Augmentation of skin flap survival by parenteral pentoxifylline

One prime factor implicated in flap necrosis is diminished blood flow. A known corollary of morbid ischaemia is an energy-dependent reduction in red blood cell deformability associated with an increase in whole blood viscosity. The newly available drug pentoxifylline is alleged to improve this red cell membrane defect in the low flow state, thereby improving the rheologic characteristics of blood. We studied its effect in a flap model with an ischaemic component and also measured changes in blood viscosity. A caudally-based dorsal flap in a rat model was used. Control (saline-treated) animals exhibited 74.8 +/- 9.8% flap survival. Three groups of animals were treated at different times with pentoxifylline with respect to date of surgery; all groups showed a statistically significant increase in flap survival compared to controls, ranging from 92.3 to 94.3% (p less than .01). Simultaneous viscometric measurements with a cone-plate viscometer were performed. The observed increase in flap survival did not, as suggested by other investigators, correlate dependably with viscosity reduction. Reasons for this are discussed.