A new perspective on an old method: gated SPECT imaging for left ventricular contractile function assessment.

The ejection fraction (LVEF) is a commonly used marker of left ventricular function. However, because it is strongly influenced by loading conditions, it can be inaccurate in representing cardiac contractility. We therefore evaluated a gated SPECT based tool to simultaneously assess preload, afterload, and contractility. Using gated SPECT-determined ventricular volumes and arterial tension measurements, we calculated ventricular and arterial elastance (Ev and Ea), as well as end-diastolic volumes, which are surrogates for contractility, afterload, and preload, respectively. We applied this protocol to 1462 consecutive patients and assessed the ventricular function in patients with and without myocardial infarction. The median LVEF was 68% (IQR 62-74%). Patients with infarction exhibited decreased contractility (ventricular elastance of 3 mmHg/ml vs. 6 mmHg/ml), compensated by an increase of preload (end-diastolic volume of 100 ml vs. 78 ml) and a decrease in afterload (arterial elastance of 1.8 mmHg/ml vs. 2.2 ml/mmHg). These interactions yielded a preserved ejection fraction in both groups. Gated SPECT-measured volumes were consistent with values reported in the literature. In addition, the combination of nuclear imaging and arterial tension measurement accounted for not only the ejection fraction but also the loading context, providing a more accurate representation of cardiac contractility.

[Bone seeking tracers' scintigraphy for the diagnosis of transthyretin cardiac amyloidosis]. / Centellografía con fosfonatos para el diagnóstico de la amiloidosis cardíaca por transtirretina.

Transthyretin cardiac amyloidosis (ATTR) is a restrictive cardiomyopathy that leads to heart failure in considerable number of patients. Early diagnosis allows specific treatment options. However, ATTR diagnosis is complex and requires invasive procedures. The utility of 99mTc-phosphate tracers for non-invasive diagnosis is well-known but the experience in Argentina is insufficient. The aim of this work was to assess the utility of 99m Tc-phosphate tracers for the diagnosis of ATTR. A total of 46 scintigraphies for detection of cardiac amyloidosis performed between September 2016 and January 2018 were analyzed. Cardiac retention after one hour was assessed in relation to bone uptake using two methods: A semi-quantitative visual score (grade 0 = absent, I = low II = moderate-III = high) and a quantitative method (heart/lung ratio). The final diagnosis and the amyloidosis subtype were carried out by our institution cardiomyopathy team according to international guidelines. The positive and negative predictive values for Grade ≥ II were 96% and 100% respectively for diagnosis of ATTR. Using 1.38 as cut-off value for heart/lung ratio the sensitivity and the specificity were 96% and 100%, respectively for differentiating transthyretin cardiac amyloidosis from light-chain cardiac amyloidosis and other cardiopathies. Scintigraphy with 99m Tc-phosphate tracers enable noninvasive diagnosis and subtype classification of cardiac amyloidosis. The use of this non-invasive, inexpensive and widely available tool will result in better patient management.

Prevalence of transthyretin amyloid cardiomyopathy in patients admitted for acute heart failure.

INTRODUCTION: Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed cause of AHF that benefits from a specific approach. The aim was to determine the prevalence of ATTR-CM among patients hospitalized for AHF. METHODS: A prospective study was conducted on consecutive patients aged 60 or older admitted for acute AHF without cardiogenic shock. RESULTS: The study included 103 patients, a total of 16 patients (15.5 %) were compatible with ATTR-CM. The ATTR-CM group showed a higher septal wall thickness (18.1 mm vs. 11.8 mm; P = 0.001), lower systolic excursion of the tricuspid annular plane (15 mm vs. 18.3 mm, P = 0.014), and S wave of the right ventricle (8 cm/s vs. 9.2 cm/s P=0.032). CONCLUSION: ATTR-CM is an underdiagnosed condition, there are some variables associated with its diagnosis. The coexistence with other comorbidities causing AHF, highlights the importance of considering screening for this cardiomyopathy in adults hospitalized for AHF.

[Non-invasive follow-up of adjusted treatment in patients with microvascular angina]. / Seguimiento no invasivo del tratamiento ajustado en pacientes con angina microvascular.

There are currently multiple invasive and non-invasive methods that can be used to establish the diagnosis of microvascular dysfunction (MVD) in patients with INOCA (Ischemia with Non-Obstructive Coronary Arteries) and microvascular angina. However, we still do not have a specific treatment approach for this group of patients. The current trend is to adjust the treatment to the pathophysiological mechanism involved, adding calcium blockers in those patients where endothelial dysfunction is demonstrated or beta blockers in those patients who present smooth muscle-dependent dysfunction. We present three clinical cases of INOCA with suspected microvascular angina. Two of them underwent a non-invasive diagnosis of MVD by CZT-SPECT, using dipyridamole to evaluate the smooth muscle-dependent mechanism and cold pressor test to evaluate the endothelium-dependent mechanism. According to the results obtained, the treatment was adju sted, clinical follow-up was carried out and angina was assessed using the Seattle scale, with a new microcirculation assessment at 6 months. The third clinical case, on the other hand, was a patient who began empirical treatment for both mechanisms and subsequently abandoned the established treatment. Microvascular function was evaluated under pharmacological treatment and without it.

