Tratamiento del síndrome de robo del acceso vascular mediante interposición yuxtaanastomótica de un segmento protésico / Treatment of vascular access-related steal syndrome by means of juxta-anastomotic vein interposition of a prosthetic graft segment

Objetivos: El síndrome de robo es una complicación grave del acceso vascular. Nuestro objetivo es presentar los resultados iniciales de un tratamiento simple y eficaz: la interposición de un segmento protésico en la vena yuxtaanastomótica. Métodos: Entre 2009 y 2012, 14 pacientes (57 % varones, edad media 71 años) con síndrome de robo severo por un acceso vascular nativo (grados II-IV), y tras un estudio clínico y ecográfico sistemático, y angiográfico selectivo, fueron tratados mediante la interposición de un segmento de prótesis tubular, politetrafluoroetileno (PTFE) de 6 mm de diámetro en la vena yuxtaanastomótica, más reparación selectiva de estenosis arterial mediante parche (2 casos) o ligadura de colaterales venosas no útiles (8 casos). Se utilizó anestesia local o regional y un régimen ambulatorio en todos los casos. Resultados: El éxito técnico fue del 100 %. El estudio ecográfico pre y posoperatorio mostró una reducción del flujo posoperatorio del acceso del 39 % y un aumento del flujo arterial radial del 477 %. Los síntomas isquémicos se resolvieron en 12 pacientes (86 %); los otros dos requirieron procedimientos adicionales por síntomas isquémicos persistentes. Ocurrió una ruptura venosa posoperatoria, que requirió una ligadura definitiva. Ningún caso sufrió amputaciones ni hubo pérdidas ni trombosis del acceso en el seguimiento. Las permeabilidades primaria y primaria asistida libres de nuevos síntomas isquémicos fueron del 78 % y del 78 % a los 12 meses, y del 62 % y del 78 % a los 24 meses. Conclusiones: La interposición de un segmento protésico yuxtaanastomótico es una técnica sencilla, rápida y eficaz en el tratamiento del síndrome de robo vascular, con resultados prometedores a dos años de seguimiento (AU)

Objective: Steal syndrome is a severe complication of vascular access. Our aim is to present the initial results of a simple and effective treatment: the interposition of a prosthetic segment in the juxta-anastomotic vein. Method: Between 2009 and 2012, 14 patients (57 % male, average age 71) with severe steal syndrome due to vascular access (stages II-IV), following a clinical and systematic echographic study and a selective angiographic study, were treated through the interposition of a 6 mm segment of PTFE in the juxta-anastomotic vein, in addition to selective patch repair of arterial stenosis (2 cases) or ligature of useless venous collaterals (8 cases). Local or regional anaesthesia was used and outpatient care was given in all cases. Results: There was 100 % technical success. The pre- and post-operative echographical study showed a reduction of post-operative access flow by 39 % and an increase of radial artery flow by 477 %. Ischaemic symptoms were resolved in 12 patients (86 %); the other two patients required additional procedures due to persistent ischaemic symptoms. There was a post-operative venous rupture, which required a definitive ligation. No patient suffered amputations, nor were there losses or access thrombosis during the follow-up. The primary and primary-assisted patencies free of new ischemic symptoms were 78 % and 78 % at 12 months, and 62 % and 78 % at 24 months. Conclusions: The interposition of a prosthetic segment in the juxta-anastomotic vein is a simple, quick and effective technique in the treatment of vascular steal syndrome, with promising results at the 2 year follow-up (AU)

Treatment of vascular access-related steal syndrome by means of juxta-anastomotic vein interposition of a prosthetic graft segment.

