Microvascular hemodynamics in hypertension and diabetes.

Microvascular damage occurs in both diabetes and hypertension and hypertension is a risk factor for diabetic microangiopathy. In both conditions, indirect evidence suggests that capillary pressure might be raised. A servonulling pressure measuring technique has been used in conjunction with direct micropuncture of finger nailfold capillaries to determine capillary pressure dynamically. In patients with essential hypertension, capillary pressure is raised compared to matched normotensive controls. In insulin-dependent diabetic patients, capillary pressure is also raised, to a degree that correlates with recent diabetic control. In a pilot study of hypertensive diabetic patients, elevated capillary pressure has been normalized using an angiotensin-converting enzyme inhibitor. Manipulation of microvascular hemodynamics in diabetes and hypertension may provide a means of protecting against the microvascular complications of these two conditions.