Transthoracic cuffed hemodialysis catheters: a method for difficult hemodialysis access.

BACKGROUND: Recurrent vascular access failure is a major cause of morbidity in patients receiving long-term hemodialysis. Central venous catheters are often necessary for dialysis, and easily accessed vessels (ie, the internal jugular vein and subclavian vein) frequently occlude because of repeated cannulation. When standard access sites occlude, unconventional access methods become necessary. We report a technique of placing hemodialysis catheters directly into the superior vena cava (SVC). METHODS: Between January 2002 and December 2004, 22 patients with documented bilateral jugular and subclavian vein occlusion underwent transthoracic SVC permanent catheter placement. Femoral vein access was obtained, and a sheath was placed. Under fluoroscopic guidance, a diagnostic catheter was then inserted into the SVC, and a venogram was obtained. By using the fluoroscopic image as a reference guide, supraclavicular access directly into the SVC was performed with lateral and anteroposterior views to better localize the SVC. Once venous blood was obtained, a hydrophilic wire was passed into the inferior vena cava. A 5F sheath was then placed, and, with the use of an exchange catheter, the wire was switched for a stiffer wire. The hemodialysis catheter was then placed in the standard fashion over this wire. RESULTS: In a 24-month period, 22 patients underwent transthoracic permanent catheter placement. All patients had the permanent catheters successfully inserted. Two major complications occurred. One patient experienced a pneumothorax, and another patient experienced a hemothorax. Both patients were successfully treated with chest tube decompression. All permanent catheters functioned immediately with a range of 1 to 7 months. CONCLUSIONS: Transthoracic permanent catheter placement is an appropriate alternative for patients in whom traditional venous access sites are no longer available.

Stent-graft repair of traumatic thoracic aortic disruptions.

OBJECTIVE: Blunt traumatic thoracic aortic disruption results in pre-hospital death in 80% to 90% of patients. Because of the significant surgical morbidity and mortality associated with open operative repair, endovascular stent-graft repair has been investigated. The objective of this study was to evaluate the efficacy of thoracic aortic disruptions treated with commercially available proximal aortic extension cuffs. METHODS: Nine patients with multiple system trauma (age range, 16-42 years) were seen after motor vehicle accidents between January 1, 2003, and April 1, 2004. Chest x-ray findings warranted thoracic computed tomography scans, which revealed disruptions of the thoracic aorta. Aortograms delineated the extent of the aortic injuries and identified a "landing zone" (neck length range, 1.5-2.0 cm) distal to the subclavian artery but proximal to the tear. The repairs were performed with AneuRx (n= 8) and Excluder (n = 1) proximal aortic extension cuffs. A left femoral artery approach was used in 6 patients, a suprainguinal retroperitoneal approach with an iliac conduit in 2 patients, and direct tunnel in 1 patient. An Amplatz super-stiff wire was placed in the right axillary artery to enable easy tracking of the endografts, and left brachial artery access was used for arch arteriography. RESULTS: In each patient the stent-graft cuff was deployed adjacent to the left subclavian artery, with successful exclusion of traumatic disruptions verified at intraoperative arteriography and on computed tomographic scans obtained within 48 hours of initial repair. One patient required a second cuff for exclusion of a type I endoleak at the distal attachment site 1 month after the initial endograft repair. There were no procedure-related deaths; 1 patient, however, died of other injuries. CONCLUSIONS: Stent-graft repair of traumatic thoracic aortic disruptions is technically feasible. Placement of a stiff wire in the right axillary artery and percutaneous left brachial artery access for arteriography are useful adjuncts during endograft deployment. Endovascular stent grafts may enable definitive repair or serve as a bridge until the patient is stable enough to undergo an operation, if necessary. This technique warrants further investigation.

Role of prophylactic temporary inferior vena cava filters placed at the ICU bedside under intravascular ultrasound guidance in patients with multiple trauma.