OBJECTIVE: Steal syndrome is a severe complication of vascular access. Our aim is to present the initial results of a simple and effective treatment: the interposition of a prosthetic segment in the juxta-anastomotic vein. METHOD: Between 2009 and 2012, 14 patients (57 % male, average age 71) with severe steal syndrome due to vascular access (stages II-IV), following a clinical and systematic echographic study and a selective angiographic study, were treated through the interposition of a 6 mm segment of PTFE in the juxta-anastomotic vein, in addition to selective patch repair of arterial stenosis (2 cases) or ligature of useless venous collaterals (8 cases). Local or regional anaesthesia was used and outpatient care was given in all cases. RESULTS: There was 100 % technical success. The pre- and post-operative echographical study showed a reduction of post-operative access flow by 39 % and an increase of radial artery flow by 477 %. Ischaemic symptoms were resolved in 12 patients (86 %); the other two patients required additional procedures due to persistent ischaemic symptoms. There was a post-operative venous rupture, which required a definitive ligation. No patient suffered amputations, nor were there losses or access thrombosis during the follow-up. The primary and primary-assisted patencies free of new ischemic symptoms were 78 % and 78 % at 12 months, and 62 % and 78 % at 24 months. CONCLUSIONS: The interposition of a prosthetic segment in the juxta-anastomotic vein is a simple, quick and effective technique in the treatment of vascular steal syndrome, with promising results at the 2 year follow-up.

Endovenous radiofrequency ablation (venefit procedure): impact of different energy rates on great saphenous vein shrinkage.

BACKGROUND: Despite adequate treatment of varicose veins, recurrences and primary failures still occur. This article hypothesizes that increasing the dose of radiofrequency ablation (RFA) could improve efficacy through inducing a greater shrinkage of the treated vein. METHODS: A comparative clinical study of 67 extremities with varicose veins caused by great saphenous vein (GSV) reflux treated with RFA ClosureFAST was conducted. Group 1 (n = 22) received 1 treatment cycle (20 sec) and group 2 (n = 45) received 2 cycles (40 sec) along the GSV trunk. Clinical and duplex follow-up were performed at day 4, and at 1, 3, and 6 months. The main outcomes measured were GSV diameters, occlusion rate, and secondary effects. Statistical analysis was performed using the Student's t test, linear mixed model, Bland-Altman plot, Lin's concordance correlation coefficient, and intraclass correlation coefficient. RESULTS: Both groups were comparable for demographic and specific study variables with a very low intraobserver variability. The immediate occlusion rate was 100% for both groups. Group 2 showed a quicker and greater reduction in medium diameter along the period of the study (P = 0.0074). Beyond the 6-month period of study, 1 partial GSV recanalization in group 1 and 1 complete GSV recanalization in an obese patient in group 2 were detected. No skin burns, paresthesia, or deep vein thromboses appeared. CONCLUSIONS: Two cycles of RFA treatment in all segments of the GSV achieves quicker and greater vein shrinkage of the medium diameter without an increase in side effects. Further studies are needed to evaluate the implications in terms of intermediate and long-term clinical efficacy.

Correlation of serotype-specific dengue virus infection with clinical manifestations.

BACKGROUND: Disease caused by the dengue virus (DENV) is a significant cause of morbidity throughout the world. Although prior research has focused on the association of specific DENV serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) with the development of severe outcomes such as dengue hemorrhagic fever and dengue shock syndrome, relatively little work has correlated other clinical manifestations with a particular DENV serotype. The goal of this study was to estimate and compare the prevalence of non-hemorrhagic clinical manifestations of DENV infection by serotype. METHODOLOGY AND PRINCIPAL FINDINGS: Between the years 2005-2010, individuals with febrile disease from Peru, Bolivia, Ecuador, and Paraguay were enrolled in an outpatient passive surveillance study. Detailed information regarding clinical signs and symptoms, as well as demographic information, was collected. DENV infection was confirmed in patient sera with polyclonal antibodies in a culture-based immunofluorescence assay, and the infecting serotype was determined by serotype-specific monoclonal antibodies. Differences in the prevalence of individual and organ-system manifestations were compared across DENV serotypes. One thousand seven hundred and sixteen individuals were identified as being infected with DENV-1 (39.8%), DENV-2 (4.3%), DENV-3 (41.5%), or DENV-4 (14.4%). When all four DENV serotypes were compared with each other, individuals infected with DENV-3 had a higher prevalence of musculoskeletal and gastrointestinal manifestations, and individuals infected with DENV-4 had a higher prevalence of respiratory and cutaneous manifestations. CONCLUSIONS/SIGNIFICANCE: Specific clinical manifestations, as well as groups of clinical manifestations, are often overrepresented by an individual DENV serotype.

