Biomechanical properties of abdominal aortic aneurysms assessed by simultaneously measured pressure and volume changes in humans

Simultaneous pressure and volume registrations of the abdominal aortic aneurysm (AAA) are shown. Left, The volume of the AAA is determined for 15 cardiac phases from the magnetic resonance images. Middle, Average values for the pressure (in kPa) within the aneurysm are determined for the same cardiac phases. Right, A strong linear relation between the two variables is found. The slope of the best linear fit reflects the compliance of the aneurysm.

Bland-Altman plots for the (A) systolic and (B) diastolic blood pressure (BP) measurement in mm Hg. The relative difference between the distant noninvasive brachial cuff measurement and the local intra-aortic invasive blood pressure measurement is plotted against the average of these two techniques. The thick continuous lines depict the average relative difference between the techniques, whereas the dashed lines depict the variation (1.96 times the standard deviation each side) of the relative difference. Systolic blood pressure is underestimated by 5%, whereas diastolic pressure is overestimated by 12% by the brachial cuff compared with the invasively measured pressure.