following PTA, particularly following mechanical recanalization (p < 0.02), but did not change in the controls. The changes of this 'nutritional index' and those of the tcpO2 were positively correlated (r = 0.4, p = 0.023).(ABSTRACT TRUNCATED AT 250 WORDS)