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R F Kempczinski

Publications and source records attributed to R F Kempczinski.

At least 55 records · Page 3Linked to original sources
PubMed1988

Suggested standards for reports dealing with cerebrovascular disease. Subcommittee on Reporting Standards for Cerebrovascular Disease, Ad Hoc Committee on Reporting Standards, Society for Vascular Surgery/North American Chapter, International Society for Cardiovascular Surgery.

The evaluation of clinical reports on vascular disease is often made difficult by variations in descriptive terms, clinical classification, and outcome criteria. In 1983 the Joint Council of the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery created the Ad Hoc Committee on Reporting Standards to address these problems and recommend solutions. Some general problems were addressed in the initial report dealing with lower extremity ischemia. This article concerns clinical standards for reports dealing with cerebrovascular disease, suggests a scheme for clinical classification, and recommends standardized reporting practices for grading risk factors, angiographic and other diagnostic findings, and the results and complications of therapeutic intervention.

Cerebrovascular Disorders↗
PubMed1987

Effects of Nd:YAG laser energy on the arterial wall: evaluation of a new contact delivery system.

Although there has been much recent interest in the application of lasers to arterial occlusive disease, a detailed understanding of the effects of laser energy on vessel walls is lacking. This study compared the effect of a conventional, non-contact delivery system of Nd:YAG laser energy to a contact system using a 600 microns, artificial sapphire tip in eight mongrel dogs. A small section of the luminal surface of the carotid and femoral arteries was exposed to 10 or 15 joules of Nd:YAG laser power and flow was restored in the vessel. The animals were sacrificed at 0, 1, 2, 4, 7, 14, 21, and 30 days and the vessels were removed. The surface area of the laser injury for each artery was quantitated by computerized planimetry and all histologic sections were examined under light microscopy by an independent observer. Transmural necrosis occurred in 64% (20/31) of the non-contact lesions versus only 29% (9/31) of the contact lesions (P less than 0.01). Both types of laser injuries followed a predictable course with initial medial necrosis followed by formation of a fibrin erythrocyte coagulum overlying the lesions at 24 hr. The usual zones of vaporization, coagulation necrosis, and thermal damage were noted with both types of delivery systems, but the contact system resulted in more intimal vaporization. Healing of all lesions was rapid with complete endothelial coverage at two weeks. Thrombosis occurred in only 1 of 32 (3%) arteries, and there were no false aneurysms. Contact delivery of Nd:YAG laser energy produces significantly less transmural injury than does non-contact.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Management of a complex, posttraumatic, pelvic arteriovenous fistula with the use of cardiopulmonary bypass: case report and review of the literature.

A 34-year-old man had a posttraumatic, pelvic arteriovenous fistula (AVF) and false aneurysm of 18 years' duration. He had undergone four previous unsuccessful attempts at operative repair, the last of which almost resulted in exsanguination. After the false aneurysm was exposed, the patient was placed on cardiopulmonary bypass. Core cooling (25 degrees C) allowed the perfusion flow rates to be lowered (less than 0.5 L/min/m2) while the aneurysm was opened, thereby permitting visualization and ligation of the arteriovenous communications within the aneurysm. Total circulatory arrest was not required. There were no complications and the patient was discharged on the eleventh postoperative day. Arteriography 5 months later showed complete ablation of the AVF. We believe that cardiopulmonary bypass with hypothermia and reduced blood flow is a useful adjunct in the repair of complex AVFs and arteriovenous malformations. This technique avoids the use of total circulatory arrest, which increases the risks of air embolism and ischemic organ injury.

Adult↗
PubMed1987

A microcomputer-based system for the management of vascular surgical references.

As the number and diversity of contributions to the medical literature continue to grow at an astronomic rate, vascular surgeons are feeling increasingly frustrated in their efforts to remain current with the latest developments in their specialty. The introduction of powerful, inexpensive microcomputers and "user-friendly" programs for data base management has made it possible to organize large amounts of information for subsequent review. Using such a microcomputer-based system, we developed a practical approach to the storage and retrieval of vascular surgical references, which permits virtually unlimited numbers of articles to be catalogued and quickly retrieved with multiple search parameters. This system has been operational in our Division of Vascular Surgery for nearly a year and currently contains more than 3000 journal articles that are readily available for resident teaching, patient care, and research.

