Multi-perspective ultrasound evaluation of Carotid Intima-Media thickness in hemodialysis access patients and its possible use to predict clinical outcomes.

BACKGROUND: Hemodialysis (HD) patients present an increased carotid intima-media thickness (CIMT) and calcified plaques, and studies have demonstrated that CIMT is predictor for cardiovascular death in this patient population; hence, the importance of identifying early non-invasive markers of atherosclerosis. We aim to propose a new three-perspective CIMT measuring method in HD population, and to further investigate the possible use and value of this method to predict outcomes. METHODS: A cross-sectional study was conducted, the CIMT was measured with duplex ultrasound during the perioperative access planning. Software provided maximum CIMT in a 10 mm (mm) width of the common carotid artery. CIMT was measured in Right (R) and Left (L) carotid arteries, both in anterior (a), lateral (l), and posterior (p) view. The sum of these values (Ra+Rl+Rp+La+Ll+Lp) was completed and termed as Sixth Carotid Intimal (SCI) score. We stratified either in low (summation <4) or high (>=4) SCI score groups. Demographics, patency rates, complications, and mortality were collected; chi-square test was used for our analysis. RESULTS: A total of 30 patients (mean age 49 years and 56% females) that underwent access creation in the upper arm from 2010 to 2016 were selected and studied. A low SCI score was found 19 patients and 11 had high SCI, no significant difference was observed in demographics, history cardiovascular disease, and clinical outcomes as early thrombosis, and primary, primary-assisted patency at 12 months. Interestingly, during the follow up period of 36 months a significant higher difference in late thrombosis rates occurred (63.6% vs 26.3%, p = .044) and a higher all-cause mortality (54.4% vs 15.7%, p = .025) in patients with SCI score group above 4. CONCLUSIONS: The SCI score method, might offer a screening tool for traditional cardiovascular risk factors in HD patients. In this study, we demonstrate an increased rate in late thrombosis and mortality in those with high SCI. Further research is necessary to better define the role of CIMT in vascular surgical procedures.

Review of surgical treatment of iatrogenic iliofemoral artery injury in the pediatric population after catheterization.

Trauma is the leading cause of death in the pediatric population. Although vascular trauma has an incidence of 6% in civilian population, iatrogenic injuries are the leading cause, and the most frequent injured vessel is the iliofemoral sector. However, little information is available and there are no guidelines about its treatment. Therefore, this review aimed to describe the information available concerning pediatric iatrogenic arterial trauma, focusing on the iliofemoral segment and present 3 cases. We described 11 articles with 171 patients, of whom 61% underwent surgery to treat iatrogenic trauma. Mean age was 3.28 years (standard deviation of 3.5 years), and 54% were female. Most iliofemoral injuries occurred after arterial catheterization for hemodynamic monitorization and therapeutic or diagnostic cardiac catheterization (due to congenital heart diseases, including septal defects, tetralogy of Fallot, aortic coarctation, and patent ductus arteriosus). For acute complications, arterial thrombosis was the leading injury, followed by pseudoaneurysm, hematoma, dissection, transection, avulsion, eversion, and combined lesions.

Efforts for detection of aortic aneurysms and human resources training for the optimization of their treatment.

OBJECTIVE: To review admissions, interventions and in-hospital mortality associated to Abdominal Aortic Aneurysms (AAA), and to analyze the impact of the introduction of a training program and imaging screening at our institution. METHODS: Retrospective study where hospitalizations, procedures and mortality secondary to AAA were recorded. The national databases (ND) from the Secretariat of Health were utilized from 2010 to 2020. In-hospital lethality was calculated and compared with the experience at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ). The statistical analysis was completed with the STATA version 17. RESULTS: According to the ND, 899 (91%) hospital admissions secondary to AAA occurred, while in the INCMNSZ 85 (9%). Most of them belonged to the male gender (68%); 811 (82%) patients underwent open surgical repair, and 173 (18%) to an endovascular exclusion (EVAR), the latter approach was significantly more frequently performed at our institution (p = 0.007). The 30-day hospital mortality was 22.5%; in the ND was 23.9 vs. a 16.4% in the INCMNSZ without significant difference (p = 0.1). CONCLUSIONS: AAA remain unrecognized in our country. The introduction of University programs and imaging screening might impact in the early detection, and to reduce the morbidity and mortality associated to emergency procedures.

