Quantitative assessment of changes in aortic dimensions in response to in situ perfusion fixation at physiological pressures.

The study of atherosclerosis often involves evaluation of aortic tissue. The effects of the fixation process on aortic dimensions is and issue of concern. Using aortography we have quantitatively assessed changes in aortic dimensions during in situ perfusion fixation at physiological pressures with 2 commonly used fixative solutions. Two dimensional aortic luminal (TDAL) areas, obtained by planimetry from X-ray images after opaque dye injection (aortography), decreased both early during perfusion fixation and later with cessation of the physiological pressure. These reductions were variable, irrespective of the fixation solution used. Long-term perfusion fixation (10 1/2-12 h) reduced, but did not prevent, changes in TDAL area compared with changes observed following a 1-h perfusion fixation period.