Duplex-directed vena caval filter placement: report of initial experience.

BACKGROUND: Fluoroscopy, cost, and patient transport contribute to difficulties occasionally associated with the placement of vena caval filters. Follow-up data in the literature document the use of duplex ultrasonography in visualizing the filter and determining caval patency. Filter placement at the bedside or in the vascular laboratory with duplex ultrasonography may simplify this common procedure. We have attempted to define the feasibility of this method. METHODS: Patients referred to the vascular surgery service for vena caval interruption were evaluated for ability to visualize the renal veins and inferior vena cava. Location of renal veins, maximum diameter of the vena cava, and presence or absence of thrombus were documented. If visualization was adequate, placement was performed at the bedside for patients in intensive care or in the vascular laboratory for nonmonitored patients. The initial 10 patients and subsequent patients in whom there was a question of adequate deployment underwent completion abdominal roentgenography. Patient follow-up was difficult. Duplex ultrasonography was used to assess migration, thrombus adherent to the filter, and vena caval patency. Patients in whom filter placement was prophylactic were given anticoagulants at the discretion of the primary physician. Inadequate visualization or vena caval size greater than 28 mm prompted fluoroscopic placement of the vena caval filter, because only Greenfield titanium filters were used in the study. RESULTS: Twenty-nine patients were referred for vena caval interruption. Inadequate visualization occurred in four obese patients, and filters were placed by fluoroscopy. There were no vena caval measurements greater than 24 mm. Twenty-five filters were placed without technical difficulty. One filter tilted into the right renal vein, requiring a suprarenal filter placed by fluoroscopy. Patient retrieval for follow-up has been difficult, but by ultrasonography there has been one vena caval thrombosis and no major filter migration. There have been no reported pulmonary emboli other than the one patient with initial tilt of the filter. CONCLUSIONS: Placement of vena caval filters is feasible with duplex ultrasonography. Visualization is the only limiting condition to placement and occurs rarely. Reducing the need for fluoroscopy, lowering costs, and not needing to transport the critically ill patient support the use of this system. Intravascular ultrasonography in selected patients may eliminate the need for fluoroscopic placement of vena caval filters.

Aortoiliac occlusive disease and gastrointestinal malignancy: changing therapeutic options.

Treatment of gastrointestinal malignancy encountered unexpectedly during procedures involving the abdominal aorta continues to be debated. Previously, simultaneous vascular procedures with intra-abdominal malignancy were rare. Most underwent vascular reconstruction followed by a delayed aortic procedure. With recent improvement in axillobifemoral graft patency, a one-stage procedure for aortoiliac disease should be entertained. We recently encountered a small bowel lymphoma while beginning an aortic replacement for aortic occlusion. Resection of a near-obstructing small bowel tumor immediately after axillofemoral reconstruction provided treatment of both entities at one time. Since the early description of axillofemoral bypass in 1963, varying success with extra-anatomic bypass has been reported. Early data for axillofemoral bypass were dismal, but with recent technical and graft improvements patency has been improved. Occult malignancy during aortic procedures is uncommon, about 2 to 4 per cent, but when met is usually dealt with after the patient recovers from the vascular procedure. With improvements in extra-anatomic bypass results, a single operative period can be entertained.

Technical complications of endovascular abdominal aortic aneurysm repair.

PURPOSE: Results from 34 endovascular repairs of abdominal aortic aneurysms are reviewed to identify technical complications and relate them to anatomic and technical features of the operation. METHODS: Twenty-one patients underwent attempted tube graft repair (mean follow-up, 13 months). Thirteen patients underwent placement of a bifurcated graft (mean follow-up, 7.2 months). RESULTS: Twenty-five patients (74%) underwent repair without technical complication (16 tube graft and nine bifurcated graft). Of five patients who had tube graft complications, two involved small iliac arteries and resulted in arterial injury. One of these patients needed a femorofemoral bypass procedure, and the other required conversion to standard operation. Two patients had distal leaks associated with the attachment system, and one patient had misplacement of the distal attachment system. The two patients who had leaks were followed-up; one required operation after 7 months, whereas the other leak sealed. The patient who had distal attachment system misplacement had a second endograft placed within the first to provide a distal seal. The four patients who had bifurcated graft complications involved two graft limb stenoses, one managed with a Palmaz stent and the other with balloon angioplasty. The patient treated with balloon angioplasty had graft thrombosis 1 week after the operation, which resulted in the need for a femorofemoral bypass procedure. Another bifurcated graft patient had a graft limb twist, which has resulted in chronic claudication. One patient had placement of a limb too proximal in the common iliac artery with chronic leak, and an open operation was performed 18 months later. CONCLUSIONS: Technical complications in this series seem to be associated with short distal necks, small iliac arteries, tortuous iliac arteries, and atherosclerosis at the aortic bifurcation. We believe that experience and understanding of these issues will reduce the risk of these complications in the future.

Severe intraoperative coagulopathy following routine aortobi-iliac bypass with knitted Dacron graft.

