Case report: gastrointestinal hemorrhage caused by a pancreas transplant arteriovenous fistula with large psuedoanuerysm 9 years after transplantation.

Reported cases of arteriovenous fistulae in transplant recipients are uncommon. We present a case of an arteriovenous fistula associated with a large pseudoaneurysm in the root of the small bowel mesentery of a pancreas transplant. Uniquely, in our case, the arteriovenous fistula presented with an episode of gastrointestinal (GI) hemorrhage 9 years postoperatively. Radiographic imaging including coronal computed tomography angiogram and conventional angiogram demonstrated an arteriovenous fistula in the patient's pancreas transplant between the distal superior mesenteric artery (SMA) and superior mesenteric vein (SMV) with 6 cm aneurysmal dilatation. The tremendous flow in the fistula in the root of the graft small intestine mesentery led to graft duodenal mucosal congestion and lower GI hemorrhage. After successful embolization of the SMA-SMV fistula and pseudoaneurysm using interventional radiographic techniques, the arteriovenous fistula remained thrombosed. The patient had no further episodes of GI bleeding and her endoscopic evaluation was otherwise negative. The presence of arteriovenous fistulae and pseudoaneurysms in pancreas transplant recipients is uncommon, but has been previously documented. This case is further distinguished from previous reports by the notable 9-year interval between transplantation and the onset of hemorrhage. Historically, symptomatic vascular malformations have been associated with significant patient morbidity and mortality. Successful patient management involves timely and accurate diagnosis and intervention.

Effect of screw length on bioabsorbable interference screw fixation in a tibial bone tunnel.

Initial tibial fixation strength is the weak link after anterior cruciate ligament reconstruction with a quadrupled hamstring tendon graft fixed with bioabsorbable interference screws. The purpose of this study was to determine the biomechanical differences between 28-mm and tapered 35-mm interference screws for tibial fixation of a soft tissue graft in 16 young cadaveric tibias. Failure mode, displacement before failure, and ultimate failure load were tested with a testing machine aligned with the tibial tunnel to simulate a worst-case scenario. The mode of failure was graft slippage past the screw in all but one of the specimens. The mean maximum load at failure of the 28-mm screw was 594.9 +/- 141.0 N, with mean displacement at failure of 10.97 +/- 2.20 mm. The mean maximum load at failure of the 35-mm screw was 824.9 +/- 124.3 N, with a mean displacement to failure of 14.38 +/- 2.15 mm. The 38% difference in mean maximal load at failure was significant. Important variables in hamstring tendon graft fixation within a bone tunnel include bone mineral density, dilatation, gap size, screw placement, and screw width and length. Attention to these variables will help to provide secure graft fixation during biologic incorporation throughout the rehabilitation period.

Intravascular sonography in the assessment of traumatic injury of the thoracic aorta.

OBJECTIVE: The objective of this study is to describe the use of intravascular sonography in the evaluation of suspected injury of the thoracic aorta as an adjunctive tool to digital subtraction arteriography (DSA). SUBJECTS AND METHODS: Images of the thoracic aorta were obtained using DSA and intravascular sonography in 20 consecutive patients who underwent arteriography after chest trauma. A 6-French, 12.5-MHz sonography catheter was used for the intravascular sonography study. Diagnoses based on the review of both studies were compared. RESULTS: Five of 20 patients had aortic or great vessel injuries confirmed by surgery. Intravascular sonographic findings were positive (one false-positive) in seven patients, whereas DSA findings were positive in six patients (one false-positive and one false-negative). Surgery showed the lesion that was false-positive using both techniques to be a ductus diverticulum. Intravascular sonographic findings included intimal flaps, intramural lesions (hematomas), pseudoaneurysms, and perivascular hematomas. CONCLUSION: In our initial limited experience, intravascular sonography of the thoracic aorta and great vessels effectively identified traumatic injuries. Intramural injury without pseudoaneurysm formation or obvious intraluminal flap was visualized by intravascular sonography in one patient but was not detected by DSA. On the other hand, a ductus diverticulum was erroneously interpreted as trauma using both techniques. Intravascular sonography is a relatively new procedure with an obvious learning curve in the interpretation of the findings. An atypical ductus diverticulum may still be mistakenly interpreted as a sign of traumatic injury of the aorta. Familiarity with intravascular sonography in the setting of aortic trauma is necessary for correct interpretation of the images. The sonographic findings offer views of the aorta that are complementary to those of aortography.

