The endovascular management of visceral artery aneurysms and pseudoaneurysms

OBJECTIVE: Visceral artery aneurysms may be treated by aneurysm exclusion, excision, revascularization, and endovascular techniques. The purpose of this study was to review the outcomes of the management of visceral artery aneurysms with catheter-based techniques. METHODS: Between 1997 and 2005, 90 patients were identified with a diagnosis of visceral artery aneurysm. This was inclusive of aneurysmal disease of the celiac axis, superior mesenteric artery (SMA), inferior mesenteric artery, and their branches. Surveillance without intervention occurred in 23 patients, and 19 patients underwent open aneurysm repair (4 ruptures). The endovascular treatment of 48 consecutive patients (mean age 58, 60% men) with 20 visceral artery aneurysms (VAA) and 28 visceral artery pseudoaneurysms (VAPA) was the basis for this study. Electronic and hardcopy medical records were reviewed for demographic data and clinical variables. Original computed tomography (CT) scans and fluoroscopic imaging were evaluated. RESULTS: The endovascular treatment of visceral artery aneurysms was technically successful in 98% of 48 procedures, consisting of 3 celiac axis repairs, 2 left gastric arteries, 1 SMA, 12 hepatic arteries, 20 splenic arteries, 7 gastroduodenal arteries, 1 middle colic artery, and 2 pancreaticoduodenal arteries. Of these, 29 (60%) were performed for symptomatic disease (5 ruptured aneurysms). Procedures were performed in the endovascular suite under local anesthesia with conscious sedation (94%). The femoral artery was used as the preferential access site (90%). Coil embolization was used for aneurysm exclusion in 96%. N-butyl-2-cyanoacrylate (glue) was used selectively (19%) using a triaxial system with a 3F microcatheter for persistent flow or multiple branches. The 30-day mortality was 8.3% (n = 4). One patient died from recurrent gastrointestinal bleeding after gastroduodenal embolization, and the remaining died of unrelated causes. All perioperative deaths occurred in patients requiring urgent or emergent intervention in the setting of hemodynamic instability. No patients undergoing elective intervention died in the periprocedural period. Postprocedural imaging was performed after 77% of interventions at a mean of 16 months. Complete exclusion of flow within the aneurysm sac occurred in 97% interventions with follow-up imaging, but coil and glue artifact complicated CT evaluation. Postembolization syndrome developed in three patients (6%) after splenic artery embolization. There was no evidence of hepatic insufficiency or bowel ischemia after either hepatic or mesenteric artery aneurysm treatment. Three patients required secondary interventions for persistent flow (n = 1) and recurrent bleeding from previously embolized aneurysms (n = 2). CONCLUSION: Visceral artery aneurysms and pseudoaneurysms can be successfully treated with endovascular means with low periprocedural morbidity; however, the urgent repair of these lesions is still associated with elevated mortality rates. Aneurysm exclusion can be accomplished with coil embolization and the selective use of N-butyl-2-cyanoacrylate. Current catheter-based techniques extend our ability to exclude visceral artery aneurysms, but imaging artifact hampers postoperative CT surveillance.     