Information Systems↗
PubMed1987

Impact of endothelial cell seeding on long-term patency and subendothelial proliferation in a small-caliber highly porous polytetrafluoroethylene graft.

Previous reports have demonstrated that endothelial cell seeding of polytetrafluoroethylene (PTFE) grafts enhances short-term patency. This experiment was undertaken to study its impact on the long-term patency of a highly porous, experimental PTFE graft and to determine whether increasing the internodal distance of the graft material resulted in increased proliferation of the subendothelium. Ten centimeter long, 4 mm internal diameter segments of an unreinforced, experimental PTFE graft were implanted into 36 mongrel dogs as carotid interpositions. In each animal, one graft was seeded with autologous endothelial cells, enzymatically derived from the external jugular veins, whereas the contralateral graft was treated in identical fashion except that endothelial cells were not added to the preclot mixture. Nineteen animals were killed at 12 weeks; six at 22 weeks; eight at 26 weeks; and three at 52 weeks. The mean follow-up period was 20.1 weeks. The overall patency rate was 58.3% (21 of 36 grafts) for seeded grafts vs. 27.8% (10 of 36 grafts) for control grafts (p less than 0.01). The thrombus-free area was planimetrically measured at 83.4% +/- 4.5% in seeded grafts vs. 55.1% +/- 9.7% in control grafts (p less than 0.05). Scanning electron microscopy confirmed the presence of a confluent cellular monolayer in seeded grafts, whereas control grafts exhibited a variable coagulum of fibrin, platelets, and endothelial cells. The thickness of the subendothelial layer varied from 56 to 95 micron with no progressive increase in thickness between 12 and 52 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Thrombogenicity of a fibronectin-coated, experimental polytetrafluoroethylene graft.

To determine if pretreatment of polytetrafluoroethylene (PTFE) vascular grafts with fibronectin (FN) increased platelet adherence to them and adversely affected their patency, we labeled autologous canine platelets with indium III-oxine and interposed a FN-coated, experimental, 4 mm inner diameter, 10 cm long PTFE prosthesis into one carotid artery of 10 dogs. An identical graft, lacking only the FN coating, was implanted as a control in the contralateral carotid artery. A second group of 10 dogs was similarly treated, but each animal received 2 grains of aspirin and 50 mg of dipyridamole (Persantine) daily, beginning 3 days before surgery and continuing for the duration of the experiment. By means of a quantitative, gamma-camera, platelet adherence to the grafts was studied for 5 days after implantation. Graft patency was assessed with the Doppler velocity meter and was confirmed by surgical reexploration when thrombosis was suspected. FN coating increased platelet adhesion to the grafts in animals untreated with aspirin by a factor of threefold to fivefold. In those animals receiving antiplatelet drugs, patency of FN-coated grafts at 5 days was significantly (p less than 0.05) higher (80%) than in untreated animals (27.2%). In addition, mean platelet deposition on the grafts in these animals was reduced compared with untreated controls. Thus although FN coating of PTFE grafts significantly increases their affinity for platelets, this effect can be effectively abolished by pretreatment with aspirin and dipyridamole.

Animals↗
PubMed1986

Changing patterns in the practice of carotid endarterectomy in a large metropolitan area.

Changes in the practice of carotid endarterectomy were studied by review of all endarterectomies performed in the greater Cincinnati area during 1980 and from July 1983 through June 1984. The number of operations rose from 431 to 750 (74% increase). The perioperative stroke rate fell from 8.6% in 1980 to 5.1% in 1983-1984; operative mortality declined from 2.8% to 2.3%; and the combined stroke or death rate declined from 9.5% to 6.5%. Asymptomatic carotid artery disease was the indication for 50% of the endarterectomies during both time periods. The combined stroke or death rate for asymptomatic patients declined from 6.9% to 5.3%, but both rates were higher than the 3% suggested as acceptable for prophylactic carotid endarterectomy. We conclude that carotid endarterectomy is becoming an increasingly common procedure, that morbidity continues to decline, and that mortality continues to be significant. Citywide surgical morbidity and mortality remain excessive for patients with asymptomatic carotid disease.

