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Background: Eversion carotid endarterectomy is a well-described technique for carotid endarterectomy (CEA). The advantage of this technique is a completely autogenous repair. We describe a modification of eversion endarterectomy (MEE) that expeditiously extracts the plaque through a linear incision over the common carotid artery and the proximal bulbous internal carotid artery (ICA) only, allowing primary closure. Selective shunting can also be performed without difficulty., Methods: A retrospective review of CEAs using MEE at two institutions by three vascular surgeons during a 5-year period was performed. Data were collected from the medical records, with institutional review board approval. Information regarding neurologic symptoms, degree of ICA stenosis, CEA technique, ICA clamp time, shunting, electroencephalographic monitoring, and postoperative complications was tabulated. Rate of significant restenosis (stenosis >50% by duplex criteria) was also calculated during the follow-up period., Results: Between 2005 and 2009, a total of 221 patients underwent MEE for carotid artery stenosis (CAS): 69 patients (31%) underwent MEE for symptomatic and 152 (68.8%) underwent MEE for asymptomatic CAS. Neuromonitoring in the form of electroencephalography was used in 85 (39%) patients, and an intraluminal shunt was used in 29 patients (13%) who had either severe contralateral disease or a previous ipsilateral cerebral infarction. Postoperative complications included transient ischemic attack (four, 2%), cerebral infarction (three, 1%), myocardial infarction (three, 1%), and hematoma (six, 3%). Four patients (2%) required a return to the operating room (OR). within 24 hours for hematoma (one, 1%) or postoperative neurologic deficit (three, %). The 30-day mortality was 1%. One patient (1%) required patch angioplasty because of the extent of disease and inability to obtain a good end point. Average cross-clamp time for MEE was 12.8 minutes. Two patients (1%) were reported to have hemodynamically significant restenosis within 2 years, with one patient requiring intervention., Conclusions: MEE is a safe and effective way of treating CAS, with acceptable morbidity, mortality, and low rate of recurrent stenosis despite the absence of a patch. Given the brief clamp time required, routine shunting and/or neuromonitoring for this technique may have questionable clinical value and expense., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Aneurysm of the carotid artery following endarterectomy is a rare entity that historically has required reoperation. Endovascular deployment of a covered stent can theoretically exclude an aneurysm while minimizing the risks seen with reoperation. Herein, we review the scientific literature on this evolving technique and report an additional case involving successful treatment of an aneurysm that developed following remote endarterectomy.

Purpose: Current strategies to create small-diameter vascular grafts involve seeding biocompatible, compliant scaffolds with autologous vascular cells. Our purpose was to study the composition and strength of decellularized vein to determine its potential as a vascular tissue-engineering scaffold., Methods: Intact human greater saphenous vein specimens were decellularized by using sodium dodecyl sulfate (SDS). Residual cellular and extracellular matrix composition was studied with light and electron microscopy as well as immunohistochemistry. Burst and suture-holding strength was measured in vitro by insufflation and pull-through techniques. To assess initial handling and durability of decellularized vein in vivo, a canine model was developed wherein decellularized canine jugular veins were implanted as carotid interposition grafts in recipient animals. After two weeks of arterial perfusion, these grafts were studied with duplex imaging and histologic methods., Results: Human saphenous vein decellularized by using SDS was devoid of endothelial cells and >94% of the cells resident within the vein wall. Collagen morphology appeared unchanged, and elastin staining decreased only slightly. Basement membrane collagen type IV remained intact. Compared with fresh vein, decellularized vein had similar in vitro burst (2480 +/- 460 mm Hg vs 2380 +/- 620 mm Hg; P >.05) and suture-holding (185 +/- 30 gm vs 178 +/- 66 gm; P >.05) strength. Decellularized canine vein functioned well in vivo without dilation, anastomotic complication, or rupture over 2 weeks of arterial perfusion., Conclusions: Vein rendered acellular with SDS has well-preserved extracellular matrix, basement membrane structure, and strength sufficient for vascular grafting. These properties suggest proof of concept for its use as a scaffold for further vascular tissue engineering., Clinical Relevance: The following research examines the creation of a new small-diameter bypass graft. It is clinically relevant to patients who need distal arterial bypass, coronary artery bypass, or hemodialysis access, but who do not have adequate autologous vein for their surgeries. Future investigations will involve further tissue engineering of this vascular scaffold (eg, autologous endothelial seeding of its lumen) and testing the clinical usefulness of the completed graft.

