Cardiac and cerebrovascular diseases are currently the leading causes of
mortality and disability worldwide. Both the heart and brain display
similar vascular anatomy, with large conduit arteries running on the
surface of the organ providing tissue perfusion through an intricate
network of penetrating small vessels. Both organs rely on fine tuning of
local blood flow to match metabolic demand. Blood flow regulation
requires adequate functioning of the microcirculation in both organs,
with loss of microvascular function, termed small vessel disease (SVD)
underlying different potential clinical manifestations. SVD in the
heart, known as coronary microvascular dysfunction, can cause chronic or
acute myocardial ischemia and may lead to development of heart failure.
In the brain, cerebral SVD can cause an acute stroke syndrome known as
lacunar stroke or more subtle pathological alterations of the brain
parenchyma, which may eventually lead to neurological deficits or
cognitive decline in the long term. Coronary microcirculation cannot be
visualized in vivo in humans, and functional information can be deduced
by measuring the coronary flow reserve. The diagnosis of cerebral SVD is
largely based on brain magnetic resonance imaging, with white matter
hyperintensities, microbleeds, and brain atrophy reflecting key
structural changes. There is evidence that such structural changes
reflect underlying cerebral SVD. Here, we review interactions between
SVD and cardiovascular risk factors, and we discuss the evidence linking
cerebral SVD with large vessel atheroma, atrial fibrillation, heart
failure, and heart valve disease.
