Digital pressure-flow relationships in subjects with Raynaud's phenomenon.

In order to determine whether subjects with Raynaud's phenomenon have altered digital hemodynamics in the warm basal condition, we characterized the digital pressure-flow relationships in seven subjects with Raynaud's phenomenon and compared the results with age and sex matched control subjects. Digital pressure-flow relationships were measured by the use of a plethysmographic technique during passive elevation of the arm. Normal subjects demonstrated a positive finger systolic pressure at zero flow (48.3 mmHg), indicative of a critical closing pressure, however, the closing pressure was significantly higher in the subjects who had a history of Raynaud's phenomenon (64.7 mmHg, p less than .001). In contrast, there was no significant difference found in the conductance measured as the slope of the pressure-flow relationship. Subjects with Raynaud's phenomenon demonstrated a correlation between finger systolic pressure and critical closing pressure suggesting that these subjects may regulate arterial pressure through a critical closing pressure mechanism.