Endograft repair has rapidly become an alternative to conventional open repair of abdominal aortic aneurysms. Various trials continue to show decreased morbidity when compared to open repair. However, as with any new procedure, complications specifically related to this technique are being described. Herein, we report a case of an isolated ischemic jejunal stricture presenting as a small-bowel obstruction secondary to cholesterol emboli following endograft repair of an abdominal aortic aneurysms.

A postoperative superior mesenteric artery pseudoaneurysm that communicates with a pancreatic pseudocyst after aortic surgery is a difficult management problem. Untreated, this condition can lead to exsanguination. Traditional surgical treatment has many potential complications. Endovascular repair has the potential for avoidance of surgical complications. We present the first superior mesenteric artery pseudoaneurysm successfully treated with A polytetrafluorethylene covered stent.

The lateral approach to the distal peroneal artery has been used by vascular surgeons for 25 years. No complications specifically related to this approach have previously been reported. We reviewed 18 cases of peroneal bypass for limb salvage using the lateral approach with fibula resection and found that two of these cases had ipsilateral tibia fractures within 1 year of the bypass. Eight out of 18 cases were women, and two of these eight had tibia fracture. Both women suffered from osteoporosis. We conclude that tibia fracture is a possible complication of this approach, especially in elderly women with osteoporosis.

Vertebral osteomyelitis may occur with mycotic aneurysms or infected aortic grafts. A high index of suspicion for these concurrent processes as well as appropriate preoperative evaluation and interspecialty communication is critical for appropriate diagnosis and treatment. Extraanatomic bypass, wide debridement of necrotic soft tissue and bony structures, and concurrent bony stabilization are important aspects of treatment.

Clostridial infection of the aorta is a rare and life-threatening condition. The management of a mycotic aneurysm involving the thoracoabdominal aorta due to Clostridium septicum infection is presented. Successful surgical management of the aortic infection involved arterial resection, wide debridement of the surrounding tissues, and in situ graft replacement. Sixteen additional cases of clostridial infection of the aortoiliac segment reported in the literature are also summarized. In ten of these 17 cases, an associated colonic adenocarcinoma was documented.

Background: We examined our long-term results of carotid reoperation to identify risk factors for morbidity and secondary recurrence., Methods: Medical record review revealed 27 patients had reoperative surgery for recurrent stenosis. Demographics, operative details, pathology, clinical outcome, and follow-up imaging results were reviewed., Results: No neurologic deficits and no mortalities were noted perioperatively. Long-term follow-up (average 54 months) revealed an 85% 5-year and 29% 10-year estimated survival. The 5- and 10-year estimated neurologic event rates were 15% and 35%, respectively. These included 3 ipsilateral strokes and 1 ipsilateral TIA; only the TIA involved secondary restenosis. Follow-up imaging revealed a 21% incidence of secondary restenosis, occurring more frequently in patients with hyperlipidemia (P < 0.05) and previous contralateral endarterectomy (P < 0.05)., Conclusions: (1) Reoperation provides long-term protection from stroke due to recurrent stenosis. (2) Secondary restenosis rates appear higher than those for primary surgery. (3) Hyperlipidemia and contralateral endarterectomy are risk factors for secondary restenosis.

