Measuring the effectiveness of endovascular treatment of abdominal aortic aneurysms

We describe an animal model for the acute and chronic monitoring of pressure within abdominal aortic aneurysms (AAAs) treated with endovascular grafts. A strain-gauge pressure transducer was placed within an AAA created from a prosthetic vascular graft. Prosthetic aneurysms were implanted into 17 canine infrarenal aortas. The intra-aneurysmal pressure was monitored and correlated with noninvasive forelimb sphygmomanometry for two weeks. After two weeks an intravascular manometer catheter was passed into the aneurysm. Simultaneous pressure measurements were obtained using the implanted strain-gauge pressure transducer, the manometer catheter and the forelimb sphygmomanometer. Angiography was performed to assess intraluminal morphology, aneurysm anastomoses and adjoining aortic vessels In addition, two control animals underwent intraaneurysmal pressure monitoring after standard surgical aneurysm repair. There was excellent correlation (R=097) between the pressure measurements obtained with the implanted strain-gauge pressure transducer and the intravascular manometer. Close correlation was also observed between the implanted strain-gauge transducer and the forelimb sphygmomanometer (R=0.88) during post-procedure monitoring. Intra-aneurysmal pressure was lowered dramatically by surgical exclusion (aneurysm, 15/5 ± 7/4 mmHg; systemic, 124/66 ± 34/17 mmHg; p<.001). Aneurysms were successfully imaged with angiography.