Comparison of jejunal and ileal surveillance biopsies in a porcine model of intestinal transplantation.

BACKGROUND: The optimal biopsy site of bowel allografts for rejection surveillance remains controversial. We compared the results of jejunal (JBx) and ileal (IBx) biopsies after bowel transplantation in a porcine model. METHODS: Eighteen Yorkshire-Landrace pigs served as donors. Eighteen recipient pigs underwent total enterectomy followed by orthotopic small bowel transplantation with or without the colon. A jejunostomy and a Bishop-Koop ileostomy were constructed for biopsies. Immunosuppression consisted of FK506 (target level 10-15 ng/ml by enzyme immunoparticle assay) and prednisone administered via the jejunostomy. Simultaneous JBx and IBx were performed twice weekly. Acute rejection was graded as mild, moderate, or severe based on previously published criteria. RESULTS: Mean overall survival after the transplant was 17.4 days. A total of 162 specimens were collected and evaluated for rejection (JBx, 81; IBx, 81). Acute rejection was detected in 41 JBx cases (50.7%) and 40 IBx cases (49.4%). The presence or absence of rejection was concordant between JBx and IBx in 70 of 81 case pairs (86.4%). Of the 11 discordant case pairs, 6 were JBx positive/IBx negative, whereas 5 were JBx negative/IBx positive. A total of 35 case pairs were synchronously positive, 24 (68.8%) of which demonstrated the same degree of rejection. CONCLUSIONS: The correlation between JBx and IBx of bowel allografts in diagnosing the presence of acute rejection is quite good. However, performing IBx alone would have missed about 7.5% of the rejection episodes. Because the early treatment of rejection in bowel transplantation is of paramount importance, in selected cases, biopsies from both the ileum and jejunum should be considered if technically feasible.

Partial hepatectomy reduces the endotoxin-induced peak circulating level of tumor necrosis factor in rats.

The pro-inflammatory cytokine tumor necrosis factor (TNF) is dramatically and transiently elevated in the circulation during endotoxic and septic shock and is a primary mediator in the pathogenesis of the sepsis syndrome. TNF peaks in the circulation 90 min after endotoxin administration with little variation, even among species. The specific cells, tissues, or organs that produce the high circulating level of TNF in septic shock remain unknown. The most likely sources are macrophage-laden tissues such as the liver and the spleen and circulating blood leukocytes. This study evaluated whether the liver is an important source producing the TNF spike 90 min after endotoxin. To test this hypothesis, we measured the peak circulating level of TNF following an endotoxin injection in rats subjected to a two-thirds hepatectomy versus sham-operated controls. Hepatechectomized rats produced 64% less TNF after endotoxin than controls (857 + or - 143 pg/mL plasma vs. 2410 + or - 491, respectively; p < .01). In contrast, splenectomy did not significantly after peak TNF levels versus sham-operated controls following an endotoxin injection (1380 + or - 148 pg/mL plasma vs. 1710 + or - 291). Furthermore, incubation of rat blood with endotoxin for 90 min did not significantly increase TNF above controls. These experiments demonstrate an important role for the liver in producing the high circulating levels of TNF after an endotoxin injection and suggest that hepatic-specific cytokine modulation deserves study for a therapeutic benefit in septic shock.

Molsidomine increases endotoxic survival and decreases cytokine production.

We hypothesized that nitric oxide (NO) may exert feedback regulatory control over cytokine production and improve survival in endotoxin (ETX) shock. To test this hypothesis, we evaluated the pre-endotoxin effect of the NO donor molsidomine (MOL) on circulating tumor necrosis factor (TNF), interleukin (IL)-1, and IL-6 levels, the production of these cytokines in the perfused liver, and endotoxic lethality in mice. Male BDF mice weighing 28-32 g were administered either 100 mg/kg MOL or saline (SAL) i.p. Thirty minutes later, the mice received either 50 mg/kg Salmonella enteriditis ETX or SAL i.p. Mice were killed at 90 min after ETX or SAL, for either the determination of plasma cytokine levels by enzyme-linked immunosorbent assays or for use in the perfused liver assessment of cytokine production. MOL treatment significantly reduced the post-ETX circulating levels of TNF to 84%, IL-1 to 65%, and IL-6 to 56%, as compared with SAL-treated ETX controls. Endotoxic livers from MOL-pretreated mice produced 82% less TNF, 88% less IL-1, and 54% less IL-6 over a 2 h perfusion, as compared with SAL-treated ETX controls. MOL pretreatment also decreased lethality in ETX shock from 90 to 50% (p < .05). Therefore, NO may provide a beneficial effect during sepsis by inhibiting hepatic cytokine production, and thus providing survival benefits.

Multiple intrasplenic hepatocyte transplantations in the dalmatian dog.

