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BACKGROUND: Heat extremes are associated with greater risk for cardiovascular death. The pathophysiologic mechanisms mediating this association are unknown. OBJECTIVE: To quantify the myocardial blood flow (MBF) requirements of heat exposure. DESIGN: Experimental study. (ClinicalTrials.gov: NCT04549974). SETTING: Laboratory-based. PARTICIPANTS: 61 participants, comprising 20 healthy young adults (mean age, 28 years), 21 healthy older adults (mean age, 67 years), and 20 older adults with coronary artery disease (CAD) (mean age, 70 years). INTERVENTION: Participants were heated until their core temperature increased 1.5 °C; MBF was measured before heat exposure and at every increase of 0.5 °C in core temperature. MEASUREMENTS: The primary outcome was MBF measured by positron emission tomography-computed tomography. Secondary outcomes included heart rate, blood pressure, and body weight change. RESULTS: At a core temperature increase of 1.5 °C, MBF increased in healthy young adults (change, 0.8 mL/min/g [95% CI, 0.5 to 1.0 mL/min/g]), healthy older adults (change, 0.7 mL/min/g [CI, 0.5 to 0.9 mL/min/g]), and older adults with CAD (change, 0.6 mL/min/g [CI, 0.3 to 0.8 mL/min/g]). This represented a 2.08-fold (CI, 1.75- to 2.41-fold), 1.79-fold (CI, 1.59- to 1.98-fold), and 1.64-fold (CI, 1.41- to 1.87-fold) change, respectively, from preexposure values. Imaging evidence of asymptomatic heat-induced myocardial ischemia was seen in 7 adults with CAD (35%) in post hoc analyses. LIMITATIONS: In this laboratory-based study, heating was limited to about 100 minutes and participants were restricted in movement and fluid intake. Participants refrained from strenuous exercise and smoking; stopped alcohol and caffeine intake; and withheld ß-blockers, calcium-channel blockers, and nitroglycerin before heating. CONCLUSION: Heat exposure that increases core temperature by 1.5 °C nearly doubles MBF. Changes in MBF did not differ by age or presence of CAD, but some older adults with CAD may experience asymptomatic myocardial ischemia. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research.
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Doença da Artéria Coronariana , Circulação Coronária , Temperatura Alta , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pressão Sanguínea/fisiologia , Doença da Artéria Coronariana/fisiopatologia , Doença da Artéria Coronariana/diagnóstico por imagem , Circulação Coronária/fisiologia , Frequência Cardíaca/fisiologia , Temperatura Alta/efeitos adversos , Tomografia por Emissão de Pósitrons combinada à Tomografia ComputadorizadaRESUMO
BACKGROUND: Given the limited access to invasive vasospastic reactivity testing in Western Countries, there is a need to further develop alternative non-invasive diagnostic methods for vasospastic angina (VSA). Hyperventilation testing (HVT) is defined as a class IIa recommendation to diagnose VSA by the Japanese Society of Cardiology. METHODS: In this systematic review and meta-analysis reported according to the PRISMA statement, we review the mechanisms, methods, modalities and diagnostic accuracy of non-invasive HVT for the diagnostic of VSA. RESULTS: A total of 106 articles published between 1980 and 2022 about VSA and HVT were included in the systematic review, among which 16 were included in the meta-analysis for diagnostic accuracy. Twelve electrocardiogram-HVT studies including 804 patients showed a pooled sensitivity of 54% (95% confidence intervals [CI]; 30%-76%) and a pooled specificity of 99% (95% CI; 88%-100%). Four transthoracic echocardiography-HVT studies including 197 patients revealed a pooled sensitivity of 90% (95% CI; 82%-94%) and a pooled specificity of 98% (95% CI; 86%-100%). Six myocardial perfusion imaging-HVT studies including 112 patients yielded a pooled sensitivity of 95% (95% CI; 63%-100%) and a pooled specificity of 78% (95% CI; 19%-98%). Non-invasive HVT resulted in a low rate of adverse events, ventricular arrhythmias being the most frequently reported, and were resolved with the administration of nitroglycerin. CONCLUSIONS: Non-invasive HVT offers a safe alternative with high diagnostic accuracy to diagnose VSA in patients with otherwise undiagnosed causes of chest pain.
