Ultrasound-guided thrombin injection is a safe and durable treatment for femoral pseudoaneurysms.

Ultrasound-guided percutaneous thrombin injection has recently been described as a treatment for postcatheterization femoral pseudoaneurysms. Although ultrasound guided compression offers another nonoperative treatment option, thrombin injection has shown superior initial success rates. Reports of follow-up for thrombin injection longer than 30 days are currently lacking. The authors reviewed their initial experience with thrombin injection and prospectively evaluated patients for occult late recurrences of pseudoaneurysm and for distal circulatory complications. Records and vascular laboratory data for all patients treated with ultrasound-guided thrombin injection were reviewed for an 18-month period. Tibial vessel Doppler waveforms and ankle/brachial indices were routinely obtained before and after thrombin injection. Follow-up duplex examinations were performed within 24 hours of initial treatment. In the prospective portion of the study, successfully treated patients underwent a repeat femoral duplex scan and lower extremity arterial examination for comparison with the pretreatment studies. Forty-nine of 52 femoral pseudoaneurysms (94%) were successfully treated with ultrasound guided thrombin injection. One immediate failure and 2 early recurrences were treated surgically. There was 1 thrombotic complication of the native circulation identified at the time of injection. Follow-up studies were obtained in 32 of 46 available patients with a mean length of follow-up of 9 months (range 3-17 months). No late recurrences of the pseudoaneurysms or arterial-venous fistulas were observed. No distal circulatory complications were detected by arterial waveform analysis. Three deaths occurred in the interim (cardiac related). Two patients were lost to follow-up. The remaining 12 patients reported no additional limb complications but declined to be restudied. Ultrasound-guided thrombin injection is a safe, effective, and durable treatment for iatrogenic pseudoaneurysms. Thrombin injection should be the therapy of choice for catheter-related femoral false aneurysms.

Elastase is not sufficient to induce experimental abdominal aortic aneurysms.

PURPOSE: Research investigating abdominal aortic aneurysms (AAAs) commonly uses a rat model dependent on aortic infusion of porcine pancreatic elastase to initiate AAA formation. Unfortunately, the sizes of AAAs generated by this model have varied widely among published studies. This may reflect lot-to-lot variations in commercial elastase preparations. This study was undertaken to investigate the ability of different lots of elastase to induce AAAs and explain the variability identified. METHODS: Four lots of elastase were evaluated in the standard rat AAA model. Saline solution was used as a control. Additional groups of rats were treated with higher concentrations of elastase with or without the macrophage activator thioglycollate medium. Aortic diameters were measured in all rats. Inflammation and elastin degradation was examined histologically. Elastase activity and purity were evaluated for all lots. RESULTS: Of the four lots tested, only one was able to consistently generate AAAs at the standard dose (P <.05). Increasing the amount of elastase infused produced AAAs in some ineffective lots. Infusion of thioglycollate medium in combination with otherwise ineffective elastase produced AAAs (P =.02). However, the elastase with the highest purity failed to generate AAAs, even at the highest dose tested or in combination with thyioglycollate medium. Thioglycollate medium alone failed to result in AAA formation. All elastase lots displayed elastolytic activity in vitro and produced elastin degradation in vivo. Elastin degradation did not correlate with AAA size in elastase-treated rats (P = NS). Aneurysm size correlated with extent of inflammation (P =.005). CONCLUSION: Induction of AAAs does not correlate with elastolytic activity. Infusion of pure elastase alone is not sufficient to induce AAA formation in spite of evidence of elastin degradation. Presumed inflammatory modifiers, which contaminate some elastase preparations, enhance AAA formation. Future use of this rat model will need to take the variability of elastase preparations into account with controls for each new elastase lot.

Carotid endarterectomy: the financial impact of practice changes.