Aged↗
PubMed1986

Fibronectin coating of an experimental PTFE vascular prosthesis.

Because of the known inefficiency of endothelial cell seeding of vascular prostheses, some investigators have pretreated their grafts with fibronectin in an effort to increase endothelial cell adhesion. However, the most efficient method of coating vascular prostheses with fibronectin has not yet been determined and more importantly, the durability of this coating following restoration of pulsatile perfusion has not yet been established. This experiment measured the adsorption of fibronectin which was perfused at three different concentrations through an experimental, highly porous PTFE vascular graft. Most efficient coating of the prosthetic appeared to occur with a 250 mg/ml concentration of fibronectin perfused through the graft for 60 min. Grafts so prepared were subsequently studied in a pulsatile perfusion system which mimicked the canine circulation. Fifteen additional fibronectin-coated grafts were also interposed in the canine carotid artery. Flow was restored, grafts were removed at varying intervals, and fibronectin disappearance was measured. In both the in vitro and in vivo models, three distinct phases of fibronectin dissociation were seen: an initial rapid loss which resulted in an average 30.5% retention of the initial concentration of fibronectin following 30 min of perfusion; a second phase, which occurred from 30 to 120 min, demonstrated an average 2.5% loss of fibronectin per hour; and a final phase, from 2 to 24 hr, during which no significant additional loss of fibronectin was seen. This study describes a new method by which PTFE vascular prostheses can be effectively coated by perfusing them with physiologic concentrations of fibronectin and demonstrates that the resulting bond between fibronectin and prosthetic is stable following restoration of pulsatile flow.

Adsorption↗
PubMed1986

The effect of fibronectin coating on endothelial cell kinetics in polytetrafluoroethylene grafts.

Despite the proven experimental success of endothelial cell seeding of prosthetic vascular grafts, the process has not been widely accepted for clinical use because of its complexity and the need for a relatively large length of autologous vein to provide the requisite number of cells. Using autologous endothelial cells radiolabeled with indium 111-oxine, we studied the effect of fibronectin coating of polytetrafluoroethylene grafts in a canine carotid interposition model on initial endothelial cell adherence and subsequent cell retention for up to 72 hours following restoration of blood flow. Since the number of harvested endothelial cells varied widely depending on the diameter and length of available vein, cellular adherence was best expressed as a percentage of the original cell harvest. More than twice as many (46.7% vs. 19.8%) endothelial cells initially adhered to fibronectin-coated grafts compared with uncoated control grafts. Fibronectin did not appear to influence the loss of cells within the first 30 minutes following restoration of blood flow. However, over the next 24 hours, it clearly reduced the mean cell loss from 3.7%/hr to 2.2%/hr and resulted in a sixfold increase (21.3% vs. 3.4%) in the number of retained cells at the end of a 24-hour period. When the endothelial cell preclot was performed with a solution of culture medium 199, as opposed to heparinized whole blood, there was no significant difference in endothelial cell retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

The influence of surgical specialty and caseload on the results of carotid endarterectomy.

Carotid endarterectomy is rapidly becoming one of the most commonly performed major surgical operations in the United States, in part because of the greater availability of noninvasive techniques to accurately diagnose extracranial carotid arterial disease and a low reported morbidity and mortality. We retrospectively reviewed the records for all carotid endarterectomies performed in the greater Cincinnati area for a recent 12-month period and examined the impact of surgical specialty and operative caseload on the results. Altogether, 750 operations were performed on 656 patients by 61 surgeons working in 16 general medical-surgical hospitals. Overall, strokes occurred in 5.1% of all patients; 2.3% of patients died. Symptomatic patients had a significantly higher risk of suffering a postoperative stroke compared with asymptomatic patients (6.5% vs. 3.7%), although the risk of death was virtually identical (2.4% vs. 2.1%). When the operating surgeons were classified into four types on the basis of their previous training, no statistically significant differences in either postoperative stroke or death could be identified. Furthermore, when the surgical caseloads of these physicians were grouped into three categories (i.e., less than 12 each year, more than 50 each year, and a group between these two extremes), no significant differences in outcome were seen. We concluded that our community-wide results for carotid endarterectomy were not comparable to those previously published from specialized centers and that these results did not appear to be influenced by the type of formal surgical specialty or operative caseload.