OBJETIVO: Revisar los ingresos, procedimientos y defunciones intrahospitalarias asociadas a aneurismas aórticos abdominales (AAA) y analizar el impacto de la introducción de programas de formación de recursos humanos y tamizaje ultrasonográfico. MÉTODOS: Estudio retrospectivo, se analizaron las bases de datos nacionales obtenidas del portal datos abiertos de la Dirección General de Información en Salud (DGIS) del año 2010 al 2020. Se calculó la letalidad intrahospitalaria anual y comparamos la experiencia del Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ). El análisis estadístico se realizó en el programa STATA versión 17. RESULTADOS: De acuerdo con la base nacional (BN), se registraron 899 (91%) ingresos, mientras que en el INCMNSZ 85 (9%). La mayoría pertenecía al sexo masculino (68%), un total de 811 (82%) pacientes fueron sometidos a cirugía abierta, mientras que 173 (18%) a terapia endovascular (EVAR), siendo este abordaje más frecuente en nuestra institución (p = 0.007). La mortalidad intrahospitalaria fue del 22.5%, en la BN fue del 23.9%, mientras que en el INCMNSZ fue del 16.4%, sin que encontráramos diferencia significativa (p = 0.1). CONCLUSIONES: Los AAA continúan siendo poco reconocidos en nuestro país. La introducción de programas universitarios de especialidad y el tamizaje podría impactar en la reducción de la morbimortalidad.

Congenital pelvic kidney perfusion during infrarenal aortic aneurysm repair.

Purpose: This case report describes a patient with a pelvic kidney associated with an aortoiliac aneurysm amenable to open repair. Methods: We chose the selective cold renal perfusion to preserve renal function. Results: Other techniques such as transient or permanent extra-anatomic bypass, extracorporeal circulation and proximal aortic double clamping are also described in this report. Conclusions: Choosing the renal perfusion technique depended on the anatomical evaluations of the kidney and the renal artery location during the preoperative period.

The effect of cilostazol on the platelet-derived growth factor-beta/beta isoform reduction on venous hyperplasia in an experimental balloon-induced injury model.

BACKGROUND: Intimal hyperplasia is the response to endothelial injury. Platelet-derived growth factor is released early and favors the formation of intimal hyperplasia. Although multiple treatments, from open surgery to endovascular techniques, have been used they remain controversial. There is currently interest in developing pharmacological strategies to address this pathology. Local vascular inflammation induced by vessel barotrauma generates intimal hyperplasia due to mechanical stress over the venous endothelium. Cilostazol is a selective phosphodiesterase type 3 (PDE3) selective inhibitor with a regulatory effect over intimal hyperplasia. The objective was to investigate cilostazol's role in inhibiting smooth muscle cell proliferation due to changes in the expression and release of PDGF-BB isoform and the effect on developing IH using an experimental model of vascular barotrauma (balloon-induced injury model). METHODS: We included 12 New Zealand rabbits. The balloon-induced injury model (BIIM) and experimental group cilostazol (20 mg/kg/day) included 6 rabbits each. Contralateral veins from 6 rabbits used in BIIM model has been taken as control group. We measured and compared the expression of PDGF-BB and the development of IH. A pathologist board chooses a PDGFRα antibody to localized its expression by immunohistochemistry analysis. Subsequently, using an automated immunohistochemical staining machine, the PDGFR expression was evaluated using a Zeiss Primo Star 4 light microscope. RESULTS: The measurement obtained in the intimal layer was: 126.12 µm2 in the CG, 232 µm2 in the BIIM group, and 178 µm2 in the EG. A statistically significant difference was observed. Baseline serum concentrations of PDGF-BB in the BIIM group were 0.22 pg/mL. At 12 h 0.42 pg/mL, and 0.17 pg/mL at seven days. In the experimental group, the basal levels were 0.33 pg/mL. With the use of cilostazol, a lower peak was obtained at 12 h (0.08 pg/mL). This difference was statistically significant. CONCLUSIONS: Cilostazol induced a significant reduction of IH caused by barotrauma in the venous endothelium, which correlates with decrease in the PDGF-BB in serum. This could be attributed to the pharmacologic effect on PDGFR expression.

