Predictability of stress-induced myocardial ischemia from coronary arteriography in patients with organic coronary artery stenosis

To establish the most meaningful scoring system, we developed the grading of stenosis which is ''critical'' or significant in the single-, double-, and triple-vessel method (SDT), and the extent of improvement in the predictive value which may be induced by accounting for the predominance of the three major coronary arteries nourishing the left ventricle. Thirty-three patients (six were women), whose average age was 58.6 years, all having exertional angina pectoris and fixed organic coronary artery stenosis documented by coronary arteriography, but no old myocardial infarction, were the subjects of this study. For these patients the mean redistribution index (RDI) was determined by ergometer stress myocardial perfusion imaging using 201Tl. The number (nST) of significant ST segment depressions by body surface ECG mapping after treadmill stress tests was compared with the Σ Pujadas grade, which is the sum of each grade assigned to each of the three major coronary arteries, and with the Pujadas score, which is the weighted sum of grades by dominance in the coronary artery distribution. The SDT method was a better predictor of ischemia if the criterion for critical stenosis is selected at a more severe stenosis (greater than 90 % diameter stenosis). Among factors predicting ischemia, the length of the stenosis and the presence of collaterals did not seem to be definitive. However, the distribution of the arteries was an important factor. Thus, the Pujadas score system was a highly sensitive and specific method for predicting ischemia during stress as assessed by combined nST and RDI. However, we have to need improve the method by adding otherinformation regarding blood flow and by using quantitative angiographic techniques which are objective in outlining the extent of the coronary artery disease. (J.P.N.)