[Silent ischemia versus angina in Tl-201 tomoscintigraphy]

The aim of this work was to describe the variables associated to silent ischemia in patients with reversible perfusion defects in poststress myocardial perfusion scintigraphy.

Tl-201 myocardial perfusion SPECT of 522 patients showing total or partially reversible perfusion defects after exercise testing were quantitatively analyzed retrospectively. Relationship between silent ischemia, size of perfusion defect and presence of risk factors was performed.

Ischemia was silent in 412 (73 %) patients. In 176 (33 %) patients exercise test was electrically positive. There were no differences in perfusion defect size between patients with and without angina in exercise test (27 +/- 12 vs 27 +/- 14), but patients with angina had a greater degree of reversibility, in left descending artery (LDA) territory (56 +/- 40 vs 45 +/- 40 p < 0.01). Silent ischemia was more frequently observed in patients with previous acute myocardial infarction (46 % vs 35 %). There was no relationship between the production of exertional angina and the presence of risk factors.

A high number of patients with reversible perfusion defects on SPECT had silent ischemia. Patients with angina during exercise test had more defect reversibility in LDA territory. Silent ischemia is more frequent in patients with previous acute myocardial infarction.