Revascularization prevents amputation among patients with diabetic foot during the COVID-19 era.

OBJECTIVE: The COVID-19 pandemic has led to significant changes in healthcare systems that impact the management of chronic diseases such as diabetic foot (DF). We hypothesized that lack of access to healthcare would increase the severity of disease and lead to worse outcomes. METHODS: The medical records of patients with DF were reviewed to determine demographic data and outcomes including wound healing, major amputation (MA), and death. Groups were divided into the pre-COVID-19 era (15 March 2019-15 March 2020) and the COVID-19 era (16 March 2020-16 March 2021); multivariable logistic analysis was performed to identify risk factors for MA. RESULTS: 261 patients with DF were included, 163 in the pre-COVID-19 era and 98 during the COVID-19 era. Patients in the COVID-19 presented with increased cardiovascular disease (19 vs 7%, p = 0.01), increased mean HbA1C (9.1 ± 2.1 vs 8.2 ± 2.1, p = 0.008) and higher WIFI-IV stage (78 vs 53%, p ≤ 0.0001). Patients with DF in the COVID-19 era were more likely to require MA (41 vs 21%, p ≤ 0.0001). Revascularization (OR = 0.12; 95% CI, 0.038-0.38) was a protective factor to reduce MA. CONCLUSIONS: MA among DF patients increased two-fold during the COVID-19 era. Revascularization avoids MA in diabetic patients even during the COVID-19 pandemic, suggesting that revascularization should be performed when possible.

Acute Venous Disease Anomalies in Critically Ill COVID-19 Patients.

INTRODUCTION: Other entities besides deep vein thrombosis (DVT) affecting the venous system, such as superficial vein phlebitis (SVP) and superficial vein thrombophlebitis (SVT), receive poor attention in the literature. However, both entities may propagate proximally into the deep venous system and progress to a DVT. To our knowledge, the relevance of other venous findings such as SVP or SVT in coronavirus disease 2019 (COVID-19) patients has not been evaluated. This work aimed to assess the clinical, biochemical, and hematological variables associated with the incidence of acute venous diseases, such as DVT, SVP, and SVT, in a cohort of 74 critically ill COVID-19 patients and their association with mortality. METHODS: Given the high thrombotic risk, all patients underwent venous imaging with bedside ultrasound. Clinical variables were obtained from medical records. Comparisons were made by the chi-square test or Fisher's exact test. We constructed Kaplan-Meier curves and used Cox proportional hazard models to calculate hazard ratios for dichotomized risk factors to identify predictors of mortality. SPSS version 21.0 (IBM Corp., Armonk, NY) was used for statistical analysis. RESULTS:  SVP occurred in 28 patients (37.8%), DVT in 22 patients (29.7%), and 28 patients died (37.8%). Elevated D-dimer was associated with DVT but not with SVP. Neither SVP nor DVT was associated with mortality. After adjusting for age, elevated troponins (OR: 2.4, 95% CI: 1.1-5.4), platelets < 244 cell/mm3 (2.4, 1.1-5.6), and IMPROVE (International Medical Prevention Registry on Venous Thromboembolism) bleeding score > 7 (2.8, 1.3-6.3) were predictors of mortality. CONCLUSIONS: Acute venous findings such as SVP and DVT are highly prevalent and independent of mortality in critically ill COVID-19 patients. These entities are not related, although they may occur synchronically. DVT is frequently presented as an asymptomatic distal bilateral finding associated with elevated D-dimer, decreased ferritin, and higher vasoactive drug use but independent from chronic venous disease. Interestingly, elevated troponins, decreased platelets, and a prognostic value > 7 of the IMPROVE bleeding score were predictors of mortality in this group of critically ill COVID-19 patients.

Prevalence of abdominal aortic aneurysms in four different metropolitan areas in Mexico.