Although there are several reports suggesting the safety of performing carotid endarterectomy (CE) within 4 weeks (early) of a nondisabling stroke, at many institutions it is not standard practice. Benefits of early surgery may include reduction in the number of strokes or carotid occlusions during the time between stroke and surgery, as well as a reduction in the cost of medical care due to the elimination of interval anticoagulation and close follow-up. This review examines the outcomes of early CE in selected patients after a nondisabling stroke. A total of 1065 CEs were performed between November 1991 and April 1998. Seventy-five patients were identified by computerized hospital record and office chart review as having CE after a nondisabling stroke. Criteria for early surgery included 1) nondisabling stroke ipsilateral to a carotid stenosis >50%, 2) neurological stability, and 3) no evidence of hemorrhagic stroke or significant cerebral edema by CT/MRI evaluation. This review suggests that early CE can be performed in selected patients with an acceptable perioperative morbidity and mortality.

Rationale and Objectives: The authors compared Doppler ultrasound (US) with computed tomographic (CT) angiography in the evaluation of stenosis of the main renal artery., Materials and Methods: Fifty-six patients who had undergone conventional angiography of the renal arteries participated in a prospective comparison of Doppler US (45 patients) and CT angiography (52 patients). US evaluation included both the main renal artery and segmental renal arteries., Results: There were 27 main renal arteries with at least 50% stenosis in 20 patients. In 36 patients, there was no significant stenosis. All cases of main renal artery stenosis detected with Doppler US of the segmental arteries were also identified with Doppler US of the main renal artery. The by-artery sensitivity (63%) of US of the main renal artery was greater than that (33%) of US of the segmental arteries. CT angiography was more sensitive (96%) than Doppler US (63%) in the detection of stenosis, but the specificity of CT (88%) was similar to that of US (89%). The difference in the area under the receiver operating characteristic curve (AUC) between CT (AUC = 0.94) and US (AUC = 0.82) was statistically significant (P = .038)., Conclusion: Doppler US of the main renal artery is more sensitive than Doppler US of segmental arteries in the detection of stenosis. CT angiography is more accurate than Doppler US in the evaluation of renal artery stenosis.

Purpose: We examined the effect of thrombin on human iliac artery endothelial cell monolayer repair and proliferation after denuding vascular injury., Methods: Human iliac artery endothelial cell monolayer repair was determined by scrape wounding confluent monolayers and measuring the advancement of the cells into the wounded area for 3 days. Proliferation studies involved plating human iliac artery endothelial cells at one tenth confluence and counting the increase in cell number every 2 days for a 2-week period. Proliferation during monolayer repair was examined by determining bromodeoxyuridine uptake in cells located at the leading edge of a scrape-wounded monolayer., Results: Thrombin (1 to 8 U/ml) inhibited human iliac artery endothelial cell monolayer repair in a concentration-related, reversible manner. The effect was augmented by decreasing serum concentration and was independent of the presence of endothelial cell growth supplement. Inactivation of thrombin's proteolytic site with diisopropylfluorophosphate eliminated its effect on monolayer repair. Thrombin (0.5 to 8 U/ml) inhibited human iliac artery endothelial cell proliferation in a dose-related manner. This effect was augmented by decreasing serum concentration. Finally, thrombin (4 U/ml) inhibited the proliferative response of cells located at the leading edge of wounded monolayers compared with control groups., Conclusion: Thrombin inhibits human arterial endothelial cell monolayer repair and proliferation after denuding vascular injury.

A case of a ruptured middle colic artery is reported. The diagnosis was initially overlooked and eventually made by selective arteriography. Aneurysms of visceral arteries are rare and rupture of them even more infrequent. Awareness of this potentially fatal and treatable entity should enable early detection by selective visceral arteriography. The roles of embolization and surgery in the management of visceral aneurysms are discussed.