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Vasoespasmo Coronário , Ecocardiografia , Eletrocardiografia , Hiperventilação , Humanos , Hiperventilação/diagnóstico , Hiperventilação/fisiopatologia , Vasoespasmo Coronário/diagnóstico , Vasoespasmo Coronário/fisiopatologia , Angina Pectoris/diagnóstico , Angina Pectoris/fisiopatologia , Sensibilidade e Especificidade , Imagem de Perfusão do MiocárdioRESUMO
Myocardial inflammation plays a central role in the pathophysiology of various cardiac diseases. While FDG-PET is currently the primary method for molecular imaging of myocardial inflammation, its effectiveness is hindered by physiological myocardial uptake as well as its propensity for uptake by multiple disease-specific mechanisms. Novel radiotracers targeting diverse inflammatory immune cells and molecular pathways may provide unique insight through the visualization of underlying mechanisms central to the pathogenesis of inflammatory cardiac diseases, offering opportunities for increased understanding of immunocardiology. Moreover, the potentially enhanced specificity may lead to better quantification of disease activity, aiding in the guidance and monitoring of immunomodulatory therapy. This review aims to provide an update on advancements in non-FDG radiotracers for imaging myocardial inflammatory diseases, with a focus on cardiac sarcoidosis, myocarditis, and acute myocardial infarction.
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Vasospastic angina (VSA), or variant angina, is an under-recognized cause of chest pain and myocardial infarction, especially in Western countries. VSA leads to a declined quality of life and is associated with increased morbidity and mortality. Currently, the diagnosis of VSA relies on invasive testing that requires the direct intracoronary administration of ergonovine or acetylcholine. However, invasive vasoreactivity testing is underutilized. Several non-invasive imaging alternatives have been proposed to screen for VSA. This review aims to discuss the strengths and limitations of available non-invasive imaging tests for vasospastic angina.
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Vasoespasmo Coronário , Humanos , Qualidade de Vida , Ergonovina , Eletrocardiografia , Acetilcolina , Angiografia Coronária/métodosRESUMO
BACKGROUNDS: High-degree atrioventricular block (AVB) recovery in CS has been shown to be highly variable despite immunosuppressive treatment, with no reliable tool available to predict odds of reversibility. This study sought to evaluate the potential of combined fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and resting myocardial perfusion imaging (rMPI) to predict reversibility of newly diagnosed high-grade AVB in cardiac sarcoidosis (CS). METHODS: We performed a single-center, retrospective analysis of patients with CS presenting with high-grade AVB who underwent combined FDG-PET/CT and rMPI. The 2016 JCS and the 2014 HRS diagnostic criteria were used for the diagnosis of CS. Patients with a history of coronary artery disease or prior immunosuppressive treatment were excluded. Patients were divided into AVB recovery and non-recovery subgroups. CS disease staging was based on FDG-PET and rMPI findings: (Stage 0) normal FDG-PET and rMPI (Stage 1) positive FDG-PET and normal rMPI (Stage 2) positive FDG-PET with perfusion deficits on rMPI (Stage 3) normal FDG-PET with perfusion deficits on rMPI. RESULTS: Twenty-seven patients, including 13 demonstrating AVB recovery, were identified. Eleven out of fourteen (78.6%) patients presenting with stage 1 CS demonstrated AVB recovery. Stage 1 CS was significantly more present in the recovery group compared to the non-recovery group (84.6% vs 21.4%, P = .002). Eleven presented with stage 2 CS, with only 2 (18.2%) recovering AV nodal conduction. Stage 2 CS presented more frequently in the non-recovery group (64.3% vs 15.4%, P = .020). CONCLUSIONS: Combined FDG-PET and rMPI employed to stage CS disease presenting with high-degree AVB appears to have good performance for predicting likelihood of recovery.
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Bloqueio Atrioventricular , Cardiomiopatias , Imagem de Perfusão do Miocárdio , Miocardite , Sarcoidose , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Fluordesoxiglucose F18 , Bloqueio Atrioventricular/diagnóstico por imagem , Estudos Retrospectivos , Cardiomiopatias/diagnóstico , Imagem de Perfusão do Miocárdio/métodos , Compostos Radiofarmacêuticos , Tomografia por Emissão de Pósitrons , Sarcoidose/complicações , Sarcoidose/diagnóstico por imagem , ImunossupressoresRESUMO
BACKGROUND: We examined the use of [18F]FDG-PET/CT for the diagnosis of native valve endocarditis (NVE). METHODS: PET/CT images in patients with suspected NVE were retrospectively reviewed independently by two experienced physicians blinded to all clinical information. The gold standard consisted of surgical findings, when available, or the modified Duke criteria. RESULTS: Fifty four subjects were included, 31 (57%) with a diagnosis of NVE. [18F]FDG-PET/CT correctly identified 21/31 (67.7%) subjects, yielding a sensitivity and specificity of 68% (95% CI 49-83%) and 100% (95% CI 85-100%), respectively. The sensitivity and specificity of the modified Duke criteria were 48% and 74%, respectively. Positive and negative predictive values of PET were 100% (95% CI 84-100%) and 70% (95% CI 51-84%), respectively. Modifying the Duke criteria to include [18F]FDG-PET positivity as a major criterion increased sensitivity to 77% without affecting specificity and led to the correct reclassification of 8/18 (44.4%) subjects from Possible IE to Definite IE. CONCLUSION: The addition of a positive [18F]FDG-PET/CT as a major criterion in the modified Duke Criteria improved performance of the criteria for the diagnosis of NVE, particularly in those subjects with Possible IE.