Actualmente existen múltiples métodos invasivos y no invasivos que pueden emplearse para establecer el diagnóstico de disfunción microvascular (DMV) en pacientes con INOCA (por sus siglas en inglés: Ischemia with Non-Obstructive Coronary Arteries) y angina microvascular (AMV). No obstante, todavía no contamos con un enfoque de tratamiento específico para este grupo de pacientes. La tendencia act ual es ajustar el tratamiento al mecanismo fisiopatológico implicado, añadiendo antagonistas del calcio en aquellos pacientes en los que se demuestre disfunción endotelial, o bien bloqueadores beta en aquellos que presenten disfunción músculo liso dependiente. Presentamos tres casos clínicos de INOCA con sospecha de AMV. A dos de ellos se les realizó diagnóstico no invasivo de DMV mediante CZT-SPECT, utilizando como apremio dipiridamol para evaluar el mecanismo músculo liso dependiente y test de frío para evaluar el mecanismo endotelio dependiente. Según los resultados obtenidos se ajustó el tratamiento, se realizó seguimiento clínico y valoración de la angina por la escala de Seattle, con nueva valoración de la función microvascular a los 6 meses. El tercer caso clínico, en cambio, es una paciente que inició tratamiento empírico para ambos mecanismos y posteriormente abandonó el tratamiento instaurado, evaluándose la función microvascular bajo tratamiento farmacológico y sin el mismo.

[Positron emission tomography in infective endocarditis associated with intracardiac devices and prosthetic valves]. / Tomografía por emisión de positrones en endocarditis infecciosa asociada a dispositivos y válvulas protésicas.

Infective endocarditis (IE) is a serious and potentially lethal condition. The diagnostic capacity of the modified Duke criteria is high for native valves, but it declines in the case of EI of prosthetic valves or EI associated with devices. Echocardiography and microbiological findings are essential for diagnosis but may be insufficient in this group of patients. Our objective was to evaluate the usefulness of positron emission tomography and fusion with computed tomography (PET / CT) in patients with suspected IE, carriers of prosthetic valves or intracardiac devices; 32 patients were studied, who underwent PET / CT with 18F-Fluorine deoxyglucose (18F-FDG). Those with intense focal and/or heterogeneous uptake with a Standard Uptake Value SUV) cut-off point greater than or equal to 3.7 were considered suggestive of infection. The initial diagnoses according to the modified Duke criteria were compared with the final diagnosis established by the Institutional Endocarditis Unit. The addition of PET / CT to these criteria, provided a conclusive diagnosis in 22 of the 32 initial cases reclassifying 11 cases in definitive EI; another 5 cases were negative for that diagnosis. EI continues to be a serious clinical problem. In those cases where the Duke criteria are not sufficient to establish the diagnosis and clinical suspicion persists, PET / CT can be a useful complementary tool to increase the diagnostic sensitivity.

La endocarditis infecciosa (EI) es una enfermedad grave y potencialmente letal. La capacidad diagnóstica de los criterios de Duke modificados es alta para válvulas nativas, pero decae en el caso de EI de válvulas protésicas o EI asociadas a dispositivos. El ecocardiograma y los hallazgos microbiológicos son fundamentales para el diagnóstico, pero pueden resultar insuficientes en este grupo de pacientes. Nuestro objetivo fue evaluar la utilidad de la tomografía por emisión de positrones y fusión con tomografía computarizada (PET/TC) en pacientes con sospecha de EI, portadores de válvulas protésicas o dispositivos intracardiacos. Se estudiaron 32 pacientes, a los cuales se les realizó un PET/CT con 18F-Flúor desoxiglucosa (18F-FDG). Se consideraron sugestivos de infección aquellos con captación intensa de tipo focal y/o heterogénea con un punto de corte de Standard Uptake Value (SUV) mayor o igual a 3.7. Los diagnósticos iniciales según los criterios de Duke modificados, se compararon con el diagnóstico final establecido por la Unidad de Endocarditis institucional. El agregado del PET/CT a esos criterios, proporcionó un diagnóstico concluyente en 22 de los 32 casos iniciales, reclasificando a 11 casos en EI definitivas y a otros 5 casos como negativos para ese diagnóstico. La EI continúa siendo un grave problema clínico. En aquellos casos donde los criterios de Duke no son suficientes para establecer el diagnóstico y la sospecha clínica persiste, el PET/CT puede ser una herramienta complementaria útil para aumentar la sensibilidad diagnóstica.

