Duplex Ultrasound Imaging with an Ultrasound Contrast Agent: The Economic Alternative to CT Angiography for Aortlc Sten tGraft Surveillance

Abstract

The use of endovascular stent graft repair for aortic aneurysmal disease has become increasingly common, with the added requirement for close postoperative surveillance to detect the presence of endoleaks or graft migration. The most commonly used technique for surveillance is computed tomography (CT) angiography, with the need for intravenous contrast posing 1 limitation in those patients with renal dysfunction and the cost of this testing presenting an economic limitation. Early results of duplex imaging in the authors' Vascular Laboratory using an intravenous ultrasound contrast agent have shown sensitivity and specificity equivalent to those of CT angiography, with no evidence of any related morbidity. They have evaluated the cost effectiveness of using duplex ultrasound imaging as the primary surveillance technique for postoperative follow-up in aortic stent graft patients. Surveillance protocols now require that 8 follow-up examinations be performed in the first 3 years after stent graft placement. The charges for CT angiography in their institution average $2,779 per study, for a 3-year total of $22,232 per patient. The charges for aortic duplex ultrasound average $525 per study, with a 3-year total of $4,200 per patient. Adding the cost of routine abdominal radiographs to confirm stent graft position ($147 per study) would bring this 3-year total to $5,376, a savings of $16,856 per patient. For every 100 patients who are followed up after stent graft placement, this represents a 3-year savings of more than $1.6M. Promising early results of duplex ultrasound imaging with an intravenous contrast agent show sensitivity and specificity equivalent to those of CT angiography in detecting aneurysm size and graft endoleaks or other hemodynamic abnormalities. If these results can be demonstrated in larger patient series, this technique should become the method of choice for stent graft surveillance, for it offers very significant economic advantages and avoids the complications of intravenous contrast-induced renal dysfunction.

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