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.

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.

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.

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.

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.

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.

Supine pedal venous measurement in patients with venous disease

The measurement of supine pedal venous pressure as a screening test for deep venous thrombosis is re-evaluated. In 83 extremities studied in 50 patients, the false-positive rate was 62%, the false-negative rate 8%. Chronic venous disease, whatever its etiology but particularly in association with the post-phlebitis syndrome, can be a source of error in relying upon this measurement.

A preliminary report of the efficacy of Debrisan (dextranomer) in the debridement of cutaneous ulcers

A randomized trial involving 50 patients has demonstrated that a new type of debriding agent, cross-linked dextran beads with the trade name Debrisan (dextranomer, Pharmacia, Inc.), will produce rapid healing of cutaneous ulcers which have been resistant to conventional therapy over the long-term. Evaluation in terms of a number of therapeutic parameters, including rate of healing, dehydration, sterilization, loss of symptoms, and improvement in physiology, is included in this preliminary study.

New approaches in the therapy of the peripheral vascular ulcer

It can readily be seen that Debrisan represents a more effective mode of therapy for several groups of patients which tend to have chronic disabling ulcers of limbs of various etiologies, including venous stasis ulcers, chronic sickle-cell ulcers, decubiti, etc. The more effective treatment of this patient populations, which is provided by Debrisan, would provide a very significant decrease in the total cost of health care in the United States, approximating half a billion dollars per year.

Intramural lymphatic cyst of bovine heterograft

An intramural lymphatic cyst of a bovine heterograft is described. This previously unreported complication presented as a pulsatile mass in the thigh of an 84-year-old woman who had undergone vascular reconstruction 12 months previously. The clinical presentation, operative findings, and pathological findings are described, and the management of the case is discussed.

Etiology of catheter-associated sepsis. Correlation with thrombogenicity

A series of 94 central venous catheters was observed at removal for gross evidence of intraluminal or surface thrombus deposition. All those that were later found to have positive cultures had been noted to display thrombus formation, while catheters having negative cultures were usually free of thrombus. Devices made of a relatively nonthrombogenic material (ethylene acrylic acid) were also relatively free of bacterial contamination.

A ten year study of heparin therapy for thrombophlebitis in ambulatory patients

During the past ten years, we have observed 407 patients with thrombophlebitis using a standardized outpatient regimen including subcutaneously self-administered heparin therapy. A definite protocol for tapering and discontinuing anticoagulants was applied which allows a correlation between duration of heparin administration, decreasing heparin resistance and symptomatic improvement. In acute and subacute thrombophlebitis, this method induced symptomatic resolution within less than two months in half of the patients and within less than six months in 78%. The number of recurrences during the follow-up period was acceptable and the frequency of complications minimal. We conclude that, except in the most severe, toxic instances of thrombophlebitis or in suspected pulmonary embolism, hospitalization--complete bedrest and intravenously administered anticoagulants--is unnecessary and wasteful.

A comparative study of several polymers for use as intravenous catheters

The widespread use of long-term intravenous catheters has produced some concern on the part of the clinician with respect to morbidity and occasional mortality associated with their use. Fourteen polymer surfaces were evaluated in experimental animals in this study. Several of the materials are commercially available; the others are experimental. In all, 160 catheters were placed in the femoral and jugular veins through side branches. The catheters were evaluated in terms of thrombosis, phlebitis, and periphlebitis, using an arbitary grading system. Scanning electron microscopy and light microscopy were employed to document the results. The most successful catheter materials were next evaluated in man, using the same experimental parameters. It is our belief that the observed thrombosis associated with morbidity is largely due to the surface characteristics of the catheter materials. These characteristics are largely surface phenomena related to the interactions between the tissue and catheter material. In this study, we have attempted to determine whether there are any significant differences in thrombogenicity and/or long-term function between the several currently available catheters. Based on this study, ethylene acrylic acid appears to be the most nonthrombogenic surface of the material tested.

The repair of extracranial carotid artery aneurysms

Aneurysm of the internal carotid artery was repaired in three instances by a combination of gas endarterectomy and aneurysmorrhaphy. No shunt was used during cross clamping. The occlusion was uncomplicated. Both patients (in one the procedure was bilateral) have been well for two years. Because of its simplicity and effectiveness, the method is recommended.

