Attachment of gelatin films to tissue using argon beam coagulator.

Cross-linked gelatin films were bonded to heart muscle and to lung pleura and parenchyma using the electrical discharge of an argon beam radiofrequency coagulator. The bonds were stable in warm saline buffer for minutes to hours. Bonding was thought to partly occur through a mechanical interlock of film and tissue elements. The interdigitation of tissue and film arose during exposure to the argon beam, which denatured protein constituents of both, and created a fluidized state that rapidly coalesced.

Development and application of modern devices in vascular surgery including comment on modern antithrombotic and lytic drug therapy.

Since modern vascular surgery started with the discovery of heparin and the development of modern vascular grafts including autogenous saphenous vein, the speciality has been technologically driven. At the outset, vascular surgery depended almost entirely on the development of specialized clamps, instruments, and tools to permit decisive attack on the problems of occlusion. No less important was the development of insight into the basis of atherosclerosis, the discovery that atherogenesis with thrombosis is electrochemically identical to corrosion in pipes and therefore subject to chemical forces, which have not yet been delineated, as well as mechanical forces which have been delineated and permit one to attack the atheroma directly. Thus, classic replumbing techniques including bypass and endarterectomy have long been a part of the fundamental firmament of vascular surgery. Most recently, modern techniques in cleaning out blood vessels, removing occlusive processes, and modern thrombus-dissolving enzymes have all come to the forefront. Frequently multiple techniques are used simultaneously. This article is an attempt to summarize various aspects of this activity and describe several of the patents which have been seminal in the ultimate application of the techniques in both experimental animals and man. This should be the first of a series of efforts to summarize this area. The process of change has never been more kinetic than now.

Ten year experience with the negatively charged glutaraldehyde-tanned vascular graft in peripheral vascular surgery. Initial multicenter trial.

The negatively charged glutaraldehyde-tanned vascular graft was developed to determine the utility of grafts of biologic origin to provide satisfactory revascularization for ischemic limbs with advanced arteriosclerotic peripheral vascular disease. The bovine carotid artery was modified under a number of conditions using a large number of variables and evaluated in the carotid artery and aorta of dogs. Eventually ficin-digested carboxylated glutaraldehyde-tanned grafts were selected as being most antithrombotic and most resistant to aneurysm formation. Under an Investigational Device Exemption with the Food and Drug Administration, 146 grafts were evaluated in 108 patients with patency approaching 67 percent for all grafts at 5 years and 59 percent at 9 years plus. Total aneurysm formation has been 4 percent (six grafts) occurring only in hypertensive patients. The graft is now undergoing clinical use and evaluation worldwide.

Electrode-biologic tissue interreactions at interfaces--a review.

This review draws attention on the accuracy and usefulness of the study of electrode phenomenon at the interfaces with an emphasis on the metals and their interreaction with surrounding cells and proteins.

The relationship between surface charge (potential characteristics) of the vascular interface and thrombosis.

Thus, it can be shown that highly theoretical experiments carried out to evaluate the electrochemistry of thrombosis can also be shown to have significance in the generation of new products, which relates the scientific findings to successful modern prosthesis and medically useful devices.

Evaluation of the Tamari-Kaplitt LVAD.

Experience with a modern inexpensive, unichambered heparinized "left ventricular assist device" in the closed chest unheparinized dog is described. The pumps were driven with EKG activated air drives. These functioned well. The major physiologic problems were absolute limitation of inflow and late mural and valve disk thrombus formation at pump times approaching 5 to 6 hrs, under the limitations of the experiment. The inexpensiveness of this LVAD, its obvious practicality in terms of application as a counter pulsator in human open heart surgery and now in experimental animals, provides some hope that an inexpensive, practical, functional preanticoagulated LVAD of this type may ultimately result in a significant improvement in the utility and cost effectiveness of this approach to left ventricular failure.

A clinical experience with the NCGT graft.

A comparison of 130 grafts done in 101 patients included 47 veins, 25 Johnson & Johnson dialdehyde-starch-tanned collagen prostheses, and 58 NCGT grafts that had been followed for a 40-month period. This study had documented the fact that in spite of frequent poor runoff, a useful result is provided by the NCGT graft apparently due in part to its built-in nonthrombogenic structure providing a cumulative patency of 73%. The patency rate was even superior with venous bypasses. Therefore, we still feel that the autogenous vein provides the most useful bypass conduit available in vascular reconstruction. In situations where a vein could not be used or was not available the NCGT graft offers an equally useful nonthrombogenic surface to maintain prolonged patency. Thus, collagen appropriately modified can provide a useful prosthesis in vascular reconstruction.

