An assessment of the distortion of arteries due to sectioning in endomyocardial biopsies.

Arteries are usually studied morphometrically after pressurized fixation and resin embedding. These procedures are impracticable when dealing with diagnostic biopsies. The accuracy of arterial morphometry is determined partly by the degree of tissue distortion during section preparation. The axial ratios of 7340 arteries were measured in 353 endomyocardial biopsies from 23 patients and then compared with those expected from mathematical modelling. An excess of elliptical arteries was found. The distribution of orientation of the long axes of these best fitted a simulated 10 per cent linear distortion in the direction of microtomy. In conclusion, these results suggest that although there is some tissue distortion during sectioning, useful data may be obtained from morphometry of arteries in routinely processed endomyocardial biopsies.