Oxidative stress in hypertensive patients induces an increased contractility in vein grafts independent of endothelial function.

Objective. To evaluate the impact of oxidative stress on vascular reactivity to vasoconstrictors and on nitric oxide (NO) bioavailability in saphenous vein (SV) graft with endothelial dysfunction from hypertensive patients (HT). Methods.

Nitric oxide modulates reactivity to angiotensin II in internal mammary arterial grafts in hypertensive patients without associated risk factors.

We investigated the effects of extraendothelial nitric oxide (NO) on angiotensin II (Ang II) reactivity in internal mammary artery (IMA) rings, as well as the impact of hypertension without associated risk factors in this response. Vascular reactivity, NO levels, and resting membrane potentials were determined in hypertensive (HT) and normotensive (NT) IMA rings. Only rings with endothelial dysfunction were included.

Internal mammary artery grafts reactivity in hypertensive patients: role of stretching in extraendothelial nitric oxide.

Background: The internal mammary artery (IMA) used in bypass coronary surgery remains efficient for a longer time than other grafts, such as saphenous veins; however, its biological characteristics are incompletely defined.

Objective: To compare in IMA grafts from hypertensive (HT) and normotensive (NT) patients the presence of endothelium and their functionability, the response to passive stretching and basal tone, the reactivity to exogenous vasoconstrictors, the role of stretching in NO release, and the possible extraendothelial NO source.

Methods And Results: IMA rings contractility, presence of endothelium, and nitrite release were studied.