Influence of age on venous physiologic parameters.

PURPOSE: The incidence of deep venous thrombosis increases significantly with age. Attempts to explain this association have failed to identify factors that could be contributory. We hypothesized that age-related changes in venous physiologic parameters might contribute to an increased risk of deep venous thrombosis.

METHODS: Air plethysmography was used to measure a number of physiologic parameters in two sets of patients. Group A consisted of 17 subjects (33 limbs), age range 23 to 40 years. Group B consisted of 11 subjects (22 limbs), age range 60 to 83 years. No subject in either group had peripheral vascular disease or a history of deep venous thrombosis. Parameters measured were venous volume, venous filling index, ejection volume, ejection fraction, residual volume fraction, and outflow fraction.

RESULTS: Venous volume and ejection fraction were significantly reduced in Group B compared with Group A. Residual volume fraction was significantly increased in Group B compared with Group A. There were no statistically significant differences in outflow fraction, venous filling index, or ejection fraction between the two groups.

CONCLUSIONS: These results suggest that the efficiency of the calf muscle pump diminishes with increasing age, possibly contributing to the increased incidence of deep venous thrombosis in the elderly.