Experiments with nonthrombogenic and thrombogenic collagen in laboratory and clinical use.

The Negatively Charged Glutaraldehyde Tanned (NCGT) graft has now encompassed 12 years in experimental animals and five years clinical experience with 134 grafts in man. It demonstrates that vessel wall structure, interface-charge, electric potential and polarity at the blood intimal interface are critical in the prevention of intravascular thrombosis in both vascular tree and vascular prosthetic grafts. The hemostatic properties of a new solvating positively charged hemostatic collagen (superstat) were first evaluated in 30 dogs using a skin pouch preparation and incisions in spleen and liver. The results were striking. The effectiveness in man has been determined by more than 130 applications in various surgical procedures. In several, it was used in emergencies to produce hemostasis which could not be obtained by any other material available. Hemostasis is obtained rapidly with Superstat, an effective electron sink, even in heparinized patients. Finally, the material has demonstrated that it rapidly produces hemostasis while dissolving, does not develop abnormal adhesions, fibroplasia of foreign body reaction.

Alleviation of autotransfusion-induced haematological damage by corticosteroids.

Thrombocytopenia and haemolysis in intraoperative autotransfusion result mainly from extravascular tissue contact and therefore are not correctable by mechanical improvements in the autotransfusion apparatus. Instead, attention must be directed towards prevention of blood 'recognition' of extravascular tissue or stabilization of blood components against this damage. Methylprednisolone is shown to be effective in alleviating red cell and platelet damage induced by intraoperative autotransfusion in the canine model.

Long-term function of NCGT vascular conduits in a multicenter trial: evaluation of physical chemical parameters.

Our experience with the NCGT graft has now encompassed 12 years in experimental animals and 4.5 years clinical experience with 134 grafts in man. It has previously been suggested that vessel wall structure, interface-charge, electric potential, and polarity of the blood intimal interface appear critical in the prevention of intravascular thrombosis in all vascular prosthetic bypass grafts. This concept has now been confirmed using ferritin, colloidal iron and fluorescamine intimal labelling. These provide a quantitative special characterization of the surface charges of several grafts, including the NCGT graft. Study indicates that each step in the production of the NCGT graft results in a cumulative increase in the structured negative charge of the vascular interface. The more dense the structured negative charge of the prosthesis, the more resistant is the graft to short and long-term thrombosis in experimental animals and man. The experience has been confirmed with a comparative analysis of implantation results in 105 patients up to 4.5 years with 65 to 70% patency rate over that time interval. Statistical analysis of parameters confirm again that the polarity and structure of the vascular interface is important in the effective function and patency rate of the grafts.

A new effective intraoperative hemostat - Superstat.

A new effective solvating hemostatic agent, Superstat, has been developed and evaluated in animals and man. It appears to work in part because of its large electron absorbing surface and in part due to the physiologic concentration of contained calcium. The available information from the first 130 patients in which it has been evaluated suggest that it has few, if any, side effects, leaves no residue following use, and is an extremely effective hemostat under most conditions and in all tested operative areas in man. Available data indicate that it has local effects which represent biochemical and ultra-structural interactions with shed blood.

Aneurysm of the inferior mesenteric artery.

Current diagnostic techniques make it possible to diagnose unsuspected aneurysms. Two unsuspected cases of aneurysms of the inferior mesenteric artery are reported. One was iatrogenic and represented a false aneurysm of the proximal end of the inferior mesenteric artery following resection of an abdominal aortic aneurysm. The second was an aneurysm of the proximal protion of the inferior mesenteric artery in a patient with occlusion of the celiac axis, superior mesenteric artery and left ileofemoral system. The authors believe this to be the first published aneurysm of the inferior mesenteric artery.

In vitro and in vivo evaluations of dacron velour and knit prostheses.

Dacron velour and knit prostheses were compared with respect to long-term patency when used as canine aortic implants. These grafts were rated, according to the average numerical value of six equally weighted criteria, in decreasing order of performance: velour I, velour II, circular knit III, velour IV, circular knit V, warp-knit VI, warp-knit VII and VIII, warp-knit IX and warp-knit X. In general, compacting and crimping methods using halogenated hydrocarbons produced the least successful grafts. Grafts of identical brand but compacted and crimped by different methods exhibited different patencies. No true healing of the grafts was observed. Layered deposits of inner fibrous capsule were formed at rates and thicknesses characteristic for each type of graft employed. A functioning Dacron femoral-popliteal bypass removed from a human after 9 months exhibited inner and outer fibrous capsules similar to those from canine implants.