PURPOSE: New techniques in the management of extracranial carotid occlusive disease have focused attention on the outcome and economics of carotid endarterectomy (CEA). Changing practice patterns for CEA must be assessed to allow accurate comparisons. The purpose of this study was to evaluate the effect of practice modifications related to CEA on patient outcome and cost data. METHODS: Data on patients undergoing CEAs at a single institution from fiscal year 1992 to 1998 were prospectively collected and entered into a computerized database. Records were reviewed for patient demographics and outcome with regard to stroke and death. Selected years that corresponded to transitions in perioperative management were audited for complete hospital financial information from. RESULTS: We performed 960 CEAs during the study period, with a combined stroke and death rate of 1.1%. Inflation-adjusted hospital costs per patient in 1998 dollars for the years 1992, 1996, and 1998 were $5494, $4476, and $3350, respectively. In 1998, costs for patients who required arteriography were $1825 greater than those operated on during duplex scan examination alone in 1998. Statistically significant differences occurred in the year-to-year comparisons in the use of arteriography, intensive care unit monitoring, same day admissions, and length of stay. There were no statistically significant differences in the stroke and death rate between years. CONCLUSION: Practice changes related to CEA have resulted in significant savings without detriment in patient outcome. Comparisons between CEA and endovascular techniques will need to be evaluated within this context. Given these advances in perioperative management, it will be difficult to justify carotid stenting on the basis of current economic considerations.

Prevention of adhesions to polypropylene mesh in a traumatized bowel model.

BACKGROUND: Polypropylene mesh (PPM) is an effective material for the repair of abdominal wall defects, but has a tendency to induce dense adhesions when in contact with viscera. Seprafilm (Genzyme Corp, Cambridge, MA), a bioresorbable membrane, has been shown to reduce adhesion formation after midline closures in humans and to PPM in animals. Given the increased inflammatory response expected with surgical trauma, its efficacy under surgical conditions has been questioned. STUDY DESIGN: A prospective, randomized, blinded study was conducted using a rabbit model. Standardized abdominal wall defects were created in three groups of New Zealand white rabbits. The cecum was deserosalized to simulate the effects of trauma. The abdominal defect was then repaired with PPM. In the control group, no Seprafilm was used. In the first experimental group Seprafilm was placed between the mesh and the abdominal viscera. In the second experimental group Seprafilm was placed over the deserosalized area and between the mesh and abdominal viscera. Animals were sacrificed at 30 days and adhesions were categorized and quantified using digital image analysis of inked specimens. The strength of incorporation was also determined. RESULTS: The formation of adhesions between the viscera and mesh repair was dramatically reduced in both experimental groups compared with the control group. The incidence of visceral adhesions was reduced by 80% in the single film group (p = 0.0004) and 90% in the double film group (p = 0.00008). The reduction in surface area of adhesions was 96.4% in the single film group (p = 0.000019) and 99.4% in the double film group (p = 0.00002). Omental adhesions were reduced by 30% but this did not achieve statistical significance. Strength of incorporation was not adversely affected in either group. CONCLUSIONS: Seprafilm is highly effective in preventing adhesions to PPM. This effect was not diminished by the presence of visceral trauma and its resultant inflammatory response. The use of Seprafilm does not adversely affect tissue incorporation. Clinical trials are warranted to determine if the protective effects of Seprafilm demonstrated in this study are applicable in the clinical setting.

The effects of preperitoneal carbon dioxide insufflation on cardiopulmonary function in pigs.

BACKGROUND AND OBJECTIVES: Although considerable experimental and clinical knowledge exists on the physiology of pneumoperitoneum, insufflation of the preperitoneal space has not been extensively studied. The purpose of this study is to evaluate the physiology associated with preperitoneal carbon dioxide (CO2) insufflation in a porcine model. METHODS: Eleven pigs weighing 35 to 45 kg were anesthetized and placed on mechanical ventilation. A pulmonary artery catheter and an arterial line were inserted. Balloon dissection of the preperitoneal space and insufflation to 10 mm Hg for 1.5 hours, followed by an increase to 15 mm Hg for an additional 1.5 hours, was performed. Hemodynamic and arterial blood gas values were determined every 15 minutes throughout the stabilization and three-hour insufflation period. Hemodynamic parameters and blood gas values were analyzed using one-way analysis of variance with respect to insufflation time and pressure. RESULTS: Analysis of hemodynamics (CO, CVP, PAD, PAS, PCWP) did not demonstrate statistical significance with respect to time. However, there was a statistical difference in CO (p=.01), CVP (p<.01), and PCWP (p=.034) when comparing a pressure of 15 mm Hg to a pressure of 10 or 0 mm Hg. The other parameters did not demonstrate significant differences among the three pressure groups. Arterial PCO2 and pH were highly significant with respect to time (p<.01 and P<.01, respectively) and among the pressure groups (p<.01 and P<.01, respectively). CONCLUSIONS: Insufflation of the preperitoneal space with CO2 gas does not cause significant alterations in hemodynamics and blood gas changes at a pressure of 10 mm Hg. However, when a pressure of 15 mm Hg is used to insufflate this space, there is evidence of decreased pH and cardiac output, with elevated CVP and CO2 retention. This correlates with greater pneumodissection of the gas within the layers of the abdominal wall when elevated pressures are used.

