Comparison of results of intracoronary implantation of the Plamaz-Schatz stent with conventional balloon angioplasty in chronic total coronary arterial occlusion.

We compared angiographic and clinical outcomes after successful revascularization of chronic total coronary arterial occlusion with the placement of the Palmaz-Schatz stent (43 patients) and conventional balloon angioplasty (53 patients). After the procedure, the coronary stent led to a greater minimal lumen diameter than conventional balloon angioplasty (2.6 vs 1.7 mm, p < 0.001), resulting in a smaller residual stenosis (6.5% vs 36.7%, p < 0.001). At 6-month follow-up, there was no significant difference in late loss between the groups, resulting in a larger minimal lumen diameter at follow-up in the stent group (1.8 vs 1.1 mm, p < 0.001). The incidence of restenosis was lower in the stent group (27.9% vs 56.6%, p < 0.005). The frequency of the combination of myocardial infarction and coronary artery bypass graft surgery tended to be less in the stent group (2.3% vs 11.3%, P = 0.09). Placement of the Palmaz-Schatz stent improved left ventricular ejection fraction by 26% in patients who had reduced left ventricular function (p < 0.05), but conventional balloon angioplasty did not. Thus, placement of the Palmaz-Schatz stent provided a wider lumen than did conventional balloon angioplasty and, therefore, reduced the incidence of restenosis in chronic total coronary arterial occlusion. The lower restenosis rate of coronary stenting would be beneficial for long-term clinical outcome in patients with chronic total occlusion.

Prediction of functional recovery and prognosis in patients with acute myocardial infarction by 123I-BMIPP and 201Tl myocardial single photon emission computed tomography: a multicenter trial.

123I-BMIPP [15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid] was developed for metabolic imaging with SPECT. A multicenter collaborative study was conducted on a large patient series to determine whether 123I-BMIPP and 201Tl myocardial SPECT are of use in predicting the prognosis and ventricular function after acute myocardial infarction (AMI). Patients with uncomplicated first AMI underwent resting 123I-BMIPP and 201Tl myocardial SPECT in the subacute phase after the onset of AMI. Of these, 167 patients who had been followed up for an average of 22 months were retrospectively reviewed to predict serious cardiac events and recurrent ischemia. In addition, the association between changes in radionuclide parameters and recurrent ischemia was investigated in Subgroup A (58 patients) who had repeated SPECT in the chronic phase. Furthermore, prediction of the ejection fraction (EF) was investigated in Subgroup B (94 patients) and Subgroup C (76 patients) in whom left ventriculography was performed at the time of discharge and 90 days or more after the onset, respectively. The prognosis was generally favorable, with 4 cases of cardiac death (2%), 3 of heart failure (2%), 4 of nonfatal reMI (2%), and 25 of recurrent ischemia (15%). The results of Cox multivariate regression analysis revealed a high probability of serious cardiac events in patients who were elderly (p = 0.04), who had 90% or more residual stenosis of the infarct-related artery (p = 0.09), and who had a high BMIPP defect score (p = 0.17). There was a high probability of recurrent ischemia in elderly patients (p = 0.10) who had multi-vessel disease (p = 0.03), but no association was found with radionuclide parameters in the subacute phase. In Subgroup A, however, the probability of recurrent ischemia tended to be high in patients with a large mismatch scorebetween 123I-BMIPP and 201Tl in the subacute to chronic phase. An important observation was that the extent of BMIPP defect was more strongly correlated with EF at the time of discharge and 90 days or more after the onset than the extent of Tl defect (r = -0.60 vs. r = -0.47, and r = -0.53 vs. r = -0.43, respectively). In addition, multiple regression analysis showed that parameters related to the BMIPP defect were also better predictive factors of EF both at the time of discharge and 90 days or more after the onset. In conclusion, resting 123I-BMIPP and 201Tl myocardial SPECT performed in the subacute phase of AMI were shown to be useful in predicting prognosis and ventricular function for patient management.

Assessment of left ventricular dysfunction by thallium-201 lung uptake during exercise in coronary artery disease.

To determine the clinical significance of an increased thallium-201 (Tl-201) activity in the lung and of its clearance from the lung after exercise, computer-quantitated Tl-201 lung activity was measured and compared with hemodynamic parameters at rest and during exercise in 35 patients with coronary artery disease (CAD). All patients underwent a supine bicycle ergometer exercise test and mean pulmonary artery wedge pressure (PAWP) was measured by a Swan-Ganz catheter. Coronary angiography was also performed. On computer-generated initial and 2 and a half hours delayed anterior images, regions of interest were selected over the myocardium (M) and lung (L), and the initial L/M ratio and the (initial L)/(delayed L) ratio were calculated as indices of an increased Tl-201 lung uptake and lung clearance, respectively. The initial L/M ratio and the (initial L)/(delayed L) ratio had no significant correlation with mean PAWP at rest and had a weak negative correlation with the resting ejection fraction (r = -0.57 and r = -0.58, respectively). However, both ratios showed good correlations with mean PAWP during peak exercise (r = 0.85 and r = 0.80, respectively), suggesting that they provide useful indices for assessing the severity of exercise-induced left ventricular dysfunction.

