[Clinical significance of negative dipyridamole perfusion scintigram]

Six hundred seventy-one patients who had dipyridamole perfusion scintigraphy were classified into two groups; ie, 242 patients without perfusion defect (Group A) and 429 patients with perfusion defect (Group B). Clinical significance of negative scintigram was then assessed and correlated with coronary angiographic findings and prevalence of cardiac events. 1) Significant coronary artery disease (greater than 50% luminar narrowing) was present in 7 of 92 patients (8%) in Group A and in 235 of 285 patients (82%) in Group B. Multi-vessel coronary artery disease was found only in 2 patients (2%) in Group A and in 119 patients (42%) in Group B. 2) During a mean follow-up period of 29 months, 48 cardiac death (8%) and 19 nonfatal cardiac events (3%) occurred in 619 medically treated patients. These cardiac complications were observed in 7 of 242 patients (3%) in Group A and in 60 of 377 patients (16%) in Group B, including 4 (2%) and 44 (12%) cardiac deaths, respectively. In conclusion, it is rare to see severe organic coronary artery disease and future cardiac event in patients with negative dipyridamole perfusion scintigram. It may be, therefore, stated that it is unnecessary to perform coronary angiography in these patients, unless they have symptoms which cannot be controlled medically.