‘Distensibility’ of the papaverine-relaxed vascular bed in human subcutaneous tissue

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Abstract
The effect of an increase in vascular transmural pressure on blood flow in 2 s.c. vascular beds, maximally dilated by papaverine was studied in 6 healthy humans. Blood flow as measured on the dorsum of the hand and at the lateral malleolus by the local 133Xe washout technique. Increase in vascular transmural pressure was induced by lowering the labeled area various distances below heart level. Lowering the area caused an increase in blood flow. The increase was less pronounced in the legs than in the hand. As arterial perfusion pressure head remained constant during lowering indicating that the relative decrease in vascular resistance was smaller in the leg than in the hand. Experimental edema did not influence the relative decrease in vascular resistance. Distensibility of the resistance vessels is apparently smaller in the leg than in the hand and might be due to a structural adaptation of the wall of vessels often subjected to increased hydrostatic pressure i.e., as in hypertension.