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Endocardite , Fluordesoxiglucose F18 , Endocardite/diagnóstico por imagem , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Compostos Radiofarmacêuticos , Estudos RetrospectivosRESUMO
BACKGROUND: Pyrophosphate (PYP) scintigraphy provides high diagnostic accuracy for the detection of transthyretin (ATTR) cardiac amyloidosis (CA). There has recently been emerging interest in using 18F-sodium fluoride (NaF) for this application, yet its sensitivity has never been directly compared to that of PYP, the current molecular gold standard METHODS: Twelve subjects with ATTR-CA and 5 controls referred for PYP-SPECT were prospectively enrolled. 18F-NaF PET/CT scans were performed at 1 and 3 hours. Qualitative and quantitative analyses of the images were performed, and the sensitivity of 18F-NaF PET/CT and PYP-SPECT were compared RESULTS: Visual interpretation of NaF PET/CT yielded a sensitivity of 0.25 (95% CI 0.089 to 0.53) for the detection of ATTR-CA, which is significantly inferior to that of PYP-SPECT/CT (100%, P = .016). Visual interpretation at 3 hours yielded a similar sensitivity of 0.30 (95% CI 0.11 to 0.60, P = 1.00). There were no false-positive NaF PET studies. Mean target-to-background ratio (TBRmean) at 1h did not differ significantly (P = .21) in ATTR-CA subjects (0.83 ± 0.15) compared to controls (0.72 ± 0.15). Receiver operating characteristic (ROC) analysis yielded an area under the curve (AUC) of 0.69 ± 0.16 (95% CI 0.37 to 1.00, P = .23). CONCLUSION: With qualitative and quantitative analyses, sensitivity of NaF PET/CT is significantly inferior to that of PYP-SPECT for the diagnosis of ATTR-CA.
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Amiloidose , Fluoreto de Sódio , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tomografia por Emissão de Pósitrons/métodos , Sódio , Pirofosfato de Tecnécio Tc 99mRESUMO
OBJECTIVE: Evaluate the impact of 82-Rubidium positron emission tomography (PET) myocardial perfusion imaging (MPI) availability on patient management presenting at the emergency department (ED) with chest pain (CP). METHODS: This is a single-center retrospective study of clinical databases. Patients presenting with CP with a non-definitive suspicion of acute coronary syndrome (ACS) at the ED between April 2016 and February 2020 were divided into 2 groups based on PET availability. The proportion of invasive coronary angiography (ICA) without significant coronary artery disease (CAD), length of stay (LoS), and additional downstream testing were evaluated. RESULTS: There were 21,242 ED visits for CP without definitive ACS: 5,492 when PET is not available and 15,750 when PET is available. When PET is available, proportion of patients undergoing a MPI study was greater (20.7% vs 17.6%, P<0.0001), proportion of ICA without significant CAD was similar (18.5% vs 21.4%, P=0.24), and median ED LoS was shorter (16.6 vs 18.1 hours, P=0.03). Patients undergoing SPECT MPI had significantly more downstream testing (8.9% vs 6.4%, P=0.003) and a higher rate of coronary angiogram without significant CAD (21.2% vs 14.2%, P=0.09) compared to those who underwent PET MPI. CONCLUSION: Availability of PET MPI was associated with an increased number of MPI referral from the ED, similar rates of ICA without significant CAD, decreased LoS, and fewer downstream testing.
OBJETIVO: Evaluar el impacto de la tomografía por emisión de positrones (PET) con 82-Rubidio y la disponibilidad de imágenes de perfusión miocárdica (MPI) en el manejo de los pacientes que se presentan en el servicio de urgencias (ED) con dolor torácico (CP). MéTODOS: Este es un estudio retrospectivo de bases de datos clínicas de un solo centro. Pacientes que presentaron CP con sospecha no definitiva de síndrome coronario agudo (ACS) en el ED entre abril de 2016 y febrero de 2020, se dividieron en 2 grupos según la disponibilidad de PET. Se evaluó la proporción de angiografía coronaria invasiva (ICA) sin enfermedad arterial coronaria (CAD) significativa, la duración de la estancia (LoS) y las pruebas posteriores adicionales. RESULTADOS: Hubo 21,242 visitas al ED por CP sin ACS definitivo: 5,492 cuando no se dispone de PET y 15.750 cuando se dispone de PET. Cuando se dispone de PET, la proporción de pacientes sometidos a estudio de MPI fue mayor (20.7% vs 17.6%, p=0.03). Los pacientes que se sometieron a SPECT MPI tuvieron significativamente más pruebas posteriores (8.9 % frente a 6.4 %, p = 0.003) y una tasa más alta de angiografía coronaria sin CAD significativa (21.2 % frente a 14.2 %, p = 0.09) en comparación con los que se sometieron a PET MPI. CONCLUSIóN: La disponibilidad de PET MPI se asoció con un mayor número de referencias de MPI desde el ED, tasas similares de ICA sin CAD significativa, disminución de LoS y menos pruebas posteriores.
