[Noninvasive assessment of endothelial function in hemodialyzed hypertensive patients by laser Doppler flowmetry]

End stage renal disease and hypertension are associated with higher cardiovascular mortality. Endothelial dysfunction plays an important role in the pathogenesis of cardiovascular diseases. The authors investigated the endothelium-dependent and -independent vasodilation in the forearm skin microcirculation and the plasma markers of endothelial damage in hypertensive hemodialysed patients and in normotensive control subjects.

Laser Doppler flowmetry with iontophoresis of acetylcholine and sodium nitroprusside and the postocclusive reactive hyperemia test was performed in 22 normal control subjects and in 21 hemodialysed patients with hypertension. Levels of endothelin-1, big-endothelin, and von Willebrand Factor were measured, as well.

The average hyperemic response to the two doses of acetylcholine iontophoresis was 474 +/- 83%; 836 +/- 97% in the control subjects, and 160 +/- 26%; 360 +/- 67% in the hemodialysed patients group (p < 0.05). The vasodilation after the two doses of sodium nitroprusside was 381 +/- 60%, 782 +/- 81% in the control group and 186 +/- 42%; 379 +/- 63% in the dialysed patients group (p < 0.05 compared to control, respectively). The average peak flow during the postocclusive reactive hyperemia test was significantly lower in hemodialysed hypertensives (234 +/- 48%) compared to healthy control subjects (434 +/- 36%, p < 0.05). Levels of endothelin-1, big endothelin, von Willebrand Factor and von Willebrand Factor activity were significantly higher in the patient group compared to the control subjects.

In hemodialysed hypertensive patients, both endothelium-dependent and -independent vasodilation are impaired. Markers of endothelial damage are elevated referring the progression of vascular disease.