Samir K. Shah

Hypogastric and subclavian artery patency affects onset and recovery of spinal cord ischemia associated with aortic endografting.

OBJECTIVE Spinal cord ischemia (SCI) is a devastating complication associated with aortic aneurysm repair. The aim of the current study was to evaluate factors affecting outcomes from SCI associated with endovascular aortic aneurysm repair. METHODS A total of 1251 patients underwent endovascular repair of aortic aneurysm as part of a device trial between 1998 and 2010 utilizing endovascular abdominal aortic aneurysm repair (n = 351), thoracic endovascular aortic aneurysm repair (n = 201), fenestrated endovascular aortic aneurysm repair (n = 227), and visceral branched endografts (n = 472). Records and imaging studies were reviewed to supplement prospective outcome data. Demographics, type of repair, collateral bed (hypogastric/subclavian) patency, clinical presentation, and outcomes were evaluated on patients with SCI. Survival was calculated using life-table analysis. RESULTS SCI occurred in 2.8% (n = 36) of patients: abdominal aortic aneurysm, 0.3%, juxtarenal, 0.4%, thoracic aortic aneurysm, 4.6%, and thoracoabdominal aortic aneurysm, 4.8%). Four (11%) required carotid-subclavian bypass prior to endografting, and two underwent coverage of the left subclavian artery. Unilateral hypogastric artery occlusion was present in 11 (31%) patients prior to endograft placement, and three had bilateral occlusions. An additional seven patients had occlusion of at least one hypogastric artery during surgery. SCI was apparent immediately in 15 (42%) patients. Immediate onset of symptoms was observed in 73% of patients with at least one occluded collateral bed but in only 24% of those with patent collateral beds (P = .021). Of those presenting in a delayed fashion, nine (43%) had a clear precipitating event prior to onset of SCI (hypotension, n = 6, and segmental artery drain removal, n = 3). Recovery occurred in 24 (67%) patients, most within 7 days. Immediate presentation was a negative predictor of recovery (P = .025), as was occlusion of at least one collateral bed (P = .035). Mean follow-up was 22 ± 4 months with 30-day and 1-year survival of 92 ± 4.6% and 56 ± 8.3%. Survival was only 36% at 3 months in those with permanent SCI compared with 92% (P < .001) in those with temporary symptoms. CONCLUSIONS SCI continues to complicate aortic surgery despite the advent of endovascular therapy. Occlusion of a single collateral bed is associated with an increased risk for immediate onset of SCI and lack of recovery. These factors are harbingers of poor outcomes and increased short-term mortality. This may be prevented by preserving collateral bed patency in patients undergoing extensive endovascular procedures.

The contemporary management of splenic artery aneurysms

OBJECTIVES The management of patients with splenic artery aneurysms (SAAs) is variable since the natural history of these aneurysms is poorly delineated. The objective of this study was to review our experience with open repair, endovascular therapy, and observation of SAAs over a 14-year interval. METHODS Between January 1, 1996 and December 31, 2009, 128 patients with SAAs were evaluated. Sixty-two patients underwent surgical repair (n = 13) or endovascular coil/glue ablation (n = 49), while 66 patients underwent serial observation. The original medical records and computed tomography (CT) imaging were reviewed. Statistical analyses were performed using χ(2) or Fishers exact test for categorical patient characteristics and t-test for continuous variables. Kaplan-Meier estimates for survival were calculated. Mortality was verified via the Social Security Death Index. RESULTS Patients (61 ± 11 years, 69% female) were investigated for abdominal symptoms (49%) or had the incidental finding of SAA (mean size, 2.4 ± 1.4 cm). Seven patients (5.5%) presented with rupture and were treated emergently with two perioperative mortalities (29%). Patients requiring surgical or endovascular treatment were more likely male (40% vs 21%, P = .031), younger (58 vs 64 years; P = .004), and current smokers (18% vs 5%; P = .035). Increased aneurysm calcification was associated with decreased SAA size (P = .013). The mean aneurysm size at initial diagnosis was 1.67 cm for patients undergoing observation and 3.13 cm for the treated group (P < .001). Endovascular repair was safe and durable with a mean 1.5-mm regression in SAA size over 2 years. The mean rate of growth for observed SAA was 0.2 mm/y. Ten-year survival was 89.4% (95% confidence interval: 82.0, 97.4) for all patients (observed group, 94.9%; treated group, 85.1%; P = .18). No late aneurysm-related mortality was identified. CONCLUSIONS Ruptured SAAs are lethal. Large SAAs can undergo endovascular ablation safely with durable SAA regression. Smaller SAAs (<2 cm) grow slowly and carry a negligible rupture risk.