Myocardial perfusion SPECT in the diagnosis of apical hypertrophic cardiomyopathy.

BACKGROUND: Apical hypertrophy cardiomyopathy (ACM) is a rare condition characterized by asymmetric myocardial hypertrophy of the apex of the left ventricle. When two-dimensional echocardiography is limited by a poor acoustic window, patients are often referred for MRI. Our hypothesis is that a cheaper and more widely available diagnostic modality like myocardial perfusion single photon emission computed tomography (SPECT) may be helpful in the diagnosis of ACM. OBJECTIVE: The purpose of this prospective study was to define the characteristics of rest and stress SPECT studies in patients with known ACM, and whether SPECT may be helpful in the diagnosis of ACM. METHODS: Adult patients with ACM were enrolled in the study. Diagnosis was made with 2-D echo. A rest and exercise or dipyridamole stress SPECT study was performed in all patients with Tc-99m sestamibi. RESULTS: We enrolled 20 patients (mean age 60 +/- 16 years), 9 were female, with ACM. SPECT at rest revealed in 15 patients (75%) an increased apical tracer uptake, a spade-like deformity of the left ventricular chamber, and the "Solar Polar" map pattern consistent with ACM. The sensitivity, specificity, positive predictive value, and negative predictive value of SPECT for detecting ACM were 75%, 100%, 100%, and 80%, respectively. CONCLUSION: Three-fourths of adult patients with ACM showed, on myocardial perfusion SPECT, characteristic findings which were not seen in age-matched control subjects, such as a significant increased apical tracer uptake, a spade-like deformity of the left ventricle, and the "Solar Polar" map. Nuclear physicians should be aware of these SPECT findings because many ACM patients may first end up in the nuclear labs due to their markedly abnormal ECG for exclusion of obstructive coronary artery disease.

Remodelado del ventrículo izquierdo postinfarto: una mirada desde la perfusión miocárdica gated-SPECT / Left Ventricular Remodeling After Myocardial Infarction: A Perspective from Gated-SPECT Myocardial Perfusion Imaging

RESUMEN Introducción: El estudio gatillado de perfusión miocárdica con tomografía computarizada por emisión de fotón único, o gated-SPECT (por su denominación en inglés) es un método apropiado para cuantificar la magnitud de la escara necrótica y establecer su territorio. El análisis de pacientes con infartos de pequeña y mediana extensión que evolucionan con deterioro de la fracción de eyección ventricular izquierda (FEVI), podría arrojar luz acerca de los factores que influyen en la presencia de remodelado adverso y la consiguiente evolución a disfunción ventricular. Objetivos: a) evaluar la prevalencia de FEVI disminuida y factores asociados en una población de pacientes derivados para estudios de gated-SPECT, y b) definir la prevalencia de remodelado adverso y factores asociados en el subgrupo de pacientes con carga necrótica intermedia a baja. Material y métodos: Realizamos un análisis retrospectivo de pacientes consecutivos que se realizaron gated-SPECT durante el año 2017. Se excluyeron los pacientes con enfermedad valvular significativa o arritmias que produjeran alteración del gatillado. Se consideró remodelado adverso a la conjunción de FEVI disminuida (FEVI < 50%) y porcentaje de miocardio necrótico menor que 20 %. Resultados: Se incluyeron 1902 pacientes. La prevalencia de FEVI disminuida fue del 8 % (n =148). En el análisis multivariado, las variables independientes asociadas a disfunción ventricular fueron el género masculino (OR 2,50; IC 95% 1,30-4,90, p = 0,005), la diabetes (OR 1,83; IC 95% 1,12-3, p = 0,01), y compromiso necrótico mayor que 6,6 % (OR 39 IC 95% 25-61,28, p = 0,00001). En el subgrupo de pacientes con carga necrótica menor que 20% (n =197), la prevalencia de remodelado adverso fue del 25% (n =50). El análisis multivariado arrojó que la diabetes (OR 2,83; IC 95% 1,31 - 6,10 p = 0,007) y el género masculino (OR 5; IC 95% 1,10 - 22,9 p = 0,007) presentaron asociación independiente con el remodelado adverso. Conclusión: La gated-SPECT podría utilizarse en la valoración del remodelado adverso y factores asociados. Dicha valoración surge de la combinación de variables que no requieren un software adicional y se usan en la práctica diaria.

