Fibrin sealant coated stents compared with non-coated stents in a porcine carotid artery model. Preliminary study report.

BACKGROUND: Balloon expandable metal stents (BEMS) are used to treat restenosis following percutaneous transluminal angioplasty (PTA) and as primary treatment. Intimal proliferation (IP) and resultant restenosis occurs in 25-50% of patients despite all preventive measures. OBJECTIVE: to test the intra-arterial response to the insertion of a fibrin sealant (FS) coated BEMS vs an uncoated BEMS by measuring endothelization and IP. HYPOTHESIS: that a BEMS coated with FS will lead to rapid endothelization and prevent or reduce IP. RATIONALE: FS consists of fibrinogen and thrombin. Thrombin affects endothelial cell proliferation and reduces smooth muscle proliferation, the forerunner of IP and restenosis. Normal endothelium also releases substances that promote vascular relaxation and normal smooth muscle tone regulation. METHODS: Thirty-40 kg pigs (EA), Palmaz-Shatz BEMS (Cordis), FS Tissucol (Baxter Immuno). Stents were uniformly coated with FS in a special mold. Both coated and uncoated stents were mounted on balloon catheters and deployed caudad in the carotid arteries via an arteriotomy. Angiograms were obtained postdeployment. All specimens were examined grossly, photographed then fixed for histology and in some cases, scanning electron microscopy (SEM). RESULTS: Fifteen animals form this preliminary report. Sacrifice at five days as per original protocol showed insufficient stent incorporation. Thereafter 1/2 of the animals were sacrificed at 15 days and 1/2 at 30 days. PATENCY: coated stents: 6 patent, 9 thrombosed. UNCOATED: 7 patent, 8 thrombosed. Of five EA given postoperatively low molecular weight heparin (LMWH) 4 animals had patent stents 80%. HISTOLOGY: varying degrees of IP were seen in all specimens. In general the coated stents showed a greater degree than the uncoated. STENOSIS: presacrifice angiography revealed that where the stents were patent no stenosis was present, in fact, some demonstrated mild dilatation. This was particularly the case with the coated stents. CONCLUSIONS: Coating stents with FS is not detrimental. IP in these EA at 30 days did not produce stenosis. Postoperative LMWH appears helpful in maintaining patency in a thrombogenic experimental animal. Further study maintaining EA for 6-12 months should resolve whether the IP seen had achieved its maximum expression or would progress and produce stenosis.

Late infection of a Dacron carotid endarterectomy patch--a case report.

This unique case reports the nonsurgical management of a late (2 years) methicillin-resistant Staphylococcus aureus neck infection around a Dacron-patched carotid endarterectomy. Because the patient was elderly with multiple serious risk factors and no drainable material, IV and oral antibiotics were selected as initial management. Follow-up computed tomography of the neck, however, documented complete resolution of the phlegmon. While the authors remain uncertain of the long-term outcome the patient is free of local infection 2 years after diagnosis and nonoperative treatment.

Autologous vein lined and vein covered stents in swine arteries. An experimental study to assess and compare patency and intimal hyperplastic response.

BACKGROUND: Despite the success of arterial angioplasty as well as arterial stent placement, restenosis remains a significant problem in prolonging blood vessel patency. This animal model was used to test the theory that a stent lined (VLS) or covered (VCS) with autologous vein would be more biologically compatible with the arterial intima. If successful, this technique would prevent angioplasty failure due to intimal hyperplasia (IH) by supplying a healthy endothelial surface and help to eliminate elastic recoil mechanism (ERM) by the use of a stent rendered less thrombogenic in both stenosed and restenosed arteries. There might in addition, be other applications for these modified stents. METHODS: Nine 50 kg -young pigs had Gianturco-Roubin VLS and VCS mounted on a balloon angioplasty catheter implanted via a transverse arteriotomy. VLS were implanted in 3 left iliac and 6 left carotid arteries and VCS were placed in the matching contralateral arteries. The change from iliac to carotid arteries was due to the initial perception that the iliac artery was the right size for this device. It proved to be too large and the carotid artery, which was initially felt to be too small proved to be the right size. Operative angiography was performed to ensure proper placement. Duplex imaging of the carotid artery placements were performed at 10-14 days. All animals were sacrificed at 30-33 days and specimens examined grossly and microscopically. Three 16.5% of the devices were found to be patent, two VILS and one VCS. The remaining 14 (78%) were occluded by distortion or thrombus or both. RESULTS: Five devices migrated distally, 2 of which remained patent albeit of smaller diameter. One device migrated to the brain, was not recovered and was presumed occluded. All arteries and veins, with two exceptions, demonstrated varying degrees of IH. We believe failure was due to the inability of the stents to resist ERM in these healthy pig arteries. The IH observed, we believe, is due to the forced dilatation required to seat the devices. CONCLUSIONS: Based on the observations of the patent devices we suggest that arteries can be relined and supported with modifications of this technique, using a more ERM resistant stent that may be placed without forceful dilatation. This will require further study.

Influence of HIV-infection risk on resident physicians.

