CIRCADIAN VARIATION OF SKIN PERFUSION IN ARTERIAL OCCLUSIVE DISEASE

Background: Many physiological processes are subjected to circadian va riation. We tested if circadian changes of skin perfusion can be detec ted by measuring laser Doppler flux (LDF) in the foot and if such vari ations are different in patients with peripheral arterial occlusive di sease (PAOD). Patients and Methods: LDF was recorded hourly during a 2 4-hour period in 10 healthy subjects and in 19 PAOD patients, 9 presen ting with claudication (stage II according to Fontaine, ankle artery p ressures (AP) 80 +/- 11 mmHg) and 10 with skin necrosis (stage IV, AP 42 +/- mmHg). Results: Circadian variability of LDF was significantly reduced in stage IV patients compared both with stage II patients and controls (p < 0.01). An increase in LDF could be observed early in the afternoon and, same extent in healthy and PAOD patients in stage II s ignificant and a decrease was observed in two patients. LDF and local skin temperature were correlated in controls and stage II patients (me an r = 0.69 +/- 0.12 and 0.07 +/- 0.14, respectively), but not in stag e IV (mean r = 0.23 +/- 0.18). A further limitation of LDF variability and nocturnal increase was seen in the presence of diabetes. Conclusi on: Circadian variations of skin blood flow are comparable in controls and patients with claudication but markedly reduced in patients with severe PAOD presenting with ulcers, in whom skin perfusion seems uncou pled from temperature regulation, possibly due to local factors causin g continuous arteriolar vasodilation.