OBJECTIVE: Epidemiological data on aneurysmal disease affecting the abdominal aorta in Latin American countries are limited. In our institution, the National Institute of Medical Sciences and Nutrition Salvador Zubiran (INCMNSZ), we have reported an Abdominal Aortic Aneurysm (AAA) prevalence of 3.26% in patients at risk from our Ultrasound (US) screening program. We aim to determine and compare the prevalence of undetected AAA in four different Metropolitan areas in Mexico to justify further US screening efforts. METHODS: A cross-sectional multicenter study was conducted in 9 different academic institutions. Abdominal Computed Tomographies (CT) from patients with age equal or greater than 55 years in our center (INCMNSZ), and in 65 year old patients and older in the remainder institutions were systematically reviewed. Abdominal aortic diameters were measured at the level of the superior (SMA) and inferior mesenteric arteries (IMA) in nonaneurysmal aortas and maximum diameters in the found AAA. Categorical data were analyzed by nonparametric statistic test at significance level (P < 0.05), the Pearson test was used to determine the correlation of age and aortic diameters. RESULTS: The cohort included a total of 12, 936 patients paired with respect gender (53% females, with a mean age of 69 years), the AAA prevalence found in the studied Mexican population was 3.08% (399 AAA patients). In centers where more than 200 CTs scans were reviewed, the prevalence was 4.03%, compared to the 4.63% found in centers with less than 200 studies (P = 0.41). In patients between the ages of 55 to 64 from INCMNSZ (3889 total), the prevalence was 0.77%, supporting the need of focused US-screening programs in individuals at the age of 65 and older in our country. CONCLUSIONS: The introduction of a national US Screening Program for the detection of AAA in Mexico represents a challenge in our current health system. This Multicenter initiative demonstrates that our AAA prevalence is not different to other international reports; imaging screening might represent cost-effective strategy for reduction of aneurysm-related mortality.

Systemic lupus erythematosus diagnosis impacts clinical outcomes of arteriovenous fistulas in comparison to other end-stage renal disease etiologies.

OBJECTIVES: Arteriovenous fistulas primary patency at one-year occurs in 43-85% of the patients with end-stage renal disease. The diagnosis attributable to end-stage renal disease has been suggested to impact arteriovenous fistulas outcomes. The objective was to compare primary patency at one week, 1, 3, 6, and 12 months of follow-ups, among systemic lupus erythematosus patients and two control groups; additionally, we evaluated the impact of systemic lupus erythematosus to predict early patency loss. METHODS: A retrospective review of charts from arteriovenous fistulas created between 2008 and 2017 was performed. One-hundred thirty-four patients were identified and classified according to end-stage renal disease attributable diagnosis as: systemic lupus erythematosus cases (N = 14), control-group-1 (91 patients with primarily diabetes and hypertension), and control-group-2 (29 patients with idiopathic end-stage renal disease). A case-control matched design (1:2:1) was proposed. Logistic regression analysis and Kaplan-Meier curves were used. Institutional Review Board approval was obtained. RESULTS: More systemic lupus erythematosus patients lost primary patency at 3 (28.6%) and 12 months (71.4%) than patients from control-groups-1 (vs. 3.6% and 35.7%, respectively) and -2 (vs. 0% and 14.3%, respectively), (p ≤ 0.011 for both). Days of primary patency survival were shorter in systemic lupus erythematosus patients (p = 0.003). Systemic lupus erythematosus diagnosis was the only factor associated with early patency loss, HR: 3.141, 95%CI: 1.161-8.493 (systemic lupus erythematosus diagnosis vs. control-group-1) and HR: 12.582, 95%CI: 1.582-100.035 (systemic lupus erythematosus diagnosis vs. control-group-2). CONCLUSIONS: Diagnosis attributable to end-stage renal disease has a major impact on arteriovenous fistula outcomes in patients. Systemic lupus erythematosus patients have an increased risk of arteriovenous fistulas patency loss within the first six months of follow-up. Patients with idiopathic end-stage renal disease had an excellent one year arteriovenous fistula patency survival.

Cilostazol as a noninferiority pharmacologic option to paclitaxel in early intimal hyperplasia inhibition after venous balloon angioplasty in a rabbit model: a preliminary study.