Tratamiento endovascular de las úlceras penetrantes de aorta torácica: seguimiento a medio plazo / Endovascular treatment of penetrating aortic ulcers: mid-term follow-up

Introducción y objetivos. Se presentan los resultados a corto y medio plazo del tratamiento endovascular de las úlceras penetrantes de aorta torácica. Métodos. Entre 1998 y 2010, se trató a 22 pacientes con úlceras penetrantes de aorta torácica mediante endoprótesis (media de edad, 69,8 años; el 91% varones). La indicación se realizó por un síndrome aórtico agudo (el 50%: dolor torácico en 8, rotura en 1, fístula aortobronquial en 1, embolización en 1) o por el diámetro aórtico o de la úlcera (50%). Todos los datos preoperatorios, intraoperatorios y de seguimiento fueron analizados prospectivamente siguiendo el protocolo EUROSTAR. Resultados. El éxito técnico fue del 100%, sin muertes ni conversiones intraoperatorias; 6 casos (27,3%) requirieron revascularización previa de troncos supraaórticos, y se utilizaron 1,3 dispositivos por paciente; el 27,3% tuvo complicaciones intrahospitalarias, y el 9,1% requirió reintervenciones antes del alta. La mortalidad acumulada a 30 días fue del 4,5%. Tras un seguimiento medio de 52,3 (0,1-122) meses, la supervivencia acumulada libre de complicaciones y reintervenciones a 100 meses fueron del 61,7 y el 79,5% respectivamente, con un 95,5% de supervivencia acumulada libre de mortalidad relacionada con la aorta o el procedimiento. No se han identificado factores pronósticos significativos de mala evolución clínica intraoperatoria o postoperatoria. Conclusiones. El tratamiento endovascular de las úlceras penetrantes de la aorta torácica es posible y eficaz, a pesar de tratarse de pacientes con elevadas comorbilidades. Aunque se asocia a una considerable tasa de complicaciones y reintervenciones (el 38,3 y el 20,5% a 100 meses), sobre todo intrahospitalarias, la tasa de mortalidad relacionada a largo plazo es baja (4,5%) (AU)

Introduction and objectives. The aim of this work is to describe the short- and mid-term results of endovascular treatment of penetrating ulcers in the thoracic aorta. Methods. Between 1998 and 2010, 22 patients with penetrating ulcers in the thoracic aorta received endografts (mean age 69.8 years, 91% male); 50% were indicated for acute aortic syndrome (8 chest pain, 1 aortic rupture, 1 aortobronchial fistula, 1 distal embolization) and 50% for aortic or ulcer diameter. All preoperative, operative and follow-up data were recorded prospectively and met EUROSTAR criteria. Results. Technical success was 100% with no intraoperative deaths or open conversions; 6 (27.3%) required preoperative supraaortic trunk debranching and 1.3 endografts were used per patient; 27.3% developed complications in-hospital and 9.1% required reintervention prior to discharge. Mortality at 30 days was 4.5%. After a mean 52.3 month follow-up (range 0.1-122), cumulative survival free from complications and reinterventions at 100 months was 61.7% and 79.5% respectively, with 95.5% cumulative survival free from aorta- or procedure-related death. We identified no factors significantly related to poor intra- or postoperative clinical course. Conclusions. Endovascular treatment of penetrating aortic ulcers is both possible and effective despite high patient comorbidity. Although a substantial rate of complications and reinterventions can be expected -especially in-hospital- (38.3% and 20.5% respectively at 100 months), long-term mortality is low (4.5%) (AU)

Update on endovenous radio-frequency closure ablation of varicose veins.

