Changing Concepts of the Role of Coronary

Acute myocardial infarction had generally been con-sidered to be the result of thrombotic occlusion of a major extramural coronary artery until postmortem observations of the infrequency of coronary thrombi began to accumulate in patients who died of extensive myocardial infarction. Roberts and Buja ' found coro-nary artery thrombi in 40 (54%) of 74 patients with transmural necrosis, in none of 9 with only subendocar-dial necrosis, and in 2 (8%) of 24 who died suddenly. On the basis of their own data and of the literature, which reported the frequency of coronary thrombosis in fatal acute myocardial infarction as ranging from 21 % to 91%, they claimed that coronary thrombi are conse-quences rather than causes of acute myocardial infarc-tion. Similar conclusions were reached by other investi