Iatrogenic injuries of the groin are becoming more common after increasingly sophisticated vascular intervention. These injuries are accurately detected by duplex and color Doppler ultrasonography. Recent treatment of these lesions by ultrasound-guided compression repair (UGCR) has been described. During a 1-year period we identified 18 femoral artery injuries, including 17 pseudoaneurysms and one arteriovenous fistula. Three of the pseudoaneurysms thrombosed spontaneously before attempted treatment. The remaining 15 lesions underwent a trial of UGCR. Successful closure was accomplished in 10 patients (56%). Seven of these lesions were successfully treated during the initial session, and thrombosis was accomplished after repeat compression in three additional lesions. Three patients who were given anticoagulants had a failed UGCR, but their pseudoaneurysms thrombosed after administration of anticoagulants was discontinued. Two patients had failed UGCR and required operation. Seven (88%) of eight patients who were not given anticoagulants were successfully treated. In contrast only two (29%) of seven patients given therapeutic doses of anticoagulant medication were successfully treated by the technique. There was no statistical difference between mean pseudoaneurysm diameter, mean width and length of pseudoaneurysm neck, or depth of pseudoaneurysm neck from skin surface in patients in whom successful initial closure was achieved when compared with those patients in whom the initial attempt failed. UGCR is a safe, simple, noninvasive technique that can be used to treat many femoral artery injuries that traditionally were treated with surgery. The technique can be applied by any laboratory that has the necessary ultrasonography equipment and is currently the method of choice for treating uncomplicated iatrogenic femoral artery injuries at our institution.

Great progress has been made in the last several years in our ability to culture human endothelial cells. In addition, techniques to immediately procure and utilize these cells have also been developed. The purpose of this paper is to present an overview of the current and potential uses of these cells in both vascular and nonvascular conditions. It is likely that endothelial cells will be used in a variety of applications in the near future. Immediately procured and cultured cells will be used to resurface vascular prosthetic grafts. They may also be used on the surface of vessels following procedures such as balloon angioplasty or atherectomy. In addition, they may be placed upon the surface of implantable devices such as expandable stents. Through the mechanism of genetic engineering, these cells may be modified to produce proteins, which may modify thrombogenicity and perhaps decrease the rate of recurrent stenosis by influencing cellular hyperplasia. Genetically modified endothelial cells also have great potential in nonvascular disease. Their contact with circulating blood makes them an ideal cell for production of proteins to correct systemic conditions such as the insulin deficiency found in diabetes mellitus. The application of endothelial cell biology in both vascular and nonvascular science represents one of the most exciting fields of research active today.

Endothelial cell (EC) transplantation has been proposed as a method to reduce the thrombogenicity of both vascular grafts as well as injured native blood vessels. While techniques have been developed to establish EC monolayers on these surfaces, a major question that remains is whether the cells that exist on the blood flow surface are the same cells placed on the surface at the time of transplantation. We have developed an intravital fluorescent staining technique that permits isolated, autologous, fat-derived microvascular endothelial cells (MVEC) to be labeled and subsequently detected following their transplantation. In our study, rat abdominal aortas (AA) were injured with a 3F embolectomy catheter, and the injured surfaces were immediately treated with fluorescently labeled MVEC. Five days after transplantation, AA were evaluated by both scanning electron and fluorescence microscopy. Results of scanning electron microscopy showed the existence of nonthrombogenic regions in the areas of injury, and fluorescence microscopy of the identical areas established that these cells contained fluorescent dye. Our results indicate that the cells that line these injured areas of native vessels are the same cells that were originally transplanted. Our intravital fluorescence technique provides a method to trace the origin and disposition of transplanted cells on the vascular surfaces.

The initial outcome of a consecutive series of 43 intra-arterial urokinase infusions for thrombosed infrainguinal grafts in 37 patients was analyzed. There was an 88% (38/43) technical success rate (complete clot lysis) and a 74% (32/43) clinical success rate. Complications occurred in 10 patients (23%) and were related to bleeding in four patients (9%). Patient age, graft age, location, material, and the duration of occlusion did not significantly influence the initial outcome, although there was a trend toward a higher bleeding complication rate among grafts less than or equal to 1 month of age at the time of thrombolysis. A second group of 43 infrainguinal grafts successfully recanalized using regional infusions of thrombolytic agents were followed for long-term patency. This group included 32 grafts successfully treated with urokinase and 11 grafts recanalized with streptokinase. By life-table analysis there was a 55.6% 1-year patency, which fell to 42.4% at 4 years. Vein grafts had significantly (p = 0.01) better long-term patency than prosthetic grafts (69.3% versus 28.6% at 30 months). Grafts with flow-limiting lesions identified and corrected by angioplasty or surgery also had significantly (p = 0.01) better long-term patency than those without such lesions (79.0% versus 9.8% at 2 years). Based on the results of our study compared with a survey of long-term results following secondary surgical procedures for thrombosed infrainguinal grafts, thrombolysis can be recommended in several circumstances. Thrombolysis is indicated for thrombosed vein grafts or when thrombus is present in distal runoff vessels. Thrombosed prosthetic grafts should be replaced by autogenous vein grafts whenever possible.(ABSTRACT TRUNCATED AT 250 WORDS)

