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Abstract

We thank Dr Mower and Dr Quinones for their interest in our article. In their comment they express their concern about several issues. As they correctly pointed out, the correlation coefficient is not useful for detecting differences in pressure. For this reason, we also compared the pressure measurements in the radial artery and in the thrombus mass by using a Bland and Altman plot.1Bland JM Altman DG Statistical methods for assessing agreement between two methods of clinical measurement.Lancet. 1986; i: 307-310Abstract Scopus (37066) Google Scholar This plot is very useful for showing the level of agreement between both pressure measurements. Therefore, in our opinion, the conclusion that the thrombus does not reduce pressure to the aneurysmal wall is justified. The measurement of the systemic pressure in the radial artery will lead to a higher systolic pressure and a lower diastolic pressure compared with the pressure measurements in the abdominal aorta.2Remington JP Wood EH Formation of peripheral pulse contour in man.J Appl Physiol. 1956; 9: 433PubMed Google Scholar, 3Nichols WW O'Rourke MF McDonald's blood flow in arteries.in: 3rd ed. Edward Arnold, London1990: 382Google Scholar The radial measurements will have a wider pulse pressure, but the mean pressure will not change significantly compared with the pressure in the abdominal aorta.3Nichols WW O'Rourke MF McDonald's blood flow in arteries.in: 3rd ed. Edward Arnold, London1990: 382Google Scholar If we would compensate the fact that the radial pulse pressure is wider than the aortic pulse pressure, the level of agreement between the arterial pulse pressure and the pulse pressure in the thrombus would probably be even greater. Although claimed by Dr Mower and Dr Quinones, the reference quoted by them4Latham R Westerhof N Sipkema P Rubal B Reuderink P Murgo J Regional wave travel and reflections along the human aorta: a study with six simultaneous micromanometric pressures.Circulation. 1985; 72: 1257-1269Crossref PubMed Scopus (347) Google Scholar does not mention the level of change in mean pressure and pulse pressure between the abdominal aorta and arteries in the extremities. This article shows the change in pulse wave from the ascending aorta to the iliac arteries in nine patients, a number equal to our patient number, but claimed to be too small to draw conclusions. However, we do agree about the indistinct effect of thrombus on the aneurysmal wall. In case of aneurysmal growth and rupture, the pressure on the aneurysmal wall is only one of the main responsible factors. By the performance of direct pressure measurements just inside the aneurysmal wall, a protective effect of thrombus by lowering the mean and pulse pressure on the aneurysmal wall in a clinically significant way could not be documented in patients. 24/41/111749