The haematological hazards of autotransfusion

Fourteen heparinized dogs were autotransfused from 1-5 to 6 times calculated blood volume. Five animals retransfused 12 litres from an intraperitoneal bleed had marked decreases in all cellular elements, haematuria and a large (82 percent) drop in fibrinogen. All these animals died within 12 hours and post-mortem examination revealed evidence of disseminated intravascular coagulopathy. The dogs in which a smaller volume (3-6 litres) was recycled showed similar, but less devastating, changes. Haematocrit and platelet count dropped by a half and fibrinogen by 20 per cent. A leucocytosis of about 30 000/mm3 occurred within 24 hours. Autotransfusion of salvaged blood which was not allowed extravascular tissue contact significantly lessened these adverse effects. We conclude that the risk of cellular destruction and defibrination in large volume intra-operative autotransfusion is significant and must be weighed against its potential benefits in each case, and that red cell and platelet damage results primarily from extravascular tissue contact and is therefore unavoidable.

The computer as an unbiased medical investigator. Experience on an active surgical service

An adaptable on-line computer system for entry, retrieval, and analysis of medical discharge summaries has been developed and applied in the Trauma Service of a busy city hospital. Each summary occupied 5 to 10 minutes of the physician's time and compared favorably in cost to the standard dictated summary. While the average dictated summary contained 15 +/- 7 relevant facts, the machine-generated summaries were found to have 53 +/- 20 relevant facts. The summaries are well organized, easily comprehensible, and a duplicate copy can be obtained at any time by using the patient's name or number for identification. To date, 495 discharge summaries have been entered and reside in the memory of the computer. Statistical analysis from the data base is done by the computer, thus eliminating human prejudice. It provides facility for rapid and accurate retrospective studies as well as pattern-of-care and individual case review.

FURTHER STUDY OF NITINOL WIRE AS CONTRACTILE ARTIFICIAL MUSCLE FOR AN ARTIFICIAL HEART

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Thromboresistance of glass after glow discharge treatment in argon

Glow discharge treated (GDT) inorganic materials are sterile and free of all organic contaminants. Such materials implanted in the canine inferior vena cava often demonstrate significant thromboresistance. Standard Pyrex glass tubing was GDT in argon to provide a surface free energy above 70 dynes/cm, slight surface negativity, and other surface-physical modifications of its interface. Chromic acid cleaned lengths of the same tubing, and short segments whose edges were not fire-polished were used as controls. Upon canine implantation, the in vivo results were similar in independent surgical laboratories. The glass was implanted as 1.4 cm long rings or as 5 cm long tubes in separate medical centers according to different protocols. GDT specimens remained patent; all controls accumulated thrombi. A remarkably pure, low critical surface tension, labile protein coating covered all cylindrical lumens after 2 hr in vivo. This coating diminished within 2 weeks and was essentially absent after 480 days, eeven though scanning EM showed evidence of a micron thick luminal film, probably eroding glass. No emboli were found in the implant animal's kidney or lungs at any stage.

Nonthrombogenic ac polarized copper prosthesis

In previous studies from our laboratories, it was shown that metals and alloys which register negative potentials in blood vs the normal hydrogen electrode tend to be antithrombogenic while those with positive potentials are invariably thrombogenic. The present paper deals with a novel approach of maintaining an implanted metallic prosthesis at a negative potential. A copper vascular prosthesis in a dog was maintained at cathodic potentials by a small amplitude (+/- 10 mV) high-frequency ac (100 kHz) on the prosthesis. The prostheses were removed after 2 hours, 6 hours, 1 day, and 42 days, with subsequent visual and scanning electron microscopic examination of the prostheses completed. All tubes were free of thrombus deposits. Minimal junctional thrombi were found, probably due to differences in physicochemical characteristics of the vascular prostheses and recipient vessels. The results are compared with those in the control group (copper tubes with no current) and dc polarized copper tubes. While the control tubes occluded in 2 to 6 hours, the dc and ac polarized tubes remained patent. Of the ac and dc polarized tubes, the former tubes lasted up to 6 weeks with less thrombus deposit. The mechanism of operation of the ac polarized copper prosthesis is not fully understood.

Hormonal steroids: effects on the vascular system

An increase in the incidence of thromboembolic disorders has been associated with oral contraceptive use, though the causative mechanisms remain unclear. Our studies indicate that the contraceptive steroids, irrespective of the intermediary metabolic processes involved, cause changes in the surface charge characteristics of the blood vessel wall and blood cells in the following cases: (i) in experiments using dogs, the hormonal steroids result in a greater reduction in the pore surface charge of veins than in arteries; (ii) in rats, the current induced mesenteric occlusion times are significantly lowered following administration of combined contraceptives steroids; (iii) in humans, the electrophoretic mobilities of erythrocytes and platelets from women taking Ovral and Demulen are lower than in controls, and (iv) there is no significant alteration of plasma coagulation times of women who are on injectable progestin therapy. Demulen and Ovral appear to result in a slight decrease in activated partial thromboplastin times compared to controls.