The addition of an endothelial cell lining to a prosthetic vascular graft may reduce the thrombogenicity of the blood-contacting surface. An endothelialized mesoatrial graft was implanted in a patient with Budd-Chiari syndrome caused by a primary inferior vena caval leiomyosarcoma. During the initial surgery a Dacron vascular graft was preclotted with plasma and then lined with microvascular endothelial cells derived from the patient's subcutaneous adipose tissue. The patient did well initially but 9 months later required resection of a mechanical stricture of the graft that occurred as it passed beneath the costochondral junction. Grossly, the luminal surface of the resected graft was free of thrombus, with a smooth, glistening, white surface. Light microscopy demonstrated a surface layer of cells morphologically consistent with an endothelial cell monolayer, a subendothelial layer composed of extracellular matrix and spindle-shaped cells, and granulation tissue around the Dacron fabric. Immunohistochemistry and electron microscopy confirmed the presence of vascular endothelium on the luminal surface. This report documents the successful achievement of a human endothelial cell monolayer that persisted for 9 months in the midportion of a Dacron vascular graft.

Right hepatic trisegmentectomy which removes the right lobe and the medial segment of the left lobe is necessary to remove completely lesions which extend beyond the true right lobe of the liver. The procedure has been described in detail in excellent reviews. We describe a technique of bile duct preservation during right trisegmentectomy. This is accomplished by cannulating the left hepatic duct with a Silastic catheter which is introduced through the stump of the right hepatic duct. This technique allows palpation of the duct during the dissection. With positive identification, the numerous small branches to the medial segment of the left lobe can be ligated safely. A completion cholangiogram through the catheter is always done to identify and repair any extensive bile duct leaks. Finally, the technique can be adapted for use in other resections, such as left trisegmentectomy by simply cannulating the appropriate duct.

We have developed a system for the in vitro evaluation of the interaction of human adult endothelial cells (HAEC) with prosthetic vascular graft material. HAEC, isolated from adult human iliac veins, proliferated vigorously in culture for approximately 70 population doublings. The large number of HAECs produced permitted high-density seeding of prosthetic grafts. Samples of prosthetic material were immobilized on a plastic ring and were used either untreated or coated with extracellular matrix, fibronectin, or plasma. HAEC were seeded at high density and adherence was evaluated by light and electron microscopy after a 2-hr incubation. While essentially no HAEC adhered to untreated grafts, treatment of grafts with either extracellular matrix, plasma, or fibronectin resulted in dramatic adherence of HAEC. The highest density of HAEC adherence was observed on collagen-coated Dacron grafts, and was equal to the cell density observed in confluent monolayers of HAEC grown on gelatin-coated tissue culture plastic. This study demonstrates a method capable of determining HAEC-graft biocompatibility prior to the use of an in vivo system.