The development of venous intimal hyperplasia (VIH) has not been fully studied. At present, there are no drugs approved for VIH inhibition; to investigate such alternatives, we aimed to compare paclitaxel with cilostazol in VIH early inhibition in a preliminary experimental model of balloon angioplasty. Twenty-eight male New Zealand rabbits were randomly divided into two groups: cilostazol (A) and paclitaxel (B), which underwent femoral vein barotrauma by a 4 mm balloon angioplasty. The VIH model was previously tested in controls obtaining an 80% increase of subintimal area (SIA) compared with veins without injury (from 0.12 mm2 [standard deviation (SD), 0.05] to 0.86 mm2 [SD, 0.08]). Group A received 20 mg/kg twice daily; group B angioplasty was performed with a single-dose paclitaxel-coated balloon. Seven days later rabbits were euthanized, and vein tissue samples were taken for histological analysis. The primary end point was SIA measure expressed in mm2, and the anticipated difference between treatments was 0.21 mm2. Other measurements were immunohistochemistry expression of hypoxia inducible factor-1 alpha, platelet derived growth factor, and smooth muscle actin, as surrogates of cell migration and oxidative stress. SIA of group A was 0.33 mm2 (SD, 0.15; 95% CI, 0.24-0.42 mm2), and that of group B was 0.31 mm2 (SD, 0.14; 95% CI, 0.22-0.40 mm2). Both drugs showed a reduction of 61% and 63%, respectively, in SIA, compared with controls. The difference between both drugs was 0.0193 mm2 (95% CI, -0.1175 to 0.156 mm2); the statistical difference was found in hypoxia inducible factor-1 alpha expression between both groups. CLINICAL RELEVANCE: Although veins have a thinner middle layer compared with arteries, smooth muscle cells appear to play an important role in venous stenosis after angioplasty. The study of smooth muscle cell response after barotrauma may have clinical applications in the endovascular treatment of venous stenosis, because at the moment, there is no medication indicated to prolong patency after venous endovascular procedures, for example in May Thurner syndrome. Paclitaxel and cilostazol seem to have a promising role. Finally, the present study could inspire a research line to reduce stent placement and increase patency after venous angioplasty.

Investigation of an Immunogenetic Profile in Patients with Abdominal Aortic Aneurysms and Possible Applications in Screening and Surveillance.

BACKGROUND: The pathogenesis of atherosclerotic abdominal aortic aneurysms (AAAs) remains not fully understood. Histological analyses confirm chronic adventitial and medial inflammatory cell infiltration, and its pathophysiology involves the upregulation of proteolytic pathways; added to this, genetic factors have been suggested to favor the susceptibility for AAA. The aim of the present study was to analyze the association between genetic polymorphism of the class II human leukocyte antigens (HLAs, HLA-DRB1) with the susceptibility to develop AAA in Mexican patients and to initiate a pilot study of single-nucleotide polymorphisms (SNPs) rs1024611 in the monocyte chemoattractant protein-1 (MCP-1/CCL2) gene to investigate a possible role in the AAA pathogenesis. METHODS: In a cohort of patients with AAA, HLA molecular typing was completed for DRB1 loci with LABType SSO-One Lambda kit in 39 patients (69% men with a mean age of 72 years) and compared with 99 without the disease (60% men, mean age 65 years) (control group). Genotyping of rs1024611 in the MCP-1 gene was performed using TaqMan predesigned SNP genotyping assays in 27 patients with AAA (63% men, mean age of 71). Gene frequencies (gfs) and genotype frequencies (Gfs) were determined; categorical data were analyzed by nonparametric statistic test at significance level (P < 0.05), and odds ratios (ORs) were calculated using the STATA v14 software and StatCalc software Epi Info™ 7.2.2.2. RESULTS: Seventy-eight HLA-DRB1 alleles of patients with AAA and 198 from the control group were studied. We observed that the gf of HLA-DRB1*01 was 0.128 in the AAA group compared with 0.05 in the control group (P = 0.03, OR: 2.6, 95% confidence interval [CI]: 1.04-6.5); the gf of HLA-DRB1*16 was 0.115 in the AAA and 0.025 in control group (P = 0.002, OR: 5, 95% CI: 1.6-16.9). The Gf for SNP rs1024611 were 0.51 in the GA genotype, 0.30 in AA, and 0.19 of GG. Four patients with the proinflammatory homozygous genotype GG (80%) were women and younger than patients with other genotypes, and only one had a history of dyslipidemia. CONCLUSIONS: The dissection and interpretation of an immunogenetic profile in patients with AAA is an active and complex field of research that might assist in a more precise identification of those patients at genetic risk. Our study demonstrated increased frequencies of HLA-DRB1*01 and HLA-DRB1*16 alleles in Mexican patients with AAA compared with an ethnically matched control group.

