Cutaneous vascular control in the arms of women with postmastectomy oedema

The control of forearm skin blood flow was examined in the swollen arms of twelve women with oedema caused by breast cancer treatment. The swollen arm was compared with the opposite unaffected (control) arm. Using laser Doppler flux (LDF) and continuous finger blood pressure (BP) measurements, vascular control was tested by applying a range of provocations previously shown to alter cutaneous vascular resistance (CVR) in healthy subjects. The tests and the accepted mechanism were: post-ischaemic hyperaemia (locally mediated vasodilatation), inspiratory gasp and cool reflex (both sympathetically mediated vasoconstriction), arm dependency (locally mediated vasoconstriction), and core heat load (sympathetically mediated vasodilatation). CVR was calculated as BP/(LDF-biological zero). Three differences between the control and swollen arms were identified. (i) The laser Doppler biological zero signal was significantly higher on the swollen side (P = 0.005, Student's paired t test). (ii) Baseline LDF was significantly lower on the swollen side (P = 0.002), and apparent CVR correspondingly higher. (iii) Cumulative reactive hyperaemia (area under the LDF curve above baseline) was significantly less on the swollen side (P = 0.03), although peak flux was not significantly different. Inspiratory gasp, cool reflex, arm dependency and core heat load produced changes of similar magnitude in both arms. It appears that sympathetic neural control and local vasoconstrictor control in arm dependency are normal in arm lymphoedema but that locally mediated vasodilator control is impaired. In addition, baseline skin blood flow may be reduced in this condition. The results provide no support for impairment of vascular tone as a contributory factor to the oedematous state.