Renal autotransplantation was performed in five patients and extracorporeal vascular reconstruction was required in two of these cases. One had a carcinoma of the mid-ureter with a solitary kidney. Two patients had ureteral injury. One was iatrogenic from a prior operation, and the other had intrinsic ureteral disease secondary to schistosomiasis. The fourth patient had renovascular hypertension with disease extension into the interlobar renal arteries and a single kidney. The final patient had a large, renal arteriovenous malformation and polycystic kidneys. All have functioning grafts at follow-up ranging from 10 to 36 months. There is no evidence of tumor recurrence after 30 months in the patient with ureteral malignancy. The patient with renovascular hypertension has adequate blood pressure control with medication 12 months after surgery. His creatinine which had risen in the post-operative period to 4.2 mg/dl, has returned to its pre-operative valve of 1.8 mg/dl. None of the other four patients had any post-operative decline in renal function. These cases illustrate that the technique of nephrectomy, extracorporeal surgery, and renal autotransplantation can be applied to a variety of benign and malignant diseases of the kidney and ureter not amenable to conventional in-situ correction, thus allowing maximal preservation of renal parenchyma. We also have demonstrated that the procedure can be successfully performed in the presence of significant infectious risk (Case 2: indwelling nephrostomy), and retroperitoneal infection (Case 3: schistosomiasis). We feel that this procedure is currently underutilized.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of the present study was to culture human adult endothelial cells (HAECs) on a long-term basis in the laboratory. Previous inability to accomplish this has been the major impediment to the in vitro study of endothelialization of prosthetic grafts with human cells, a problem of significant clinical relevance. We have been successful in developing a technique that allows HAECs from human adult arteries, veins, and capillaries to proliferate vigorously in culture for up to 80 population doublings. HAECs are grown on a gelatin surface (medium 199 containing 20% fetal calf serum). Heparin and endothelial cell growth factor (ECGF) are required for optimal growth. With this technique, which will be described in detail, over 10(23) HAECs can be produced from each 1 cm2 of vascular tissue. This makes large numbers of HAECs available for high-density seeding on prosthetic grafts prior to implantation. It also permits for the first time with human cells the in vitro study of prosthetic grafts--HAEC interactions and the factors that enhance optimal growth and adherence to prosthetic materials. It is hoped that identification of the factors promoting graft endothelialization in combination with high-density seeding will lower graft thrombogenicity and therefore result in greater graft longevity than has been possible heretofore.

The initial surgical management of neck metastases from head and neck cancer may be complicated if the tumor mass invades the carotid vessels. Acute carotid ligation is associated with a high stroke rate. Consequently preservation of flow to the internal carotid artery is desirable. We will describe two patients in whom preservation of flow was accomplished with the use of a saphenous vein bypass from the axillary artery to the internal carotid artery. The technique is described and has several advantages. First, it preserves flow to the internal carotid artery; second, it allows radical excision of tumor without compromising the margins of resection; and finally, at least one suture line and most of the graft are outside the field of radiation and remote from the wound closure. We believe that this technique is useful in the management of patients with disease that has metastasized to the neck.

Successful endothelialization of vascular grafts by seeding with endothelial cells (EC) at implantation is related to the number of EC which initially adhere to the graft. Using an in vitro system we examined the initial adherence of EC from human perinephric fat capillaries to woven Dacron that was either unmodified or precoated with several substrates. We studied capillary EC because they have not been investigated as a source of EC for graft seeding, although transinterstitial capillary ingrowth is one possible mechanism for spontaneous graft endothelialization. EC were isolated using collagenase and characterized morphologically and functionally including positive factor VIII-related antigen staining. EC were studied at three phases in culture: (A) primary EC with no subcultivations (EC-0); (B) EC after two subcultivations with trypsin (EC-2); and (C) EC after 10 subcultivations with trypsin (EC-10). EC were seeded onto graft material at a density of 10(5) cells/cm2 (100% confluence) and examined for cell counts and morphology after one day in culture by light and electron microscopy. Results are as follows: (table; see text) The conclusions are: (1) All capillary EC demonstrated adherence to Dacron, but this initial adherence was strongly influenced by graft pretreatment with collagen or plasma. (2) Serially subcultivated EC (EC-2 and EC-10) had significantly higher initial adherence to pretreated Dacron compared to the primary cells (EC-0) (P less than .05). This suggests that briefly cultured and subcultivated EC have superior initial adherence characteristics to treated dacron compared to primary EC with no subcultivations. (3) Fat capillary EC are easily procured and cultured and provide a rich source of human EC for endothelializing vascular prostheses.