ABSTRACT Background: Gated single-photon emission computed tomography (gated-SPECT) myocardial perfusion imaging is a suitable technique for measuring the infarct scar size and defining its territory. Analyzing patients with small and medium myocardial infarctions that develop reduced left ventricular ejection fraction (LVEF) could provide additional information of the factors that contribute to adverse remodeling and its outcome. Objectives: a) To evaluate the prevalence of reduced LVEF and associated factors in a population of patients referred for gated-SPECT imaging, and b) to define the prevalence of adverse remodeling and associated factors in the subgroup of patients with intermediate to low necrotic burden. Methods: We conducted a retrospective analysis of consecutive patients undergoing gated-SPECT imaging during 2017. Patients with significant valvular heart disease or arrhythmias that could difficult adequate ECG gating were excluded from the study. Adverse remodeling was considered as the combination of reduced LVEF (LVEF < 50%) with percent myocardium scar < 20%. Results: A total of 1902 patients were included. The prevalence of reduced LVEF was 8% (n = 148). On multivariate analysis, the variables with independent association with ventricular dysfunction were male sex (OR 2.50; 95% CI 1.30-4.90, p = 0.005), diabetes (OR 1.83; 95% CI 1.12-3, p = 0.01), and percent myocardium scar > 6.6 % (OR 39; 95% CI 25-61.28, p = 0.00001). In the subgroup of patients with scar burden < 20 % (n = 197), the prevalence of adverse remodeling was 25 % (n = 50). On multivariate analysis, diabetes (OR 2.83; 95% CI 1.31 - 6.1 p = 0.007) and male sex (OR 5; 95% CI 1.1 - 22.9, p = 0.007) showed an independent association with adverse remodeling. Conclusion: Gated-SPECT could be used to assess adverse remodeling and its associated factors. This assessment is the result of combining variables used in daily practice which do not require any additional software.

¿Debemos seguir considerando el monto isquémico en los síndromes coronarios crónicos? / Should We Continue to Consider Extent of Ischemic Myocardium in Chronic Coronary Syndromes?

RESUMEN El surgimiento de nueva evidencia científica en los últimos años en relación con los síndromes coronarios crónicos (SCC) lleva a reconsiderar las recomendaciones diagnósticas y terapéuticas que históricamente guiaron nuestra práctica médica. Sin embargo, es importante destacar que gran parte de la información difundida carece de un análisis crítico riguroso, lo que nos expone al riesgo de incorporar nuevos algoritmos en la práctica clínica que podrían no ser completamente aplicables a nuestra población. En esta revisión se analiza la literatura científica disponible relacionada a los SCC, para tratar de establecer si realmente el monto isquémico carece de significado clínico y pronóstico tal como se afirma en algunas publicaciones.

ABSTRACT In the last years, new scientific evidence related to chronic coronary syndromes (CCS) has led to reconsider the diagnostic and therapeutic recommendations that historically guided our medical practice. However, it is important to point out that the disseminated information lacks a precise critical analysis, with the risk of incorporating new algorithms in clinical practice that might not be completely applicable to our population. The present review analyses the available scientific CCS literature to establish whether the extent of ischemic myocardium has no real clinical and prognostic significance as reported in some publications.

Absence of myocardial dysfunction during cold pressor stress echocardiography in patients with endothelial dysfunction.

BACKGROUND: Several methods are available for the assessment of coronary endothelial function, but there are no reports to date regarding the usefulness of cold pressor stress echocardiography (CPSE). OBJECTIVE: To assess regional systolic and diastolic left ventricular function using CPSE in patients with endothelial dysfunction. METHODS: We studied 24 patients, of whom 10 were men, aged 27 to 68 years, who had coronary risk factors and a normal exercise MP-SPECT test. They were compared with 10 normal subjects (6 men), aged 21 to 44 years. All patients underwent a CPSE. RESULTS: The cold pressor-MP-SPECT revealed myocardial ischemia in 10 patients (Group I) and was normal in 14 patients (Group II). All normal subjects (Group III) had normal cold pressor-MP-SPECT. The cold pressor test caused a significant increase in systolic BP in the three groups (baseline 117 +/- 17 mmHg vs. postcold test 137 +/- 16 mmHg, P < 0.05), without changes in heart rate, PR interval, or the corrected QT interval. During the CPSE, no patient developed WMA in 2D echo or changes in regional systolic or diastolic LV function in the pulsed Doppler tissue imaging. CONCLUSIONS: In patients with endothelial dysfunction and no known coronary artery disease, the ischemic response to the cold pressor-MP-SPECT is not accompanied by WMA or changes in regional systolic or diastolic LV function during CPSE. Such negative findings indicate that the amount of ischemia that occurs secondarily to endothelial dysfunction does not involve sufficient myocardial mass to cause contractile dysfunction.

Actual impact of screening for myocardial ischemia with single-photon emission tomography among patients undergoing peripheral vascular interventions.

