[The normal wall segment in coronary stenoses--a postmortal study (author's transl)].

In 384 stenotic coronary segments of extramural arteries (left main coronary artery, LAD, LCX, RCA) with degrees of obstruction greater than 50% (but less than 100%) when assessed histologically, the extent and incidence of the normal wall segment (NWS) analysed from the histological cross section were carefully evaluated. Incidence and extent of the NWS proved to be unexpectedly high: 45% of all obstructions showed a NWS of more than 25% and 74% a NWS of more than 8% of the total histological circumference of the coronary artery. Furthermore, 25% of all obstructions showed a NWS of more than 50% and 71% a NWS of more than 16% of the circumference of the residual lumen. The incidence of obstructions was highest in the LAD (41%) and lowest in the left main coronary artery (8%). In the three vessels of the left coronary artery (left main, LAD, LCX) excentric obstructions were seen more often than in the RCA. The results are discussed with regard to the pathogenesis esp. of unstable angina pectoris, but also to the pharmacological and mechanical dilatation of coronary obstructions.