Svedman C, Cherry G W, Ryan T J
Department of Dermatology, Churchill Hospital, Oxford, U.K.
Acta Derm Venereol. 1998 Jul;78(4):258-61. doi: 10.1080/000155598441819.
Posture-induced microcirculatory changes in the lower leg were studied in venous leg ulcer patients and in control subjects by means of laser Doppler imaging (LDI), a technique which allows almost real-time mapping of the perfusion from a distance, each perfusion value constituting the mean of a number of measurements at separate sites. LDI values for intact skin with the subject supine were 0.39 (0.32, 0.47) V [geometric mean (gm -SD, gm +SD)] and 0.32 (0.15, 0.70) V in two age groups of controls and 0.91 (0.66, 1.24) V in patients (NS). Values were 2.04 (1.25, 3.35) V for skin at the ulcer margin, and 1.44 (0.72, 2.88) V in the ulcer proper. With the lower leg passively dependent, lower LDI values were obtained at all sites in all groups, the reduction in intact skin value being 62 +/- 11% (arithmetic mean +/- SD) (p < 0.01) in the younger controls, 43 +/- 24% (p < 0.01) in the older controls and 62 +/- 19% (p < 0.001) in the patient group, and the reduction in ulcer values being 45 +/- 27% (p < 0.05) for the margin and 52 +/- 23% (p < 0.001) for the ulcer proper. Thus, a high degree of postural vasoconstriction was present overall, even in the ulcer itself. Vasomotor tone in the skin of the lower leg was assessed by topical application of methyl nicotinate, a vasodilator. The skin perfusion value (supine position, no stimulus) was 71 +/- 31% (p < 0.01) of the drug-induced (assumed peak) hyperaemia value [0.60 (0.30, 1.10) V] in patients and 24 +/- 25% (p < 0.001) of the hyperaemia value (1.30 (0.64, 2.62) V] in the controls. It would appear that in ulcer patients the veno-arteriolar reflex, despite being comparable in magnitude to that in controls, may nonetheless be insufficient to reduce tone during dependency to a level similar to that in healthy controls.
通过激光多普勒成像（LDI）技术，对下肢静脉性溃疡患者和对照受试者因姿势改变引起的微循环变化进行了研究。该技术可对远处的灌注情况进行几乎实时的成像，每个灌注值是在不同部位多次测量的平均值。在两个对照组中，受试者仰卧时完整皮肤的LDI值分别为0.39（0.32，0.47）V [几何均值（gm - SD，gm + SD）]和0.32（0.15，0.70）V，患者组为0.91（0.66，1.24）V（无显著性差异）。溃疡边缘皮肤的值为2.04（1.25，3.35）V，溃疡部位的值为1.44（0.72，2.88）V。当下肢被动下垂时，所有组在所有部位的LDI值均降低，年轻对照组完整皮肤值降低62±11%（算术均值±标准差）（p < 0.01），老年对照组降低43±24%（p < 0.01），患者组降低62±19%（p < 0.001）；溃疡边缘值降低45±27%（p < 0.05），溃疡部位降低52±23%（p < 0.001）。因此，总体上存在高度的姿势性血管收缩，即使在溃疡本身部位也是如此。通过局部应用血管扩张剂烟酸甲酯评估小腿皮肤的血管运动张力。患者皮肤灌注值（仰卧位，无刺激）为药物诱导（假定峰值）充血值[0.60（0.30，1.10）V]的71±31%（p < 0.01），对照组为充血值（1.30（0.64，2.62）V]的24±25%（p < 0.001）。看起来在溃疡患者中，尽管静脉 - 小动脉反射的幅度与对照组相当，但在下肢下垂时可能仍不足以将血管张力降低到与健康对照组相似的水平。