Until recent years, the gold standard for treatment of truncal varicose veins has been high ligation and stripping of the saphenous vein. In the course of the last decade, new minimally invasive techniques based on endothermal ablation are progressively supplanting conventional surgery in the treatment of varicose veins. The endovenous treatment of varicose veins has been developed to reduce complications associated with conventional surgery and to improve quality of life. Radio frequency ablation (RFA) available since 1999 is now established as a safe and efficacious treatment for the ablation of refluxing saphenous veins. Among the emerging therapies, RFA with VNUS ClosureFAST is promising because it has eliminated almost all disadvantages associated with conventional surgery by "stripping" (bruises, scars, ecchymosis, inguinal recurrence, neovascularization, and mainly, prolonged incapacity) with an immediate occlusion rate close to 100%. When it is compared with endovenous laser ablation, RFA technology is associated with less postprocedural pain, less ecchymosis and tenderness, and better quality of life (QOL) measures. The aim of this article is to summarize the available evidence in the RFA treatment of varicose veins.

Endovascular treatment of penetrating aortic ulcers: mid-term follow-up.

INTRODUCTION AND OBJECTIVES: The aim of this work is to describe the short- and mid-term results of endovascular treatment of penetrating ulcers in the thoracic aorta. METHODS: Between 1998 and 2010, 22 patients with penetrating ulcers in the thoracic aorta received endografts (mean age 69.8 years, 91% male); 50% were indicated for acute aortic syndrome (8 chest pain, 1 aortic rupture, 1 aortobronchial fistula, 1 distal embolization) and 50% for aortic or ulcer diameter. All preoperative, operative and follow-up data were recorded prospectively and met EUROSTAR criteria. RESULTS: Technical success was 100% with no intraoperative deaths or open conversions; 6 (27.3%) required preoperative supraaortic trunk debranching and 1.3 endografts were used per patient; 27.3% developed complications in-hospital and 9.1% required reintervention prior to discharge. Mortality at 30 days was 4.5%. After a mean 52.3 month follow-up (range 0.1-122), cumulative survival free from complications and reinterventions at 100 months was 61.7% and 79.5% respectively, with 95.5% cumulative survival free from aorta- or procedure-related death. We identified no factors significantly related to poor intra- or postoperative clinical course. CONCLUSIONS: Endovascular treatment of penetrating aortic ulcers is both possible and effective despite high patient comorbidity. Although a substantial rate of complications and reinterventions can be expected-especially in-hospital-(38.3% and 20.5% respectively at 100 months), long-term mortality is low (4.5%).

Intra-operative factors predicting 1-month arteriovenous fistula thrombosis.

PURPOSE: The aim of this study is to determine clinical and ultrasound intra-operative factors related to 1-month autogenous arteriovenous fistula (AVF) thrombosis in end-stage renal failure patients. METHODS: A prospective study was designed, including AVF performed between October 2009 and May 2010. Patient characteristics and intra-operative measurements (clinical and ultrasound findings in both artery and vein: diameters, peak-systolic, end-diastolic and mean velocities, flow and resistance index) were recorded. At 1-month follow-up, AVF primary patency was analyzed. Stepwise logistic regression and ROC curves of the resulting test were used. RESULTS: 111 autogenous end-to-side AVF (44 radiocephalic, 45 brachiocephalic, 22 brachiobasilic) in 101 patients were performed. One-month primary patency rate was 84.7%. Intra-operative absence of bruit following skin closure could predict 1-month AVF thrombosis (70.6% sensitivity and 80.9% specificity, better than absence of thrill: 35.3% and 87.2%). However, logistic regression identified intra-operative end-diastolic velocity in the proximal feeding artery after AVF creation (EDV) as the best independent predictor of 1-month AVF thrombosis (OR=1.072, 95%CI 1.036-1.109; 76.5% sensitivity and 84.0% specificity for EDV<24.5 cm/s). This is a slight improvement on isolated clinical findings, but nevertheless a low positive predictive value (46.4%) is attained. CONCLUSIONS: Prediction of AVF thrombosis with intra-operative ultrasound measurements (proximal artery EDV under 24.5 cm/s) can slightly improve isolated clinical findings, helping to establish an intra-operative criterion to review AVF and increase surgical efficiency, assuming a relatively low positive predictive value.

Sentinel surveillance of influenza-like-illness in two cities of the tropical country of Ecuador: 2006-2010.