Prevention of adhesions to polypropylene mesh in a rabbit model.

The purpose of this study was to develop a quantitative model for evaluating adhesion formation and to determine whether Seprafilm (HAL-F) bioresorbable membrane (Genzyme Corp., Cambridge, MA) is effective in preventing adhesions to polypropylene mesh (PPM). PPM has been shown to be an effective material for the repair of abdominal wall defects. One disadvantage of PPM is its tendency to form dense adhesions when in contact with abdominal viscera. HAL-F, a sodium hyaluronate/carboxymethylcellulose absorbable membrane, has been shown to prevent adhesion formation after midline closures. Its efficacy in preventing adhesions to PPM has not been examined previously. A 5 x 7-cm anterior abdominal wall defect was created in 24 New Zealand White rabbits. This defect was then repaired with PPM. In the experimental group, a 5 x 7-cm piece of HAL-F was placed between the mesh and the abdominal viscera. At 30 days, the animals were killed and adhesions were categorized and quantified using digital image analysis of inked specimens. The strength of mesh incorporation into surrounding tissues was also examined using an Instron tensiometer. The formation of adhesions between the viscera and mesh repair was significantly reduced by the use of HAL-F. The surface area involved for bowel adhesions was reduced 94 per cent (P = 0.00132). The strength of incorporation was not adversely affected. HAL-F is highly effective in preventing adhesions to PPM, without adversely effecting the strength of mesh incorporation.

The adverse effects of octreotide on wound healing in rats.

Octreotide acetate is a long-acting somatostatin analogue with protean physiologic effects. It is used primarily as an inhibitory paracrine hormone to treat a variety of medical and surgical disorders, including endocrine tumors and several gastrointestinal hypersecretory states. Because of octreotide's known inhibition of multiple trophic and anabolic hormones, we suspected that it may have deleterious effects on wound healing. Twenty-four rats were randomized to one of three groups: control, steroid (a negative control), or octreotide. Dorsal midline incisions were made and closed primarily. Wound-breaking strength measurements were performed 7 days later. The mean peak load (+/- standard error of the mean) for each group was calculated: control = 754 +/- 89 g; steroid = 378 +/- 32 g; and octreotide = 427 +/- 41 g. The difference between the control group and each of the other groups was statistically significant with P < 0.030. We conclude that octreotide has significant adverse effects on wound healing in the rat model and that these effects are comparable in magnitude to those caused by steroids.

Laparoscopic gastrostomy using four-point fixation.

Percutaneous endoscopic gastrostomy (PEG) has become an effective alternative to surgical gastrostomy in patients who require enteral access or gastric decompression. Technical considerations, however, limit the application of PEG in selected patients and those who have contraindications to PEG. Laparoscopic gastrostomy tube placement has been introduced as an alternative to PEG. A technique for laparoscopic gastrostomy tube placement that emphasizes four-point fixation of the anterior gastric wall is presented.

Complications of percutaneous endoscopic gastrostomy.

Percutaneous endoscopic gastrostomy (PEG) has become a commonly performed procedure to provide nutritional support to chronically ill patients. Following a PEG-related death, we retrospectively reviewed our complication rate with that of the published values. In the past 48 months at Madigan Army Medical Center and Eisenhower Army Medical Center, 147 PEGs have been performed. We have had 20 minor complications and 5 major complications, with 2 reported deaths directly related to the procedure. Minor complications included 14 cases of localized cellulitis and 5 cases of prolonged ileus. The major complications included two cases of necrotizing fasciitis (both fatal), two cases of tube extubation within 24 hours, both resulting in surgical gastrostomy, and one bowel obstruction requiring laparotomy. Both patients who developed necrotizing fasciitis had several predisposing factors including diabetes, malnutrition, obesity, and long-term hospitalization. In conclusion, we believe PEG is an extremely valuable procedure which should be utilized with caution in the immunocompromised or morbidly obese patient.