Abstract
We thank Dr Ohki for his valuable comments on our article1Dias N.V. Ivancev K. Resch T.A. Malina M. Sonesson B. Endoleaks after endovascular aneurysm repair lead to nonuniform intra-aneurysm sac pressure.J Vasc Surg. 2007; 46: 197-203Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar and appraise his unique contribution on the introduction of implantable pressure sensors. Our study is the first report on late pressure measurements in the endoleak nidus (flow channel) and the thrombus with the same technique and confirms a difference in pressure gradient between these two locations. The previously reported association of aneurysm shrinkage with intra-sac depressurization in the absence of endoleaks2Dias N.V. Ivancev K. Malina M. Resch T. Lindblad B. Sonesson B. Intra-aneurysm sac pressure measurements after endovascular aneurysm repair: differences between shrinking, unchanged, and expanding aneurysms with and without endoleaks.J Vasc Surg. 2004; 39: 1229-1235Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar seems also to be present with endoleaks. The degree of depressurization seems nevertheless to be different. Pressure measurements in the presence of an endoleak need, therefore, to be assessed cautiously, no matter how the measurement was obtained. Implantable pressure sensors have the advantage of allowing repeated measurements over time.3Ellozy S.H. Carroccio A. Lookstein R.A. Jacobs T.S. Addis M.D. Teodorescu V.J. et al.Abdominal aortic aneurysm sac shrinkage after endovascular aneurysm repair: correlation with chronic sac pressure measurement.J Vasc Surg. 2006; 43: 2-7Abstract Full Text Full Text PDF PubMed Scopus (64) Google Scholar, 4Ohki T. Ouriel K. Silveira P.G. Katzen B. White R. Criado F. et al.Initial results of wireless pressure sensing for endovascular aneurysm repair: the APEX Trial–Acute Pressure Measurement to Confirm Aneurysm Sac EXclusion.J Vasc Surg. 2007; 45: 236-242Abstract Full Text Full Text PDF PubMed Scopus (97) Google Scholar We share the view that pressure sensors may eventually become useful in the follow-up of patients after EVAR. Before that happens, the aforementioned issues common to all pressure measurement systems in the presence of endoleaks need to be solved and the long-term accuracy of implantable sensors needs to be established. Implantable devices have been validated in the immediate period after EVAR, but thrombus can change with time acquiring a non-uniform structure5Wang D.H. Makaroun M. Webster M.W. Vorp D.A. Mechanical properties and microstructure of intraluminal thrombus from abdominal aortic aneurysm.J Biomech Eng. 2001; 123: 536-539Crossref PubMed Scopus (172) Google Scholar, 6Di Martino E. Mantero S. Inzoli F. Melissano G. Astore D. Chiesa R. et al.Biomechanics of abdominal aortic aneurysm in the presence of endoluminal thrombus: experimental characterization and structural static computational analysis.Eur J Vasc Endovasc Surg. 1998; 15: 290-299Abstract Full Text PDF PubMed Scopus (157) Google Scholar, 7Adolph R. Vorp D.A. Steed D.L. Webster M.W. Kameneva M.V. Watkins S.C. Cellular content and permeability of intraluminal thrombus in abdominal aortic aneurysm.J Vasc Surg. 1997; 25: 916-926Abstract Full Text Full Text PDF PubMed Scopus (178) Google Scholar that can influence transmission of pressure.8Vallabhaneni S.R. Gilling-Smith G.L. Brennan J.A. Heyes R.R. Hunt J.A. How T.V. et al.Can intra-sac pressure monitoring reliably predict failure of endovascular aneurysm repair?.J Endovasc Ther. 2003; 10: 524-530Crossref PubMed Scopus (31) Google Scholar, 9Hinnen J.W. Koning O.H. Visser M.J. Van Bockel H.J. Effect of intraluminal thrombus on pressure transmission in the abdominal aortic aneurysm.J Vasc Surg. 2005; 42: 1176-1182Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar Some of these issues are expected to be answered by on-going trials, which will hopefully include a validation against the validated direct intra-aneurysm sac pressure measurements (DISP) with tip-pressure sensors. Regarding “Endoleaks after endovascular aneurysm repair lead to nonuniform intra-aneurysm sac pressure”Journal of Vascular SurgeryVol. 47Issue 4PreviewI read with interest the article by Dias et al1 describing the measurement on intra-aneurysm sac pressure in patients with endoleaks post-endovascular aneurysm repair (EVAR) and congratulate the authors for their pioneering work in the area of sac pressure measurement. However, I believe it necessary to challenge certain statements in the manuscript that apply to alternative technologic approaches to long-term surveillance of EVAR patients. Full-Text PDF Open Archive
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