Contemporary results of juxtarenal aneurysm repair

OBJECTIVE: The increasing use of aortic endografts predictably will add to the complexity of open abdominal aortic aneurysm (AAA) repair and, therefore, the proportion of surgically treated infrarenal AAAs that are juxtarenal in location (JRA) will grow. This study reviews a single-center experience with JRAs. METHODS: Between June 1994 and December 2000, 138 patients underwent elective repair of a JRA, comprising 16.1% of 859 consecutive asymptomatic and intact symptomatic nonruptured infrarenal AAAs repaired over the same period. All patients with JRA needed proximal suprarenal clamping (SRC) or supravisceral (SVC) clamping. Patient demographics, selected risk factors, and operative details were recorded. Univariate analyses of selected risk factors for an adverse perioperative event were assessed, and multivariate analyses were performed with linear and logistic regression with backwards selection. RESULTS: SRC was used in 95 patients (69%), and 43 patients (31%) underwent SVC. The mortality rate was 5.1% (7/138) for JRA repair, and 2.8% (20/720) for infrarenal AAA repair (P =.03). The mortality rate was significantly greater for those patients who received SVC compared with SRC (11.6% versus 2.1%; P =.02). Multivariate analysis identified SVC position as the only independent predictor of mortality (odds ratio [OR], 6.1; 95% CI, 1.1 to 32.9; P =.035). Transient renal insufficiency occurred in 39 patients (28.3%), but only eight patients (5.8%) needed dialysis. Patients who had SVC had a significantly greater rate of renal insufficiency than those who received SRC (41.9% versus 22.1%; P =.02). Multivariate analysis showed SVC position (OR, 3.3; 95% CI, 1.4 to 7.8; P =.008), diabetes (OR, 3.7; 95% CI, 1.1 to 12.9; P =.04), and preoperative renal insufficiency (OR, 5.8; 95% CI, 2.2 to 15.4; P <.001) were independent predictors of postoperative renal insufficiency. Renal ischemia during proximal clamping cannot alone explain renal complications because clamp time was shorter in patients with SVC (24.9 +/- 2.4 minutes versus 32.2 +/- 1.5 minutes; P =.009). CONCLUSION: JRA repair can be accomplished with a low mortality rate, but a more proximal clamp position may adversely affect outcome in these patients. Postoperative renal insufficiency is related to diabetes, preoperative renal insufficiency, and SVC position. These results suggest SRC is safer than SVC for proximal aortic clamp control of JRAs. Although clamp level must be tailored to patient anatomy, outcome may be improved if the clamp level can be kept distal to the superior mesenteric artery origin.     

Reoperative lower extremity revascularization with cadaver vein for limb salvage

We evaluated our experience using cryopreserved cadaver vein allografts (CVGs) for infrageniculate revascularization in patients with a history of failed bypass or no suitable autogenous vein. Records of all patients who underwent lower extremity revascularization with CVG for critical limb ischemia were reviewed. Patient demographics, vessel treated, and postoperative course were analyzed. Patients who had a redo cadaver vein bypass were compared to those with a first-time cadaver vein bypass. Cumulative patency rates, limb salvage, mortality, and factors associated with outcomes were determined using the Kaplan-Meier method with Cox proportional hazards. Between January 2000 and December 2006, 66 CVGs were done in 56 patients out of 1,726 total bypasses. There were 36 men and 20 women, and the mean age was 71.67 +/- 10.50 years. Mean follow-up was 12.12 +/- 14.16 months. Seventy-eight percent of patients had previous bypasses, and 50% of all failed bypasses were failed expanded polytetrafluoroethylene bypasses. Operative indications were tissue loss (73%) and ischemic rest pain (27%). The mean preoperative ankle-brachial index was 0.43 +/- 0.16, and this increased to 0.89 +/- 0.18 at 30 days (p = 0.001). Procedure-related complications included graft infection (3, 4%), graft thrombosis (3, 4%), pseudoaneurysm (3, 4%), and bleeding (2, 3%). Cumulative 1-year primary, primary assisted, secondary patencies, limb salvage, and survival rates with confidence intervals were 0.19 (0.10-0.36), 0.29 (0.18-0.47), 0.42 (0.29-0.60), 0.73 (0.62-0.86), and 0.77 (0.65-0.90). Reoperative procedures fared the same as primary procedures. Multivariable analysis showed that predictors for increased risk of secondary patency loss were age >70 (hazard ratio [HR] = 3.13, p = 0.009) and patients with secondary revascularization (HR = 3.36, p = 0.015). Older patients (HR = 2.92, p = 0.042) and those with renal insufficiency (HR = 2.92, p = 0.019) were at increased risk of mortality. CVG remains an option for reoperative lower limb revascularization for limb salvage if there is no autogenous vein available. However, patency rates are poor, and patients older than 70 are more likely to have inferior outcomes.     

