Only recently, technology has been sufficient to assess microcirculatory function in intact humans. As a result, it is becoming apparent that the microcirculation is importantly involved in a variety of pathological conditions, and that microvascular dysfunction may herald, either as a marker or as a mechanism, the development of cardiovascular disease (CVD).
This review will discuss the growing recognition that the microcirculation contributes to the development of atherosclerotic CVD, review regulation of the coronary microcirculation in humans, and discuss potential novel functions of the microcirculation, beyond regulating perfusion that might explain the intimate link to CVD.
Growing recognition that microcirculatory abnormalities contribute to cardiac prognosis supports the need for a more direct and focused understanding of how microvascular function is regulated in humans.
A number of conditions are closely associated with microvascular dysfunction. Diabetes mellitus manifests multiorgan pathology resulting from microvascular dysfunction. Nahser et al17 showed lower CFR and reduced metabolic dilation in diabetes mellitus, signs of impaired microvascular function. Di Carli et al18 expanded this observation by showing normal baseline flow but similarly reduced endothelium-dependent and endothelium-independent (dilation to adenosine) microvascular dilator capacity in young subjects with either type I or type II diabetes mellitus. Reduced dilation to adenosine persisted after controlling for duration of diabetes mellitus, insulin treatment, and autonomic neuropathy.18