Current State of Diagnosis and Management of Critical Limb Ischemia

Critical limb ischemia represents the most severe form of peripheral arterial disease and carries with it severe morbidity and mortality risks. Because of comorbidity risks, early diagnosis and aggressive medical management make up an important part of the treatment paradigm for these individuals. However, in addition to managing these comorbid conditions, the physician caring for these individuals must be able to provide revascularization options that will improve arterial flow to the threatened extremity and assure healing of complicated wounds. Both open surgical and endovascular therapies have proven beneficial in restoring flow to severely ischemic limbs in these patients. Additionally, combinations of the above therapeutic methods have offered more available options for these patients. This article reviews care of patients with critical limb ischemia with critical assessment of options for medical and revascularization options.

Lower extremity amputations: factors associated with mortality or contralateral amputation.

Background: Tissue loss or gangrene in the setting of lower extremity peripheral artery disease (PAD) may result in amputation. Previous studies have demonstrated elevated mortality rates after major transtibial and transfemoral amputation. Also, amputation of 1 leg may be associated with subsequent major amputation of the contralateral leg. The aim of our study was to identify patient variables associated with mortality and contralateral amputation. Methods: We reviewed the medical records of patients who underwent transfemoral or transtibial amputation secondary to PAD from 2004 to 2009. A total of 454 consecutive major amputations were performed on 391 patients, with 63 of these having a subsequent contralateral amputation. Standard demographic information, comorbidities, prior vascular interventions, and relevant procedural information were extracted from patient records. Kaplan-Meier estimates of survival were calculated. Cox proportional hazard models were used to estimate the risk of death and contralateral amputation. Multivariate Cox proportional hazards models were fit for all variables shown to be marginally associated in the univariate model. Results: In 391 amputees, the mean age was 67.3 years, 63% were male and 62% were caucasian. Patients had high rates of diabetes (63%), hypertension (83%), renal insufficiency (35%), hyperlipidemia (51%), and prior ipsilateral vascular intervention (75%). Seventy percent of patients had below-knee amputations. Perioperative mortality was 9.2% (n = 36). Survival at 12 and 24 months was 70% (95% confidence interval [CI], 65%-74%) and 60% (95% CI, 55%-65%), respectively. Multivariate analysis demonstrated that several independent factors were detrimental to survival including chronic obstructive pulmonary disease (hazard ratio [HR] 1.82, P = .002), dialysis dependence (HR 2.50, P < .001), high cardiac risk (HR 2.20, P < .001), and guillotine amputation (HR 2.49, P = .004). Dialysis (HR 2.42, P = .002) and revision of the index ipsilateral amputation to a higher level (HR 2.02, P = .014) were associated with a subsequent contralateral amputation. Conclusions: Patients with advanced PAD that require lower extremity amputation have diminished survival and significant contralateral amputation rates. Elderly patients on dialysis are particularly prone to dying or losing the other leg after a major amputation. These data support strategies to enhance limb preservation and optimize medical comorbidities in these patients.

Suprasternal bronchogenic cyst

Bronchogenic cysts are congenital anomalies that are typically found in the mediastinum or within the lung. Subcutaneous and cutaneous lesions are rare and most likely represent ectopic or displaced mesenchyme during early development. We report the presentation and results of resection of a suprasternal, subcutaneous bronchogenic cyst in a 23-month-old female infant that was successfully treated with simple excision.

Comparing methods to collect saliva from children to analyze cytokines related to allergic inflammation.