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Síndrome Coronariana Aguda , Doença da Artéria Coronariana , Imagem de Perfusão do Miocárdio , Humanos , Rubídio , Angiografia Coronária/métodos , Estudos Retrospectivos , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/complicações , Dor no Peito/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia por Emissão de Pósitrons/métodos , Radioisótopos de Rubídio , Síndrome Coronariana Aguda/diagnóstico por imagem , Síndrome Coronariana Aguda/terapia , Imagem de Perfusão do Miocárdio/métodosRESUMO
PURPOSE OF REVIEW: The purpose of this review is to provide an overview of the role of PET MPI in the detection of CAD, focussing on the added value of MBF for diagnosis and prognostication. RECENT FINDINGS: Positron emission tomography (PET) myocardial perfusion imaging (MPI) is increasingly used for the risk stratification of patients with suspected or established coronary artery disease (CAD). PET MPI provides accurate and reproducible non-invasive quantification of myocardial blood flow (MBF) at rest and during hyperemia, providing incremental information over conventional myocardial perfusion alone. Inclusion of MBF in PET MPI interpretation improves both its sensitivity and specificity. Moreover, quantitative MBF measurements have repeatedly been shown to offer incremental and independent prognostic information over conventional clinical markers in a broad range of conditions, including in CAD. Quantitative MBF measurement is now an established and powerful tool enabling accurate risk stratification and guiding patients' management. The role of PET MPI and flow quantification in cardiac allograft vasculopathy (CAV), which represents a particular form of CAD, will also be reviewed.
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Doença da Artéria Coronariana , Reserva Fracionada de Fluxo Miocárdico , Imagem de Perfusão do Miocárdio , Humanos , Imagem de Perfusão do Miocárdio/métodos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Angiografia Coronária/métodos , Tomografia por Emissão de Pósitrons/métodos , Circulação Coronária , PrognósticoRESUMO
BACKGROUND: Pulmonary hypertension (PH) complicating idiopathic pulmonary fibrosis (IPF) is associated to worse outcome. There is a great need for a non-invasive diagnostic modality to detect and evaluate the severity of pulmonary vascular disease (PVD). 99mTc-PulmoBind is a novel imaging agent that binds to the adrenomedullin (AM) receptor on the pulmonary microvascular endothelium. SPECT imaging employing the endothelial cell tracer 99mTc-PulmoBind was used to assess PVD associated with lung fibrosis. METHODS: Rats with selective right lung bleomycin-induced fibrosis were compared to control rats. SPECT imaging was performed after three weeks with 99mTc-PulmoBind and 99mTc-macroaggregates of albumin (MAA). PH and right ventricular (RV) function were assessed by echocardiography. Lung perfusion was evaluated by fluorescent microangiography. Lung AM receptor expression was measured by qPCR and by immunohistology. Relevance to human IPF was explored by measuring AM receptor expression in lung biopsies from IPF patients and healthy controls. RESULTS: The bleomycin group developed preferential right lung fibrosis with remodeling and reduced perfusion as assessed with fluorescent microangiography. These rats developed PH with RV hypertrophy and dysfunction. 99mTc-PulmoBind uptake was selectively reduced by 50% in the right lung and associated with reduced AM receptor expression, PH and RV hypertrophy. AM receptor was co-expressed with the endothelial cell protein CD31 in alveolar capillaries, and markedly reduced after bleomycin. Quantitative dynamic analysis of 99mTc-PulmoBind uptake in comparison to 99mTc-MAA revealed that the latter distributed only according to flow, with about 60% increased left lung uptake while left lung uptake of 99mTc-PulmoBind was not affected. Lung from human IPF patients showed important reduction in AM receptor expression closely associated with CD31. CONCLUSIONS: SPECT imaging with 99mTc-PulmoBind detects PVD and its severity in bleomycin-induced lung fibrosis. Reduced AM receptor expression in human IPF supports further clinical development of this imaging approach.
