Prognosis of PTCA application for infarcted myocardium without redistribution by stress Tl-201 myocardial scintigraphy

The purpose of this study was to establish the predictability of myocardial scintigraphy and two-dimensional echocardiography for improvement of myocardial perfusion in the infarcted area after percutaneous transluminal coronary angioplasty (PTCA). The subjects were 29 patients with prior myocardial infarction who underwent PTCA and had no redistribution on planar images. According to Tl uptake ratio after PTCA, 13 patients had more than 5% increase (Group I), and the other 16 patients had 5% or less increase (Group II). The initial Tl uptake ratio was determined using the polar map obtained from myocardial SPECT images; there was significant difference (p<0.01) between group I (57±6.3%) and group II (43±7.0%). On the basis of the presence or absence of redistribution on SPECT before PTCA, 8 patients in Group I and 6 patients in Group II had minimal redistribution (Subgroup M) and the other 5 in Group I and 10 in Group II had no redistribution (Subgroup N). The initial uptake ratios were similar in Subgroups M and N (56±7.4% vs. 58±4.5%) for Group I, nor was there any significant difference between Subgroup M (42±8.3%) and Subgroup N (44±6.5%) for Group II. Wall motion and thickness of the infarcted zone was assessed before and after PTCA using two-dimensional echocardiography. Six patients in Group I had improvement of the left ventricular wall motion abnormality, as assessed by wall motion score, but none of the patients in Group II had it (p<0.01). On the contrary, although thinning of the wall was observed in 11 patients in Group II, it was not observed in any patient in Group I (p<0.01). In conclusion, an initial Tl uptake ratio of more than 50% and no thinning of the left ventricular wall may have implications for surviving and hibernating myocardium, aiding in the assessment of improvement of the myocardium after PTCA. (N.K.)