Prognostic value of myocardial perfusion scintigraphy in type 2 diabetic patients with mild, stable angina pectoris

Aim: To determine the prognostic value of reversible myocardial perfusion defects on myocardial perfusion scintigraphy (MPS) in patients with type 2 diabetes mellitus and mild anginal complaints. Methods and results: In the MERIDIAN trial, patients with diabetes mellitus type 2, stable, mild anginal symptoms (Canadian Cardiovascular Society classification (CCS) I-II/IV) and reversible perfusion defects were randomized to either continued pharmacological treatment or early invasive treatment. In this sub analysis, the severity of the myocardial perfusion defect was related to the occurrence of cardiac death and non-fatal myocardial infarction, in 319 patients (63% male, 65 ± 9 years). During follow-up (2.2 ± 0.6 years), 14 patients had a cardiac event: 3 in 171 patients without myocardial ischemia and 11 in 148 patients with myocardial ischemia. Annual event rates rose from 0.8% to 5.8% with increasing severity of myocardial ischemia. Multivariable analysis identified the presence of severe myocardial ischemia (hazard ratio (HR) 5.45, 95%CI 1.89-15.71) and insulin use (HR 4.00, 95%CI 1.25-12.75) as independent predictors of cardiac events. Conclusions: Type 2 diabetics with mild anginal symptoms with no or moderate myocardial ischemia have a low annual cardiac event rate. In patients with severe myocardial ischemia event rate increased 3-6 fold

Warranty period of normal stress myocardial perfusion imaging in diabetic patients: A propensity score analysis

Background: We evaluated the relationship between diabetes and temporal characteristics of cardiac risk at long-term follow-up in a propensity score-matched cohort of diabetic and non-diabetic patients with normal stress myocardial perfusion single-photon emission computed tomography (MPS). Methods and Results: We studied 828 consecutive patients with suspected or known coronary artery disease and normal perfusion at stress MPS. To account for differences in baseline characteristics between diabetics and non-diabetics, we created a propensity score-matched cohort considering clinical variables and stress type. After matching, clinical characteristics were comparable in 260 diabetic and 260 non-diabetic patients. All patients were followed for at least 1 year (median 53 months). End-point events were cardiac death or nonfatal myocardial infarction. At Cox analysis, diabetes (hazard ratio 3.9, P <.01) and post-stress left ventricular ejection fraction (LVEF) (less-than or equal to)45% (hazard ratio 4.1, P <.01) were independent predictors of events. At parametric analysis, non-diabetic patients with post-stress LVEF >45% remained at low risk for the entire length of follow-up, while the highest probability of events and the major risk acceleration was observed in patients with diabetes and post-stress LVEF (less-than or equal to)45%. Conclusions: After a normal stress MPS, diabetic patients are at higher risk for cardiac events than non-diabetic subjects also after balancing clinical characteristics and stress type by propensity score analysis. The warranty period of a normal stress MPS varies according to diabetic status and post-stress LVEF. (copyright) 2013 American Society of Nuclear Cardiology

Nuclear Imaging to Assess Infarction, Reperfusion, No-Reflow, and Viability

Thrombolytic therapy and primary percutaneous coronary have improved the survival of patients with acute myocardial infarction. However, this superior survival leads to an increased prevalence of left ventricular systolic dysfunction and development of heart failure at follow-up. Nuclear imaging permits comprehensive evaluation of patients with coronary artery disease. In the setting of acute myocardial infarction, 99mTc-sestamibi SPECT provides information on myocardium at risk, infarct size and myocardial salvage, well-known measures of the efficacy of reperfusion therapy, and important prognostic markers. In addition, nuclear imaging permits the assessment of no-reflow phenomenon that may take place during thrombolysis or percutaneous revascularization techniques. Timely detection of this phenomenon may help to select the most appropriate therapies to improve the microcirculation of the infarcted areas and, consequently, to improve the contractile function of the myocardium at follow-up. Furthermore, nuclear imaging plays a central role in the evaluation of ischemic heart failure patients with a substantial amount of dysfunctional but viable myocardium who may benefit from coronary revascularization with significant improvements in left ventricular function, heart failure symptoms, and prognosis. This chapter will review the role of nuclear imaging in acute myocardial infarction, with special focus on the relevance of this technique to assess the efficacy of reperfusion therapy. In addition, a detailed appraisal of multimodality imaging for noninvasive assessment of hibernating myocardium will be provided

Cintilografia de perfusão miocárdica sob baixa dose de dobutamina na identificação do miocárdio viável Low-dose dobutamine myocardial perfusion scintigraphy in the identification of viable myocardium