Genetic polymorphism of HLA-DRB1 alleles in Mexican mestizo patients with abdominal aortic aneurysms.

BACKGROUND: Multiple factors are implicated in the etiology and pathogenesis of Abdominal Aortic Aneurysms (AAA). Available literature of genetic studies has previously suggested the possible roles of autoimmunity, genetic predisposition and ethnic susceptibility. Due to the association with autoimmune diseases and proven application in population genetics, we aimed to investigate alleles of the Class II Human Leukocyte Antigens (HLA-DRB1) in the Mexican Mestizo population with aortic aneurysms and determine possible associations with susceptibility. METHODS: We performed a case Control Study; the HLA molecular typing was completed for DRB1 loci by LabType Sequence-Specific Oligonucleotide (SSO) SSO-OneLambda kit (Applied Biosystems; Thermo Fisher Scientific. Inc.) in the studied individuals. Allele frequencies (af) were determined, associations were assessed by chi square or fisher exact tests at significance level (< 0.05), and Odds Ratios (OR) were calculated using the STATA software version 14. RESULTS: The genetic polymorphism of HLA-DRB1 of fifty one patients (70% males with a mean age of 71 years) with atherosclerotic or also known as degenerative AAA were compared with 99 unrelated patients (60% males, mean age 65 years) without the disease [Control group (CG)] from the same ethnic group. We examined a total of 102 Class II HLA-DRB1 alleles of AAA patients and 198 from CG. When comparing af, we observed the HLA-DRB1*01 af of 0.139 in the AAA compared to 0.05 in the CG [p = 0.015, OR 3, 95% confidence interval (CI) 1.29-7.08], the HLA-DRB1*16 af were 0.109 in the AAA and 0.025 in CG (p = 0.006, OR 4.7, 95% CI 1.59-13.98). CONCLUSIONS: Our study confirmed increased frequencies of the alleles HLA-DRB1*01 and HLA-DRB1*16 and their association to the development of AAA in Mexican Mestizo patients. The utility of genetic testing may assist in identifying individuals at genetic risk for the development of this disease in different ethnic groups, who might benefit from earlier ultrasound screening and closer imaging surveillance.

Factors that impact kidney function during open and endovascular reconstruction of aortic aneurysms.

BACKGROUND: To analyze the factors that influence the deterioration of postoperative renal function in patients undergoing open or endovascular aortic reconstruction, and the impact on survival. METHOD: Retrospective review of patients who underwent invasive treatment was conducted. Demographics, laboratory data, clinical, intraoperative and postoperative variables were recorded; renal function was determined, Fisher's exact test was used to find associations and Kaplan Meier analysis to estimate survival. RESULTS: From 2007 to 2017, 80 patients (mean age: 70 years) were studied. Fifty-eight (73%) were male, none of these patients had known diagnosis of chronic kidney insufficiency. Twelve (15%) patients had elevated creatinine in the postoperative period; variables such as intraoperative bleeding greater than 1500 ml were associated with acute renal failure (p = 0.005). During the follow-up period of 60 months, 8 (10%) patients progressed to chronic renal failure, 2 (2.5%) requiring hemodialysis, 18 (22%). Age, gender, comorbidities and anatomic characteristics of the aneurysm, type of intervention or level of aortic cross-clamping did not impact the postoperative renal function. CONCLUSIONS: The repair of complex aortic aneurysms continues to be a challenge. Intraoperative bleeding greater than 1500 ml and the need of blood transfusion was associated with deterioration of postoperative renal function, affecting the 5-year survival of patients.