[Clinical usefulness of exercise-nitroglycerin myocardial imaging using dual administration of thallium-201].

In order to differentiate transient myocardial ischemia from infarction, the delayed thallium-201 myocardial imaging (redistribution image) is widely utilized, however, the precise mechanism of redistribution remains unsolved. In the present study, we proposed a new method to elucidate myocardial ischemia on images. In normal subjects, patients with old myocardial infarction (OMI) without angina pectoris (AP) and patients with AP, 1.4 mCi of thallium-201 (Tl-201) was intravenously injected at the peak exercise, and immediately myocardial images were obtained in the three projections. Then, 0.3 mg of nitroglycerin (NTG) was sublingually given, and 0.6 mCi of Tl-201 was readministered. NTG myocardial images were analyzed in the left anterior oblique projection and evaluated visually and quantitatively. There was no significant difference in the relative activity on exercise to NTG images in normal subjects and patients with OMI, while patients with AP showed increased activity on exercise to NTG images. Furthermore, the increase in relative activity done by the exercise-nitroglycerin study was greater than that by the conventional exercise-redistribution study in patients with AP. It was concluded that a new method in the present study is able to image myocardial ischemia distinctly and could be useful in clinical studies.

[Tl-201 single-photon emission computed tomography for clinical assessment of dilated cardiomyopathy].

In some cases of dilated cardiomyopathy (DCM) perfusion defects are demonstrable by Tl-201 imaging at rest. This study clarified the mechanism by which the Tl scan can show myocardial perfusion defects in patients with DCM by means of Tl-201 single-photon emission computed tomography (ECT) utilizing a rotating gamma camera to assess three-dimensional T1 distribution in the myocardium. Thirteen patients with DCM were studied by conventional planar and ECT imaging, and the degree of defects was determined visually. Perfusion defects were observed in 11 of 13 cases (85%) by planar imaging and in all 13 (100%) by ECT imaging. The mean defect score was higher in ECT than in planar imaging (4.15 +/- 1.46 vs 2.23 +/- 1.46, p less than 0.025). A comparative study of defect scores and left ventricular ejection fractions (EF) using gated cardiac blood pool scans established a negative correlation on ECT imaging (r= -0.64), and no correlation on planar imaging (r= -0.38). There was no statistically significant correlation between perfusion defects on planar imaging and regional wall motion abnormalities as observed by two-dimensional echocardiography (2-DE). In contrast, most of the segments with severe defects (defect score greater than or equal to 2) on ECT images showed high grade wall motion abnormalities on 2-DE. Both perfusion defects and wall motion abnormalities in DCM may be closely related to the fibrosis or scar formation in the myocardium. These results indicated that T1-201 myocardial scintigraphy, especially ECT imaging, is of great value in the clinical assessment of patients with DCM.

[Clinical significance of early redistribution of the exercise-induced thallium-201 defect in ischemic heart disease].

This study clarified thallium-201 (Tl) kinetics in the early stage after exercise in patients with ischemic heart disease (IHD). Tl was administered for 39 patients with IHD and eight normal subjects during maximal exercise. Immediately after exercise, dynamic data were obtained using a double slant-hole collimator at one frame/2 min for a 20 min period. The data of 10 frames (20 min) were spatially smoothed, and semiquantitative segmental analyses of the uptake and kinetics of Tl were performed by computer. In eight normal subjects, Tl uptake was uniform throughout the continuous 20 min, and Tl activity was unchanged throughout the 20 min period after exercise. Among 39 patients with IHD, 39 had Tl defects in the first frame (initial defect). Among 39 initial defects, 15 (38%) showed complete or partial early redistribution as early as 20 min and Tl activity in the defect increased (10.5 +/- 1.5%) over the 20 min period. Early redistribution occurred in 10 (43%) of 23 patients with effort angina and in five (83%) of six patients with variant forms of angina, but in no patients with myocardial infarction. Patients with early redistribution showed a greater frequency either of good collateral vessels or of mild stenosis of the coronary artery, compared with those who had no early redistribution. In conclusion, analysis of Tl kinetics in the early stages after exercise can provide important information about the coronary perfusion state during recovery from transient ischemia, and early redistribution may be a sign of preserved hyperemic flow in the ischemic region.