Hisayo Yamashina

Usefulness of 123I-metaiodobenzylguanidine myocardial scintigraphy for predicting the effectiveness of β-blockers in patients with dilated cardiomyopathy from the standpoint of long-term prognosis

PurposeThe usefulness of 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy in predicting the effectiveness of β-blocker therapy in dilated cardiomyopathy (DCM) was investigated from the standpoint of long-term prognosis.MethodsThe subjects were 53 DCM patients in whom β-blockers had been successfully introduced and used for 6 months or longer. When symptoms were stable before the introduction of β-blockers and for up to 1 year thereafter, MIBG myocardial single-photon emission computed tomography was performed and the images analysed to obtain the extent score (EXT), severity score (SEV) and washout rate (WR). At the same time, echocardiography was performed to measure left ventricular ejection fraction (LVEF). Thereafter, patients were placed under observation for an average of 1,314±986 days, with the occurrence of cardiac events as the endpoint.ResultsThe degree of improvement in WR after introduction of β-blockers was a significant predictor of cardiac events. In fact, none of the patients whose improvement in WR was valued at 10 or higher had cardiac events. Accordingly, using improvement in WR of 10 as the cut-off value, the patients were divided into two groups, “improved” and “unimproved”. There were significant differences between the groups in respect of early EXT, early SEV and WR before the introduction of β-blockers . As regards predictors of WR improvement, multivariate logistic regression analysis demonstrated that early EXT, WR and LVEF were significant predictors.ConclusionThis study shows that, from the standpoint of long-term prognosis, DCM patients who would benefit the most from β-blocker therapy are those with low early EXT and early SEV and high WR before β-blocker introduction regardless of LVEF values.

Usefulness of meta-[123I]iodobenzylguanidine myocardial scintigraphy for predicting cardiac events in patients with dilated cardiomyopathy who receive long-term beta blocker treatment.

ObjectiveLarge-scale clinical trials have demonstrated that beta blocker therapy improves the prognosis of dilated cardiomyopathy (DCM), but cardiac events sometimes occur even in patients showing favourable response to the therapy. In this study, the usefulness of meta-iodobenzyguanidine (MIBG) in predicting cardiac events was investigated in DCM patients successfully receiving long-term treatment with beta blockers. MethodsThe subjects were 53 patients with DCM (including 10 women; mean age, 56.5±10.9 years) who could continue beta blocker therapy for more than 6 months. MIBG was performed within 1 year of commencing the therapy. The extent score, severity score and washout rate were obtained from single photon emission computed tomography images. At the same time, left ventricular ejection fraction (LVEF) and left ventricular end diastolic diameters were measured by echocardiography. The endpoints were cardiac events (cardiac death and admission to hospital due to heart failure or arrhythmia), and patients were observed for an average of 1314±986 days (150–4100 days). ResultsCardiac events occurred in nine patients during the observation period. The multivariate statistical analysis demonstrated that the delayed extent score was the strongest significant predictive factor, (hazard ratio 1.036, P<0.01). while LVEF was not a predictive factor. Both the improvement of LVEF and MIBG were significant predictive factors. The improvement of washout rate was the strongest. ConclusionParameters of MIBG but not of LVEF were useful in predicting cardiac events in DCM patients whose condition had been successfully stabilized by the introduction of beta blockers.

Usefulness of123I-metaiodobenzylguanidine myocardial scintigraphy in the prediction of cardiac events in patients with cardiomyopathy showing stabilization of symptoms or preserved cardiac function

Objective: It is not rare for patients with cardiomyopathy to be asymptomatic for long periods or to show improved cardiac function following various medical interventions. Conversely, cardiac events sometimes occur in those patients, requiring close observation. We assessed the usefulness of123I-metaiodobenzylguanidine myocardial scintigraphy (MIBG) to predict the occurrence of cardiac events in patients with stable cardiomyopathy.Methods: The subjects comprised 74 outpatients with stable cardiomyopathy. MIBG was performed calculate the extent score, severity score, washout rate (WR), and heart-to-mediastinum ratio. At about the same time, the left ventricular ejection fraction (LVEF) by echocardiography and the plasma brain natriuretic peptide were measured. The mean observation period extended for 741 ± 437 days with an end point of cardiac events (cardiac death, heart failure requiring hospitalization, and arrhythmias requiring hospitalization).Results: During the mean follow-up period, 15 cardiac events occurred. Results of multivariate analysis revealed that LVEF was the most powerful predictor of cardiac events (0.006, p < 0.01). However, WR was the only significant predictor of hard events such as cardiac death (1.171, p < 0.001) and cardiac events in the group of patients who preserved cardiac function with LVEF 0.4 or higher (1.079, p < 0.05).Conclusion: Combined use of LVEF and WR is useful to predict the occurrence of cardiac events in patients with stable cardiomyopathy.

Clinical application of three-dimensional myocardial imaging: Evaluation of efficacy of medical treatment on myocardial perfusion

To investigate the clinical applicability of the three-dimensional (3D) myocardial imaging using a newly developed system (the Application Visualization System-Medical Viewer), thallium-201 myocardial single photon emission computed tomography was performed in 19 patients with previous myocardial infarction before and after treatment with nisoldipine. We have developed a new method for automatically reconstructing 3D imaging for the stereoscopic evaluation of myocardial perfusion. The left ventricular myocardial volume with a radioisotope count ≧ 50% of maximum was calculated by using the conventional surface rendering method. With these images, the effect of nisoldipine on myocardial perfusion was assessed and the myocardial volume with a radioisotope count ≧ 50% of maximum was compared. In fifteen (88%) of 19 patients, myocardial perfusion increased in the infarct areas after nisoldipine treatment. Nisoldipine significantly increased the myocardial volume with a radioisotope count ≧ 50% of maximum from 141 ± 17 to 153 ± 18 ml on the stress 3D imagings. These findings indicate that nisoldipine improved myocardial perfusion during exercise. 3D imaging provided stereoscopic assessment of the changes in myocardial perfusion following treatment with nisoldipine and also detected transient enlargement of the left ventricular lumen induced by exercise.