Effects of isotonic saline solution resuscitation on blood coagulation in uncontrolled hemorrhage.

BACKGROUND: It has been suggested that fluid resuscitation before surgical control of hemorrhage may lead to increased bleeding because of the elevated blood pressures and clotting factor dilution. This study was designed to assess the effects of isotonic saline solution resuscitation on blood coagulation during uncontrolled hemorrhage. METHODS: Twenty-four female Sprague-Dawley rats were randomized into four groups with different resuscitation regimens: group A, no resuscitation; group B, 40 ml/kg in 4 minutes; group C, 80 ml/kg in 4 minutes; and group D, 80 ml/kg in 1 minute. Baseline blood samples were collected just before a sharp resection of 75% of the tail to initiate the hemorrhage; 15 minutes later the resuscitation began. Additional blood samples were obtained at 60 minutes after resection. The blood was analyzed for platelets, fibrinogen, prothrombin time, and activated partial thromboplastin time. RESULTS: The largest differences between time 0 and 60 minutes were observed in group D with platelets decreasing 43.36% +/- 7.86%, fibrinogen decreasing 57.10% +/- 16.88%, and prothrombin time increasing from an average 16.5 to 19.2 seconds. These differences was statistiacally significant (p <0.05) with the Student's test. CONCLUSIONS: The results suggested that even though the volume of resuscitation fluid did not appear to affect clotting time when compared with that of nonresuscitated animals, the rate of extremely large volume infusions may play an important role in the cessation of bleeding and consequently in the management of uncontrolled hemorrhagic shock.

Percutaneous transluminal angioplasty of visceral arterial stenoses: results and long-term clinical follow-up.

PURPOSE: To determine the efficacy and safety of percutaneous transluminal angioplasty (PTA) of the visceral arteries. PATIENTS AND METHODS: We retrospectively evaluated the results of PTA performed in 20 visceral arteries in 19 patients (10 men, nine women; mean age, 63 years). Eleven patients had symptoms characteristic of mesenteric ischemia, four had atypical abdominal pain, and four were undergoing prophylactic dilation before undergoing another procedure involving the abdominal aorta. Clinical follow-up was possible in all patients. RESULTS: PTA was technically successful in 15 of 19 patients (79%); among these 15 patients, 12 (80%) did well clinically. Of the seven PTA procedures that were immediate failures, five failed secondary to an occult malignancy or to extrinsic arterial compression by the median arcuate ligament. Ten (83%) of the 12 patients in whom the procedures were immediate clinical successes are still clinically improved at 4-73 months follow-up (mean, 25 months). PTA was successful in only one of the four patients who had symptoms atypical of mesenteric ischemia, but it was successful in 11 of the 15 patients who had symptoms of mesenteric ischemia or who underwent prophylactic dilation. Major complications occurred in three (16%) of the 19 patients. CONCLUSION: PTA of visceral artery stenoses is effective in patients with symptoms of mesenteric ischemia. It is also effective as prophylaxis in patients undergoing additional procedures in the abdominal aorta.

Recent development of rigors during infusion of urokinase: is it related to an endotoxin?

PURPOSE: This study was undertaken to determine the prevalence of rigors associated with the use of urokinase (UK) and to assay for the presence of an endotoxin in the UK solution. PATIENTS AND METHODS: Records of 75 patients who underwent 86 UK infusions between January 1988 and July 1992 were reviewed to evaluate for the development of UK-associated rigors. A modified chromogenic limulus amebocyte lysate (LAL) test was performed to determine the presence of endotoxin in four samples of UK from lots associated with rigors, one sample of UK not associated with rigors, sterile water, nonionic contrast medium, and ionic contrast medium. RESULTS: Between January 1, 1988, and July 10, 1990, 43 patients underwent 46 UK treatments (group 1) with no documented rigors (0% prevalence). In 45 of these 46 treatments, a standard, non-pulse-spray bolus of 75,000-500,000 IU of UK (mean dose, 182,222 IU) was used. Between July 11, 1990, and July 6, 1992, 38 patients underwent 40 UK treatments (group 2). In 33 of these 40 treatments, a standard bolus was given. Five patients received a pulse-spray bolus. The mean bolus was 213,768 IU (range, 100,000-500,000 IU). Eleven group 2 patients developed rigors (28% prevalence; P = .0005 vs group 1). The chromogenic LAL tests demonstrated no endotoxin in sterile water, nonionic contrast media, or ionic contrast media. Endotoxin was detected in small concentrations in the four samples of UK associated with rigors and in the UK sample not associated with rigors. CONCLUSION: The increase in the prevalence of rigors associated with the use of UK does not appear to be related to an endotoxin in UK, since the concentration of endotoxin detected is well below the threshold pyrogenic dose in humans.