OBJETIVO: Analizar qué factores influyen en el deterioro de la función renal en pacientes sometidos a reconstrucción aórtica abierta o endovascular, y su impacto en la supervivencia. MÉTODO: Estudio retrospectivo. Se analizaron variables demográficas, de laboratorio, transoperatorias y posoperatorias. Se determinó la función renal y se utilizó la prueba exacta de Fisher en la búsqueda de asociaciones, y el análisis de Kaplan-Meier para estimar la supervivencia. RESULTADOS: De 2007 a 2017, 80 pacientes (media de edad: 70 años) fueron sometidos a procedimientos de reconstrucción aórtica. Cincuenta y ocho (73%) eran de sexo masculino. Doce (15%) tuvieron elevación de creatinina en el posoperatorio y sangrado mayor de 1500 ml con necesidad de transfusión que se asoció a insuficiencia renal aguda (p = 0.005). Durante el periodo de seguimiento de 60 meses, 8 (10%) pacientes desarrollaron insuficiencia renal crónica, 2 (2.5%) requirieron hemodiálisis y 18 (22%) fallecieron. La edad, el sexo, la comorbilidad y las características anatómicas del aneurisma, así como el tipo de intervención o el nivel de pinzamiento aórtico, no impactaron la función renal posoperatoria. CONCLUSIONES: La reparación de los aneurismas aórticos complejos continúa siendo un reto. Un sangrado superior a 1500 ml, con necesidad de transfusión, se asoció a deterioro de la función renal posoperatoria e impactó en la supervivencia a 5 años.

Usefulness of preoperative three-dimensional volumetric analysis of carotid body tumors.

PURPOSE: The Shamblin classification is the commonest method to predict complications and outcomes during carotid body tumor (CBT) resection. The aim of this study is to describe the utility of the three-dimensional volumetric reconstruction (3DVR) analysis of the CBT and its relationship with postoperative outcomes. METHODS: Preoperative computed tomography angiography (CTA) was obtained to perform 3DVR of the CBT. Imaging data were analyzed and correlated with surgical outcomes: estimated blood loss (EBL), surgical time (ST), and hospital length of stay (HLOS). The Pearson test was used to determine the correlation between volume and postoperative outcomes. RESULTS: Fifty-seven patients were studied, 13 had Shamblin type I tumors with a mean 3DVR of 7.69 cm3 (standard deviation [SD 8.27]), 21 were type II with a mean 3DVR of 15.57 cm3 (SD 8.40), and 23 were type III with a mean 3DVR of 30.58 cm3 (SD 20.16). EBL mean was 559 milliliters (mL) (standard error [SE] 80.44), the mean ST of resection was 202 min (SD 67), and the mean HLOS was 5.8 days (SD 3.23). The Pearson test showed a correlation of r = 0.69 (p < 0.0001) between 3DVR and EBL, a r = 0.4 (p = 0.05) was obtained between 3DVR and ST, and finally, a r = 0.3 (p = 0.05) between 3DVR and HLOS was obtained. CONCLUSION: The preoperative 3DVR determination of CBTs allows to analyze possible predictors of surgical outcomes. We found a positive correlation between the 3DVR volume and EBL. Further research is necessary to validate this method in the evaluation of these rare neoplasms.

Interactive Effects of Black-Tailed Prairie Dogs and Cattle on Shrub Encroachment in a Desert Grassland Ecosystem.

The widespread encroachment of woody plants throughout the semi-arid grasslands in North America has largely resulted from overgrazing by domestic livestock, fire suppression, and loss of native large and small mammalian herbivores. Burrowing-herbivorous mammals, such as prairie dogs (Cynomys spp.), help control shrub encroachment through clipping of shrubs and consumption of their seedlings, but little is known about how this important ecological role interacts with and may be influenced by co-existing large herbivores, especially domestic livestock. Here, we established a long-term manipulative experiment using a 2 × 2 factorial design to assess the independent and interactive effects of black-tailed prairie dogs (Cynomys ludovicianus) and cattle (Bos taurus) on honey mesquite (Prosopis glandulosa) abundance and structure. We found that, after five years, mesquite abundance was three to five times greater in plots where prairie dogs were removed compared to plots where they occurred together or alone, respectively. While both prairie dogs and cattle reduced mesquite cover, the effect of prairie dogs on reducing mesquite abundance, cover, and height was significantly greater than that by cattle. Surprisingly, cattle grazing enhanced prairie dog abundance, which, in turn, magnified the effects of prairie dogs on mesquite shrubs. Mesquite canopy cover per hectare was three to five times greater where prairie dogs and cattle were absent compared to where they occurred together or by themselves; whereas, cumulative mesquite height was two times lower on sites where prairie dog and cattle occurred together compared to where they occurred alone or where neither occurred. Data from our experimental study demonstrate that prairie dogs and moderate grazing by cattle can suppress mesquite growth, and, when their populations are properly managed, they may interact synergistically to significantly limit mesquite encroachment in desert grasslands.

