CHRONIC INTRAANEURYSMAL PRESSURE MEASUREMENT - AN EXPERIMENTAL-METHODFOR EVALUATING THE EFFECTIVENESS OF ENDOVASCULAR AORTIC-ANEURYSM EXCLUSION

Purpose: To evaluate and compare the intraaneurysmal pressure (IAP) af ter exclusion using two different endovascular grafts. Methods: Eight mongrel dogs had a 3 x 3 cm polytetrafluoroethylene (PTFE) aneurysm se wn as an interposition graft of the infrarenal aorta. A pressure trans ducer implanted into the aneurysm wall permitted continuous electronic IAP monitoring. Four aneurysms were excluded with a transluminally pl aced endovascular graft made of a PTFE graft and two Palmaz stents (PT FE-EG), three were excluded with a tantalum-Dacron endovascular graft (TD-EG), and one was surgically treated with a standard PTFE graft (PT FE-Surg). The dogs were observed for 18 to 50 days (mean, 37.5 days) a nd were evaluated after surgery with duplex and spiral computed tomogr aphic scans. Results: All grafts successfully excluded the aneurysms w ithout perigraft channels or leaks as documented by arteriogram and du plex and computed tomographic scans. The mean IAPs after repair with a ll PTFE-EGs were significantly lower (p < 0.001) than the mean systemi c pressures. In addition, the mean IAP reduction was significantly gre ater (p < 0.005) in the PTFE-EG group than in the TD-EG group. Conclus ions: Aneurysm exclusion with PTFE-EG significantly lowered IAP, did s o significantly better than the TD-EG, and approached the IAP reductio n obtained by standard repair. Such pressure reduction is necessary fo r effective protection against aneurysm rupture.