Aged↗
PubMed1986

Serial hemodynamic assessment of aortobifemoral bypass.

Clinical, arteriographic, and vascular diagnostic laboratory (VDL) data on 157 patients undergoing aortobifemoral bypass (ABF/BP) more than 5 years previously were compared in terms of the perspective provided by noninvasive testing, particularly when performed in the face of superficial femoral artery (SFA) occlusion. To the traditional outcome criteria (operative mortality rate, 3.2%; amputation rate, 1.4%; early patency rate, 98%; and late patency rate, 86%), VDL data added an initial hemodynamic failure rate of 14% and a late deterioration rate of 8%. Those patients with occluded SFAs fared worse in regard to initial patency (94% vs. 100%), initial hemodynamic failure (29% vs. 2%), late deterioration (8.8% vs. 5.4%), and late failure rates (16% vs. 10%), whereas those patients with open SFAs suffered more distal disease progression (11.5% vs. 1.3%). "Prediction" of postoperative ankle/brachial index (ABI) from preoperative thigh/brachial index (TBI) and ABI was 92% accurate for limbs with open SFAs but only 84% for limbs with occluded SFAs; prediction was made with a formula based on proportional transmission and with TBI measured with a regularly sized cuff (best combination). Neither additive transmission formula nor measurement of TBI with a large cuff allowed accurate prediction when the SFA was occluded. No advantage, in terms of initial hemodynamic result or late outcome, could be demonstrated for limited profundaplasty in the absence of significant profunda femoral stenosis and end-to-end vs. end-to-side proximal anastomosis.

Amputation, Surgical↗
PubMed1985

Bacterial adherence to vascular grafts after in vitro bacteremia.

All currently used arterial prosthetics have a greater susceptibility to infection following bacteremia than does autogenous tissue. This experiment compares quantitative bacterial adherence to various prosthetic materials after bacteremia carried out in a tightly controlled and quantitative fashion. Ten centimeters long, 4 mm i.d. Dacron, umbilical vein (HUV), and polytetrafluoroethylene (PTFE) grafts, as well as PTFE grafts with a running suture line at the midportion were tested. Each graft was interposed into a pulsatile perfusion system modified from a Waters MOX 100 TM renal transplant pump. Indium-111-labeled Staphylococcus aureus were added to heparinized canine blood to give a mean concentration of 4.7 X 10(6) bacteria/cc. This infected blood was recirculated through each graft for 30 min at a rate of 125 cc/m, 100 Torr (sys), 60 beats/min. The gamma counts/graft were used to calculate the number of bacteria/cm2 of graft surface. After nine experiments, a mean of 9.63 X 10(5) bacteria/cm2 were adherent to the Dacron, 1.04 X 10(5) bacteria/cm2 to the HUV, and 2.15 X 10(4) bacteria/cm2 to the PTFE. These differences were all significant at the 0.05 level. The addition of a suture line increased bacterial adherence to the PTFE graft by 50%. These results suggest that PTFE is the vascular graft material of choice when a prosthetic graft must be implanted despite a high risk of subsequent clinical bacteremia. Our in vitro, pulsatile perfusion model gave accurate and reproducible results, and appears well suited for further studies of bacterial, or platelet adherence to grafts, as well as the biomechanics of vascular conduits.

Adhesiveness↗
PubMed1985

Endothelial cell seeding of a new PTFE vascular prosthesis.