OBJECTIVE: Patients with multiple trauma often have injuries that preclude the use of anticoagulation therapy or sequential compression device prophylaxis. Temporary inferior vena cava (IVC) filters (IVCFs) offer protection against pulmonary embolism during the early immediate injury and perioperative period, when risk is highest, while averting potential long-term sequelae of permanent IVCFs. The objective of this study was to evaluate the efficacy of prophylactic, temporary IVCF placement at the intensive care unit bedside under real-time intravascular ultrasound (IVUS) guidance in patients with multiple trauma. INTERVENTIONS: Ninety-four patients with multiple trauma seen between July 1, 2002, and November 1, 2003, underwent placement of OptEase (Cordis Endovascular) retrievable IVCFs under real-time IVUS guidance. Mean (+/-SD) Injury Severity Score was 25.1 +/- 2.2). Abdominal x-ray films were obtained in all patients to verify filter location. Before IVCF retrieval all patients underwent femoral vein color-flow ultrasound scanning to rule out deep vein thrombosis (DVT), and pre-procedure and post-procedure vena cavography to identify possible IVCF thrombus entrapment and post-retrieval inferior vena cava injury. RESULTS: Nineteen patients died of their injuries; no deaths were related to IVCF placement. One pulmonary embolism occurred during follow-up after filter retrieval, and 1 insertion site femoral vein DVT occurred. As verified on abdominal x-ray films, 96.8% (91 of 94) of IVCFs were placed without complications at the L2-3 level. Filter-related complications included 2 groin hematomas (2.1%) and 3 IVCFs misplaced in the right iliac vein (3.2%), early in our experience; the filters were uneventfully retrieved and replaced in the inferior vena cava within 24 hours. Thirty-one patients underwent uneventful retrieval of IVCFs after DVT or pulmonary embolism anticoagulation prophylaxis was initiated. Forty-four filters were not removed, 41 because severity of injury prevented DVT or pulmonary embolism prophylaxis and 3 because of thrombus trapped within the filter. CONCLUSIONS: Prophylactic, temporary IVCF placement at the intensive care unit bedside under IVUS guidance in patients with multiple trauma is simple and safe, and serves as an effective "bridge" to anticoagulation therapy until venous thromboembolism prophylaxis can be initiated. Further investigation of this bedside technique and the role of temporary IVCFs in patients with multiple trauma is warranted. CLINICAL RELEVANCE: Patients with multiple trauma often have injuries that preclude the use of anticoagulation therapy or sequential compression device prophylaxis. Temporary inferior vena cava filters (IVCFs) offer protection against pulmonary embolism during the perioperative and immediate injury period, when risk is highest. Ninety-four patients with multiple trauma underwent prophylactic, temporary IVCF placement at the intensive care unit bedside under real-time intravascular ultrasound. One pulmonary embolism occurred during follow-up after filter retrieval, and 1 insertion site femoral vein deep venous thrombosis occurred. Ninety-one of 94 IVCFs (96.8%) were placed without complication. Thirty-one patients underwent uneventful retrieval of IVCFs after anticoagulation prophylaxis was initiated. Forty-four filters were not removed, because of severity of injury (n = 41) or because of trapped thrombus within the filter (n = 3). Prophylactic, temporary IVCFs placed under intravascular ultrasound guidance at the bedside in patients with multiple trauma is simple, safe, and an effective bridge to anticoagulation therapy.

Real-time intravascular ultrasound-guided placement of a removable inferior vena cava filter.

BACKGROUND: Reports have demonstrated the benefit of prophylactic inferior vena cava filter (IVCF) placement to prevent pulmonary embolism. This series evaluates the potential for the bedside placement of a removable IVCF under "real-time" intravascular ultrasound (IVUS) guidance. METHODS: Twenty trauma patients underwent intensive care unit placement of a removable IVCF with IVUS guidance. All patients had ultrasonography of the femoral veins after placement to rule out postprocedure femoral vein thrombosis and radiographs to identify filter location. RESULTS: Nineteen of 20 IVCFs were placed at approximately the L2 level as verified by radiography. One patient had a large IVC (34 mm) and underwent bilateral common iliac IVCF placement under IVUS. Within 3 weeks of placement, 12 IVCFs were retrieved. Of the remaining eight patients, six had indications for permanent implantation, two had contralateral deep venous thrombosis, and one had ipsilateral deep venous thrombosis. CONCLUSION: Bedside insertion of a removable IVCF with IVUS guidance and its removal are simple, safe, and accurate.

Prevention of intimal hyperplasia; Initial results with low-dose beta-radiation applied by an external vascular polymer wrap.

