Exercise-induced central retinal vein thrombosis: possible involvement of hemorheological disturbances. A case report.

Exercise-induced impairment in blood fluidity has been supposed to increase cardiovascular risk but there is no data to support this hypothesis. We report the case of a 50 yr old marathon runner who underwent a central retinal vein thrombosis after a marathon run. We investigated his rheological response to exercise compared to control subjects of previous studies. During a standardized sub-maximal exercise-test, the increase in blood viscosity (+28%) and hematocrit (+25%) exceeded the control range but the most striking differences were found for red cell aggregation (Myrenne +47%) and disaggregation thresholds (Affibio +37%). Although some of this post-exercise hyperviscosity pattern may be due to the previous vascular event, these findings may also support the hypothesis of a role for hemorheological alterations during exercise in the pathogenesis of this marathon-induced retinal thrombosis, and indicate that after such an event hemorheological adaptation to exercise remains markedly disturbed.