The present study provides actual data with regard to the prevalence of myocardial ischemia among patients under contemporary cardiovascular prevention strategies undergoing peripheral vascular interventions. We included a total of 200 consecutive patients who underwent gated single-photon emission computed tomography myocardial perfusion study between January 2012 and January 2014 as preoperative evaluation for peripheral vascular interventions at our institution. The baseline medical treatment comprised aspirin (81%), statins (79%), and ß-blockers (54%). Thirty-two (16%) patients underwent carotid revascularization; 69 (34.5%) patients underwent lower limb revascularization, and 99 patients underwent aortic interventions. Twenty-six (13%) patients showed evidence of myocardial ischemia, with an extensive ischemic burden identified in seven (3.5%) patients. Within the group of patients with peripheral vasculopathy, those with lower limb arteriopathy had a higher prevalence of ischemia. According to the results of the myocardial perfusion study, the cardiology in charge indicated invasive coronary angiography in 11/26 (42%) patients with evidence of myocardial ischemia. Seven of the 11 (64%) patients who had coronary angiography were revascularized. After a mean follow-up of 24 months, no cardiovascular adverse events were detected.

Myocardial assistance by grafting a new bioartificial upgraded myocardium (MAGNUM clinical trial): one year follow-up.

Cell transplantation for the regeneration of ischemic myocardium is limited by poor graft viability and low cell retention. In ischemic cardiomyopathy the extracellular matrix is deeply altered; therefore, it could be important to associate a procedure aiming at regenerating myocardial cells and restoring the extracellular matrix function. We evaluated intrainfarct cell therapy associated with a cell-seeded collagen scaffold grafted onto infarcted ventricles. In 15 patients (aged 54.2 +/- 3.8 years) presenting LV postischemic myocardial scars and with indication for a single OP-CABG, autologous mononuclear bone marrow cells (BMC) were implanted during surgery in the scar. A 3D collagen type I matrix seeded with the same number of BMC was added on top of the scarred area. There was no mortality and no related adverse events (follow-up 15 +/- 4.2 months). NYHA FC improved from 2.3 +/- 0.5 to 1.4 +/- 0.3 (p = 0.005). LV end-diastolic volume evolved from 142 +/- 24 to 117 +/- 21 ml (p = 0.03), and LV filling deceleration time improved from 162 +/- 7 to 196 +/- 8 ms (p = 0.01). Scar area thickness progressed from 6 +/- 1.4 to 9 +/- 1.5 mm (p = 0.005). EF improved from 25 +/- 7% to 33 +/- 5% (p = 0.04). Simultaneous intramyocardial injection of mononuclear bone marrow cells and fixation of a BMC-seeded matrix onto the epicardium is feasible and safe. The cell-seeded collagen matrix seems to increase the thickness of the infarct scar with viable tissues and helps to normalize cardiac wall stress in injured regions, thus limiting ventricular remodeling and improving diastolic function. Patients' improvements cannot be conclusively related to the cells and matrix due to the association of CABG. Cardiac tissue engineering seems to extend the indications and benefits of stem cell therapy in cardiology, becoming a promising way for the creation of a "bioartificial myocardium." Efficacy and safety of this approach should be evaluated in a large randomized controlled trial.

Seguimiento no invasivo del tratamiento ajustado en pacientes con angina microvascular / Non-invasive follow-up of adjusted treatment in patients with microvascular angina

Resumen Actualmente existen múltiples métodos invasivos y no invasivos que pueden emplearse para establecer el diagnóstico de disfunción microvascular (DMV) en pacientes con INOCA (por sus siglas en inglés: Ischemia with Non-Obstructive Coronary Arteries) y angina microvascular (AMV). No obstante, todavía no contamos con un enfoque de tratamiento específico para este grupo de pacientes. La tendencia act ual es ajustar el tratamiento al mecanismo fisiopatológico implicado, añadiendo antagonistas del calcio en aquellos pacientes en los que se demuestre disfunción endotelial, o bien bloqueadores beta en aquellos que presenten disfunción músculo liso dependiente. Presentamos tres casos clínicos de INOCA con sospecha de AMV. A dos de ellos se les realizó diagnóstico no invasivo de DMV mediante CZT-SPECT, utilizando como apremio dipiridamol para evaluar el mecanismo músculo liso dependiente y test de frío para evaluar el mecanismo endotelio dependiente. Según los resultados obtenidos se ajustó el tratamiento, se realizó seguimiento clínico y valoración de la angina por la escala de Seattle, con nueva valoración de la función microvascular a los 6 meses. El tercer caso clínico, en cambio, es una paciente que inició tratamiento empírico para ambos mecanismos y posteriormente abandonó el tratamiento instaurado, evaluándose la función microvascular bajo tratamiento farmacológico y sin el mismo.

Abstract There are currently multiple invasive and non-invasive methods that can be used to establish the diagnosis of microvascular dysfunction (MVD) in patients with INOCA (Ischemia with Non-Obstructive Coronary Arteries) and microvascular angina. However, we still do not have a specific treatment approach for this group of patients. The current trend is to adjust the treatment to the pathophysiological mechanism involved, adding calcium blockers in those patients where endothelial dysfunction is demonstrated or beta blockers in those patients who present smooth muscle-dependent dysfunction. We present three clinical cases of INOCA with suspected microvascular angina. Two of them underwent a non-invasive diagnosis of MVD by CZT-SPECT, using dipyridamole to evaluate the smooth muscle-dependent mechanism and cold pressor test to evaluate the endothelium-dependent mecha nism. According to the results obtained, the treatment was adju sted, clinical follow-up was carried out and angina was assessed using the Seattle scale, with a new microcirculation assessment at 6 months. The third clinical case, on the other hand, was a patient who began empirical treatment for both mechanisms and subsequently abandoned the established treatment. Microvascular function was evaluated under pharmacological treatment and without it.