The temporal sequence of events was examined from initial contact of endothelial cells (ECs) to Dacron until the establishment of a monolayer. Cultured human adult ECs were radiolabeled, seeded onto Dacron, and adherence was quantified after vigorous washing. Firm adherence of 70% of the seeded ECs was seen by 2 hours to untreated Dacron, by 30 minutes to Dacron pretreated with a combination of interstitial type I/III collagen and an amnion-derived basement membrane (Type IV) collagen surface, and by 10 minutes to plasma-coated Dacron. Parallel samples were examined morphologically by scanning electron microscopy (SEM) to evaluate the adherence of ECs to surfaces. ECs seeded onto plain Dacron exhibited limited adherence, while cells on plasma-treated Dacron exhibited limited cell-cell associations. On basement membrane-treated Dacron, by 30 minutes the ECs exhibited a flat attenuated morphology, completely covering the graft surface. This time-frame is compatible with most vascular procedures, making an immediately endothelialized graft feasible.

Endothelial seeding of vascular graft surfaces may lead to a less thrombogenic surface. We examined the feasibility of using microvessel endothelial cells derived from human fat for seeding purposes. Human fat was treated with collagenase for 24 minutes, washed, and purified in a Percoll gradient separation. This yielded 1.25 +/- 0.45 X 10(6) cells/gm of fat. After a 1-hour incubation on plasma-coated Dacron, 2.8 +/- 1.5 X 10(4) cells remained firmly adherent to the surface. When exposed to flow for 2 hours at a shear stress of 0 to 80 dyne/cm2, between 50% and 100% of the initially adherent cells remained adherent. Statistical analysis of this data failed to demonstrate a strong relationship between the number of adherent cells and the shear rate. Scanning electron microscopy demonstrated endothelial cells in various stages of attachment to the plasma-coated Dacron. Although most cells were still round and only focally attached to the surface, some cells were maximally flattened, forming cell-to-cell contact. Because of the high cell yield and the firm adherence characteristics, we conclude that microvessel endothelial cells may offer the possibility for confluent endothelial cell seeding of a graft at the time of surgical implantation without the need for cell culture.

The Greenfield filter can be used with a low complication rate provided one adheres to certain principles. First, preoperative venography to define the inferior vena caval anatomy will help avoid difficulties associated with anatomic variations. At the time the study is carried out, it would be extremely useful if the radiologist places a radiopaque marker at the level of the renal veins. This will ensure that filters will be placed in the infrarenal position when appropriate, thus preventing occasional inadvertent discharge, particularly into the right renal vein. Second, use of a guide wire greatly facilitates passage of the introducer and accurate intracaval positioning. Third, intraoperative technical errors must be recognized and promptly corrected. Finally, meticulous postoperative follow-up is essential, and recurrent embolism or any change in filter position requires repeat roentgenography of the vena cava to guide appropriate corrective treatment.

"Nephrotoxicity" secondary to cyclosporine and its clinically used vehicle, Cremophor EL, was examined in the isolated perfused rat kidney model. This model allows the serial determination of renal hemodynamic and tubular functional studies over a 3-hr duration using a normothermic, low hematocrit (13-15%) perfusion system. Initial studies indicated that the addition of small quantities of Cremophor EL resulted in marked renal vasoconstriction with decreased renal blood flow and deterioration in renal tubular function. These effects were highly significant and were of the same magnitude whether or not cyclosporine was present in the system. Cyclosporine was therefore examined after being dissolved in another vehicle, methanol. A 10% (v/v) amount of plasma was necessary in the perfusate to prevent significant adsorption of cyclosporine to the perfusion apparatus. Cyclosporine at concentrations below 100 ng/ml resulted in minor changes in renal hemodynamics. Beginning at 100 ng/ml glomerular filtration rate dropped significantly and renal vascular resistance increased three-fold. Fractional excretion of sodium significantly increased and the urine:plasma inulin ratio significantly decreased. We conclude that the clinically used drug vehicle, Cremophor EL, has significantly adverse effects on renal hemodynamics and tubular function. In addition, CsA causes similar renal toxicity in a dose-dependent fashion. Simultaneous administration of these two nephrotoxic agents could contribute to the high incidence of acute renal failure seen after transplantation. These observations suggest that an alternate vehicle with less renal toxicity might significantly decrease the incidence of this clinical problem.

