Prognostic value of equivalents of transient myocardial ischemia, as evaluated by Thallium-201 stress scintigraphy in a population of 367 patients followed up to 5 years

From 1-1-1981 to 3-31-1985, 367 subjects (227 males and 140 females) were examined by means of Tl-201 myocardial scintigraphy for diagnostic purpose. A follow up period, 5 years maximum, was run in order to assess the prognostic value of the three equivalents of transient myocardial ischemia which can be demonstrated by the test (angina, reversible hypoperfusion, and ST-T segment changes). The end points were myocardial infarction and/or sudden death. Three hundred fifty-four patients complied (96%). During the observation period 9 severe ischemic events (SIE) occurred: 5 myocardial infarctions and 4 sudden deaths. As far as the predictivity of SIE is concerned, the t test for independent samples showed a statistically significant difference between the group of patients with no signs of ischemia and the group with positive scintiscan (p<0.05) and with the three equivalents of ischemia all together (p<0.05). Moreover, in the sub-group of patients with pathological scintigraphic results the probability for SIE to occur was statistically different in the patients with no hypoperfusion in the region supplied by the anterior descending coronary artery and in those with pathological scintigraphic findings in that region (p<0.05). In our opinion, the above data demonstrate the pathological signs noticeable with stress myocardial Tl-201 scintiscan to have prognostic value