BACKGROUND: Hepatocyte transplantation is an attractive potential treatment for liver-based inborn errors of metabolism and for fulminant hepatic failure. Dalmatian dogs have a metabolic error that results in hyperuricosuria. This report focuses on the effect of multiple, sequential intrasplenic transplants of fresh and cryopreserved hepatocytes in dalmatians. METHODS: Dalmatians underwent intrasplenic hepatocyte transplantation with hepatocytes taken from healthy mongrels. Dalmatian urinary uric acid excretion was measured preoperatively, and this served as the control value. Three hepatocyte transplantations were performed at 30-day intervals--the first with freshly isolated cells, and both the second and the third with cryopreserved hepatocytes from the same donor. Urinary uric acid excretion was measured postoperatively twice per week. RESULTS: The urinary uric acid excretion decreased an average of 54% after the first hepatocyte transplantation. The effect was transient and lasted an average of 22 days (range, 19-50 days). Subsequent intrasplenic hepatocyte transplantation with cryopreserved hepatocytes resulted in similar decreases in urinary uric acid excretion. Each transplant resulted in a significant decrease in urinary uric acid excretion when compared with baseline values (P = < .001). CONCLUSIONS: Sequential intrasplenic hepatocyte transplantation is feasible in this model. This method provided a significant, but transient, correction in urinary uric acid excretion that was similar with either fresh or cryopreserved hepatocytes. A substantial biologic effect provided by cryopreserved hepatocytes has important implications in clinical hepatocyte transplantation.

Expanded indications for the treatment of postcatheterization femoral pseudoaneurysms with ultrasound-guided compression.

BACKGROUND: The purpose of this study was to define the factors that predict successful ultrasound-guided compression repair (UGCR) of postcatheterization femoral pseudoaneurysms (PA) and to determine risks for recurrence, the most appropriate follow-up, and the optimal management of compression failures and recurrences. METHODS: A retrospective chart review was made. RESULTS: UGCR thrombosed 52 of 60 PA (87%). Predictors of compression failure were PA size of 8 cm and an associated arteriovenous fistula (AVF). AVF was the only predictor of recurrence. All seven recurrences (13%) were discovered on the first follow-up scan. Four were thrombosed with additional UGCR. Late rescanning after a mean of 264 days identified no recurrences. Four anticoagulated patients failed initial UGCR but were thrombosed in another session when their anticoagulation was briefly reversed. CONCLUSIONS: UGCR should be the initial management of PA because it is safe, effective, and durable. Temporary discontinuation of anticoagulation and multiple prolonged compression sessions may help treat recalcitrant cases. One follow-up scan is adequate for most patients. Recurrences should be initially treated with repeat UGCR.

Omental transfer for salvage of the moribund lower extremity.

Use of omental flaps is well documented in soft tissue reconstruction of the head and neck, chest wall, and abdomen. Three cases of omental transfer for soft tissue reconstruction of the lower extremities are presented. In two patients, free vascularized omental flaps were used to cover deep soft tissue defects over the lower leg and in one patient, a pedicle flap was used to cover a deep groin defect extending into the hip joint. In all patients, use of an omental graft allowed revascularization and subsequent wound healing with good cosmetic results.

Free tissue transfer provides durable treatment for large nonhealing venous ulcers.

BACKGROUND: Most venous ulcers (VUs) will heal with conventional treatment, which focuses on improving regional venous hemodynamics. This treatment, however, often fails to heal large, recurrent VUs that are associated with severe lipodermatosclerosis (LDS). These complicated ulcers may require correction of local venous hemodynamics and replacement of the surrounding LDS with healthy tissue. We report our experience managing 24 especially difficult VUs with debridement and free flap coverage. PATIENTS AND METHODS: Between 1987 and 1997, 25 free flap procedures were performed in 22 patients for 24 recalcitrant VUs. Ulcers had been present for a mean of 5.24 years and had failed to heal with conservative therapy and split-thickness skin grafts (STSGs) (mean, 2.2). Eleven patients (46%) had exposed bone, tendon, or joint. At operation the area of LDS was excised, and all perforating veins were ablated. The defects after excision ranged from 100 to 600 cm(2) (mean, 237 cm(2)). The free flap was inset within the defect and covered with an STSG. RESULTS: We healed all 24 ulcers with free tissue transfer (one patient required a second flap after the first failed). There were no deaths. Local complications that required repeat STSG occurred in three (13%) of the 24 successful flap transfers. Four other flaps had minor local complications that healed with local wound care. Follow-up was available for 21 of the 24 successful flap transfers. No recurrent ulcers were identified in the territory of the flap after a mean of 58 months, but three patients had new ulcers in the same leg after 6 to 77 months. Patients with severe complications were hospitalized longer than those with minor or no complications (45.7 vs 12.8 days, P <.01), and their hospital charges were greater ($76,681 vs $30,428, P <.01). CONCLUSION: Free tissue transfer can provide rapid healing and long-term relief from severe VUs that are unable to be treated with conventional therapy. This technique improves venous hemodynamics, removes all liposclerotic tissue, provides an abundant blood supply, and resolves the tissue-related components of chronic ulceration. Although further work is needed to determine the optimal indications, this technique provides a durable treatment for especially recalcitrant ulcers.