Reducing the discomfort of lidocaine administration through pH buffering.

PURPOSE: A prospective, double-blind study was undertaken to evaluate the effect of using a buffered lidocaine solution on the perception of pain experienced by a patient during its intradermal injection. PATIENTS AND METHODS: One hundred fifty patients undergoing diagnostic angiographic and interventional procedures at the authors' institution were randomly assigned to receive a 1-mL aliquot of one of three lidocaine solutions: plain 1% lidocaine, 1% lidocaine diluted with normal saline in a 10:1 ratio, and 1% lidocaine diluted with 8.4% sodium bicarbonate in a 10:1 ratio. The lidocaine solutions were administered intradermally over 10-15 seconds. A numerical value was placed on the patient's perception of pain, separate from that associated with the 25-gauge needle insertion, with use of a linear visual analog scale. RESULTS: Mean pain scores were as follows: for the 1% lidocaine solution, 2.83 +/- 2.60; for 1% lidocaine plus normal saline solution, 2.89 +/- 2.34; and for 1% lidocaine plus sodium bicarbonate solution, 1.37 +/- 1.73 (P = .0018). CONCLUSION: Buffering lidocaine significantly decreased the discomfort associated with its administration as a local anesthetic.

The diagnosis of brain death with Tc-99m HMPAO.

Evaluation of blood flow to the brain using various radiopharmaceuticals can be used to confirm brain death. Agents available for this purpose include Tc-99m HMPAO, Tc-99m pertechnetate, Tc-99m glucoheptonate, and Tc-99m DTPA. The authors evaluated the use of Tc-99m HMPAO in 17 patients suspected of brain death using flow images and static images at several time intervals: immediately, between 30 and 60 minutes, and at 2 hours. These studies were compared to several studies performed with Tc-99m glucoheptonate and Tc-99m DTPA. The results of the Tc-99m HMPAO brain death studies correlated well with the patients' clinical conditions. Static images 1 to 2 hours after the injection of 5 to 30 mCi of Tc-99m HMPAO were satisfactory for an accurate interpretation; however, an immediate answer could as easily be supplied using flow images alone. Tc-99m HMPAO was found to be more easily interpreted and less dependent on imaging technique than Tc-99m glucoheptonate and Tc-99m DTPA, and it is the agent of choice for the evaluation of brain death.

Peripheral angioplasty balloon technology.

Changes in balloon and catheter technology have led to the development of smaller, more flexible, and less traumatic balloon dilatation systems. The physical principles that govern balloon angioplasty and the current status of balloon materials and catheter designs will be reviewed. A compilation of various angioplasty catheters is also summarized.

Balloon angioplasty above the aortic arch: immediate and long-term results.

OBJECTIVE: Angioplasty above the level of the aortic arch is becoming more common, and the indications for it are increasing. We report our experience with this procedure, including life-table analysis of the long-term results. MATERIALS AND METHODS: We dilated 32 lesions in 29 patients. Early in our series, patients were referred primarily because of arm claudication or vertebrobasilar insufficiency. Subsequently, the indications were expanded to include inflow to left internal mammary-coronary artery bypass grafts, inflow to axillobifemoral bypass grafts, and inflow to dialysis fistulas in the upper extremity. A femoral artery approach was used in 18 patients and an axillary approach was used in 11. Clinical follow-up included evaluation of symptoms and bilateral measurements of peripheral pulses and blood pressure. Follow-up angiograms were obtained in nine patients. RESULTS: Eighteen of the lesions dilated were located in the left subclavian artery, eight were in the right subclavian artery, four were in the axillary or proximal brachial artery, and two were in the innominate artery. Interestingly, three of eight right subclavian arteries treated had an anomalous origin from the arch of the aorta. Initial technical success was 100%. All 29 patients had long-term follow-up of 4-88 months (mean, 36 months). In one patient, stenosis recurred 8 months after angioplasty. This patient subsequently had redilatation. Life-table analysis projected a 7.5-year cumulative primary patency rate of 96.6%. No cerebrovascular complications or embolic events occurred. CONCLUSION: Angioplasty of the great vessels is safe and effective, and the long-term results are favorable when compared with results after surgery. As a result, the indications for this procedure should be broadened.