INOCA: Evaluación no invasiva de los mecanismos fisiopatológicos mediante CZT-SPECT / INOCA: Non-Invasive Assessment of the Pathophysological Mechanisms Using CZT-SPECT

RESUMEN Introducción: Una de las causas propuestas del síndrome INOCA (por sus siglas en inglés: Ischemia with Non-Obstructive Coronary Arteries) es la disfunción microvascular (DMV), la cual puede evaluarse en forma no invasiva, mediante la cuantificación del flujo sanguíneo miocárdico (FSM) y la reserva de flujo miocárdica (RFM). Las imágenes de perfusión miocárdica (IPM) y dinámicas con CZT-SPECT en reposo - dipiridamol - y prueba de frio (PF), permiten establecer la presencia de DMV evaluando diferentes mecanismos fisiopatológicos: endotelio independiente o dependiente, respectivamente. Objetivos: Evaluar la utilidad de CZT-SPECT en el diagnóstico de DMV y los diferentes mecanismos patológicos involucrados, en pacientes con diagnóstico de INOCA. Material y métodos: Se incluyeron en forma prospectiva 93 pacientes consecutivos con diagnóstico de INOCA, a los que se les realizó IPM e imágenes dinámicas con CZT-SPECT en reposo-dipiridamol-PF. El FSM se cuantificó con el software 4DM. Se consideró respuesta anormal al dipiridamol una RFM menor a 2 y a la variación del FSM (∆FSM) menor a 1,5 con PF. Se definió DMV a la presencia de una o ambas respuestas anormales. Resultados: El CZT-SPECT detectó DMV en un 85% (n=79) de los pacientes con INOCA. El 42% tuvo respuesta anormal con ambos apremios mientras que el 43% restante, mostró una respuesta alterada del FSM sólo con PF. Conclusiones: El uso de CZT-SPECT empleando ambos apremios, permitió evaluar diferentes mecanismos fisiopatológicos que causan DMV presente en la mayoría de los pacientes con INOCA.

ABSTRACT Background: One of the causes of INOCA (Ischemia with Non- Obstructive Coronary Arteries) is microvascular dysfunction (MVD), which can be noninvasively assessed through the quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Dynamic myocardial perfusion imaging (MPI) by CZT-SPECT at rest, with dipyridamole stress test and cold pressor test (CPT) can establish the presence of two different pathophysiological mechanisms of MVD: endothelium-independent or endothelium-dependent, respectively. Objectives: The aim of this study was to evaluate the usefulness of CZT-SPECT for the diagnosis of MVD and the different mechanisms involved in patients with INOCA. Materials and Methods : A total of 93 consecutive INOCA patients were prospectively included and underwent dynamic MPI with CZT-SPECT at rest and with dipyridamole stress test and CPT. THe MBF was quantified using 4DM® software. A MFR response to dipyridamole <2, and changes in MBF (∆MBF) <1.5 with CPT were considered abnormal responses. MVD was defined in the presence of one abnormal response or both. Results: CZT-SPECT detected MVD in 85% (n=79) of the patients with INOCA. Forty-two percent had an abnormal response to both stressors while 43% presented an abnormal response of MBF only with CPT. Conclusion: The use of CZT-SPECT with both stress tests allowed the evaluation of different possible pathophysiological mechanisms of MVD present in most patients with INOCA.

Subaortic and mid-ventricular obstructive hypertrophic cardiomyopathy with an apical aneurysm: a case report.

BACKGROUND: Most patients with hypertrophic cardiomyopathy (HCM) have asymmetric septal hypertrophy and among them, 25% present dynamic subaortic obstruction. Apical HCM is unusual and mid-ventricular HCM is the most infrequent presentation, but both variants may be associated to an apical aneurysm. An even more rare presentation is the coexistence mid-ventricular and apical HCM. This case is a combination of obstructive HCM with mid-ventricular HCM and an apical aneurysm, which to date, has not been reported in the literature. CASE PRESENTATION: The patient is a 49 year-old lady who presents a combination of septal asymmetric hypertrophic cardiomyopathy (HCM) and midventricular HCM, a subaortic gradient of 65 mm Hg and a midventricular gradient of 20 mm Hg, plus an apical aneurysm. Her clinical presentation was an acute myocardial infarction in June 2005. One month after hospital discharge, the electrocardiogram (ECG) showed a right bundle branch block (RBBB) with no Q waves or ST segment elevation. Coronary angiography revealed normal coronary arteries, left ventricular hypertrophy and an apical aneurysm. CONCLUSION: This case is a rare example of an asymptomatic patient with subaortic and mid-ventricular hypertrophic cardiomyopathy, who presents a myocardial infarction and normal coronary arteries, and during the course of her disease develops an apical aneurysm.

