Aneurysm sac pressure measurements after endovascular repair of abdominal aortic aneurysms

Objectives: The goal of endovascular grafting of abdominal aortic aneurysms (AAAs) is to exclude the aneurysm sac from systemic pressure and thereby d ecrease the risk of rupture. Unlike conventional open surgery, branch vesse ls in the sac (eg, lumbar artery and inferior mesenteric artery [IMA]) are not ligated and can potentially transmit pressure. The purpose of our inves tigation was to evaluate the feasibility of various interventional techniqu es for measuring pressure within the aneurysm sac in patients who had under gone endovascular repair of AAAs. Methods: Sac pressure measurements were performed in 21 patients who had un dergone stent graft repair of AAAs. Seventeen of 21 patients had endoleaks demonstrated on 30-day computed tomographic (CT) scans. Access to the aneur ysm sac in these patients was through direct translumbar sac puncture (5 pa tients), through a patent IMA accessed via the superior mesenteric artery ( SMA) (9 patients), or by direct cannulation around attachment sites (3 pati ents). Pour patients had perioperative pressure measurements obtained throu gh catheters positioned along side of the endovascular graft at the time of its deployment. Two of these catheters were left in position for 30 hours during which time CT and conventional angiography were performed. Pressures were determined with standard arterial-line pressure transduction techniqu es and compared with systemic pressure in each patient. Results: Elevated sac pressure was found in all patients. The sac pressure in patients with endoleaks was found to be systemic (15 patients) or near s ystemic (2 patients) and all had pulsatile waveforms. Elevated sac pressure s were also found in patients without CT or angiographic evidence of endole ak (2 patients). Injection of the sacs in two of these patients revealed a patent lumbar artery and an IMA. Conclusions: It is possible to measure pressures from within the aneurysm s ac in patients with stent grafts with a variety of techniques. Patients may continue to have pressurized AAA sacs despite endovascular AAA repair. End oleaks transmit pulsatile pressure into the aneurysm sac regardless of the type. It is possible to have systemic sac pressures without evidence of end oleaks on CT or angiography.