OBJECTIVE: Endovascular brachytherapy, delivered by a variety of catheter-based devices, has proven clinically effective for the inhibition of neointimal hyperplasia (NIH) after coronary and peripheral balloon/stent angioplasty. No platform, however, has been developed to deliver low-dose radiation in concert with vascular surgical operations. The purpose of this study was to evaluate the vascular response following balloon injury to the rabbit carotid artery, with and without topical low-dose 45Ca, applied by an external vascular "wrap". METHODS: Twelve rabbit carotid arteries were subjected to balloon injury by embolectomy catheter. The common carotid artery was then "wrapped" circumferentially with a biostable polyurethane membrane (Nanoskin Secant Medical, Perkasie, PA), without radiation (n = 6), or with radiation (n = 6) (45Ca approximately 50 microCi). The animals were sacrificed at 4 weeks for histologic assessment of the treated vessels. RESULTS: The 45Ca wrap inhibited NIH evidenced by trends towards reduction of intimal area (0.46 +/- 0.19 control carotid vs. 0.35 +/- 0.15 (45)Ca-treated carotid arteries; P = .11), maximal intimal thickness (0.21 +/- 0.08 vs. 0.16 +/- 0.05; P = .12), average intimal thickness (0.12 +/- 0.06 vs. 0.08 +/- 0.03; P = .08), marginally significant reduction in percent area stenosis (33 +/- 15% vs. 21 +/- 9%; P = .06) and marked neointima suppression in areas immediately adjacent to 45Ca wrap remnants. Medial necrosis (P = .003), however, was observed slightly more for 45Ca-treated carotid arteries versus control arteries. CONCLUSION: Low-dose 45Ca beta-radiation labeled onto a polyurethane membrane appears to inhibit NIH in an animal model.

Remote superficial femoral artery endarterectomy and distal aSpire stenting: multicenter medium-term results.

OBJECTIVE: The purpose of this study was to examine the results of remote superficial femoral artery endarterectomy (RSFAE) in conjunction with distal aSpire stenting. METHODS: RSFAE is a minimally invasive procedure performed through a limited groin incision. Forty patients were included in the study. The indications for the procedure were claudication in 36 patients and limb salvage in 4 patients. RSFAE was performed with the MollRing Cutter device through a femoral arteriotomy. The distal atheromatous plaque was "tacked" with the aSpire stent, which is an expandable polytetrafluoroethylene-covered nitinol stent with high radial strength, yet is flexible and able to withstand compressive forces proximal to the knee joint. Before stent deployment, if the stent position is not optimal it can be wrapped down, repositioned, and re-expanded. Therefore, not only is the plaque end point tacked, but the collateral vessels may be preserved. All patients underwent follow-up examination with serial color-flow ultrasound scanning. RESULTS: The mean length of endarterectomized superficial femoral artery was 26.2 cm +/- 6.2 cm (range, 13-41 cm). The primary cumulative patency rate by means of life table analysis was 68.6% +/- 13.5% (SE) at 18 months (mean, 13.2 months; range, 1-31 months). During follow-up percutaneous transluminal balloon or stent angioplasty was necessary in 6 patients, for a primary assisted patency rate of 88.5% +/- 8.5% at 18 months. The locations of recurrent stenoses after RSFAE were evenly distributed along the endarterectomized artery. There were no deaths and one wound complication, and mean hospital length of stay was only 2.1 +/- 0.5 days. CONCLUSIONS: RSFAE with distal aSpire stenting is a safe and moderately durable procedure. If long-term patency rates are similar to those of above-knee femoropopliteal bypass graft, this procedure may prove to be a minimally invasive adjunct for the treatment of superficial femoral artery occlusive disease.

Cellular remodeling of depopulated bovine ureter used as an arteriovenous graft in the canine model.

BACKGROUND: One of the greatest challenges in hemodialysis access surgery is improving the durability of prosthetic grafts caused by structural deterioration. The depopulated bovine ureter SynerGraft (SG) (CryoLife, Inc) is a tissue-engineered vascular graft processed to remove the xenograft cells while maintaining an unfixed connective tissue matrix capable of autologous cell repopulation by the recipient. STUDY DESIGN: Nineteen 6-mm diameter bovine ureter SG conduits were implanted in 12 dogs as arteriovenous grafts between the carotid artery and jugular vein (n = 11) or between the femoral artery and vein (n = 8). Performance of these biologic conduits was compared with that of 15 IMPRA (Bard) ePTFE grafts implanted in 9 dogs, including 9 arteriovenous grafts between the carotid artery and jugular vein and 6 femoral artery to femoral vein grafts. After 14 days, the grafts were accessed once weekly. Histologic and immunohistochemical analyses were performed on grafts explanted between 10 to 60 weeks. RESULTS: The 6- and 12-month primary patency rates of the bovine SG were 72.6% and 58.6%, respectively, compared with 6- and 12-month primary patency for ePTFE conduits of 57.4% and 57.4%, respectively. None of the bovine SG grafts became infected, but synthetic conduits became infected within 54 days of implantation. At 10 weeks, bovine ureter SG conduit showed fibroblast cell migration and proliferation with incorporation into the surrounding subcutaneous tissue, and elongated cells expressing the contractile protein smooth muscle actin were also observed. After 24 weeks, procollagen synthesis was demonstrated in the fully colonized graft matrix. The ePTFE grafts had no evidence of cellular ingrowth and an absence of endothelium. CONCLUSIONS: The bovine SG was appropriately remodeled to its host environment through an organized process of recellularization and neovascularization. The absence of infection, similar patency rates, and cell repopulation of the matrix warrant further investigation.

