The ability to predict successful healing of ulcerations and amputations of the ischemic forefoot continues to be a major clinical challenge, particularly in diabetic patients whose systolic Doppler ankle pressures are often artifactually elevated. We have used the techniques of laser Doppler velocimetry (LD) and transcutaneous oxygen tension monitoring (tcPo2) to quantitatively measure skin blood flow in the distal foot. Fifty-nine limbs were studied (48 patients), of which 37 (63%) were in diabetic and 22 (37%) in nondiabetic patients. All patients were admitted with ischemic ulcerations or gangrenous changes of the forefoot or digit. Twenty transmetatarsal or digital amputations were performed; the remainder of the lesions were débrided and allowed to heal by secondary intention or were covered by a skin graft. Before operation, the systolic pressure (expressed in millimeters of mercury, mean ± SEM) was measured by Doppler technique at the ankle, and the ankle/arm index calculated (n = 59 limbs). The tcPO1 (also expressed in millimeters of mercury, mean ± SEM) was measured from the dorsal foot (n = 56). The baseline skin blood flow velocity (SBFV) and pulse wave amplitude (PWA) were measured with the LD (expressed in millivolts, mean ± SEM) on the plantar aspect of the foot (n = 53 limbs). Criteria for successful healing included a tcPO2 of more than 10 mm Hg, the combination of an LD-SBFV of more than 40 mV and an LD-PWA of more than 4 mV, and an ankle systolic pressure of more than 30 mm Hg. With these criteria, the outcome was predicted correctly in 53 of 56 limbs (95%) by tcPO2, in 46 of 53 limbs (87%) with LD, and in 31 of 59 limbs (52%) with Doppler ankle systolic pressures. We conclude that the estimation of skin blood flow by tcPO2 and LD is significantly (p < 0.05) better than Doppler ankle pressure measurements in predicting the healing of forefoot ulcerations and amputations in diabetic and nondiabetic patients.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine