TC-99M-ISONITRILE SPET IN THE ASSESSMENT OF MULTIVESSEL CORONARY-ARTERY DISEASE

Objective. The aim of the study was to evaluate the diagnostic yield o f 99m-Technetium-methoxy-isobutyl-isonitrile (MIBI) SPET for identific ation of individual coronary artery disease and in the prediction of m ultivessel involvement. Methods. Stess/rest myocardial SPET and corona ry arteriography were evaluated in 231 consecutive patients Cage 58 +/ - 10 years, 26% women) without prior myocardial infarction. 149 patien ts had coronary narrowing > 50%: 104 with multivesel disease and 45 wi th one vesel disease. Tomographic stress defect score was obtained by semiquantitavive analysis (maximal score 65). Univariate and multivari ate analysis was performed to identify discriminant parameters between one vesel and multivesel patients. Results. The sensitivity and speci ficity for the identification of individual artery disease was 74% and 85% for left anterior descending artery, 79%, and 85% for right coron ary and 45% and 96% for circumflex artery. In the predicction of multi vessel involvement the sensitivity was 65%, specificity 87%, positive predictive value 81% and negative predictive value 76%. In the bivaria te analysis, four parameters differed significantly between one vesel and multivesel disease patients: ST downslope > 1 mm (p = 0.01), ST do wnslope/heart rate corrected (p = 0.005), reversible defects in two or more regions (p = 0.009) and SPET score (p = 0.002). In the multivari ate analysis the probability of multivesel disease was 90% when ST dep ression >1 mm and SPET score >20 were associated and the probability w as lowered to 16% when these criteria mere not present. Conclusion. My ocardial SPET with MIBI offers an accurate localization of individual coronary artery disease, mainly in left anterior descending artery and right coronary artery lesions, Combined evaluation of ST depression a nd extension of myocardial stress defects improved prediction of multi vessel involvement.