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Adrenomedulina/análogos & derivados , Bleomicina/toxicidade , Endotélio Vascular/metabolismo , Hipertensão Pulmonar/metabolismo , Fragmentos de Peptídeos/metabolismo , Fibrose Pulmonar/metabolismo , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Adrenomedulina/metabolismo , Animais , Antibióticos Antineoplásicos/toxicidade , Endotélio Vascular/diagnóstico por imagem , Endotélio Vascular/efeitos dos fármacos , Hipertensão Pulmonar/induzido quimicamente , Hipertensão Pulmonar/diagnóstico por imagem , Masculino , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/diagnóstico por imagem , Compostos Radiofarmacêuticos/metabolismo , Ratos , Ratos WistarRESUMO
BACKGROUND: Conventional nuclear imaging with bone-seeking radiopharmaceuticals has been shown to be a sensitive test for the detection of transthyretin cardiac amyloidosis (ATTR); however, to date, few data exist on the utility of 18F-sodium fluoride (NaF) positron emission tomography (PET) in subjects with cardiac amyloidosis (CA). METHODS: Myocardial perfusion imaging and cardiac 18F-NaF PET/CT of 7 subjects with ATTR, four with light-chain CA (AL), and four controls were retrospectively reviewed. Qualitative interpretation and quantitative analyses with average left ventricular standardized uptake values (SUVmean) and target-to-background ratios (TBRmean) were performed. RESULTS: Average TBRmean was significantly increased in subjects with ATTR (0.98 ± 0.09) compared to AL (0.85 ± 0.08, P = .026) and CTL (0.82 ± 0.07, P = .020), while SUVmean was not (P = .14). Receiver-operator characteristic (ROC) analysis yielded an area under the curve (AUC) of 0.91, with a sensitivity/specificity of 75%/100% for TBRmean using a cutoff value of 0.89 for the diagnosis of ATTR. Qualitative interpretation resulted in a sensitivity/specificity of 57%/100% for ATTR. CONCLUSIONS: While 18F-NaF PET/CT demonstrates good diagnostic accuracy for ATTR, particularly when using quantitative analysis, the low TBRmean values observed in ATTR indicate poor myocardial signal. 18F-NaF PET/CT is not yet ready for clinical use in CA until further comparison studies are performed with 99mTc-DPD/PYP.
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Amiloidose/diagnóstico por imagem , Cardiomiopatias/diagnóstico por imagem , Radioisótopos de Flúor , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Fluoreto de Sódio , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Curva ROC , Compostos Radiofarmacêuticos , Estudos RetrospectivosRESUMO
BACKGROUND: Qualification and interpretation standards are essential for establishing 99mTc-SPECT MPI accuracy vs. alternative modalities. METHODS: Rest-stress 99mTc-SPECT phantom scans were acquired on 35 cameras. LV defects were quantified with summed stress (SSS) and difference scores (SDS) at 2 core labs. SDS ≥ 2 in the right coronary artery (RCA) was the qualifying standard. Twenty rest (R)-stress (S) patient images were acquired on qualified cameras and interpreted by core labs. Global scoring differences > 3 between labs or discordant clinical interpretations underwent review. Scoring, interpretation, image quality, and diagnostic parameter agreement were assessed. RESULTS: Phantom scans: visual scoring confirmed RCA-ischemia on all cameras. Regional SSS, SDS agreement was moderate to very good: ICC-r = 0.57, 0.84. Patient scans: 90% of global SSS, 85% of SDS differences were ≤ 3. Regional SSS, SDS agreement: ICC-r = 0.87, 0.86, and global abnormal (SSS ≥ 4) and ischemic (SDS ≥ 2) interpretation: ICC-r = 0.90 were excellent. Clinical interpretation agreement was 100% following review. Image quality agreement was 70%. Automated metrics also agreed: ischemic total perfusion deficit ICC-r = 0.75, reversible perfusion defect, transient ischemic dilation, and S-R LV ejection fraction ICC-r ≥ 0.90. CONCLUSION: Quantitative scoring and interpretation of scans were highly repeatable with site qualification and clinical interpretation standardization, indicating that dual-core lab interpretation is appropriate to determine 99mTc-SPECT MPI accuracy.
