Cascading processes in a changing environment: Disturbances on fluvial ecosystems in Chile and implications for hazard and risk management.

The compound hazard effects of multiple process cascades severely affect Chilean river systems and result in a large variety of disturbances on their ecosystems and alterations of their hydromorphologic regimes leading to extreme impacts on society, environment and infrastructure. The acute, neo-tectonically pre-determined susceptibility to seismic hazards, the widespread volcanic activity, the increasing glacier retreat and the continuous exposure to forest fires clearly disturb entire riverine systems and concur to trigger severe floods hazards. With the objective to refine the understanding of such cascading processes and to prospect feasible flood risk management strategies in such a rapidly changing environment we first classify the large river basins according to a set of disturbances (i.e. volcanic eruptions, earthquakes, glacier lake outburst floods, wild fires and mass movements). Then, we describe emblematic cases of process cascades which affected specific Chilean drainage basins and resulted in high losses as tangible examples of how the cascading processes may unfold in other river basins with similar characteristics. As an attempt to enrich the debate among management authorities and academia in Chile, and elsewhere, on how to sustainably manage river systems, we: a) highlight the pivotal need to determine the possible process cascades that may profoundly alter the system and b) we suggest to refine hazard and risk assessments accordingly, accounting for the current and future exposure. We advocate, finally, for the adoption of holistic approaches promoting anticipatory adaptation which may result in resilient system responses.

[Extra anatomical revascularization and endovascular stent-grafting for thoracoabdominal aneurysm repair. Report of four cases]. / Tratamiento "híbrido" del aneurisma tóraco-abdominal: revascularización visceral extraanatómica e inserción de endoprótesis.

Surgical treatment of thoracoabdominal aneurysms is a big technical challenge with a high rate of complications and mortality. It requires a large exposure and transient interruption of vital organ perfusion during its repair. Endovascular repair is a less invasive alternative available over the last decade. We report four male patients aged 44 to 76 years, with thoracic aortic aneurysms and involvement of visceral aorta, treated with a two stage procedure. During the first stage, a retrograde revascularization of the superior mesenteric and renal arteries from the infrarenal aorta was done, associated in two cases to a concomitant repair of an infrarenal aortic aneurysm. In the second stage, an endovascular graft was placed through the femoral artery, from the segment proximal to the aneurysm to the infrarenal aorta, above the origin of the visceral artery reconstructions, excluding the aneurysm from circulation. In one patient, both stages were concomitant and in three the second stage was delayed. One patient presented a postoperative bleeding that required reintervention without adverse consequences. No patient died, presented paraplegia or deterioration of renal function. After follow up of 6 to 20 months, there is no evidence of aneurysm growth or complications derived from the procedure.

Interrupción de la vena cava inferior mediante filtros de inserción percutánea: Indicaciones y resultados en 287 pacientes / Percutaneous inferior vena cava filters: Indications and results in 287 patients

Background: Anticoagulation is the treatment of choice for deep vein thrombosis (DVT) and pulmonary embolism (PE). Occasionally this treatment is contraindicated or fails to prevent PE. In these patients, inferior vena caval (IVC) interruption is indicated and insertion of a filter is the most commonly performed procedure. Aim: To report the experience with IVC filters. Material and methods: Retrospective review of all medical records and operative protocols of patients subjected to IVC filter implantations. Follow up was performed by telephone contact with the patient, relatives or primary physicians, ambulatory consultation or by death certificates. Results: During the period 1993-2005 we implanted IVC filters on 287 patients, 55.4 percent male, average age: 62.1 yrs (17-99). Indications for the procedure were DVT or PE and contraindication of anticoagulation in 141 patients (49.1 percent), DVT or PE and complication of anticoagulation in 65 patients (22.6 percent), prophylaxis in 39 patients (13.6 percent), massive PE or poor respiratory function in 31 patients (10.8 percent), paradoxal emboli in 4 patients (1.4 percent) and other causes in seven patients. All percutaneous devices were successfully inserted. There was no morbidity or mortality related to the procedure. The most frequent access site was the internal jugular vein (66.6 percent). In 24 patients (8.4 percent) the filter was intentionally deployed above the renal veins. Six patients (2.1 percent) were lost to follow up after discharge. A mean follow up of 41.5 months was achieved. Ninety one patients died, with a 5 years survival of 64.7 percent. Symptomatic recurrent PE occurred in 6 patients (2.1 percent) and was the cause of death on 3 of them (1 percent), DVT has been detected in 22 patients (7.7 percent) during the follow up period. Conclusions: IVC filter implantation is a safe and effective short and long term measure to prevent PE and its consequences.