BACKGROUND: Tropical countries are thought to play an important role in the global behavior of respiratory infections such as influenza. The tropical country of Ecuador has almost no documentation of the causes of acute respiratory infections. The objectives of this study were to identify the viral agents associated with influenza like illness (ILI) in Ecuador, describe what strains of influenza were circulating in the region along with their epidemiologic characteristics, and perform molecular characterization of those strains. METHODOLOGY/FINDINGS: This is a prospective surveillance study of the causes of ILI based on viral culture of oropharyngeal specimens and case report forms obtained in hospitals from two cities of Ecuador over 4 years. Out of 1,702 cases of ILI, nine viral agents were detected in 597 patients. During the time of the study, seven genetic variants of influenza circulated in Ecuador, causing six periods of increased activity. There appeared to be more heterogeneity in the cause of ILI in the tropical city of Guayaquil when compared with the Andean city of Quito. CONCLUSIONS/SIGNIFICANCE: This was the most extensive documentation of the viral causes of ILI in Ecuador to date. Influenza was a common cause of ILI in Ecuador, causing more than one outbreak per year. There was no well defined influenza season although there were periods of time when no influenza was detected alternating with epidemics of different variant strains.

Nuevos avances el el tratamiento de las varices: radiofrecuencia endovenosa VNUS Closure / New advances in the treatment of varicose veins: endovenous radiofrequency VNUS Closure

Las varices de las extremidades inferiores frecuentemente son secundarias a insuficiencia de la vena safena interna (VSI). El desarrollo tecnológico ha permitido la aparición de nuevos tratamientos mínimamente invasivos como la ablación por radiofrecuencia endovenosa (RFA). Esta elimina casi en su totalidad los inconvenientes asociados a la cirugía convencional (hematomas, cicatrices, neovascularización inguinal e incapacidad laboral prolongada). Además, confiere mejor calidad de vida, menor dolor e inflamación que el endoláser. Revisamos la RFA y presentamos nuestros resultados como grupo pionero en España. Entre enero de 2006 y 2011 hemos tratado 153 extremidades con un diámetro medio VSI 6,8mm (rango 4,5-19). El 71% de procedimientos fueron realizados exclusivamente bajo anestesia tumescente. El 98,5% sin abordaje quirúrgico inguinal. Seguimiento clínico y ecográfico con registro prospectivo 1.ª semana, 3, 6, 12 meses, y anualmente. Resultados: tasa de oclusión vena tratada 97%, tasa de reflujo 6,6%. Neovascularización inguinal 0,7%. No neuritis, quemadura cutánea, ni trombosis venosa profunda

Lower limb varicose veins are often secondary to greater saphenous vein (GSV) insufficiency. Technological development has led to the appearance of new minimally invasive treatments, such as endovenous radiofrequency ablation (ERFA). This almost completely eliminates the disadvantages associated with conventional surgery (haematomas, scars, inguinal neovascularisation, and a prolonged time off work). Furthermore, it gives a better quality of life, less pain and inflammation than the endolaser. We review ERFA and present our results as a pioneering group in Spain. Between January 2006 and 2011 we have treated153 limbs with a mean GSV diameter of 6.8 mm (range 4.5-19). Tumescent anaesthesia was exclusively used in 71% of the procedures, and 98.5% without an inguinal surgical approach. Clinical and ultrasound follow-up with a prospective register was performed at 1 week, 3, 6,12 months, and then annually. Results: The occlusion rate of the treated vein was 97%, and there was a reflux rate of 6.6%. Inguinal neovascularisation was present on 0.7%. There was no neuritis, skin burns or deep vein thrombosis (AU)

[New advances in the treatment of varicose veins: endovenous radiofrequency VNUS Closure®]. / Nuevos avances el el tratamiento de las varices: radiofrecuencia endovenosa VNUS Closure(®).