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Imagem de Perfusão do Miocárdio/métodos , Imagens de Fantasmas , Tecnécio , Tomografia Computadorizada de Emissão de Fóton Único/normas , Idoso , Idoso de 80 Anos ou mais , Canadá , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
BACKGROUND: Myocardial perfusion imaging (MPI) with positron emission tomography allows accurate measurements of myocardial blood flow (MBF). Stress MBF thresholds have been proposed to provide diagnostic and prognostic information in different pathology. Most studies relying on dipyridamole use a 5-minute infusion protocol, while current guidelines recommend a 4-minute infusion. The purpose of this study is to compare the effects of different dipyridamole infusion times on stress MBF. METHODS: The charts of 2,207 patients who underwent rubidium-82 MPI were retrospectively reviewed and 147 subjects with low likelihood of significant coronary artery disease (CAD) defined as calcium score = 0, body mass index < 45 kg·m-2, and summed stress score ≤ 3 were included. Of those, 65 were imaged with a 4-minute dipyridamole infusion (0.56 mg·kg-1) protocol and 82 with a 5-minute protocol (0.70 mg·kg-1). RESULTS: Stress MBF (3.23±0.76 vs 3.02±0.71 mL·min-1·g-1, P = 0.09), myocardial flow reserve (2.70±0.67 vs 2.85±0.74, P = 0.20), and coronary vascular resistance index (30±10 vs 31±9 mmHg × g × min·mL-1, P = 0.38) were not significantly different between the two protocols. The 5-minute protocol was associated with higher prevalence of symptoms (92.7% vs 81.5%, P = 0.04) and greater decrease in systolic blood pressure (- 9 vs - 6 mmHg, P = 0.03). CONCLUSIONS: The 4-minute and 5-minute dipyridamole infusion protocols produce comparable myocardial flow response, hemodynamic changes, and symptoms, in subjects with low likelihood of significant obstructive CAD.
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Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/fisiopatologia , Dipiridamol/administração & dosagem , Imagem de Perfusão do Miocárdio , Tomografia por Emissão de Pósitrons , Vasodilatadores/administração & dosagem , Adulto , Idoso , Circulação Coronária/fisiologia , Esquema de Medicação , Teste de Esforço , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Radioisótopos de RubídioRESUMO
BACKGROUND: ATTR cardiac amyloidosis (CA) can be diagnosed with Tc-99m-PYP scintigraphy. There are two recommended interpretative approaches: the quantitative heart-to-contralateral lung ratio (H/CL) at 1 hour and the semi-quantitative visual system at 3 hours. This study's aim was to compare both approaches and to apply the semi-quantitative method at 1 hour. METHODS: Tc-99m-PYP scans of 122 consecutive subjects were reviewed using both approaches. On 1 hour planar images, regions of interest were drawn over the heart and contralateral chest to determine H/CL. Myocardial uptake was graded on 1 and 3 hour SPECT images according to the semi-quantitative method. Concordance was examined using kappa statistics. RESULTS: 31, 10, and 81 studies were positive, negative, and equivocal, respectively, for ATTR-CA using the H/CL approach. Using the grading system, 35, 77, and 10 scans were positive, negative, and equivocal, respectively. The quantitative approach led to a significantly higher proportion of equivocal studies compared to the semi-quantitative approach (P < .0001). These approaches yielded discordant results in 2 subjects; biopsy results were concordant with SPECT grade. 1 and 3 hour SPECT grades provided concordant result in 99% of cases. CONCLUSIONS: The H/CL approach resulted in a high proportion of equivocal studies. Using SPECT imaging, the semi-quantitative approach minimized this proportion and showed high concordance at 1 and 3 hours.
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Neuropatias Amiloides Familiares/diagnóstico por imagem , Cardiomiopatias/diagnóstico por imagem , Compostos Radiofarmacêuticos/farmacocinética , Pirofosfato de Tecnécio Tc 99m/farmacocinética , Tomografia Computadorizada de Emissão de Fóton Único , Idoso , Idoso de 80 Anos ou mais , Neuropatias Amiloides Familiares/complicações , Cardiomiopatias/etiologia , Cardiomiopatias/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Fatores de TempoRESUMO
PURPOSE OF REVIEW: The clinical and incremental value of functional imaging with 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) for the diagnosis and management of patients with suspected native and prosthetic valve infective endocarditis (IE). RECENT FINDINGS: The diagnosis of IE is challenging because of the highly variable clinical presentations, especially in the case of prosthetic valve endocarditis (PVE). FDG PET/CT has been shown to play an important role for the diagnosis of PVE as a major Duke criterion. Whether FDG PET/CT could play a similar role in patients with suspected native valve endocarditis (NVE) is less well established. It is increasingly recognized that IE is a multisystem disorder, and identification of extra-cardiac manifestations on whole-body FDG PET/CT impacts management and prognosis of patients with IE. Finally, FDG PET/CT provides incremental prognostic value over other clinical and para-clinical parameters, enabling prediction of in-hospital mortality, IE recurrence, hospitalization, and new onset heart failure and embolic events. FDG PET/CT plays a key role in the investigation of patients with suspected IE, enabling detection of valvular infection and extra-cardiac manifestations of the infection which has important prognostic implications.
