Evaluation of materials used for vascular anastomoses using shear wave elastography.

Cardiovascular disease is the leading cause of mortality in the United States. Peripheral artery disease (PAD) affects a substantial portion of the elderly population (>70 years). PAD can be symptomatic or asymptomatic, and treatment is directed towards improving functional vessel patency and limb salvage. Revascularization surgical treatments are needed in some cases, and it is not always possible to use autologous veins for vascular grafting. In this case, synthetic materials may be used. Synthetic materials such as expanded polytetrafluoroethylene (ePTFE) and poly (ethylene terephthalate) (Dacron) have been used. These materials are much stiffer compared to normal arterial vessels so developing alternative materials is an active area of research. One such potential material is a p olyvinyl alcohol cryogel reinforced arterial model (PRAM). In this study we used shear wave elastography (SWE) techniques to compare the mechanical behavior of excised aortas and anastomoses formed between the aortas and the Dacron, ePTFE, and PRAM materials. Different initial longitudinal strains (0%-40%) and transmural pressures (20-180 mmHg) were used to test a wide range of parameters that are within physiological ranges. We found that the PRAM materials had similar mechanical behavior in terms of group velocity measured in the vessel wall with respect to the excised aortas compared to the Dacron and ePTFE that had higher values of group velocity. The ratios of the group velocity for the PRAM material with respect to the aortas ranged from 0.83 to 1.13 where the Dacron and ePTFE had ranges of 1.12-2.22 and 1.91-3.10 for the same stretch and pressure ranges. The PRAM materials provide an alternative vascular material with better mechanical matching with excised aortas.

Aneurisma de aorta abdominal justa-renal: correção endovascular combinada com derivação ilíaco-renal direita para criar colo proximal adequado / Juxtarenal abdominal aortic aneurysm: combined endovascular and open repair with right iliorenal bypass to create adequate proximal neck

Homem de 78 anos de idade, portador de múltiplas morbidades clínicas deu entrada na emergência com um aneurisma de aorta abdominal justa-renal em condições hemodinâmicas estáveis. A tomografia computadorizada caracterizou aneurisma de 6 cm de diâmetro, e a distância do colo proximal do aneurisma era de 5 mm em relação à artéria renal direita e 28 mm à esquerda. Em virtude das condições clínicas do paciente, optou-se pelo reparo endovascular, mas previamente fez-se uma derivação ilíaco-renal direita com enxerto de politetrafluoretileno, via retroperitoneal para se criar um colo proximal adequado. Após quatro dias, o aneurisma de aorta abdominal foi corrigido colocando-se uma endoprótese Excluder® sem intercorrências. O seguimento pós-operatório evidenciou boa perfusão do rim esquerdo e ausência de migração ou endoleak da endoprótese. Este caso ilustra a combinação de técnicas para tornar possível o reparo de aneurisma de aorta abdominal justa-renal em pacientes de alto risco cirúrgico e anatomia desfavorável.

A 78-year-old man with a juxtarenal abdominal aortic aneurysm and several comorbid conditions was admitted at the emergency room in hemodynamically stable conditions. Computed tomography revealed an aneurysm measuring 6 cm in diameter beginning 28 mm below the left renal artery and 5 mm below the right renal artery. Because of the patient's clinical status, a bypass from the right iliac artery to the right renal artery was performed through a retroperitoneal approach using a polytetrafluoroethylene vascular graft. Four days later, an endovascular aneurysm repair was successfully performed using an Excluder® stent-graft. Postoperative follow-up showed good left renal perfusion and no migration or endoleak. This case illustrates the effectiveness of combining open and endovascular techniques to repair juxtarenal abdominal aortic aneurysm in high-risk patients with unfavorable anatomy.

Uma mudança no tratamento dos aneurismas da aorta abdominal / A change in the treatment of abdominal aortic aneurysms

OBJECTIVE: One of the most exciting potential applications of percutaneous therapy is the treatment of abdominal aneurysms. METHODS: Of 230 patients treated with a self-expanding polyester-lined stent-graft for different aortic pathologies at our institution, we selected 80 abdominal aneurysm cases undergoing treatment (from May 1997 to December 2002). The stent was introduced through the femoral artery, in the hemodynamic laboratory, with the patient under general anesthesia, with systemic heparinization, and induced hypotension. RESULTS: The procedure was successful in 70 (92.9 percent) cases; 10 patients with exclusion of abdominal aortic aneurysms were documented immediately within the hemodynamic room and 5 patients persisted with a residual leak. Two surgical conversions were necessary. Additional stent-grafts had to be inserted in 3 (3.7 percent) cases. In the follow-up, 91.4 percent of patients were alive at a mean follow-up of 15.8 months. CONCLUSION: We believe that stent-grafts are an important tool in improving the treatment of abdominal aneurysms, and this new policy may change the conventional medical management of these patients

Tratamiento endoluminal de los aneurismas de aorta / Intraluminal treatment in abdominal aortic aneurysms

Debido al aumento de la población añosa, los cirujanos vasculares se encuentran con mayor frecuencia con pacientes portadores de aneurismas de aorta abdominal que tienen múltiples y severas enfermedades asociadas. El presente estudio se refiere a la experiencia animal y a los primeros casos clínicos de un nuevo tratamiento de los aneurismas que es la inserción retrógrada de una prótesis vascular fijada a "stends" metálicos que se implantan a través de un balón que al inflarse expande al "stends" y lo fija a la pared aórtica. En el trabajo experimental se crearon aneurismas de aorta en perros reemplazando la aorta infrarrenal con una prótesis de dacron en forma de aneurisma; después de cuatro semanas se excluye el aneurisma desde la luz implantando desde la arteria femoral, en forma retrógrada la combinación de "stend" y prótesis. Desde setiembre de 1990 se implantaron 6 pacientes. Un paciente debió ser operado después de implantar la prótesis demasiado alejada de las arterias renales. Todos los pacientes evolucionaron favorablemente

Tratamiento endoluminal de los aneurismas de aorta / Intraluminal treatment in abdominal aortic aneurysms

Debido al aumento de la población añosa, los cirujanos vasculares se encuentran con mayor frecuencia con pacientes portadores de aneurismas de aorta abdominal que tienen múltiples y severas enfermedades asociadas. El presente estudio se refiere a la experiencia animal y a los primeros casos clínicos de un nuevo tratamiento de los aneurismas que es la inserción retrógrada de una prótesis vascular fijada a "stends" metálicos que se implantan a través de un balón que al inflarse expande al "stends" y lo fija a la pared aórtica. En el trabajo experimental se crearon aneurismas de aorta en perros reemplazando la aorta infrarrenal con una prótesis de dacron en forma de aneurisma; después de cuatro semanas se excluye el aneurisma desde la luz implantando desde la arteria femoral, en forma retrógrada la combinación de "stend" y prótesis. Desde setiembre de 1990 se implantaron 6 pacientes. Un paciente debió ser operado después de implantar la prótesis demasiado alejada de las arterias renales. Todos los pacientes evolucionaron favorablemente