Endovascular stent infection with delayed bacterial challenge.

BACKGROUND: Reports of endovascular stent infection have recently been described. The purpose of this study was to determine if intravascular metallic stents in a swine model could become infected following a bacterial challenge given remote from the time of stent placement. METHODS: Balloon expandable metallic stents (Palmaz) were implanted in the iliac arteries of 14 swine. An angioplasty, without stent placement, was also performed in the contralateral iliac artery. An intravenous bacterial challenge with Staphylococcus aureus was given 4 weeks after stent placement. Euthanasia was performed 72 hours after the bacterial challenge. At the time of euthanasia, the iliac artery/stent complex and the contralateral angioplastied iliac artery were harvested and sent for microbiologic and pathologic analysis. RESULTS: Seven of the 14 stent/artery complexes were culture positive for S aureus whereas only one of the 14 angioplastied arteries was positive for S aureus (P = 0.03). On histologic examination, 6 of the 14 stent/artery complexes had evidence of acute inflammatory changes in the arterial wall. This compares with only 1 of 14 angioplastied arteries having evidence of inflammatory infiltrate in the arterial wall (P = 0.07). All 6 of the stent/artery complexes with inflammatory infiltrate were culture positive. CONCLUSION: In the swine model, intravascular metallic stents have the potential to become infected when a bacterial challenge is given 4 weeks after stent placement. Further studies evaluating the incidence of stent infections in humans are needed.

Abscess formation following spilled gallstones during laparoscopic cholecystectomy.

OBJECTIVE: Our purpose was to report the occurrence of abscess following spilled gallstones during laparoscopic cholecystectomy as experienced at Good Samaritan Hospital, and to compare it to the experience of other institutions in order to identify the incidence, characteristics and possible risk factors for the development of this complication. METHODS: Four case reports of abscess following spilled gallstones during laparoscopic cholecystectomy are presented. The English literature was reviewed, and characteristics of the case reports found in the literature were compared. RESULTS: In four years at this institution, four reports of abscess formation following laparoscopic cholecystectomy have been identified. Two occurred in elderly females and were located in the right flank in both. Two were in middle-aged men, both diabetic. One abscess was in the right flank and one in the right pleural space. Twenty-three cases were found in the literature. The average age was 65 years; there were 12 men and 11 women. The locations of abscess formation were trocar sites (most common), right subphrenic space, right flank or retroperitoneum, and pelvis. The average time to presentation was 4-5 months (range 4 days-12 months). CONCLUSIONS: Abscess formation following spilled gallstones during laparoscopic cholecystectomy occurs infrequently, but can be debilitating and require more than one procedure. The older population appears to be at greater risk. Future prospective studies of patients who undergo laparoscopic cholecystectomy are needed to more accurately determine the incidence of this complication and to identify the population at risk.

Infection of endovascular stents in a swine model.

BACKGROUND: Percutaneous balloon angioplasty with intravascular metallic stent placement has rapidly gained popularity for the treatment of arterial occlusive disease. Although the incidence of vascular prosthetic infection is well described, the risk of infection following metallic stent placement is unknown. The purpose of this study was to determine if intravascular metallic stents could become infected following systemic bacterial challenge. METHODS: Balloon expandable metallic stents were implanted in the iliac arteries of 10 swine following balloon catheter angioplasty. A second angioplasty, without stent placement, was also performed in the contralateral iliac artery. A bacterial challenge with Staphylococcus aureus was then infused into the aorta immediately after stent placement. Group 1 (n = 5) was killed at 72 hours, and group 2 (n = 5) at 3 weeks. A third group (n = 5) underwent stent placement without bacterial challenge and was killed at 3 weeks. At the time of death, the stents were cultured, and both iliac arteries were submitted for pathologic examination. Arterial patency and evidence of systemic infection were also assessed. RESULTS: In the animals sacrificed at 72 hours (group 1), 80% had stent cultures with significant growth of S aureus; while at 3 weeks (group 2), 60% of cultures were positive. Of the stents placed without bacterial challenge (group 3), none had a positive culture at 3 weeks. In group 2, 40% of the stented arteries remained patent, while 100% of group 3 remained patent until sacrifice at 3 weeks. All of the stented arteries which were patent at 3 weeks were culture negative, while all those which were thrombosed were culture positive for S aureus. When compared to angioplasty alone, the presence of a stent was strongly associated with pathologic evidence of inflammation [93% versus 7%]. The quality of inflammation in the stented groups also differed. Ninety percent of the stented arteries in groups 1 and 2 had acute inflammation, compared to only 20% in group 3. The remainder of the stented arteries in group 3 had chronic inflammation or were normal. CONCLUSION: In the swine model, intravascular metallic stents have the potential to become infected. This is associated with acute inflammation of the arterial wall and vessel thrombosis. Further studies evaluating the incidence of stent infections in humans are needed.

Analysis of autogenous vein femoral-infrapopliteal bypass for limb salvage in the elderly.

The hypothesis that older patients undergoing femoral-infrapopliteal bypass have a similar outcome as a matched younger group of patients undergoing the same operation was tested. Seventy-six femoral-infrapopliteal autogenous saphenous vein bypasses for critical limb ischemia were performed from 1985 to 1990. By using the life-table method, the primary and secondary patency, limb salvage and survival rates are analyzed and compared for older and younger age groups. Forty cases (53%) were performed in an elderly group, defined as age 70 or older. At 4 years, there was no significant difference between age groups in limb salvage and patency rates. However, operative mortality for the older age group was 12%, compared with 0% in the younger group (P = 0.0004). Thus, femoral-infrapopliteal autogenous vein bypass can be performed with comparable limb salvage and patency rates for an older age group, but the risk of operative mortality appears to be increased with age.

Management options for hepatic artery aneurysms.

A 70-year-old woman underwent an elective sigmoid resection for chronic diverticulitis. On the third postoperative day she suddenly developed abdominal pain and hypotension after a coughing episode. Radiologic evaluation demonstrated the presence of a hemoperitoneum. A celiac arteriogram was obtained in an effort to determine the cause of the hemorrhage. Four aneurysms of the intrahepatic portions of the left and right hepatic arteries were found. These aneurysms were successfully treated using steel coil embolization. Surgery has traditionally been the "gold standard" treatment of this rare entity. Recent reports have demonstrated the utility of embolization in treating aneurysms of the hepatic arteries. This report reviews the current treatment options available in the management of hepatic artery aneurysms. Embolization of the aneurysms is recommended.