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Endocardite Bacteriana , Endocardite , Próteses Valvulares Cardíacas , Infecções Relacionadas à Prótese , Fluordesoxiglucose F18 , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos RadiofarmacêuticosRESUMO
BACKGROUND: IQ-SPECT has been shown to significantly reduce acquisition time and administered dose while preserving image quality in myocardial perfusion imaging. Whether IQ-SPECT provides accurate left ventricular ejection fractions (LVEF) with gated blood pool SPECT (GBPS) remains unknown. METHODS: Sixty patients underwent IQ-SPECT GBPS and planar imaging. Among those patients, 11 underwent both cMRI and GBPS. GBPS LVEF, LVEDV, and LVESV were calculated using 2 validated software; QBS (Cedars-Sinai Medical Center, Los Angeles, USA) and MHI (Montreal Heart Institute, Montreal, Canada). LVEF, LVEDV, and LVESV obtained with the different modalities were compared. RESULTS: Average planar LVEF was 48 ± 11% (mean ± SD), average LVEDV was 177 ± 59 mL (range 63 to 342 mL), and average LVESV was 96 ± 46 mL (range 16 to 234 mL). GBPS LVEF and their correlation coefficient with planar LVEF were 40 ± 12% (r = 0.70) and 44 ± 12% (r = 0.83) with QBS and MHI, respectively. Correlation coefficient between cMRI and planar LVEF was 0.65 and were 0.69 and 0.52 between cMRI and GBPS using QBS and MHI, respectively. CONCLUSIONS: LVEF calculated with GBPS using IQ-SPECT correlates with planar measurements. Correlation is best using the MHI method and variation is independent of LVEDV.
Assuntos
Angiografia/métodos , Coração/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Feminino , Imagem do Acúmulo Cardíaco de Comporta/métodos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Masculino , Pessoa de Meia-Idade , Miocardite/diagnóstico por imagem , Software , Volume Sistólico , Disfunção Ventricular Esquerda , Função Ventricular EsquerdaRESUMO
PURPOSE OF REVIEW: The aim of this review is to give an update on the molecular imaging tools currently available as well as to discuss the potential roles and limitations of molecular imaging in cardiac amyloidosis. RECENT FINDINGS: Molecular imaging plays a central role in the evaluation of patients with suspected cardiac amyloidosis. It can be used to diagnose and distinguish between the different types of cardiac amyloidosis. The diagnostic properties of bone scintigraphy are such that it allows reliable diagnosis of transthyretin cardiac amyloidosis without the need of endomyocardial biopsy in a significant proportion of patients. Furthermore, molecular tracers assessing amyloid plaque burden and sympathetic innervation may be useful for the non-invasive evaluation diagnosis and risk stratification of patients with suspected cardiac amyloidosis. Cardiac amyloidosis is an under-recognized cause of left ventricular hypertrophy and heart failure in the elderly. The role of molecular imaging in cardiac amyloidosis is expected to grow considering the arrival of new therapies and molecular imaging probes.
Assuntos
Amiloidose/diagnóstico por imagem , Cardiomiopatias/diagnóstico por imagem , Coração/diagnóstico por imagem , Imagem Molecular/métodos , Idoso , Técnicas de Imagem Cardíaca , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Pré-AlbuminaRESUMO
Previous studies have suggested good adaptation of cardiac transplant (CTx) recipients to exposure to a high altitude. No studies have investigated the cardiopulmonary and biomarker responses to acute hypoxic challenges following CTx. Thirty-six CTx recipients and 17 age-matched healthy controls (HC) were recruited. Sixteen (16) patients (42%) had cardiac allograft vasculopathy (CAV). Cardiopulmonary responses to maximal and submaximal exercise at 21% O2 , 20-minutes hypoxia (11.5% O2 ), and following a 10-minute exposure to 11.5% O2 using 30% of peak power output were completed. Vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), suppression of tumorigenicity 2 (ST2) were measured at baseline and at peak stress. Endothelial peripheral function was assessed using near-infrared spectroscopy. Compared with HC, CTx presented a lesser O2 desaturation both at rest (-19.4 ± 6.8 [CTx] vs -24.2 ± 6.0% O2 [HC], P < 0.05) and following exercise (-23.2 ± 4.9 [CTx] vs -26.2 ± 4.7% O2 [HC], P < 0.05). CTx patients exhibited a significant decrease in peak oxygen uptake. IL-6 and VEGF levels were significantly higher in CTx recipients in basal conditions but did not change in response to acute stress. CTx patients exhibit a favorable ventilatory and overall response to hypoxic stress. These data provide further insights on the good adaptability of CTx to exposure to high altitude.
