Intra-aneurysm Sac Pressure in Patients with Unchanged AAA Diameter after EVAR

Abstract

Objective: To assess whether limitations of randomised controlled trials (RCTs) of endovascular aneurysm repair (EVAR) can be addressed by evidence from non-randomised studies.Design: Analysis of data from a systematic review. Methods:We conducted a review of EVAR versus open repair or non-surgical management of abdominal aortic aneurysms. In addition to RCTs, we included pre-specified registries of EVAR and open repair.Results: The six included RCTs randomised patients in 2003 and earlier. Of the three registries included, one contributed data on a large (Ͼ8000) sample of patients treated with newer generation EVAR devices and followed up for up to 8 years. However, treatment dates of these patients overlapped with those of the RCTs. The other registries were of limited usefulness. A large (Ͼ45,000) controlled observational study published while the review was in progress broadly supported the findings of RCTs comparing EVAR with open surgery. A comparison of outcomes across all studies did not support the hypothesis that the findings of the RCTs are no longer representative of clinical practice.Conclusions: Both randomised and non-randomised sources of evidence have strengths and weaknesses for assessing the effectiveness of EVAR. Further research should explore the optimum use of registry data, including patient-level analyses.

Multilayer Flow Modulator Treatment of Abdominal and Thoracoabdominal Aortic Aneurysms With Side Branch Coverage

“…Further, persistent flow between the stent-graft and the arterial wall could be a positive rather than adverse prognostic factor regarding sac expansion. 12,33,34 The alternative solution represented by the MFM involves modulation of blood flow dynamics to organize a laminar flow into branch vessels and avoid the extra steps involved in cannulation. The shear stress caused by turbulent blood flow within an aneurysm damages the arterial wall and induces degradation, resulting in growth of the aneurysm.…”

Noninvasive Estimation of Aneurysm Sac Pressurization Following Endovascular Aneurysm Repair Using M-Mode Ultrasonography to Evaluate Significance of Endoleaks

“…Previous research used percutaneous translumbar puncture of the sac under fluoroscopic guidance to record intrasac pressure and investigate early failure modes of EVAR. 13–16 Owing to its invasive nature, this technique has not gained wide applicability in routine clinical settings. 13–16 Nevertheless, the investigators suggested that high intra-aneurysm pressure may be associated with AAA enlargement and low pressure with shrinkage, thus providing the rationale to develop methods that noninvasively record post-EVAR sac pressurization.…”

“…13–16 Owing to its invasive nature, this technique has not gained wide applicability in routine clinical settings. 13–16 Nevertheless, the investigators suggested that high intra-aneurysm pressure may be associated with AAA enlargement and low pressure with shrinkage, thus providing the rationale to develop methods that noninvasively record post-EVAR sac pressurization. 13 They also postulated that there may be a wide variance of intrasac pressure in patients with a type II endoleak, but again, high values are associated with enlargement.…”

“…Such methods have been used only for research purposes since their invasive nature precludes wide application in the usual clinical setting. 13–16…”

Aneurysm sac shrinkage after endovascular treatment of the aorta: Beyond sac pressure and endoleaks

“…23 Changes in wall mechanics after EVAR Dias et al recently reported that in 18 AAAs that had unchanged maximum diameters for more than 1 year after EVAR, invasive intrasac pressure monitoring revealed no postoperative fluid accumulation and no endoleak. 25 Among them, three AAAs expanded, five shrank and 10 remained unchanged during follow-up. Though the samples were small, it was interesting to note that neither intrasac pulse and mean pressure nor the mean pressure index was able to differentiate the last two categories, further implying that the fate of an AAA after EVAR does not solely depend on intrasac pressure levels.…”