Inability of the submaximal treadmill stress test to predict the location of coronary disease

Two hundred patients had submaximal treadmill stress tests (STSTs) and selective coronary arteriography performed within 2 months of each other. An attempt was made to assess the predictability of disease isolated to any given coronary vessel by performance on the treadmill. This was not possible for disease isolated to the right coronary, the left anterior descending, the circumflex branch of the left coronary, or a combination of right coronary and circumflex arteries. Eleven patients had disease in the left main coronary artery; all had associated disease of some other branch as well. One of these patients had a negative submaximal treadmill stress test but was unable to reach 90% of his maximum predicted heart rate. The remaining 10 patients had positive STSTs. Patients with 26-50% narrowing of any branch had treadmill results similar to those with 51-75% narrowing. There was a large number of patients with single-vessel disease in the study and most of the negative STSTs occurred in this group. Nevertheless, within this group no one vessel gave a higher incidence of positive STSTs than any other. It is concluded that (1) a positive STST is more likely to be associated with increased severity and extent of coronary artery disease; (2) a negative STST is more likely to be found in disease limited to a single vessel; and (3) within the latter group, the STST is of no value in predicting the specific coronary artery involved.