Physical and biochemical forces exist that are necessary for the persistent attachment and function of ECs on native and prosthetic blood vessels. The optimization of conditions that permit regeneration of these attachment forces may allow rapid establishment of a durable, biocompatible EC monolayer. We examined the effects of three major factors, protein substrate, EC incubation time, and shear stress, on the attachment kinetics of human adult ECs to two different polymers. ECs were incubated up to 30 minutes on polymers (PS or PET) coated with extracellular matrix proteins: collagen I/III, fibronectin, collagen IV/V, laminin, gelatin, or saline control. After incubation, continued attachment in the presence of shear stress (created in a rotating disc device) between zero and 90 dynes/cm2 for 30 minutes was evaluated. Maximal adherence was observed on all substrates by 30 minutes. Therefore, after a 30-minute incubation, the percentage of cells attached (postshear ECs/preshear ECs/preshear ECs X 100) was measured as a function of shear stress. ECs attached to a matrix of fibronectin or collagen I/III demonstrated shear-resistant adherence after as little as 5 minutes of static incubation before initial shear exposure. By 30 minutes, more than 90% of the ECs on both matrices demonstrated the ability to remain attached in the presence of 90 dynes/cm2 of shear stress. We conclude that forces that attach ECs to surfaces are affected by temporal factors (incubation time) and substrate composition and may be quantified with a defined shear stress detachment assay. Understanding and manipulating these temporal physiochemical parameters should allow one to re-create an optimal EC monolayer on a blood-contacting surface.

A new retrievable inferior vena cava (IVC) filter was tested in nine pigs. Insertion was through a 14 French sheath using both the femoral and jugular approaches. All insertions were successful, and there was a 100% postinsertion IVC patency rate (8/8 pigs at one week and 1/1 pig at one month). Addition of an apical hook to the filter design allowed transjugular retrieval of two filters at one week postinsertion. Three of nine filters migrated to the upper IVC. The filter's design allows paraxial blood flow despite trapped thrombus and inhibits filter tilting. In vitro, the filter captured 95% to 100% of 5 X 5 mm clots. If problems with migration can be solved, the new filter may provide effective short- and long-term prophylaxis against pulmonary embolism.

Acute cardiovascular collapse in the hospitalized patient is associated with a high mortality rate and remains a therapeutic dilemma. Survival could be improved in the subgroup of patients with massive pulmonary thromboembolism if prompt surgical intervention is undertaken. This report presents the cases of two patients with cardiovascular collapse who survived transvenous catheter pulmonary embolectomy (herein described in detail). This procedure can be performed in any hospital with angiographic facilities and personnel trained in the technique. In our opinion it is the procedure of choice in patients with refractory cardiovascular collapse from massive pulmonary thromboembolism.

The authors have evaluated the risk of pulmonary embolism both as a primary event or as a secondary embolus despite adequate anticoagulation in 39 patients with phlebographically documented inferior vena caval (IVC) thrombosis. Twenty-six of these patients had thrombi characterized as free floating, and 13 had thrombi that were adherent to the IVC wall without a free-floating component. The incidence of initial pulmonary embolism confirmed by either pulmonary arteriography or high probability ventilation-perfusion lung scanning was 50 per cent (13/26) in those patients with free-floating IVC thrombi, but 15 per cent (2/13) in those with closely adherent mural thrombi (P less than 0.05). Pulmonary embolism despite adequate anticoagulation occurred in 27 per cent (7/26) of patients with free-floating clots, but in only 17 per cent (1/8) of cases with adherent thrombi (P greater than 0.05). These data strongly suggest that patients with documented free-floating inferior vena caval thrombi are at a significant risk for pulmonary embolism as an initial event and perhaps also as a recurrent embolus, even in the presence of adequate anticoagulation. When such thrombi are identified, the overall incidence of pulmonary embolus is high and conventional anticoagulant treatment with heparin may not be sufficient.