Toshio Iizuka

Redistribution in Thallium-201 Myocardial Imaging Soon After Successful Coronary Stenting

To evaluate the clinical significance of reversible perfusion defects that were observed soon after the successful deployment of a coronary stent, 47 patients underwent thallium-201 myocardial scintigraphy and radionuclide angiography in conjunction with adenosine-induced coronary hyperemia before and after complete revascularization. Coronary angiography showed a significant decrease in the percent diameter stenosis (from 87+/-11% before stenting to -1+/-5% after stenting, p<0.01) with no major dissection, residual stenosis, or intra-stent formation of thrombus. Even after the angiographically successful procedure, reversible perfusion defects were present in 17 (36%) of the 47 patients, none of whom showed any wall motion abnormalities during the infusion of adenosine. Disease duration was significantly longer and collateral vessels were more common in the patients with than in those without thallium redistribution, whereas the other clinical, pre- and post-stent angiographic and hemodynamic factors were similar. In conclusion, reversible perfusion defects without wall motion abnormalities were demonstrated during the infusion of adenosine in approximately one-third of patients soon after coronary stenting, and were not consistently related to acute unfavorable outcomes of stent placement.

Predictive value of left ventricular response to exercise in patients with dilated cardiomyopathy--assessment by radionuclide ventriculography.

The objective of this study was to determine noninvasively the likelihood of recovery of the left ventricular ejection fraction (LVEF) in patients with dilated cardiomyopathy (DCM) verified by radionuclide ventriculography. Twenty patients with DCM were clas sified into two groups according to the LVEF by M-mode echocardiographic findings two years after ventriculographic examination. The LVEF recovered to ≥ 50% in 10 patients (Group A), while it was sustained at < 50% in 10 patients (Group B). The clinical features of each group were compared, based on results of physical examination, radionuclide ventriculography, and other diagnostic tests performed on their referral to hospital. Only the systolic blood pressure differed significantly between the two groups, being slightly, but significantly, increased in Group A over that in Group B (P < 0.05). LVEF at rest by radionuclide did not differ (Group A: 31.5 ±10.3% vs Group B: 26.5 ±9.4%). Peak exercise EF-EF at rest (peak Δ EF) in Group A was apparently increased (3.4 ±4.0%), while that in Group B was decreased (-4.4 ±5.2%). The positive peak Δ EF had a highly predictive value of 90% for patients with DCM whose LVEF will recover to more than 50%. The recovery EF-EF at rest did not differ significantly between groups (Group A: 8.4 ±4.7 vs Group B: 3.9 ±2.3, P < 0.05). Other clinical parameters such as functional class, cardiothoracic ratio, LVEF by echocardiography, cardiac index by Swan-Ganz catheter examination, and histologic examination of biopsied endocardium were indistinguish able in the two groups. The authors conclude that peak Δ EF of radionuclide ventricu lography on exercise indicates a preservation of LVEF and predicts a good clinical recovery in patients with DCM.