Detection of restenosis after successful percutaneous transluminal coronary angioplasty by exercise thallium scintigraphy

The usefulness of serial exercise thallium scintigraphy (ETS) in the detection of restenosis after successful percutaneous transluminal coronary angioplasty (PTCA) was evaluated. The study was undertaken on 73 patients (45 without significant residual coronary stenosis; 28 with partial anatomic correction) who received coronary angiography (CAG) after over 6 month period following successful PTCA or after a recurrence of angina pectoris. ETS was performed serially before, soon after, at 3 months, and at 6 months after PTCA in order to determine the presence of chest pain (CP) and significant ST-segment depression (ST) during exercise, and of reversible defect (RD) in thallium images. Redistribution of 10 % or above on delayed images were considered as positive reversible defects. Restenosis was defined as an increase of the diameter stenosis of the dilated lesion above the 75 % level. Rate of restenosis was 29 % for patients followed for over 6 months with recurrences of angina early at 2.4 ± 1.9 months (mean ± SD). As to the positive ETS cases, 77 % were detected within the first 3 months, and 92 % whithin the 6 months. In the detection of restenosis, figures for RD sensitivity and specificity were 96 % and 88 % respectively, which were superior to those figures for CP (59 %, 85 %) and ST (74 %, 82 %). ETS was particularly useful in the identification of the restenotic vessel as well as in the detection of restenosis in patients with multi-vessel disease or partial anatomic correction, and thus has proven to be of extreme value in follow-up after PTCA. (author)