Intraaneurysmatische Druckverteilung nach endovaskulärer Therapie von Bauchaortenaneurysmen : Möglichkeiten der Endoleckdetektion mithilfe eines implantierbaren, telemetrischen Drucksensors

Aachen / Publikationsserver der RWTH Aachen University (2008) [Dissertation / PhD Thesis]

Page(s): 126 S. : Ill., graph. Darst.

Abstract

The endovascular repair of abdominal aortic aneurysms (AAA) was first published in 1991 and has gained an increasing acceptance among elective procedures for AAA repair due to the lower peri- and postoperative morbidity. One of the major complications of this therapy is the occurrence of different types of endoleaks. These complication may lead to the necessity of a later reintervention or conversion to a conventional open AAA repair. In the presented study the influence of endoleaks on the intraaneurysmatic pressure was studied by means of a pulsatile in-vitro model of a AAA. Different types and sizes of endoleaks as well as various conditions of lumbar arteries were simulated in multiple systemic pressure ranges. The intraaneurysmatic pressure was measured at different positions within the aneurysm sac by means of wired and telemetric pressure sensors. The aim of this study was also to investigate whether in thrombosed aneurysm sacs compartmentalization leads to pressure differences and whether a preferred localization for pressure measurement exists. The intraaneurysmatic pressure measured at different positions within the aneurysm sac did not indicate any clinically significant differences in pressure increase after opening of an endoleak in all conditions investigated. This was true for the non-thrombosed and thrombosed aneurysm sac. In case of a successful excluded aneurysm the intraaneurysmatic pressure was maximal 18.2 ± 0.8 mmHg in the middle intraaortic pressure range and did not further increase after an increase in systemic pressure. The measured intraaneurysmatic pressure oscillated only in a minimal range at the respective mean pressure. After opening of an endoleak the intraaneurysmatic pressure increased to almost 100% of the systemic pressure, the amplitude of the intraaneurysmatic pressure oscillations increased but did not reach the systemic one. The observed pressure increase was statistically significant (p < 0,0001) in all conditions investigated and was in the lowest applied systemic pressure range about 75 mmHg. This pressure increase could be detected without any problems and clearly distinguished from other disturbing factors. All three investigated endoleak sizes were detectable but not differentiable. In case of a thrombosed aneurysm sac a suspected compartmentalization could not be observed. The relevant conditions of the systematic wire based pressure measurements were exemplarily repeated to evaluate the operability of a newly developed telemetric pressure sensor. The telemetric pressure sensor was implanted into the aneurysm sac and measured pressure readings were compared to the ones simultaneously obtained with wired pressure sensors. It could be shown that the telemetric pressure sensor was able to observe a significant pressure increase (p < 0,0001) in all conditions investigated. The observed differences between the telemetric and wired pressure measurements were insignificant in case of a non thrombosed and thrombosed aneurysm sac. Within an endovascular excluded aneurysm sac it is possible by means of wired as well as of telemetric pressure sensors to detect a clinically relevant pressure increase as well as to verify the successful exclusion of the aneurysm sac. The possibility of a permanent telemetric control of intraaneurysmatic pressure may be helpful to detect clinically relevant endoleaks earlier and subsequently perform a possibly necessary reintervention. In this way the follow-up may be designed less expensive, more convenient as well as with less radiation exposure to the patient.