Role of Endovascular Aortic Repair in the Treatment of Infected Aortic Aneurysms Complicated by Aortoenteric or Aortobronchial Fistulae.

BACKGROUND: The aim of this study was to compare outcomes and identify factors related to increased mortality of open surgical and endovascular aortic repair (EVAR) of primary mycotic aortic aneurysms complicated by aortoenteric fistula (AEF) or aortobronchial fistula (ABF). METHODS: Patients with primary mycotic aortic aneurysms complicated by an AEF or ABF treated by open surgery or endovascular repair between January 1993 and January 2014 were retrospectively reviewed. Outcomes were compared between the open surgery and endovascular groups, and a Cox's proportional hazard model was used to determine factors associated with mortality. RESULTS: A total of 29 patients included 14 received open surgery and 15 received endovascular repair. Positive initial bacterial blood culture results included Salmonella spp., oxacillin-resistant Staphylococcus aureus, and Klebsiella pneumoniae. Mortality within 1 month of surgery was higher in the open surgery than in the endovascular group (43 vs. 7%, respectively, p = 0.035). Shock, additional surgery to repair gastrointestinal (GI) or airway pathology, and aneurysm rupture were associated with a higher risk of death. Compared with patients without resection surgery, the adjusted hazard ratio of death within 4 years in patients with resection for GI/bronchial disease was 0.25. Survival within 6 months was better in the endovascular group (p = 0.016). CONCLUSION: The results of this study showed that EVAR/thoracic EVAR (TEVAR) is feasible for the management of infected aortic aneurysms complicated by an AEF or ABF, and results in good short-term outcomes. However, EVAR/TEVAR did not benefit long-term survival compared with open surgery.

Biphasic modulation of the mitochondrial electron transport chain in myocardial ischemia and reperfusion.

Mitochondrial electron transport chain (ETC) is the major source of reactive oxygen species during myocardial ischemia-reperfusion (I/R) injury. Ischemic defect and reperfusion-induced injury to ETC are critical in the disease pathogenesis of postischemic heart. The properties of ETC were investigated in an isolated heart model of global I/R. Rat hearts were subjected to ischemia for 30 min followed by reperfusion for 1 h. Studies of mitochondrial function indicated a biphasic modulation of electron transfer activity (ETA) and ETC protein expression during I/R. Analysis of ETAs in the isolated mitochondria indicated that complexes I, II, III, and IV activities were diminished after 30 min of ischemia but increased upon restoration of flow. Immunoblotting analysis and ultrastructural analysis with transmission electron microscopy further revealed marked downregulation of ETC in the ischemic heart and then upregulation of ETC upon reperfusion. No significant difference in the mRNA expression level of ETC was detected between ischemic and postischemic hearts. However, reperfusion-induced ETC biosynthesis in myocardium can be inhibited by cycloheximide, indicating the involvement of translational control. Immunoblotting analysis of tissue homogenates revealed a similar profile in peroxisome proliferator-activated receptor-γ coactivator-1α expression, suggesting its essential role as an upstream regulator in controlling ETC biosynthesis during I/R. Significant impairment caused by ischemic and postischemic injury was observed in the complexes I- III. Analysis of NADH ferricyanide reductase activity indicated that injury of flavoprotein subcomplex accounts for 50% decline of intact complex I activity from ischemic heart. Taken together, our findings provide a new insight into the molecular mechanism of I/R-induced mitochondrial dysfunction.

Cell transplantation for myocardial injury: a preliminary comparative study.

BACKGROUND AIMS: Cell transplantation may restore viable muscle after myocardial infarction. Because many studies have focused on one cell type, we compared the characteristics of skeletal myoblasts (SKM), bone marrow stromal/stem cells (BMSC) and smooth muscle cells (SMC) and their effects on cardiac function after myocardial injury. METHODS: In vitro cell characteristics, including proliferation, hypoxic survival and vascular endothelial cell growth factor (VEGF) expression, of SKM, BMSC and SMC were compared. An in vivo left anterior descending artery ligation rat model was used, and cells were implanted into the infarct (n = 16 per cell type). Cell survival was determined by PKH26 staining and real-time polymerase chain reaction (PCR). Cardiac function, tissue VEGF and stem cell factor (SCF) expression and vasculogenesis were evaluated. RESULTS: Although cell morphologies were distinct, in vitro proliferation was similar. In vitro studies showed that SKM had the highest hypoxic survival, whereas BMSC had the lowest hypoxic survival but the highest VEGF expression. After implantation, SKM showed the highest overall survival and in vivo SCF expression, and both SMC and SKM expressed the highest VEGF levels. Vasculogenesis was significantly (P < 0.001) improved after transplantation of each cell type. Overall, BMSC and SKM promoted the greatest improvement in cardiac function. CONCLUSIONS: SKM, BMSC and SMC expressed VEGF and SCF and promoted vasculogenesis. Although BMSC showed the greatest regenerative potential relative to cell survival and growth factor expression, the greatest improvement in cardiac function was observed with BMSC and SKM.