Previous attempts to line polytetrafluoroethylene (PTFE) prostheses with enzymatically derived endothelial cells have not been as successful as similar work with Dacron grafts because of the failure of such prostheses to develop a satisfactory subendothelium. This article reports our experience with a new, highly porous, unreinforced PTFE prosthesis that appears to circumvent this problem. Segments (4 mm I.D., 10 cm in length) of this new graft were implanted in 41 mongrel dogs as carotid interposition grafts. One graft in each dog was seeded with the dog's own endothelial cells, whereas the contralateral graft was treated in an identical fashion except for the inclusion of endothelium. After a mean period of 7 weeks of implantation, the grafts were harvested, their patencies were noted, the thrombus-free area of their luminal surface was calculated with computerized quantitative planimetry, and graft segments were submitted for scanning and transmission electron microscopy. In seven dogs the luminal surface was scraped from each graft and measured quantitatively. Although seeded grafts failed to show a statistically significant increase in patency during the short course of this experiment, a trend in that direction was quite striking. Furthermore, seeded grafts had a significant increase in thrombus-free area on their luminal surface as well as a significant reduction in the volume of luminal thrombus. Histologically, seeded grafts developed a substantial 75 to 100 microns cellular subendothelium beneath a confluent endothelial lining. No endothelial lining was noted in control grafts. We believe that the superior handling characteristics of this new prosthesis and its ability to develop a substantial subendothelium with a confluent endothelial lining suggest potential future applications and warrant further investigation.

Animals↗
PubMed1985

Bacterial adherence to endothelial-seeded polytetrafluoroethylene grafts.

Since infections of an arterial prosthesis pose a serious threat to life and limb, efforts to produce a graft that is resistant to hematogenous bacteremia continue. We studied the effect of endothelial seeding on bacterial adherence to polytetrafluoroethylene grafts in a canine model. Enzymatically derived venous endothelial cells were seeded in 10 cm long, 4 mm inner diameter polytetrafluoroethylene grafts, which were then implanted as carotid interpositions opposite contralateral unseeded controls. After 4 to 8 weeks, each dog received an intravenous infusion of 3 X 10(8) radiolabeled Staphylococcus aureus. Seeded grafts had significantly fewer adherent viable bacteria than had control grafts (mean, 432 versus 989; p less than 0.05) and significantly fewer radiolabeled bacteria (mean, 2 X 10(5) versus 8 X 10(5); p less than 0.05). Seeded grafts also had significantly more thrombus-free, luminal surface area than had control grafts (mean, 72% versus 40.6%; p less than 0.05). Scanning electron microscopy and autoradiography of seeded grafts confirmed that the sites of bacterial adherence largely corresponded to accumulations of surface thrombus. In this experiment, endothelial seeding appeared to protect against bacterial adherence after a hematogenous challenge 4 to 8 weeks after implantation by reducing luminal thrombi.

Adhesiveness↗
PubMed1985

Kinetics of endothelial cell seeding.

Endothelial cell seeding improves patency of small-diameter Dacron grafts and facilitates the development of a complete endothelial flow surface. However, the ideal number of cells relative to the length of graft to be seeded has not been determined. With a canine model previously shown to result in a well-endothelialized graft within 4 to 6 weeks, this study measured the quantity of autogenous endothelial cells labeled with indium 111-oxine that initially adhered to 10 cm long, experimental, porous 4 mm I.D. polytetrafluoroethylene grafts and then calculated their subsequent disappearance following implantation as carotid interposition grafts. Graft radioactivity was monitored with a gamma camera and compared with that of control vials of indium 111 implanted in the same animals. Counts were measured immediately at implantation and for up to 72 hours following restoration of flow. Data were analyzed by linear regression. The mean number of harvested endothelial cells was 6.2 X 10(5). A mean of 19.8% of the harvested cells were adherent to the grafts initially after seeding. In the first 30 minutes following restoration of flow, there was a rapid loss of these cells to a mean value, which was 70.2% of those initially present. From 30 minutes to 24 hours, cell losses continued at a constant rate of 3.7%/hr (r = -0.922, p less than 0.001). Beyond 24 hours, further loss was insignificant. Consequently, approximately 2.72 X 10(4) cells, or only 4.4% of all cells originally harvested, appear adequate to seed 12.5 cm2 of graft.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