PURPOSE: To determine the influence of the risk of contracting the human immunodeficiency virus (HIV) on the attitudes and behavior of resident physicians. METHOD: A 15-item questionnaire was sent in January 1994 to the 268 residents in the major specialty training programs at the three clinical campuses of the University of Medicine and Dentistry of New Jersey. The residents' responses about HIV were analyzed in light of their specialty, postgraduate-year level, and training location. Z-tests were used to determine the statistical significance of the responses, and Yates corrections were applied to all calculations. RESULTS: A total of 121 residents (45%) responded. These residents were similar demographically to the non-respondents. Fifty-one of the responding residents (42%, p < .02) reported that they tended to minimize performing invasive procedures on HIV-positive patients. A surprisingly high number-73 (60%, p < .005)-had been tested for HIV. Only 14 had sustained needle-stick injuries. The risk of HIV infection had not appreciably affected the residents' choices of specialty, but it did dampen their enthusiasm for the practice of medicine. It also influenced their choices of training location, with 34 (28%, p < .001) listing HIV as an important factor. Given the hypothetical situation that they themselves were infected with HIV, 89 (75%, p < .001) of the residents reported that they would not terminate their careers, but 70 (61%, p < .005) indicated that they would refrain from performing invasive procedures. CONCLUSION: The residents' responses show a high level of emotional stability as well as a practical acceptance of the reality of HIV in the workplace. The impact on resident physicians of HIV requires further attention by medical educators and program directors.

Metastatic endometrial carcinoma: rare cause of extrahepatic obstructive jaundice.

We report a very rare case of endometrial carcinoma causing extrahepatic bile duct obstruction. Management of this case and probable mechanism of spread are presented.

A rare association of fibromuscular dysplasia of the femoral artery with aneurysm and occlusion treated alternatively.

A unique case of fibromuscular dysplasia of the femoral artery with aneurysm and occlusion of the superficial femoral artery component is presented. This aneurysm was treated by dacron wrap. External dacron grafts have been previously reported and used with success in a variety of arterial aneurysms. The authors present their rationale and indication for its use in this unusual arterial problem.

Reverse tapered vs. straight PTFE (Gore-Tex) grafts in dogs.

Reversed Autogenous Saphenous Vein (RASV) remains the material of choice in infrainguinal arterial bypass. A characteristic of RASV not seen in other grafts is its reverse tapered (RT) configuration. The purpose of this study was to investigate this geometric configuration. Straight 6 mm PTFE (gore-tex) grafts (SG) and 4-7 mm reverse tapered PTFE (gore-tex) grafts (RTG) were both implanted in the aorto-iliac position in 16 mongrel dogs. Specimens of surviving dogs were examined by the usual methods. In terms of absolute patency, 9 of 14 RTG (64%) and 5 of 14 SG (36%) P = 0.05, anastomotic thrombus formation 6 of 14 (43%) RTG vs. 10 of 14 (71%) SG P = 0.05 and in midgraft thrombus deposition P = 0.025 the RTG performed significantly better than the SG. In light of these results and other considerations, the reverse tapered configuration merits clinical investigation with other materials and in other species.

Identification of hormonally responsive proteins in primary Sertoli cell culture medium by anion-exchange high performance liquid chromatography.

Twenty day-old rats were used to prepare Sertoli cell-enriched cultures which were grown for 4 days in serum-free medium supplemented with human transferrin, epidermal growth factor, and insulin. Proteins in the medium were first fractionated by anion-exchange HPLC. Forty-five to 50 fractions were collected, and each was examined by electrophoresis in sodium dodecyl sulfate-containing polyacrylamide gels. Using silver nitrate as a stain, more than 30 proteins were routinely identified. Rat androgen binding protein and rat transferrin were measured by immunoassays. When the cultures were supplemented with either testosterone, FSH, or both hormones and the media fractionated by HPLC and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, these proteins could be tentatively categorized as follows: unresponsive to added hormones; responsive primarily to testosterone; responsive primarily to FSH; or responsive to testosterone or FSH but maximally responsive to both hormones. This report provides a method for identifying proteins in Sertoli cell-enriched cultures and has allowed us to show for the first time that many are responsive to hormones. The procedure takes advantage of the large loading capacity of the HPLC column to allow fractionation of liter quantities of medium. The high resolving power of the column permits preparation of fractions which are highly enriched with one or a limited number of proteins. The purification of many of these proteins is now feasible. The approach described is generally applicable for isolation of proteins from media from a variety of cells.

Magnification limitations of a contact lens telescope.

A contact lens telescope (CLTS) may have some applications as a low vision aid. In certain circumstances, it offers the possibility of a larger field of view and may simplify the optical alignment difficulties of the user who has a central scotoma. Such devices in the past have usually been limited to magnifications of 2X or less. I examined the magnification potential of these devices by using an unusually high contact lens power and measuring the actual visual acuity improvement (functional magnification) achievable by young, normally sighted subjects. The results show the functional magnification to be significantly reduced compared with the theoretical magnification calculated by the afocal telescope magnification formula. This degradation of functional magnification would be expected to be even greater when used by the visually impaired.

The practical and ethical defects of surgical randomised prospective trials.

This paper presents a strong criticism of the current enthusiasm for clinical randomised prospective studies in surgery. In the process, the author probes the 'intellectualism' or lack thereof in present day surgical attitudes. The subjects are examined against a framework of ethics and inescapable dilemmas. Ways of correcting the more obvious weaknesses are suggested. The manuscript is, and is meant to be, provocative and is particularly aimed at the academic audience served by this journal.

KIE: Despite current enthusiasm for clinical randomized prospective studies in surgery, Byer, himself a surgeon, sees little merit in this method of evaluating experimental procedures. Problems in selection of patient populations, data collection and evaluation, the rigidity of protocol requirements, and the danger of obsolescence before completion of a study may expose patients to unnecessary risks and create ethical dilemmas for physicians. In his brief commentary, Baum, also a surgeon, vigorously defends randomized controlled trials and criticizes Byer's approach to scientific inquiry, which favors small study groups, case reports, and other "anecdotal" observations.

Carotid endarterectomy utilizing the exclusion clamp.

Carotid endarterectomy is useful in the treatment of the uncomplicated pre-stroke patient. Use of the exclusion clamp makes possible a short period of carotid occlusion without the use of either internal or external shunts. Forty-two patients were operated on using this technic.