Predictive value of distal perfusion pressure in the healing of amputation of the digits and the forefoot.

To evaluate the role of distal perfusion pressure in predicting the healing of 31 digit and forefoot amputations preoperative digital, transmetatarsal and ankle systolic pressures were retrospectively compared with the eventual results of amputation. A photoplethysmography transducer placed distal to an occluding cuff was used to measure digital and transmetatarsal level systolic blood pressure. Ankle pressures were measured with Doppler ultrasound. Twenty-six amputations healed initially, whereas, four required reamputation proximal to the ankle. There was no difference in mean ankle Doppler pressure between the healed and failed groups. Mean photoplethysmography derived transmetatarsal pressure was significantly higher in the healed group, 116 +/- 47 millimeters of mercury as compared with the failed group, 44 +/- 88 millimeters of mercury. The difference in mean photoplethysmography digital pressure in the healed and failed groups--75 +/- 36 and 4 +/- 9 millimeters of mercury, respectively--was highly significant, p less than 0.001. Failure of digit or forefoot amputation occurred in all limbs with photoplethysmography derived pressures of less than 20 millimeters of mercury. A transmetatarsal or digital photoplethysmography pressure of greater than 20 millimeters of mercury was associated with amputation healing in all instances. These data suggest that photoplethysmography distal perfusion pressures may be valid predictors of the healing potential of minor foot amputations for end stage ischemia.