Coagulopathy associated with aortic operation is generally described in patients undergoing supraceliac aortic clamping or ruptured abdominal aortic aneurysm repair. This intraoperative complication is managed with component blood replacement and occasional use of aminocaproic acid. The presence of intraoperative coagulopathy associated with aortic reconstruction for occlusive disease is not described. We report a case of severe intraoperative coagulopathy associated with aortobi-iliac artery bypass with a knitted Dacron prosthesis. Management of this complication was accomplished with administration of blood components, aminocaproic acid and explant of the Dacron prosthesis with polytetrafluoroethylene graft placement. The possibility of fibrinolysis induced by the knitted Dacron prosthesis is suggested.

Limb ischemia: surgical therapy in acute arterial occlusion.

Mortality and amputation rates from acute arterial occlusion are reported from 7 to 37 per cent and 10 to 30 per cent, respectively. Recent data from thrombolysis or peripheral arterial surgery suggest no significant differences between initial management with surgical or thrombolytic therapy. Mortality and amputation rates were in the above ranges. The last 230 procedures (216 patients) over 10 years were reviewed. All graft occlusions, cardiac catheterization injuries, and aortic balloon-related thromboses were excluded. Immediate and delayed amputation rates were 6.5 and 0.9 per cent. Death occurred in 21 patients (9.7%), with only 6 deaths over the last 6 years (3.8%). Except for transesophageal echocardiography, perioperative studies were of limited value. Long-term anticoagulation was also not effective in preventing recurrent episodes. A mortality rate of 9.7 per cent and amputation rate of 7.4 per cent justifies an early aggressive surgical approach. Limited perioperative studies and less prolonged anticoagulation may also improve cost containment.

Expanding the physician care team: its effect on patient care, resident function, and education.

Recent attempts to improve surgical resident working conditions have taken many forms. We evaluated a system in which a well-trained physician extender had been hired to assist residents taking call on a busy cardiothoracic teaching service. The physician extender ("night nurse," NN) helped with perioperative care using well-defined protocols. The NN, who was in-house Sunday-Friday, 7 pm-7 am, rounded with the residents at the beginning of the evening. Concerns were discussed and care plans formulated. Thereafter, all pages (except codes and extreme emergencies) were directed to the NN, freeing the residents to complete work-ups, patient assessments, or study. The NN assessed patients and initiated care plans including orders that followed either care protocols or plans previously arranged with the resident. For unanticipated concerns, the resident was notified for input and/or patient assessment. For 30 consecutive nights, the patient load and acuity were evaluated. Residents and NN kept diaries of all pages received. The residents also documented time slept and times awakened. Residents received 10 times fewer calls when the NN was available (21.8 +/- 10.5 vs 2.9 +/- 2.4) and slept an average of 2.5 hr more (135 +/- 106.1 vs 286.2 +/- 68.2 min). Care was maintained as judged by morbidity and mortality statistics. Such a system has allowed us to avoid cross coverage, thereby maintaining resident continuity of care and involvement in meaningful care plans, while providing increased time for patient evaluation, self-education, and increased uninterrupted sleep.

Selective intraportal hepatocyte transplantation in analbuminemic and Gunn rats.

Although significant progress has been achieved in isolated hepatocyte transplantation, the optimal site of cell implantation has not yet been determined. We have developed a novel experimental method of intraportal hepatocyte transplantation that allows easy assessment of the morphology and function of transplanted hepatocytes. Donor hepatocytes were harvested from Sprague-Dawley rats by in situ EDTA/collagenase perfusion. Fifteen recipient Nagase analbuminemic rats (NAR) underwent cannulation of the gastroduodenal vein under ether anesthesia. Either the posterior or anterior liver lobes were selectively infused with cells by occluding the portal venous supply of the nontransplanted liver lobes. Normal donor hepatocytes (2 x 10(7)) suspended in normal saline were infused over 1 min (4 ml). Recipients were treated with cyclosporine for the duration of the experiment. Plasma albumin levels were determined by ELISA, before and at various intervals after transplantation. In NAR rats transplanted with normal hepatocytes, there was a significant (P < 0.003) and sustained (12 weeks) increase in plasma albumin levels. Control NAR rats transplanted with NAR hepatocytes (n = 8) showed no significant changes in plasma albumin levels. Similarly, normal Wistar hepatocytes were infused intraportally into the posterior lobes of Gunn rats (n = 4), which lack the ability to conjugate bilirubin. Pre- and posttransplantation bile was collected following bile duct cannulation. Bile analysis by HPLC, demonstrated a significant (P = 0.04) increase in the level of bilirubin conjugates following transplantation and a corresponding decrease in total serum bilirubin (P = 0.04). Our experimental data demonstrate that direct selective intraportal infusion of hepatocytes is an effective technique of hepatocyte transplantation in the rat.

Development of a hybrid bioartificial liver.