OBJETIVO: Verificar se a cintilografia de perfusão miocárdica duoisotópica(99mTc-sestamibi/tálio-201), método de alta sensibilidade para identificação do músculo viável, tem sua especificidade aumentada com a inclusão de informações sobre reserva contrátil miocárdica obtidas simultaneamente através de gated SPECT na vigência de baixas doses de dobutamina de forma semelhante ao ecocardiograma. MATERIAIS E MÉTODOS: Estudaram-se 260 segmentos miocárdicos de 13 pacientes com infarto do miocárdio, encaminhados para pesquisa de viabilidade antes do procedimento de revascularização. Avaliaram-se a integridade celular e a reserva contrátil pela cintilografia de perfusão miocárdica duoisotópica com imagens de repouso e redistribuição do tálio-201 e de estresse (99mTc-sestamibi gated SPECT), em condições basais e na vigência de baixas doses de dobutamina. A melhora do desempenho contrátil em controle cintilográfico pós-revascularização (99mTc-sestamibi gated SPECT) confirmava a presença de viabilidade. Para análise dos resultados quantificaram-se os parâmetros funcionais dos segmentos miocárdicos nas diferentes etapas do estudo, estratificando-os quanto à viabilidade para posterior comparação funcional pós-revascularização. RESULTADOS: No tratamento estatístico a análise do espessamento sistólico se destacou como parâmetro de avaliação da reserva contrátil miocárdica pelo método, mostrando tendência a incremento na especificidade (84%), demonstrando valores superiores aos da literatura. CONCLUSÃO: O método tende a apresentar contribuições efetivas na busca do miocárdio viável.<br>OBJECTIVE: To evaluate the increase in specificity of dual isotope myocardial perfusion gated SPECT (99mTc-sestamibi/thallium-201), a highly sensitive method to detect viable myocardium, with addition of data on contractile reserve simultaneously acquired by low-dose dobutamine gated SPECT, similarly to echocardiography. MATERIALS AND METHODS: A total of 260 myocardial segments were assessed in 13 patients with myocardial infarction referred for investigation of myocardial viability before undergoing revascularization. Cellular integrity and contractile reserve were evaluated by dual isotope perfusion myocardial gated SPECT with thallium rest and redistribution images and post-stress 99mTc-sestamibi gated-SPECT images under basal conditions and with low-dose dobutamine. The improvement in the contractile performance detected by post-revascularization 99mTc-sestamibi gated SPECT was the parameter considered for determining myocardial viability. For the purpose of results analysis, the functional parameters of the myocardial segments were quantified at the different phases of the study and stratified according to their viability for a later post-revascularization functional comparison. RESULTS: In the statistical analysis, systolic wall thickening demonstrated to be a relevant parameter in the evaluation of myocardial contractile reserve by this method, with a tendency of improvement in the specificity (84%), demonstrating higher values than those observed in the literature. CONCLUSION: This method tends to present an effective contribution in the assessment of myocardial viability

Prognostic value of myocardial perfusion scintigraphy in elderly patients with hypertension: a 10-year follow-up analysis

The aim of the study was to assess the role of myocardial perfusion scintigraphy (MPS) in the prediction of future cardiac events in elderly hypertensive patients and to investigate if its prognostic value is maintained during a 10-year follow-up period.A total of 229 consecutive patients a parts per thousand yen 65 years old (range 65-88 years) with arterial hypertension, who were referred to our institution for stress/rest Tc-99m-sestamibi MPS between January 2000 and November 2001, were followed up for 10-12 years. Cardiac death, myocardial infarction and a coronary revascularization procedure were considered as events. Survival curves were computed by the Kaplan-Meier method. A stepwise Cox proportional hazards analysis was used to identify predictors of events.Follow-up was completed in 221 (96.5 %) patients; 26 patients experienced cardiac death, 29 myocardial infarction and 51 coronary revascularization. Annual event rates for cardiac death, cardiac death/myocardial infarction and cardiac death/myocardial infarction/coronary revascularization were, respectively, 0, 0.2 and 0.4 % for patients with a normal scan and 1.5, 3.0 and 5.3 % after an abnormal MPS. Event-free survival was significantly different according to extent and severity of perfusion defects (all p < 0.01). An increase in global chi-square in predicting cardiac events occurred when MPS data were added to pre-scan information (from 47.28 to 88.87; p < 0.001).MPS provides incremental prognostic information for the prediction of cardiac events in elderly patients with hypertension. Subjects with a normal scan have an excellent 10-year outcome, and the risk of experiencing a cardiac event increases with extension and severity of stress perfusion defect