Renal cell carcinoma invading the inferior vena cava: use of a "temporary" vena cava filter to prevent tumor emboli during nephrectomy.

Renal cell carcinoma with tumor thrombus extension into the inferior vena cava (IVC) remains a difficult operative challenge. Placement of a suprarenal "temporary" IVC filter, with its ease of insertion and removal, makes it the ideal treatment to prevent pulmonary embolism in these difficult cases. We report the first 2 cases of temporary suprarenal IVC filters placed at the time of radical nephrectomy to eliminate the possibility of perioperative pulmonary embolus and avoid the potential long-term sequelae of a permanent suprarenal IVC filter.

Retrohepatic vena cava and hepatic vein injuries: a simplified experimental methods of treatment by balloon shunt.

BACKGROUND: Fecal contamination from colon injury has been thought to be the most significant factor for the development of surgical site infection (SSI) after trauma. However, there are increasing data to suggest that other factors may play a role in the development of postinjury infection in patients after colon injury. The purpose of this study was to determine the impact of gastric wounding on the development of SSI and nonsurgical site infection (NSSI) in patients with colon injury. METHODS: Post hoc analysis was performed on data prospectively collected for 317 patients presenting with penetrating hollow viscus injury. One hundred sixty-two patients with colon injury were subdivided into one of three groups: patients with isolated colon wounds (C), patients with colon and stomach wounds with or without other organ injury (C+S), and patients with colon and other organ injury but no stomach injury (C-S) and assessed for the development of SSI and NSSI. Infection rates were also determined for patients who sustained isolated gastric injury (S) and gastric injury in combination with organ injuries other than colon (S-C). Penetrating Abdominal Trauma Index, operative times, and transfusion were assessed. Discrete variables were analyzed by Cochran-Mantel-Haenszel chi2 test and Fisher's exact test. Risk factor analysis was performed by multivariate logistic regression. RESULTS: C+S patients had a higher rate of SSI infection (31%) than C patients (3.6%) (p = 0.008) and C-S patients (13%) (p = 0.021). Similarly, the incidence of NSSI was also significantly greater in the C+S group (37%) compared with the C patients (7.5%) (p = 0.07) and the C-S patients (17%) (p = 0.019). There was no difference in the rate of SSI or NSSI between the C and C-S groups (p = 0.3 and p = 0.24, respectively). The rate of SSI was significantly greater in the C+S patients when compared with the S-C patients (31% vs. 10%, p = 0.008), but there was no statistical difference in the rate of NSSI in the C+S group and the S-C group (37% vs. 24%, p = 0.15). CONCLUSION: The addition of a gastric injury to a colon injury has a synergistic effect on the rate of postoperative infection.

External heating of stents by radio waves: pilot studies in rabbit aorta.

PURPOSE: This experiment was designed to assess the feasibility of radio frequency energy delivered by a prototype radio frequency generator inductive heating device (REVAX) positioned external to the body, for transient heating of stents after arterial implant. METHODS AND MATERIALS: Twenty-one New Zealand White rabbits underwent stenting of their infrarenal aorta. Nine rabbits were stented and immediately placed in the REVAX for external stent heating with internal temperature probes in place. Twelve rabbits were stented and 3 days later either heated or placed in the generator as a sham for 20 min. The animals were terminated 28 days later. RESULTS: The REVAX was able to heat the aortic stents in a controlled fashion; in Phase II experiments, the stent temperature was raised to 42 degrees C for 20 min. In Phase I mild necrosis was noted at the stent struts. In Phase II, necrosis and mineralization of the media was seen at the stent struts, and evidence of neointimal suppression was observed. CONCLUSION: This study demonstrated that external heating of stents in a blood vessel in a live animal via radio frequency energy is feasible. Further studies will be needed to assess whether any specific heating regimen might inhibit fibrocellular neointimal hyperplasia.