Peripheral vascular disease (PVD) is associated with numerous pathophysiological adaptations of the microvasculature. Considering this, active and passive pressure-dependent and pressure-independent mechanisms of vascular control were studied in small resistance arteries isolated from patients with PVD. Using pressure myography and confocal microscopy, human skeletal muscle arteriolar structure and function were compared between paired arteries; one isolated from the healthy non-diseased proximal skeletal muscle vascular bed (PSM, internal control) and the other from the diseased ischaemic part of the leg [distal skeletal muscle (DSM)]. Structurally, arteries isolated from the diseased part of the leg displayed significant atrophy compared with the non-diseased arteries. Functionally, no differences were observed in the fundamental ability small resistance arteries to contract or relax. However, active pressure-dependent myogenic contraction was significantly reduced in DSM arteries compared with PSM arteries. DSM versus PSM; 3 ± 1% versus 22 ± 4% and 3·4% ± 1·1% versus 25 ± 4% at 80 and 120 mmHg, respectively. Furthermore, structural remodelling in DSM arteries could also be correlated with significant changes in vascular wall mechanics. DSM arteries displayed significantly greater incremental dispensability, wall stress and wall strain compared with PSM arteries as a product of pressure-dependent distension. These alterations in pressure-dependent active myogenic tone and passive mechanical properties goes some way to explain uncontrolled orthostatic-dependent changes in leg fluid volume and oedema formation experienced by these patients.
- peripheral vascular disease
- pathophysiological adaptations
- arteriolar structure