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OBJECTIVES:
Computerized tomography angiography (CTA) is an important tool for anatomic delineation and pre-procedure planning in patients who are being considered for endovascular repair of an abdominal aortic aneurysm (EVAR). The iodinated contrast volume required for conventional CTA in patients with pre-existing renal dysfunction may result in further renal function deterioration. The aim of this study was to evaluate the utility of CTA using direct intra-aortic injection of a low volume of iodinated contrast in patients being considered for EVAR.
METHODS:
The patients were brought to the angiography suite the day prior to planned EVAR. Through common femoral artery percutaneous access, the infusion end of a 5F high-flow angiographic catheter was positioned in the mid-thoracic aorta. CTA was then performed using a multidetector scanner, with image acquisition starting simultaneously with power injection of 10 mL of iopamidol 76% diluted with normal saline to a total volume of 50 mL (10 mL iodinated contrast + 40 mL saline), at 6 mL/sec through the angiographic catheter. Aortic enhancement was assessed with a circular region-of-interest cursor within the aorta and values >=150 HU were considered adequate.
RESULTS:
Six patients with AAA and associated chronic renal dysfunction underwent CTA with intra-arterial contrast injection for endovascular therapy planning. Mean age was 80.2±5.7 years, 67% were male, mean BMI 27.8±2.9 and baseline creatinine 1.7±0.5 mg/dL. Adequate CTA aortic enhancement was obtained in all cases (mean intra-aortic density 259.9±10.5 HU). Using acquired CTA images EVAR was performed the following day. The total contrast volume used for the CTA and the endovascular repair combined was 33.3±25.2 mL, with four of the patients receiving less than 30 mL of contrast. No significant change in renal function occurred perioperatively, as demonstrated by equivalent creatinine clearance pre and post-procedure (36.1±4.6 mL/min versus 37.8±6.9 mL/min, P = .53). Successful EVAR was achieved in all patients. Patients remained in hospital for an average 3.2±0.4 days. No endoleak or aneurysm growth occurred over a median follow-up of 379 days (range 30-764).
CONCLUSIONS:
The use of direct intra-aortic injection of a low volume of iodinated contrast provides an adequate and reproducible pattern of aortic enhancement on CTA. The CTA so acquired can be used for planning and successful execution of EVAR while limiting the total volume of iodinated contrast required.