Ventricular-arterial coupling assessment using gated single-photon emission computed tomography: relationship with reserve pulse pressure and repolarization abnormalities.

AIMS: In patients with normal myocardial perfusion, ST-segment depression and reserve pulse pressure (rPP) can identify patients at higher risk of cardiovascular events. We aimed to explore the prevalence of impaired ventricular-arterial coupling (VAc) in patients with normal myocardial perfusion imaging and its relationship with ST-segment depression and rPP. METHODS AND RESULTS: The present study included consecutive patients with normal myocardial perfusion imaging by single-photon emission computed tomography and ST-segment depression. Stroke volume, end-systolic pressure, arterial elastance (Ea), ventricular elastance (Ev), and VAc (Ea/Ev) were estimated both at rest and during stress. The difference between stress and rest (ΔVAc) was calculated. A positive ΔVAc was considered an impaired ΔVAc (iVAc). RESULTS: A total of 92 patients were prospectively included. iVAc was identified in 44 (59%) patients with ST-segment depression compared with 3 (16%) patients with normal repolarization (P=0.001). A higher incidence of abnormal rPP was identified in patients with ST-segment depression compared with the control group (61 vs. 16%, P=0.0001). ST-segment depression was identified as the only independent predictor of iVAc (adjusted OR 7.5; 95% CI 1.9-30.0, P=0.004). CONCLUSION: Noninvasive assessment of VAc is feasible with gated single-photon emission computed tomography and appears to be related to ST-segment depression and reserve rPP.

Relationship between endothelial progenitor cells and vascular endothelial growth factor and its variation with exercise.

BACKGROUND: The aim of our study was to evaluate the effect of programmed physical activity and a single exercise test on the number of CD309+ circulating endothelial progenitor cell (EPC) and their relation to the variation in plasma levels of VEGF in chronic coronary patients. METHODS: 21 patients <75 years with chronic stable coronary artery disease were included. All patients underwent exercise myocardial perfusion SPECT. Then, participants were divided into two groups: one group (11 patients) underwent cardiac rehabilitation program and the other (10 patients) continued with the standard treatment. Blood samples were obtained at baseline, 30 min after exercise ended and at one and three months during follow-up. RESULTS: VEGF values decreased significantly after exercise SPECT test. After one month, there was a significant increase in VEGF levels compared to those measured immediately after exercise. All patients showed a decrease in the values of EPC at 1 and 3-month follow-up. There was an inverse and statistically significant relation between change of EPC and VEGF between the baseline and 1 month. CONCLUSIONS: The increase of VEGF at 1-month, with respect to baseline values correlated with decreased levels of EPC. This association was independent of the onset of ischemia in the perfusion study.

Factores asociados a placa blanda en pacientes con score de calcio igual a cero / Factors Associated with Non-calcified Plaques in Patients with Coronary Artery Calcium Score of Zero

RESUMEN Introducción: El score de calcio es una prueba utilizada en la estratificación de riesgo de pacientes asintomáticos. Aunque la enfermedad coronaria puede producirse en ausencia de calcificaciones, no se han descripto afecciones asociadas a la presencia de placa blanda en este contexto, más allá de la presencia de síntomas. Objetivos: Determinar asociaciones entre la presencia de placa blanda y variables independientes en pacientes con un score de calcio de cero. Material y métodos: Se incluyeron pacientes consecutivos con un score de calcio de 0 unidades Agatston que se hubieran realizado, además, una angiotomografía coronaria. Se determinaron asociaciones a partir de análisis univariado. Se calculó la sensibilidad, especificidad, VPN, VPP, +LR y -LR. Resultados: Se incluyeron en el estudio 93 pacientes. El 10% (n = 9) presentaron placa blanda. La ergometría positiva se asoció a placas de cualquier gravedad (OR 6,5; IC del 95%: 1,3-33, p = 0,02). Esta asociación persistió para placas no graves cuando se combinó la ergometría positiva con perfusión miocárdica SPECT o ecocardiograma estrés negativos para isquemia (OR 12,4 IC 95% 1,5-101, p = 0,02). La sensibilidad y la especificidad del infradesnivel del ST para placa blanda de cualquier nivel de gravedad fue del 44,4% y del 86%, respectivamente. El VPN fue del 94% y el VPP del 25%, LR+ fue de 3,11 y LR- fue de 0,65. Conclusiones: El infradesnivel del ST se asociaría a la presencia de placa blanda en pacientes sin calcificaciones coronarias, incluso en contexto de perfusión miocárdica o motilidad parietal en esfuerzo normales (enfermedad no obstructiva).