Trace elements in pacific Dunlin (Calidris alpina pacifica): patterns of accumulation and concentrations in kidneys and feathers

Ecotoxicology - Trace element concentrations were measured in Pacific Dunlin (Calidris alpina pacifica) to identify factors that influence accumulation and to assess toxicity risks. We report...     

N-acetyl transferase genotypes in relation to risk of developing systemic lupus erythematosus

OBJECTIVE: To examine the association between N-acetyl transferase (NAT) genotype (NAT1 and NAT2) and risk of developing systemic lupus erythematosus (SLE). METHODS: DNA samples were collected from 243 recently diagnosed cases and 298 controls enrolled in a population based case-control study conducted in 60 counties in North Carolina and South Carolina, USA. RESULTS: There was no association between SLE and NAT1 genotype (OR 0.96, 95% CI 0.65, 1.4 for the presence of a *10 allele) or NAT2 genotype (OR 1.1, 95% CI 0.73, 1.6 for the slow- compared with fast-acetylation genotype). We saw some evidence of interaction between NAT genotypes and use of hair dyes (a source of arylamines), with higher risk seen among hair dye users who had both the *10 NAT1 allele and the NAT2 slow-acetylation genotype (OR 2.9, 95% CI 1.2, 6.9 in this subgroup compared with all others). CONCLUSION: Our results suggest that although there is little overall association between NAT genotypes and risk of developing SLE, the interaction between NAT1 and NAT2 and specific exposures such as hair dyes may be important. This finding highlights the need to consider exposure when assessing genetic susceptibility.     

Expression analysis in a rat psychosis model identifies novel candidate genes validated in a large case–control sample of schizophrenia

Antagonists of the N-methyl-D-aspartate (NMDA)-type glutamate receptor induce psychosis in healthy individuals and exacerbate schizophrenia symptoms in patients. In this study we have produced an animal model of NMDA receptor hypofunction by chronically treating rats with low doses of the NMDA receptor antagonist MK-801. Subsequently, we performed an expression study and identified 20 genes showing altered expression in the brain of these rats compared with untreated animals. We then explored whether the human orthologs of these genes are associated with schizophrenia in the largest schizophrenia genome-wide association study published to date, and found evidence for association for 4 out of the 20 genes: SF3B1, FOXP1, DLG2 and VGLL4. Interestingly, three of these genes, FOXP1, SF3B1 and DLG2, have previously been implicated in neurodevelopmental disorders.     

A mitochondrial superoxide theory for oxidative stress diseases and aging

Fridovich identified CuZnSOD in 1969 and manganese superoxide dismutase (MnSOD) in 1973, and proposed ”the Superoxide Theory,” which postulates that superoxide (O₂^•−) is the origin of most reactive oxygen species (ROS) and that it undergoes a chain reaction in a cell, playing a central role in the ROS producing system. Increased oxidative stress on an organism causes damage to cells, the smallest constituent unit of an organism, which can lead to the onset of a variety of chronic diseases, such as Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis and other neurological diseases caused by abnormalities in biological defenses or increased intracellular reactive oxygen levels. Oxidative stress also plays a role in aging. Antioxidant systems, including non-enzyme low-molecular-weight antioxidants (such as, vitamins A, C and E, polyphenols, glutathione, and coenzyme Q₁₀) and antioxidant enzymes, fight against oxidants in cells. Superoxide is considered to be a major factor in oxidant toxicity, and mitochondrial MnSOD enzymes constitute an essential defense against superoxide. Mitochondria are the major source of superoxide. The reaction of superoxide generated from mitochondria with nitric oxide is faster than SOD catalyzed reaction, and produces peroxynitrite. Thus, based on research conducted after Fridovich’s seminal studies, we now propose a modified superoxide theory; i.e., superoxide is the origin of reactive oxygen and nitrogen species (RONS) and, as such, causes various redox related diseases and aging.