Thrombogenic properties of vascular catheter materials in vivo. A device and objective method of comparing thrombus formation on vascular catheter materials

Blood flow into vascular catheters of different size and number of sideholes. Model experiments with flush fluid injections

Using an experimental model of the arterial circulation system, inflow of blood into polyethylene catheters following injection of contrast medium and isotonic saline solution was evaluated. The experiments included an analysis of the influence of density and viscosity of the flush solutions as well as the effect of catheters of different sizes with and without sideholes.

Blood inflow into vascular catheters following injection of saline solution and contrast medium. Model experiments

Using an experimental model of the arterial system, inflow of blood into polyethylene catheters following injection of two contrast media, isotonic and hypertonic saline solutions was investigated. The experiments included an analysis of the influence of the density of the solutions and the orientation of the catheter as well as the effect of single fluid injection and continuous flushing of the catheter.

Role of catheter surface morphology on intravascular thrombosis of plastic catheters

The role of catheter surface roughness in initiation and propagation of intravascular catheter thrombosis was studied in dogs, utilizing the scanning electron microscope. Catheters were inserted in major arteries and veins for 200 min and the animals then sacrificed. Catheter segments, both with and without associated thrombi, were scrutinized with the scanning electron microscope. No correlation was found between catheter surface roughness and thrombus formation, suggesting that the inherent chemical characteristics of the catheter is most important in the initiation of intravascular catheter thrombus formation.

Heparinized catheters for long-term intraarterial infusion of 5-fluorouracil in liver metastases

A heparinized catheter was used for the regional infusion of 5-fluorouracil in seven patients with liver metastases. The hepatic artery was catheterized from the left brachial artery. The period of treatment varied from one to 13 weeks. Pull-out angiograms, obtained after eight catheterizations, revealed complete occlusion of the brachial artery in five and partial occlusion in three, although no patient had ischemic symptoms in the hand. Thus, heparinization of the catheter did not prevent thrombosis during long-term infusion therapy.

Blood inflow into intra-arterial catheters following injection of contrast medium

Inflow of blood into intra-arterial catheters following injection of contrast medium into the common carotid artery in patients and into the aorta in dogs is investigated. Influence of form and orientation of the catheter in the vessel and the effect of constant flushing are determined as well.

Drug effects on platelet adherence to collagen and damaged vessel walls

The interaction of platelets with damaged vessel walls leads to the formation of platelet-fibrin thrombi and may also contribute to the development of atherosclerotic lesions because platelets adherent to exposed collagen release a mitogen that stimulates smooth muscle cell proliferation. The first step in thrombus formation, platelet adherence to an injured vessel wall, can be studied quantitatively by the use of platelets labeled with 51chromium. In these investigations, rabbit aortas were damaged by passage of a balloon catheter and segments of the aortas were everted on probes that were rotated in platelet suspensions. Collagen-coated glass cylinders were also used. Adherence was measured in a medium containing approximately physiologic concentrations of calcium, magnesium, protein and red blood cells. Conditions of testing influence the effect of non-steroidal anti-inflammatory drugs, sulfinpyrazone, and dipyridamole on platelet adherence. Aspirin and sulfinpyrazone were not inhibitory when tested in a medium with a 40% hematocrit; this indicates that products formed by platelets from arachidonate probably do not play a major part in the adherence of the first layer of platelets to the surface, although they may be involved in thrombus formation. Indomethacin, dipyridamole, prostaglandin E1, methylprednisolone and penicillin G and related antibiotics did inhibit platelet adherence although the concentrations required were higher than would likely be achieved in vivo upon administration to human patients. None of the non-steroidal anti-inflammatory drugs inhibited the release of granule contents from adherent platelets. Pretreatment of the damaged vessel wall with aspirin increased platelet adherence, presumably because it prevented the formation of PGI2 by the vessel wall. Platelet adherence to undamaged or damaged vessel walls was enhanced by prior exposure of the wall to thrombin. Platelet reactions with aggregating agents and platelet survival can be modified by changes in dietary lipids but there is very little evidence concerning the effects of lipids on platelet adherence. If some forms of dietary fat damage the endothelium, platelet interaction with the damaged area and release of the mitogen for smooth muscle cells would contribute to the development of atherosclerotic lesions.

Thrombus formation on indwelling venous cannulae in sheep : effects of time, size and materials

Three experiments were performed to measure thrombus formation on plastic cannulae inserted by cut-down into veins of sheep. On polyethylene tubing, considerable thrombus was present after one day and the amount increased in the subsequent 13 days. When different sized polyethylene tubings were tested, thrombus tended to form in relation to the surface area. Smaller tubings had smaller proportions of their lengths covered with thrombus. There were differences between types of plastics with one batch of polyvinylchloride tubing being virtually non-thrombogenic.

Thromboembolism associated with pigtail catheters

Three incidents of asymptomatic arterial thromboembolism associated with polyurethane pigtail catheters occurred during 1,417 cases of left ventricular angiocardiography. No similar incident occurred with polyethylene pigtail or (dacron) Eppendorf and Gensini (style) catheters. In vitro comparison of hydraulic characteristics of polyurethane (Cordis) and polyethylene (Cook) pigtail catheters showed higher flow-pressure transmission through the tip of the Cordis polyurethane catheter favoring dislodgment of any existing clot. The problem of thrombogencity of polyethylene compared with polyurethane remains unsettled. Our experience with polyurethane pigtail catheters has resulted in limitation of their use in our laboratory.