Endovascular versus conventional surgery: competitive or complementary methods?

Human umbilical vessels are devoid of nerves and therefore endothelial cells may play an important role in the control of feto-placental blood flow. The pharmacological effects of 5-hydroxytryptamine, histamine and endothelin were examined in umbilical arteries and veins from legal terminations (gestational age 8-17 weeks, n=12) and normal term vaginal deliveries (gestational age 38-41, n=12). Immunocytochemistry of human unbilical vessels indicated that 5-hydroxytryptamine, histamine and endothelin were localised in subpopulations of endothelial cells of both artery and vein in late, but not early, pregnancy. 5-Hydroxytryptamine (10 nM-30 microM) caused sustained concentration-dependent contractions in all vessels from early and late pregnancy. Histamine (0.1 microM-30 mM) also caused sustained contractions in all vessels from late pregnancy but only 27% of arteries and 41% of veins from early pregnancy responded. Endothelin (10 pM-30 nM) caused slow long-lasting contractions in all vessels from early and late pregnancy. Atrial natriuretic peptide and neuropeptide Y did not alter vascular tone. The endothelium may thus play an autocrine/paracrine role, by synthesizing and releasing the above reactive substances in late pregnancy to influence feto-placental blood flow.

Arteries↗

PubMed1996

Vascular anatomy of the galeal occipitalis flap: a cadaver study.

The vascular anatomy of the galeal occipitalis flap was studied in 10 fresh cadavers by an intraarterial dye injection technique. The scalp flap was based posteriorly, incorporating both the occipital and posterior auricular arteries. A good transmidline anastomosis was demonstrated between the two occipital arteries in the full-thickness scalp flap. However, in the isolated galeal flap, although the axial distribution of the occipital artery was maintained, fewer transmidline connections were seen between the two occipital arteries. The posterior auricular artery was consistently visualized in all dissections, and it showed good connections with the ipsilateral occipital artery. However, there were very few anastomoses between the two posterior auricular arteries across the midline. The rich anastomotic network between the occipital artery and the posterior auricular artery extended well beyond the vertex. This study showed that a large flap can be raised if both the occipital artery and the posterior auricular artery are included in its base. The occipital artery is a vessel of satisfactory size and is potentially a good vascular source for a thin galeal free flap. It is recommended that the flap be raised at the subperiosteal level for ease of dissection and protection of the vessels, which are initially in the subgaleal plane and then arborize in the galea.

Arteries↗