The efficacy of aortic stent grafts in the management of mycotic abdominal aortic aneurysm-institute case management with systemic literature comparison.

BACKGROUND: Conventional surgery (CS) for treatment of mycotic aortic aneurysm has rather high surgical morbidity and mortality rates. The use of endovascular aortic repair (EVAR) might simplify the procedure and provide a good alternative for this critical condition, but this remains to be proved. We analyzed all mycotic abdominal aortic aneurysm (AAA) cases treated by CS or EVAR in our institute and the reported cases treated by EVAR from the literature to determine the risk factors for aneurysm-related mortality and morbidity and to clarify the efficacy of the EVAR technique. METHODS AND RESULTS: All relevant literature reports of EVAR management of mycotic AAA and all cases treated in our institute, 41 cases, were included and analyzed. Of the 20 cases treated by EVAR, one had early mortality (1/20, 5%); of the remaining 21 cases that received CS, the early mortality rate was 4.8% (1/21). Patients in the CS group had a higher late mortality rate than those in the EVAR group (45% vs. 10.5%, p<0.05). However, the 24-month actual survival rate and actuarial aneurysm-related event-free rate were 83.9+/-8.6% and 78.3+/-9.7%, respectively, for the EVAR group and did not significantly differ from the CS group (70.4+/-10.2% and 80.1+/-8.9%). The significant predictors for aneurysm-related mortality and morbidity were age, Salmonella species infection, and leukocytosis, and possibly aortoenteric fistula and shock, but not the EVAR or CS procedures themselves. CONCLUSION: Compared with CS, EVAR might be an alternative strategy for managing mycotic AAAs.

Bacteroides fragilis aortic arch pseudoaneurysm: case report with review.

We present a case of 58-year-old woman with underlying diabetes mellitus, hepatitis C virus-related liver cirrhosis, and total hysterectomy for uterine myoma 11 moths ago, who was diagnosed ruptured aortic arch mycotic pseudoaneurysm after a certain period of survey for her unknown fever cause. After emergent surgery with prosthetic graft interposition, all her blood cultures and tissue cultures revealed pathogen with Bacteroides fragilis. Although mycotic aneurysms have been well described in literatures, an aneurysm infected solely with Bacteroides fragilis is unusual, with only eight similar cases in the literature. Here we reported the only female case with her specific clinical and management course and summarized all reported cases of mycotic aneurysm caused by Bacteroides fragilis to clarify their conditions and treatments, alert the difficulty in diagnosis, and importance of highly suspicious.

Outcome after endovascular stent graft treatment for mycotic aortic aneurysm: a systematic review.

BACKGROUND: Surgical treatment for mycotic aortic aneurysms is not optimal. Even with a large excision, extensive debridement, in situ or extra-anatomical reconstruction, and with or without lifelong antibiotic treatment, mycotic aneurysms still carry very high mortality and morbidity. The use of endovascular aneurysm repair (EVAR) for mycotic aortic aneurysms simplifies the procedure and provides a good alternative for this critical condition. However, the question remains: if EVAR is placed in an infected bed, what is the outcome of the infection? Does it heal, become aggravated, or even cause a disastrous aortic rupture? In this study, we tried to clarify the risk factors for such an adverse response. METHODS: A literature review was undertaken by using MEDLINE. All relevant reports on endoluminal management of mycotic aortic aneurysms were included. Logistic regressions were applied to identify predictors of persistent infection. RESULTS: A total of 48 cases from 22 reports were included. The life-table analysis showed that the 30-day survival rate was 89.6% +/- 4.4%, and the 2-year survival rate was 82.2% +/- 5.8%. By univariate analysis, age 65 years or older, rupture of the aneurysm (including those with aortoenteric fistula and aortobronchial fistula), and fever at the time of operation were identified as significant predictors of persistent infection, and preoperative use of antibiotics for longer than 1 week and an adjunct procedure combined with EVAR were identified as significant protective factors for persistent infection. However, by multivariate logistic regression analysis, the only significant independent predictors identified were rupture of aneurysm and fever. CONCLUSIONS: EVAR seems a possible alternative method for treating mycotic aortic aneurysms. Identification of the risk factors for persistent infection may help to decrease surgical morbidity and mortality. EVAR could be used as a temporary measure; however, a definite surgical treatment should be considered for patients present with aneurysm rupture or fever.

Clinical significance and mechanism of gas formation of pyogenic liver abscess due to Klebsiella pneumoniae.

We enrolled 22 patients with gas-forming pyogenic liver abscess in a study to assess the mechanism of gas formation. Klebsiella pneumoniae was cultured from specimens from all patients. Gas and pus samples from abscesses revealed four major components: nitrogen, oxygen, carbon dioxide, and hydrogen; this implicates mixed acid fermentation of glucose as the mechanism of gas formation.