EFFECTS OF PENTOXIFYLLINE ON CHOROIDAL BLOOD-FLOW IN NONPROLIFERATIVEDIABETIC-RETINOPATHY

Objective: Diminished blood flow plays an important role in the progre ssion of diabetic retinopathy Since increased blood viscosity is a con tributing factor to hypoperfusion, it was of interest to determine whe ther therapy intended to decrease blood viscosity and induce vasodilat ion could increase blood flow in patients with diabetic retinopathy. M ethodology: Ten patients, 4 with nonproliferative diabetic retinopathy and 6 age-matched, nondiabetic controls, were studied by a noninvasiv e system to index choroidal blood flow. Pentoxifylline was administere d daily at an oral dose of 400 mg tid in the diabetic patients for nin e months. Results: The control group had pulse amplitude=2.87 +/- 0.67 mm Hg with pulsatile choroidal blood flow=714 +/- 196 muL/minute. Rep roducibility studies in the control group (6 patients measured on thre e separate occasions) demonstrated an intraclass correlation coefficie nt of reliability, r=0.83. In the diabetic patients, pulsatile flow=27 6 +/- 68 muL/minute, 61% lower than the age-matched nondiabetic subjec ts (P=0.003). After nine months of pentoxifylline therapy the diabetic patients had an increase in pulsatile choroidal blood flow to 469 +/- 152 muL/minute (P < 0.002). Conclusions: Pentoxifylline therapy broug ht blood flow levels in the diabetic patients closer to those of the n ondiabetic age-matched control population so that following therapy th ere was no statistically significant difference between the two groups although the former were still lower. The potential efficacy of pento xifylline in improving ocular blood flow in patients with diabetic ret inopathy should be tested in a large controlled clinical trial.