Human saliva is a complex fluid, rich in immunological components, which reflects real time systemic concentrations. Advances in biotechnology have enabled us to measure minute concentrations of immunological components such as cytokines in saliva samples with precision and accuracy 1. There are few data evaluating how the collection method may influence the results in addition to other methodological challenges, resulting in lack of consensus on a universally accepted saliva collection technique2, especially in children. Specifically, the impact of saliva collection methods on detection and analysis of salivary concentrations of allergic inflammatory cytokines such as the interleukin (IL)-4, IL-5, IL-13, eotaxin 3 (Eo3) and thymic stromal lymphopoietin (TSLP), that mediate allergic inflammation3 has not been reported. These cytokines play an important role in the development of allergic inflammatory states in increasingly prevalent conditions such as allergic rhinitis (AR), food allergy (FA), asthma (AS), atopic dermatitis (AD), and eosinophilic esophagitis (EoE)4. The overall goal of this study was to compare two methods of saliva collection in the detection and analysis of salivary concentrations of IL-4, IL-5, IL-13, Eo3 and TSLP in children. Our study was approved by the Baylor Institutional Review Board and informed consent was obtained from the parent and assent, where appropriate, from the child. We studied 20 children; median age: 14 years (9–17, IQR), female: 14 (64%), Caucasian: 13 (59%). Three (15%) children did not report any allergies and the remaining 17 (85%) children reported one or more of following commonly prevalent allergic conditions: AD (n=1), oral allergy syndrome (n=1), AS (n=2), FA (n=2), AR (n=6) and EoE (n=9). No attempt was made to distinguish salivary cytokine profiles between children with and without allergies in this study. Participants were nil per os for at least 4 hours. They rinsed their mouth with water, and following a 10 min. period, passive drool (PD) was collected followed by saliva collection via an oral swab (OS), in order to minimize the effect of saliva on the flow rate and concentration of cytokines in PD. PD samples were obtained with the head tilted forward while drooling down a 5.5 cm polypropylene Salimetrics Collection Aid® (Salimetrics LLC, State College, PA). Next, the participant placed a Salimetrics Oral Swab® (Salimetrics LLC, State College, PA) in their mouth and gently rolled it side-to-side for approximately 60–90 sec. to saturate the swab, which was then placed in a storage tube that allows saliva to be centrifuged. All samples were collected between 7:30 am and 12:30 pm. Two (9%) participants aged 11 and 14 years were unable to provide PD because they were not able to direct their drool into the collection device. All participants were able to use the OS. After providing paired saliva samples, all children responded to a short questionnaire assessing their knowledge of salivary diagnostics, asking them to rate their experience in providing each saliva sample in terms of perceived ease of use, acceptability and safety. Only 23% were aware of saliva testing in the surveillance of health or disease. A significantly higher proportion of children preferred the OS over PD sampling (82 % vs. 18 %; P < 0.05). Ease (68%) and speed (14%) of providing samples were the most common reasons cited by those who preferred the OS. Saliva samples were maintained at 4°C and transport ed to the laboratory within 2 hr of collection and were centrifuged at 3,000 rpm for 15 minutes. Supernatants were stored in aliquots and frozen at −80°C. On the day of anal ysis, samples were brought to room temperature, vortexed, and centrifuged for 15 minutes at 3,000 rpm. A magnetic, high sensitivity human multi-analytes profiling bead-based assay kit was used (EMD Millipore, Billerica, MA; lower limit of detection (LLD) for IL-4, IL-5, and IL-13: 0.13 pg/mL, and coefficient of variation (CV) < 10%, <6% and <8% respectively; Eo3 and TSLP: LLD: 3.2 pg/mL, and CV < 9% and <12% respectively). All cytokines were measured on 96-well plates (50 µL saliva/well). The standards and controls were plated on every run using a saliva based sample matrix. Plates were read on the Luminex® 200™ platform (Luminex, Austin, TX) according to the manufacturer’s recommendations. Intraassay precision was performed using 10 samples in duplicates and CV was calculated. IL-4, -5 and -13 were detected in all PD and OS samples. Eo3 and TSLP were undetectable in 3 (17%) PD samples but were detectable in all OS samples. The Wilcoxon-rank sum test revealed that the median concentrations were similar between PD and OS samples (Table); however greater precision was noted in OS compared to PD concentrations. Bland-Altman analysis5 showed no systematic bias and revealed insufficient agreement between PD and OS, suggesting that PD and OS may not be used interchangeably. Table Salivary concentrations (pg/mL) cytokines associated with allergic inflammation in passive drool (PD) and saliva collected in oral swab (OS). To our knowledge, this is the first study to describe the presence of cytokines related to allergic inflammation in saliva in a pediatric population. Our results suggest that OS provides more precise concentrations and is more acceptable than PD for detection and analysis of cytokines related to allergic inflammation. Furthermore, our data suggest that PD and OS may not be used interchangeably. Our data extend previous findings showing that saliva collection method can affect the salivary concentrations of stress and non-allergic inflammatory markers 6–9. Strengths to our study included the ability to minimize the effects of external factors such as tooth brushing and recent meals by collecting saliva samples from children who were nil per os for an acceptable period of time prior to providing saliva samples. We were successful in collecting saliva samples (both PD and OS) from children as young as 6 years of age. Limitations to our study include our use of a small convenience sample. In addition, our focus was on cytokines relevant to allergic inflammation. It is possible that either PD or OS may be acceptable for other biomarkers. Presence of eosinophils, eosinophil degranulation products, and/or epithelial cells and their influence on the concentrations of specific cytokines in PD or OS remains unclear. In summary, in pediatric population, saliva collected by OS appears to offer methodological advantages over PD in analyzing cytokines related to allergic inflammation. Adequately designed studies to evaluate the potential of salivary cytokines as non-invasive, point of care markers to diagnose and/or manage common allergic conditions affecting children are warranted.

Management of thoracic aortic graft infections with the omental flap.