Assuntos
Adaptação Fisiológica , Biomarcadores/análise , Sistema Cardiovascular/fisiopatologia , Exercício Físico , Transplante de Coração/métodos , Hipóxia/fisiopatologia , Pulmão/fisiologia , Altitude , Estudos de Casos e Controles , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , Estudos ProspectivosRESUMO
PURPOSE: The adrenomedullin receptor is densely expressed in the pulmonary vascular endothelium. PulmoBind, an adrenomedullin receptor ligand, was developed for molecular diagnosis of pulmonary vascular disease. We evaluated the safety of PulmoBind SPECT imaging and its capacity to detect pulmonary vascular disease associated with pulmonary hypertension (PH) in a human phase II study. METHODS: Thirty patients with pulmonary arterial hypertension (PAH, n = 23) or chronic thromboembolic PH (CTEPH, n = 7) in WHO functional class II (n = 26) or III (n = 4) were compared to 15 healthy controls. Lung SPECT was performed after injection of 15 mCi 99mTc-PulmoBind in supine position. Qualitative and semi-quantitative analyses of lung uptake were performed. Reproducibility of repeated testing was evaluated in controls after 1 month. RESULTS: PulmoBind injection was well tolerated without any serious adverse event. Imaging was markedly abnormal in PH with â¼50% of subjects showing moderate to severe heterogeneity of moderate to severe extent. The abnormalities were unevenly distributed between the right and left lungs as well as within each lung. Segmental defects compatible with pulmonary embolism were present in 7/7 subjects with CTEPH and in 2/23 subjects with PAH. There were no segmental defects in controls. The PulmoBind activity distribution index, a parameter indicative of heterogeneity, was elevated in PH (65% ± 28%) vs. controls (41% ± 13%, p = 0.0003). In the only subject with vasodilator-responsive idiopathic PAH, PulmoBind lung SPECT was completely normal. Repeated testing 1 month later in healthy controls was well tolerated and showed no significant variability of PulmoBind distribution. CONCLUSIONS: In this phase II study, molecular SPECT imaging of the pulmonary vascular endothelium using 99mTc-PulmoBind was safe. PulmoBind showed potential to detect both pulmonary embolism and abnormalities indicative of pulmonary vascular disease in PAH. Phase III studies with this novel tracer and direct comparisons to lung perfusion agents such as labeled macro-aggregates of albumin are needed. CLINICAL TRIAL: ClinicalTrials.gov, NCT02216279.
Assuntos
Endotélio Vascular/diagnóstico por imagem , Hipertensão Pulmonar/diagnóstico por imagem , Pulmão/irrigação sanguínea , Imagem Molecular/efeitos adversos , Segurança , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Hipertensão Pulmonar/patologia , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Stress-induced dyssynchrony has been shown to be independently correlated with clinical outcomes in patients with dilated cardiomyopathy (DCM) and narrow QRS complexes. However, the extent to which stress levels affect inter- and intraventricular dyssynchrony parameters remains unknown. METHODS: Ten large dogs were submitted to tachycardia-induced DCM by pacing the right ventricular apex for 3-4 weeks to reach a target ejection fraction (EF) of 35% or less. Stress was then induced in DCM dogs by administering intravenous dobutamine up to a maximum of 20 µg·kg-1·min-1. Hemodynamic and ventricular dyssynchrony data were analyzed by left ventricular (LV) pressure measurements and gated blood pool SPECT (GBPS) imaging. In order to assess mechanical dyssynchrony in DCM subjects and compare it with that of 8 normal counterparts, we extracted the following data: count-based indices of LV contraction homogeneity index (CHI), entropy and phase standard deviation, and interventricular dyssynchrony index. RESULTS: A significant LV intraventricular dyssynchrony (CHI: 96.4 ± 1.3% in control vs 78.6% ± 10.9% in DCM subjects) resulted in an intense LV dysfunction in DCM subjects (EF: 49.5% ± 8.4% in control vs 22.6% ± 6.0% in DCM), compared to control subjects. However, interventricular dyssynchrony did not vary significantly between the two groups. Under stress, DCM subjects showed a significant improvement in ventricular functional parameters at each level (EF: 22.6% ± 6.0% at rest vs 48.1% ± 5.8% at maximum stress). All intraventricular dyssynchrony indices showed a significant increase in magnitude of synchrony from baseline to stress levels of greater than or equal to 5 µg·kg-1·min-1 dobutamine. There were individual differences in the magnitude and pattern of change in interventricular dyssynchrony during the various levels of stress. CONCLUSIONS: Based on GBPS analyses, different levels of functional stress, even in close intervals, can have a significant impact on hemodynamic and intraventricular dyssynchrony parameters in a DCM model with narrow QRS complex.