Internal to external carotid artery transposition to repair recurrent stenosis after carotid artery stenting.

Recently, carotid artery stenting (CAS) has emerged as a treatment option for carotid artery stenosis. Since the procedure is new, management of its complications is not standardized. This case report describes one method of arterial reconstruction after failed CAS. A 64-year-old male underwent CAS of his right internal carotid artery (ICA) for an asymptomatic 65% stenosis. Seven months later the stented area had narrowed to 95%. Arteriography revealed that the common and external carotid arteries (ECA) were free of disease so we elected to perform a transposition of the distal ICA onto the proximal ECA. The ECA and its branches were completely mobilized and the ascending pharyngeal and lingual arteries divided. The ICA was divided distal to the stent. Transection of the occipital artery provided an arteriotomy for an end ICA to side ECA anastamosis, thus preserving ECA flow. Postoperative surveillance after 8 months has revealed no recurrent stenosis. Operative repair of restenosis after CAS may be challenging if standard endarterectomy is not possible. Other options for reconstruction are feasible but if the common and external carotid arteries are disease-free, an ICA to ECA transposition provides a simple all-arterial repair that avoids bypass and prosthetic material.

Vertical ramus osteotomy allows exposure of the distal internal carotid artery to the base of the skull.

Exposure of the distal internal carotid artery (ICA) above the level of the second cervical vertebra can be difficult and often require maneuvers such as division of the digastric muscle or mandibular subluxation. These techniques increase exposure but may not provide adequate access. We report a series of eight cases in which vertical division of the mandibular ramus provided access of the ICA up to the base of the skull. Over the last 10 years, eight patients underwent vertical ramus osteotomy (VRO) to aid in distal ICA exposure. Preoperative arteriography revealed ICA lesions within 1.5 cm of the skull base. Indications for surgery were compelling and included gunshot wounds to zone III of the neck (n = 2), transient ischemic attack (n = 2), and preocclusive stenosis (n = 4). VRO was performed through a standard vertical neck incision and was created from the depth of the sigmoid notch to the angle of the mandible after elevating the masseter muscle from the bone. Miniature titanium plates were used to reapproximate the mandible after endarterectomy (n = 5), bypass (n = 2), or arterial repair (n = 1). We found that VRO provides reliable exposure of the distal ICA up to the base of the skull. Unlike mandibular subluxation, it requires no pre-incision preparation, thus mandibulotomy can be performed after carotid artery dissection has begun, and may even be avoided. VRO is especially useful when carotid artery pathology unexpectedly extends beyond the usual field of exposure. Work on the carotid artery at the skull base is associated with significant complications and should be reserved for compelling indications.

Growing the vascular surgical practice: venous disorders.

For the 48th meeting of the International Society for Cardiovascular Surgery, North American Chapter in June 2000, we were asked to organize a presentation with the title displayed above. We welcomed this opportunity because the phrase 'growing the practice' literally means giving greater service to underserved patients with vascular disorders. Underserved individuals with vascular disorders include those with nonatherosclerotic arterial disorders, patients with lymphedema, and individuals with a variety of venous disorders including venous insufficiency. The majority of these conditions are not surgical, but venous insufficiency commands attention because its treatments are interventional. Therefore, this presentation will discuss prevalence of venous insufficiency, a unifying concept of its pathophysiology, how treatment may be selected, what the new technology provides, and then a description of coding issues and whether or not interventions are actually worthwhile from the point of view of the patient.

Arteriovenous fistulae complicating cardiac pacemaker lead extraction: recognition, evaluation, and management.

Transvenous pacemaker lead extraction has become a commonly performed procedure that is associated with a small but significant risk. We report two cases where lead extraction was complicated by arteriovenous fistulae between branches of the aortic arch and the left brachiocephalic vein. Presenting signs and symptoms included severe chest or back pain, persistent or copious bleeding from the venous puncture site, unexplained hypotension or anemia, superior vena cava syndrome, and signs of central venous hypertension or acute heart failure. One patient whose injury was not recognized immediately and who did not undergo repair died rapidly, whereas the other patient who was diagnosed quickly underwent successful repair. Immediate diagnosis with arteriography and rapid intervention with surgery or percutaneous techniques are indicated and may prevent mortality.