BackgroundInfection of thoracic aortic grafts occurs infrequently; however, once present, it is associated with high patient morbidity and mortality. We report our successful experience in the treatment of 11 patients who developed infection of their thoracic aortic graft. MethodsThis is an institutional review board–approved retrospective review of 11 patients who had documented thoracic aortic graft infections with associated mediastinitis or empyema. After diagnosis, plastic surgery consultation was obtained, and the patients underwent formal operative debridement with cardiovascular service. Intraoperative cultures were obtained, and the patients were placed on specific antibiotic regimens. After the wound bed was adequately prepared, the omentum was harvested and was based on the right gastroepiploic vessels. The flap was circumferentially wrapped around the aortic graft and simultaneously used to fill the mediastinal dead space. In a certain subset of patients, a cryopreserved homograft replaced the synthetic graft before omental flap reconstruction. ResultsThe infections were eventually controlled in all surviving patients. Ten of 11 patients were discharged either to a rehab or to a nursing facility. There was 1 perioperative death secondary to multisystem organ failure. Mean follow-up period was 36 months and revealed a greater than 90% survival rate. Serial imaging reported no suture-line complications. ConclusionsWe report our series on the treatment of patients with infection of thoracic aortic grafts. Debridement and tissue coverage with an omental flap provided these patients with successful recovery and survival.

Assessing the safety and efficacy of combined abdominoplasty and gynecologic surgery.

Background:Combined surgery is an attractive option for both patients and surgeons. Unfortunately, it remains unclear to patients whether plastic surgery can be combined safely and efficaciously with other surgeries, particularly gynecologic surgery. The goal of this study was to determine the safety and efficacy of combined abdominoplasty and gynecologic surgery. Methods:A case-control study of 25 patients undergoing combined abdominoplasty and intra-abdominal gynecologic surgery was performed. These combined patients were compared with control group patients undergoing abdominoplasty alone and gynecologic surgery alone. Demographic data, operative time, estimated blood loss, pre- and postoperative hemoglobin, length of hospitalization, and complications were compared between combined and control groups. Results:Statistically significant reductions were seen in operative time, estimated blood loss, and total days of hospitalization when comparing the combined group to the sum of the control groups. In this study, no major complications, including the need for blood transfusion or pulmonary embolus, were noted in any of the patients. Conclusions:These results demonstrate success in performing abdominoplasty with gynecologic surgery, which may be an acceptable option for patients.

Bacitracin: Substantiation and Elimination of Contaminating Proteolytic Activity and Use as an Affinity Chromatography Ligand to Purify a Siderophore-Degrading Enzyme

Bacitracin is a commercial general peptidase inhibitor that may be used to purify proteases. Significant protease contamination of a commercial bacitracin preparation was noted and four procedures were developed to overcome the contamination. Dialysis, gel-filtration chromatography, molecular weight cutoff filters, and heat inactivation were effective, resulting in the diminution or elimination of proteolysis while maintaining the inhibitory effect of bacitracin. Attachment of bacitracin to an affinity chromatography resin did not immobilize a siderophore-degrading enzyme, as has been noted with peptidases. It did, however, result in its partial purification from some of the contaminating proteins originally present.

Impact of body mass index and gender on wound complications after lower extremity arterial surgery

Objective: Wound complications (WCs) after lower extremity arterial surgery (LEAS) are common, resulting in readmissions and reinterventions. Whereas diabetes and obesity are known risk factors for WCs, gender‐specific variability in body fat distribution (android vs gynoid) may drive differential risks of WCs after LEAS. We analyzed the independent and synergistic effects of gender and body mass index (BMI) on WCs. Methods: We performed a retrospective review of prospectively collected data from a published, randomized, multicenter trial assessing the incidence of WCs (dehiscence, surgical site infections, seroma, and hematoma) after LEAS. Postoperative outcomes were compared between genders. A multivariable regression model assessed the impact of gender and BMI on WCs. Subanalysis focused on the synergy of gender and body habitus, groin‐only incisions, and clinical outcomes. Results: There were 502 patients who underwent LEAS between October 2010 and September 2013. The cohort was elderly (67.6 ± 10.5 years), mostly male (72%), and overweight (BMI, 27.6 ± 5.7); 225 (45%) patients had a groin‐only incision. In 171 patients (37.9%), a WC developed within 30 days, 85% of which were infectious in etiology. On multivariable regression, obesity (odds ratio [OR], 2.10; 95% confidence interval [CI], 1.17‐3.77), morbid obesity (OR, 2.87; 95% CI, 1.32‐6.23), and female gender (OR, 1.17; 95% CI, 1.06‐2.75) were independent predictors of infectious WCs at 30 days. When stratified by groin‐only incision, BMI was no longer significant, but female gender (OR, 2.70; 95% CI, 1.24‐5.87) was predictive of infectious WCs at 30 days. There was no synergistic effect of BMI and gender on WCs. Conclusions: WCs are common after LEAS. BMI is an independent risk factor for the development of any WC. Female gender, a potential surrogate for high hip to waist ratio body habitus, is also an independent predictor of groin WCs, suggesting the clinical importance of gynoid vs android fat distribution.