A simple method for bile duct anastomosis and interval bile collection in the liver-transplanted rat.

A mini T-tube is introduced for the bile duct anastomosis of rat liver transplantation as well as interval bile collection. The validity of the T-tube was evaluated in 14 liver-transplanted rats and compared to 14 rats using traditional stent for bile duct anastomosis. Changes of biliary tree after the T-tube anastomosis were examined by T-tube cholangiography on sample rats at 4 days and at 4 months after liver grafting. Additionally, bile volumes and rates of bile salt secretion were compared in the continuously flowing cannula and the chronic T-tube fistula in normal rats. The results show that the mini T-tube facilitates bile duct anastomosis and study of bile secretion after liver transplantation in rats without increase in surgical difficulty or interference of biliary enterohepatic circulation.

Inferior vena cava filters. Indications, safety, effectiveness.

BACKGROUND: Preventing pulmonary embolization by interrupting vena caval flow has been attempted since 1893. Inferior vena cava (IVC) filters have been available for 20 years, and currently there are five filters commercially available in the United States (Greenfield filter, Titanium Greenfield filter, Simon-Nitinol filter, Bird's Nest filter, and LGM or Vena Tech filter) and two other filters under development (Amplatz filter and Günther filter). Although these devices are widely used, their clinical utility and safety have not been completely evaluated. Controlled clinical trials to determine the clinical role for IVC filters have not been attempted, but numerous case series describing the outcomes of the seven current filters have been published. We have systematically reviewed these studies to clarify what is known about the indications, safety, and effectiveness of IVC filters. METHODS: Using the MEDLINE database, all English-language publications since 1970 that included follow-up clinical information after filter insertion were reviewed and eight methodologic guidelines were employed to assess the scientific quality of the clinical information. RESULTS: Twenty-four case series were reviewed: 16 concerned the Greenfield filter (1632 patients), and eight dealt with newer designs (925 patients). Commonly noted methodologic problems included failure to report the initial extent of thromboembolic disease, incomplete description of the patient assembly process, and incomplete and potentially biased outcome assessment. Recurrent clinical pulmonary embolism was rare after filter placement, and only eight deaths from pulmonary embolism were reported. Filter complications were common but rarely life threatening; four (0.16%) deaths from filter complications were noted among the reviewed studies. Thrombotic complications following filter placement included insertion-site deep vein thrombosis and IVC obstruction. These events were rare, but they occurred with all filter types. CONCLUSIONS: Inferior vena cava filters appear to be effective in preventing recurrent pulmonary embolism. Despite the large published experience with IVC filters, many questions remain about their indications, safety, and effectiveness. Anticoagulant therapy, if not contraindicated, should be used in conjunction with filters. While there is no ideal filter, some situations call for specific filters. Filter selection and insertion require experience, modern angiographic technique, and collaboration between clinicians caring for patients and the interventional radiologists or surgeons inserting the device.

Treatment of hemodialysis fistula pseudoaneurysms with detachable balloons: technique and preliminary results.

Pseudoaneurysm formation is commonly encountered during the life of a dialysis fistula. When these become excessively large or numerous, surgical revision of the graft has been the only treatment option. The authors have treated seven patients by using percutaneous placement of a detachable balloon to occlude a pseudoaneurysm of an upper extremity graft. In four cases the balloon was directed into the pseudoaneurysm from a femoral artery approach. In three cases a direct puncture was made into the pseudoaneurysm for placement of the balloon. The patients were followed up from 1 week to 7 months. Initial technical success was achieved in all seven cases with no complications. Thrombosis of two grafts occurred during the first week after the procedure: one because of herniation of the balloon out of the pseudoaneurysm and one for unknown reasons. One balloon was inadvertently punctured and deflated during subsequent dialysis. Treatment in the other four cases was successful, as evidenced by no further enlargement of the pseudoaneurysms. Direct puncture of the pseudoaneurysm simplifies the procedure and probably decreases the likelihood of balloon herniation because of the orientation of the balloon.