OBJECTIVE: The authors developed an extracorporeal liver support system and tested its efficacy in experimental animals with liver failure. The first clinical use of this system to treat a patient with liver failure is reported. SUMMARY BACKGROUND DATA: Multiple attempts have been made, ranging from plasma exchange to use of charcoal columns, to develop liver support systems for treating patients with acute severe liver failure. None of these systems has achieved wide clinical use. There is a need for providing liver support as a "bridge" to transplantation and for treating patients with potentially reversible liver dysfunction. METHODS: A hybrid liver support system has been developed consisting of plasma perfusion through a charcoal column and a porous hollow fiber module inoculated with 5 x 10(9) matrix-attached hepatocytes. The system was tested in dogs with ischemic liver failure (n = 7) who underwent plasmapheresis; a control group (n = 6) underwent charcoal perfusion alone. A patient with liver failure was treated with this hybrid system. RESULTS: After 6 hours of hybrid liver support treatment, animals had significantly decreased serum ammonia and lactate levels, increased glucose level, normal prothrombin time, and increased systolic blood pressure compared with controls treated with charcoal perfusion alone. Use of the system to treat a patient was well tolerated with evidence of clinical improvement. CONCLUSIONS: Plasma perfusion through a system consisting of a charcoal column and matrix-attached porcine hepatocytes had significant beneficial effects in animals with liver failure and was well tolerated by a patient with liver failure.

Use of a novel bioartificial liver in a patient with acute liver insufficiency.

We have developed a bioartificial liver support system (BAL) using porcine hepatocytes attached to microcarriers and placed on the outer surface of hollow fibers. The BAL system was attached to a plasmapheresis device that was then used to treat the plasma of a patient with acute liver failure. Our aim was to test the efficacy and safety of this system after a single short treatment period. A patient with alcohol-induced, severe, acute liver failure manifested by coagulopathy, rising plasma ammonia level, and deteriorating mental status was studied. The procedure was well tolerated by the patient, who remained hemodynamically stable throughout the treatment period. A marked increase in coagulation factor V, VII, VIII, and IX activities, a decrease in serum ammonia level (120 to 32 mumol/L), a twofold increase in all serum amino acids except for aminobutyric acid, and an improvement in mental status were noted after a 6-hour treatment period. This preliminary report of the first use of this novel BAL system in conjunction with plasmapheresis appears promising. A clinical study is now in progress to prove its efficacy.

In vivo regional delivery of retrovirally mediated foreign genes to rat liver cells: need for partial hepatectomy for successful foreign gene expression.

A novel surgical technique was developed to deliver retroviral gene vectors directly to a rat liver lobe in vivo. It was observed that viral infection efficiency was enhanced by inducing hepatocyte DNA synthesis by prior partial hepatectomy. Two retroviral vectors were used to integrate specific bacterial genes: an amphotropic virus expressing the hph gene for hygromycin B phosphotransferase and an ecotropic virus expressing the lac-Z gene for beta-galactosidase. The vectors were directed to the liver by in situ selective perfusion of the posterior liver lobes with a viral suspension with inflow and outflow catheters. Male Sprague-Dawley rats were divided into three groups. Animals in the first group underwent 70% partial hepatectomy and the remnant liver lobes were allowed to regenerate for 20 hours before perfusion with the viral supernatant. Group 2 rats were perfused with viral supernatant and 2 hours later underwent 70% partial hepatectomy. Animals in the third group were perfused with the viral supernatant without partial hepatectomy. Viral transduction of hepatocytes was assessed 4 or 6 days after treatment. Hygromycin B-resistant hepatocytes were isolated from the liver remnants of rats in group 1 (21.6%) and group 2 (26.9%). No resistant hepatocytes could be detected in hepatocytes from either control rats perfused with medium alone or those from rats that did not undergo hepatectomy (group 3). In animals that received the ecotropic virus, only those that underwent hepatectomy before virus exposure (group 1) showed a small number of hepatocytes expressing beta-galactosidase in liver sections.

Development of a bioartificial liver: properties and function of a hollow-fiber module inoculated with liver cells.

We have developed a bioartificial liver support system utilizing hollow-fiber bioreactor, plasmapheresis and microcarrier cell culture technologies. Liver cells were obtained through portal vein perfusion with ethylenediaminetetraacetate or ethylenediaminetetraacetate/collagenase. A mathematical model of mass transport in a hollow-fiber module, at various plasma flow velocities and system configurations, was developed. The bioartificial liver's ability to carry out specific differentiated metabolic liver functions was tested in vitro and in vivo. A reproducible large-animal model of acute ischemic liver failure was developed. Most major first-generation cyclosporine and 19-norterstosterone metabolites were isolated after substrate addition to the bioartificial liver in vitro. After bioartificial liver treatment for 6 hr (with dog or pig liver cells), dogs with acute liver failure had significantly lower serum ammonia and lactate levels and significantly higher serum glucose levels than did control animals treated with a bioartificial liver system inoculated with microcarriers alone. In addition, bioartificial liver-treated animals had significantly higher mean systolic blood pressures than did controls. Liver cell viability at the end of the 6-hr in vivo experiment was greater than 90%.