UNLABELLED: Lower limb varicose veins are often secondary to greater saphenous vein (GSV) insufficiency. Technological development has led to the appearance of new minimally invasive treatments, such as endovenous radiofrequency ablation (ERFA). This almost completely eliminates the disadvantages associated with conventional surgery (haematomas, scars, inguinal neovascularisation, and a prolonged time off work). Furthermore, it gives a better quality of life, less pain and inflammation than the endolaser. We review ERFA and present our results as a pioneering group in Spain. Between January 2006 and 2011 we have treated 153 limbs with a mean GSV diameter of 6.8 mm (range 4.5-19). Tumescent anaesthesia was exclusively used in 71% of the procedures, and 98.5% without an inguinal surgical approach. Clinical and ultrasound follow-up with a prospective register was performed at 1 week, 3, 6, 12 months, and then annually. RESULTS: The occlusion rate of the treated vein was 97%, and there was a reflux rate of 6.6%. Inguinal neovascularisation was present on 0.7%. There was no neuritis, skin burns or deep vein thrombosis.

Arboviral etiologies of acute febrile illnesses in Western South America, 2000-2007.

BACKGROUND: Arthropod-borne viruses (arboviruses) are among the most common agents of human febrile illness worldwide and the most important emerging pathogens, causing multiple notable epidemics of human disease over recent decades. Despite the public health relevance, little is know about the geographic distribution, relative impact, and risk factors for arbovirus infection in many regions of the world. Our objectives were to describe the arboviruses associated with acute undifferentiated febrile illness in participating clinics in four countries in South America and to provide detailed epidemiological analysis of arbovirus infection in Iquitos, Peru, where more extensive monitoring was conducted. METHODOLOGY/FINDINGS: A clinic-based syndromic surveillance system was implemented in 13 locations in Ecuador, Peru, Bolivia, and Paraguay. Serum samples and demographic information were collected from febrile participants reporting to local health clinics or hospitals. Acute-phase sera were tested for viral infection by immunofluorescence assay or RT-PCR, while acute- and convalescent-phase sera were tested for pathogen-specific IgM by ELISA. Between May 2000 and December 2007, 20,880 participants were included in the study, with evidence for recent arbovirus infection detected for 6,793 (32.5%). Dengue viruses (Flavivirus) were the most common arbovirus infections, totaling 26.0% of febrile episodes, with DENV-3 as the most common serotype. Alphavirus (Venezuelan equine encephalitis virus [VEEV] and Mayaro virus [MAYV]) and Orthobunyavirus (Oropouche virus [OROV], Group C viruses, and Guaroa virus) infections were both observed in approximately 3% of febrile episodes. In Iquitos, risk factors for VEEV and MAYV infection included being male and reporting to a rural (vs urban) clinic. In contrast, OROV infection was similar between sexes and type of clinic. CONCLUSIONS/SIGNIFICANCE: Our data provide a better understanding of the geographic range of arboviruses in South America and highlight the diversity of pathogens in circulation. These arboviruses are currently significant causes of human illness in endemic regions but also have potential for further expansion. Our data provide a basis for analyzing changes in their ecology and epidemiology.

Dengue virus serotype 4, northeastern Peru, 2008.

In 2008, dengue virus serotype 4 (DENV-4) emerged in northeastern Peru, causing a large outbreak and displacing DENV-3, which had predominated for the previous 6 years. Phylogenetic analysis of 2008 and 2009 isolates support their inclusion into DENV-4 genotype II, forming a lineage distinct from strains that had previously circulated in the region.

Thrombosis of a bifurcated endograft following lower-back microwave therapy.

PURPOSE: To describe an unusual case involving thrombosis in an aortic endograft limb following microwave therapy (MWT) for lumbar pain. CASE REPORT: A 77-year-old man had successful repair of an abdominal aortic aneurysm with a Vanguard endograft. He had been free of complications during the 3-year follow-up. Five days after the 36-month surveillance angiogram, the patient was treated with MWT for chronic left-sided lumbar pain due to vertebral arthrosis. Immediately after this session, the patient presented with acute ischemia in the left lower limb. Computed tomographic angiography showed a thrombosis of the left limb of the endograft. A femorofemoral crossover bypass was performed. No complication was observed in later surveillance. CONCLUSIONS: It may be advisable to avoid MWT and other deep heating therapies in patients with endografts. This caution is applicable to other metallic stents.

Avances en el tratamiento médico y mínimamente invasivo de la isquemia crónica de miembros inferiores / Advances in the medical and minimally invasive treatment of chronic ischemia of lower limbs

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