Thromboembolectomy with the transluminal extraction catheter (TEC) as an adjunct to thrombolysis.

Multiple surgical and percutaneous interventional radiologic techniques have been used to restore blood flow in an acutely ischemic extremity. The transluminal extraction catheter (TEC) system was used as a mechanical thromboembolectomy device to supplement pharmacologic thrombolysis in one patient. In this case, 40 hours of direct intraarterial infusion of urokinase into the occluded vascular segments of a threatened lower extremity resulted in incomplete thrombolysis. Therefore, a 7-F TEC system was advanced percutaneously through the occluded vessels with restoration of luminal patency in all vessels treated. No distal embolization occurred. The TEC system facilitated prompt recanalization of vessels occluded by acute thrombus superimposed on atherosclerotic disease.

Normal venous anatomy and collateral pathways in upper extremity venous thrombosis.

Collateral pathways are well known in superior vena cava occlusion but not in axillary or subclavian vein occlusion, even though these occlusions are becoming more common. In a series of 127 arm venograms obtained for suspected venous thrombosis, the authors found 32 instances of subclavian or axillary vein occlusion. The authors reviewed the cases for site of occlusion and definition of collateral pathways. In 15 cases, the occlusion was in the subclavian vein, with collateral flow established chiefly via veins in the neck. Ten cases of axillary vein occlusion with chest wall collateral pathways were identified. Seven cases could not be categorized. Knowledge of these pathways is useful for accurate interpretation of upper extremity venograms. A more thorough understanding of venous pathways in the upper body may aid in the treatment of patients with chronic disease and longterm indwelling central venous catheters.

Interventional radiology of trauma.

Percutaneous transcatheter embolization has become an integral part of the trauma team's armamentarium. Still, it is probably underused in many centers because of lack of familiarity on the part of both the trauma team and the radiologists. Recognition of the role of interventional radiology in vascular trauma can have a significant impact in decreasing the morbidity and mortality associated with this ever-growing problem in our society.

Circumferential rupture of an angioplasty balloon with detachment from the shaft: case report.

Rapidly evolving angioplasty balloon techniques need continual evaluation for the type or frequency of balloon-related complications. We recently encountered a case where a new narrow shaft polyethylene terephthalate balloon completely separated from the catheter following circumferential rupture. The balloon was successfully retrieved using grasping forceps and a basket. Patterns of balloon rupture and subsequent management are discussed. Problems of this type were more frequent in the early days of balloon angioplasty, but have since become rare. Close surveillance of new low profile balloons is recommended to determine whether this represents an isolated occurrence or a return to the earlier experience.

Use of methylene blue and selective embolization of the pudendal artery for high flow priapism refractory to medical and surgical treatments.

High flow priapism is often treated effectively with intracavernous vasoconstrictive agents or surgical shunting. If these maneuvers fail treatment is unclear. A 21-year-old black man, who had failed previous pharmacological and surgical therapies, temporarily (8 hours) responded to intracavernous methylene blue, which is known to antagonize endothelial derived relaxation factor. Recurrent priapism was managed successfully by embolization of the left internal pudendal artery with absorbable gelatin sponge. Review of the literature reveals that only 7 patients have been managed with arterial embolization and our case represents the first in which intracavernous methylene blue produced detumescence.

Results and complications of angioplasty in fibromuscular disease.

Percutaneous transluminal angioplasty (PTA) was used to treat 66 patients with 85 renal artery stenoses due to fibromuscular dysplasia. The hypertension was refractory to medical management in 46 patients, and the initial success rate was 100%. Clinical follow-up has been obtained in all patients, who were followed for as long as 121 months. The recurrence rates were 8% of lesions and 10% of patients. Cumulative patency rate predicted for 10 years was 87.07%. The mean systolic pressure decreased by 52 mm Hg and the mean diastolic pressure decreased by 35 mm Hg in response to treatment. Twenty-six patients (39%) were cured, 39 (59%) were classified as improved, and one (2%) did not respond to PTA. Fourteen of the patients also had elevated blood urea nitrogen and creatinine levels. Renal function was improved in 86% of the patients and stabilized in 14% of the patients. Analysis of the long-term results suggests that PTA should be the initial treatment for choice of patients with fibromuscular dysplasia in the renal arteries.