Tratamiento "híbrido" del aneurisma tóraco-abdominal: revascularización visceral extraanatómica e inserción de endoprótesis / Extra anatomical revascularization and endovascular stent-grafting for thoracoabdominal aneurysm repair: Report of four cases

Surgical treatment of thoracoabdominal aneurysms is a big technical challenge with a high rate of complications and mortality. It requires a large exposure and transient interruption of vital organ perfusion during its repair. Endovascular repair is a less invasive alternative available over the last decade. We report four male patients aged 44 to 76 years, with thoracic aortic aneurysms and involvement of visceral aorta, treated with a two stage procedure. During the first stage, a retrograde revascularization of the superior mesenteric and renal arteries from the infrarenal aorta was done, associated in two cases to a concomitant repair of an infrarenal aortic aneurysm. In the second stage, an endovascular graft was placed through the femoral artery, from the segment proximal to the aneurysm to the infrarenal aorta, above the origin of the visceral artery reconstructions, excluding the aneurysm from circulation. In one patient, both stages were concomitant and in three the second stage was delayed. One patient presented a postoperative bleeding that required reintervention without adverse consequences. No patient died, presented paraplegia or deterioration of renal function. After follow up of 6 to 20 months, there is no evidence of aneurysm growth or complications derived from the procedure.

[Endovascular treatment of descending aorta trauma]. / Tratamiento endovascular del trauma de aorta descendente.

BACKGROUND: Mortality of traumatic aortic lesions is over 80%. A group of those who survive, develop a chronic pseudo aneurism, usually asymptomatic, that is detected during imaging studies. Since conventional surgical treatment of traumatic aortic lesions has a great mortality, endovascular treatment has been used as an alternative treatment in the last decade. AIM: To report our experience with endovascular treatment of traumatic aortic lesions. PATIENTS AND METHODS: Report of seven patients aged 22 to 65 years, with traumatic aortic lesions. Under general anesthesia an endovascular prosthesis was inserted through the femoral artery. RESULTS: No complications were observed in the postoperative period, and after a follow up ranging from 4 to 40 months, no endoleaks or other complications have been detected. CONCLUSIONS: Endovascular treatment of traumatic aortic lesions has good immediate and midterm results.

Tratamiento endovascular del trauma de aorta descendente / Endovascular treatment of descending aorta trauma

Background: Mortality of traumatic aortic lesions is over 80 percent. A group of those who survive, develop a chronic pseudo aneurism, usually asymptomatic, that is detected during imaging studies. Since conventional surgical treatment of traumatic aortic lesions has a great mortality, endovascular treatment has been used as an alternative treatment in the last decade. Aim: To report our experience with endovascular treatment of traumatic aortic lesions. Patients and methods: Report of seven patients aged 22 to 65 years, with traumatic aortic lesions. Under general anesthesia an endovascular prosthesis was inserted through the femoral artery. Results: No complications were observed in the postoperative period, and after a follow up ranging from 4 to 40 months, no endoleaks or other complications have been detected. Conclusions: Endovascular treatment of traumatic aortic lesions has good immediate and midterm results.

Transección traumática aguda de la aorta torácica: tratamiento endovascular / Endovascular treatment of acute traumatic rupture of the thoracic aorta: report of 1 case

Traumatic rupture of the aorta has a near 80 percent mortality. Most patients die on the site of the accident. Conventional surgical repair of these lesions has a high morbidity and mortality, generally associated to the severity of associated lesions. Over the last decade, endovascular treatment has become an effective therapeutic alternative. We report a 40 years old male, that suffered a traumatic rupture of the descending thoracic aorta in a car accident. A successful endovascular repair was performed, installing an endoprothesis on the site of the lesion, using a femoral artery approach. The patient had a good postoperative evolution and was discharged from the hospital once complete rehabilitation of his associated lesions was obtained

Cuerpos extranos en la via aerea inferior. / Foreign bodies in the lower airway

El material presentado esta constituido por 69 pacientes, observados con cuerpos extranos aspirados en las vias aereas que se analizan de acuerdo a: edad: 76,8% menores de 4 anos - sexo: 66,0% varones- naturaleza: 90,7% radiolucidos - Ubicacion: 23,4% laringea, l5,9% traqueal, 6l,9% bronquial. Desde el punto de vista clinico, antecedentes, sintomas y signos fueron insuficientes para precisar la presencia y localizacion del cuerpo extrano. Los hallazgos radiologicos y adecuada interpretacion de signos indirectos, constituyeron un singular apoyo para el diagnostico. La endoscopia fue el principal procedimiento de extracccion, (97%). El 7,2% de los pacientes eliminaron en forma espontanea el material aspirado. La letalidad alcanzo a un 4,5%. Se insiste la necesidad de un alto indice de sospecha de este problema, frente a trastornos respiratorios de iniciacion brusca y en las complicaciones inmediatas, mediatas y a largo plazo que originan los cuerpos extranos en la via aerea. Se destaca las situaciones clinicas provocadas por cuerpos extranos abandonados, como asimismo las dificultades para el diagnostico que ofrecen los cuerpos extranos plasticos por el caracter no irritativo, su pequeno tamano y por ser radiolucidos