Mitigation of coagulation by removing clotting factors part 2: heparin-free extracorporeal circulation in a porcine model.

A subpopulation of patients would benefit from an anticoagulation strategy during extracorporeal circulation (ECC) that does not involve systemic administration of heparin and protamine. Inhibition of coagulation by adsorption of plasma clotting factors using protamine immobilized on a Sepharose matrix (PSM) has been explored. This investigation extends previous in vitro studies and demonstrates the feasibility of heparin-free ECC.

Mitigation of coagulation by removing clotting factors part 1: in vitro feasibility study.

Heparin is associated with adverse effects in some patients during extracorporeal circulation. A potential alternate anticoagulation strategy explored in this investigation involved mitigation of coagulation by removing clotting factors from blood by adsorption on a protamine-immobilized Sepharose matrix (PSM). Human or porcine plasmas treated with PSM in vitro were tested for clotting factors I (fibrinogen), II (prothrombin), VIII, and X, and proteins C and S, and for prothrombin time (PT), activated partial thromboplastin time (APTT), and total protein concentration.

Different responses by cultured aortic and venous smooth muscle cells to gamma radiation.

Background: Stenosis of hemodialysis arteriovenous grafts is usually focal and caused by the proliferation of vascular smooth muscle cells (SMCs). External radiation of the graft is a potential strategy to prevent stenosis; however, the relative responsiveness of arterial and venous SMCs to radiation is unknown.

Methods: Human aortic and saphenous vein SMCs were cultured in a medium containing growth factors and serum and treated with 0 to 50 Gy in a gamma irradiator.

Inhibition of neointimal hyperplasia in vascular grafts by sustained perivascular delivery of paclitaxel.

Background: Neointimal hyperplasia occurs commonly at the anastomoses of arteriovenous grafts for chronic hemodialysis, causing stenosis and occlusion. Antiproliferative drugs may be effective in inhibiting hyperplasia, but local drug delivery would be required to minimize systemic side effects. We examined the feasibility of local drug delivery to inhibit neointimal hyperplasia at dialysis grafts in a canine model.

In vitro pharmacological inhibition of human vascular smooth muscle cell proliferation for the prevention of hemodialysis vascular access stenosis.

Background: Vascular access for chronic hemodialysis often fails as a result of stenosis caused primarily by the proliferation of vascular smooth muscle cells (VSMC). Various drugs have been shown to inhibit the proliferation of VSMC under different conditions.

Methods: In this study, we compared the inhibitory effect of ten drugs on the proliferation of human aortic smooth muscle cells (SMC) in culture.