AN EXPERIMENTAL-MODEL FOR THE ACUTE AND CHRONIC EVALUATION OF INTRA-ANEURYSMAL PRESSURE

Purpose: To develop an animal model for the acute and chronic monitori ng of pressure within abdominal aortic aneurysms (AAAs) to be treated with endovascular grafts. Methods: A strain-gauge pressure transducer was placed within an AAA created from a prosthetic vascular graft. Pro sthetic aneurysms were implanted into If canine infrarenal aortas. The intra-aneurysmal pressure was monitored and correlated with noninvasi ve forelimb sphygmomanometry for 2 weeks. After this time, an intravas cular manometer catheter was passed into the aneurysm. Simultaneous pr essure measurements were obtained using the implanted strain-gauge pre ssure transducer, the manometer catheter, and the forelimb sphygmomano meter. Angiography was performed to assess intraluminal morphology, an eurysm anastomoses, and adjoining aortic vessels. In addition, two con trol animals underwent intra-aneurysmal pressure monitoring after stan dard surgical aneurysm repair. Results: There was excellent correlatio n (r = 0.97) between the pressure measurements obtained with the impla nted strain-gauge pressure transducer and the intravascular manometer. Close correlation was also observed between the implanted strain-gaug e transducer and the forelimb sphygmomanometer (r = 0.88) during postp rocedural monitoring. Intra-aneurysmal pressure was lowered dramatical ly by surgical exclusion (aneurysm: 15/5 +/- 7/4 mmHg; systemic: 124/6 6 +/- 34/17 mmHg; p < 0.001). The prosthetic aneurysms were successful ly imaged with angiography. Conclusions: This animal model provides an accurate and reproducible means for measuring intra-aneurysmal pressu re an an acute and chronic basis. It may be possible to use this model in the assessment of endovascular devices to determine their efficacy in reducing intra-aneurysmal pressure. Evaluation of complications as sociated with their use, such as patent aneurysm side branches, perigr aft channels, and perianastomotic reflux, may also be possible.