Black-tailed prairie dogs, cattle, and the conservation of North America's arid grasslands.

Prairie dogs (Cynomys spp.) have been eliminated from over 95% of their historic range in large part from direct eradication campaigns to reduce their purported competition with cattle for forage. Despite the longstanding importance of this issue to grassland management and conservation, the ecological interactions between cattle and prairie dogs have not been well examined. We address this issue through two complementary experiments to determine if cattle and prairie dogs form a mutualistic grazing association similar to that between prairie dogs and American bison. Our experimental results show that cattle preferentially graze along prairie dog colony edges and use their colony centers for resting, resembling the mutualistic relationship prairie dogs have with American bison. Our results also show that prairie dog colonies are not only an important component of the grassland mosaic for maintaining biodiversity, but also provide benefits to cattle, thereby challenging the long-standing view of prairie dogs as an undesirable pest species in grasslands.

Successful treatment of flail chest with chondrosternal disruption and traumatic parasternal lung hernia with titanium rib bridges.

The surgical principles for the treatment of flail chest have yet to be fully established. Furthermore, the relationship between flail chest and lung hernias is unclear. We report here a rare case of chondrosternal traumatic disruption and lung hernia that was treated with a novel technique using titanium rib bridges and clips, which successfully reduced the hernia defect and provided stability to the chest wall. This procedure was beneficial in minimising the patient's ventilation time and time away from work.

Irving Lichtenstein, maestro de la cirugía inguinal: semblanza de su vida y obra / Irving Lichtenstein, master of inguinal surgery: a profile of his life and work

El Dr. Irving Lichtenstein fue un reconocido cirujano de origen estadounidense que a lo largo de su vida desarrolló diferentes estudios enfocados a la patología inguinal; describió una de las técnicas de reparación con material protésico más utilizadas en todo el mundo. La reparación inguinal libre de tensión, descrita por Lichtenstein, presentaba además un porcentaje más bajo de recidivas, menor estancia hospitalaria, reducción de riesgos anestésicos, reincorporación temprana a la vida laboral y menores costos. El Maestro Lichtenstein no sólo describió técnicas quirúrgicas para hernias inguinales en su variante directa o indirecta: aportó conocimientos para el tratamiento de protrusiones femorales, recurrencias, incisionales, semilunares, gigantes y de la pared posterior abdominal (hernias de Grynfeltt y Petit), comparó sus propias técnicas y de manera paulatina formó un selecto ejército de médicos cirujanos seguidores a nivel mundial, que bajo sus preceptos se sienten seguros al reparar un defecto herniario.

Rapid response of a grassland ecosystem to an experimental manipulation of a keystone rodent and domestic livestock.

Megaherbivores and small burrowing mammals commonly coexist and play important functional roles in grassland ecosystems worldwide. The interactive effects of these two functional groups of herbivores in shaping the structure and function of grassland ecosystems are poorly understood. In North America's central grasslands, domestic cattle (Bos taurus) have supplanted bison (Bison bison), and now coexist with prairie dogs (Cynomys spp.), a keystone burrowing rodent. Understanding the ecological relationships between cattle and prairie dogs and their independent and interactive effects is essential to understanding the ecology and important conservation issues affecting North American grassland ecosystems. To address these needs, we established a long-term manipulative experiment that separates the independent and interactive effects of prairie dogs and cattle using a 2 x 2 factorial design. Our study is located in the Janos-Casas Grandes region of northwestern Chihuahua, Mexico, which supports one of the largest remaining complexes of black-tailed prairie dogs (C. ludovicianus). Two years of posttreatment data show nearly twofold increases in prairie dog abundance on plots grazed by cattle compared to plots without cattle. This positive effect of cattle on prairie dogs resulted in synergistic impacts when they occurred together. Vegetation height was significantly lower on the plots where both species co-occurred compared to where either or both species was absent. The treatments also significantly affected abundance and composition of other grassland animal species, including grasshoppers and banner-tailed kangaroo rats (Dipodomys spectabilis). Our results demonstrate that two different functional groups of herbivorous mammals, burrowing mammals and domestic cattle, have distinctive and synergistic impacts in shaping the structure and function of grassland ecosystems.