ABSTRACT Background: The coronary artery calcium score is used for risk stratification in asymptomatic patients. Although coronary artery disease can occur in the absence of coronary artery calcifications, no conditions associated with the presence of soft non-calcified plaques have been described in this scenario, beyond the presence of symptoms. Objectives: The aim of this study was to determine the associations between non-calcified plaques and independent variables in patients with coronary artery calcium score of zero. Methods: Consecutive patients with coronary artery score of zero Agatston units who also underwent computed tomography coronary angiography were included in the study. Univariate logistic regression analysis was used to find associations. (15) Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LH+) and negative likelihood ratio (LH-) were calculated. Results: Among a total of 93 patients, 10% (n=9) presented non-calcified plaque. A positive exercise stress test was associated with plaques of any degree of severity (OR 6.5; 95% CI, 1.3-33, p=0.02). This association persisted for non-severe plaques when the positive exercise stress test was combined with a negative myocardial perfusion SPECT or stress echocardiography for ischemia (OR, 12.4; 95% CI 1.5-101, p=0.02). Sensitivity and specificity of ST-segment depression for non-calcified plaque of any degree of severity was 44.4% and 86%, respectively, with NPV of 94%, PPV of 25%, LR+ of 3.11 and LR- of 0.65. Conclusions: ST-segment depression could be associated with non-calcified plaques in patients without coronary artery calcifications, even with normal exercise stress myocardial perfusion or wall motion (non-obstructive disease).

Tomografía por emisión de positrones en endocarditis infecciosa asociada a dispositivos y válvulas protésicas / Positron emission tomography in infective endocarditis associated with intracardiac devices and prosthetic valves

La endocarditis infecciosa (EI) es una enfermedad grave y potencialmente letal. La capacidad diagnóstica de los criterios de Duke modificados es alta para válvulas nativas, pero decae en el caso de EI de válvulas protésicas o EI asociadas a dispositivos. El ecocardiograma y los hallazgos microbiológicos son fundamentales para el diagnóstico, pero pueden resultar insuficientes en este grupo de pacientes. Nuestro objetivo fue evaluar la utilidad de la tomografía por emisión de positrones y fusión con tomografía computarizada (PET/TC) en pacientes con sospecha de EI, portadores de válvulas protésicas o dispositivos intracardiacos. Se estudiaron 32 pacientes, a los cuales se les realizó un PET/CT con 18F-Flúor desoxiglucosa (18F-FDG). Se consideraron sugestivos de infección aquellos con captación intensa de tipo focal y/o heterogénea con un punto de corte de Standard Uptake Value (SUV) mayor o igual a 3.7. Los diagnósticos iniciales según los criterios de Duke modificados, se compararon con el diagnóstico final establecido por la Unidad de Endocarditis institucional. El agregado del PET/CT a esos criterios, proporcionó un diagnóstico concluyente en 22 de los 32 casos iniciales, reclasificando a 11 casos en EI definitivas y a otros 5 casos como negativos para ese diagnóstico. La EI continúa siendo un grave problema clínico. En aquellos casos donde los criterios de Duke no son suficientes para establecer el diagnóstico y la sospecha clínica persiste, el PET/CT puede ser una herramienta complementaria útil para aumentar la sensibilidad diagnóstica.

Infective endocarditis (IE) is a serious and potentially lethal condition. The diagnostic capacity of the modified Duke criteria is high for native valves, but it declines in the case of EI of prosthetic valves or EI associated with devices. Echocardiography and microbiological findings are essential for diagnosis but may be insufficient in this group of patients. Our objective was to evaluate the usefulness of positron emission tomography and fusion with computed tomography (PET / CT) in patients with suspected IE, carriers of prosthetic valves or intracardiac devices; 32 patients were studied, who underwent PET / CT with 18F-Fluorine deoxyglucose (18F-FDG). Those with intense focal and/or heterogeneous uptake with a Standard Uptake Value (SUV) cut-off point greater than or equal to 3.7 were considered suggestive of infection. The initial diagnoses according to the modified Duke criteria were compared with the final diagnosis established by the Institutional Endocarditis Unit. The addition of PET / CT to these criteria, provided a conclusive diagnosis in 22 of the 32 initial cases reclassifying 11 cases in definitive EI; another 5 cases were negative for that diagnosis. EI continues to be a serious clinical problem. In those cases where the Duke criteria are not sufficient to establish the diagnosis and clinical suspicion persists, PET / CT can be a useful complementary tool to increase the diagnostic sensitivity.

Relation of depression to heart rate nonlinear dynamics in patients > or =60 years of age with recent unstable angina pectoris or acute myocardial infarction.

Depression is common among older patients and it has been related to a worsened coronary prognosis. The basis for this association is controversial. The aim of this study was to ascertain whether patients with a recent acute coronary event show depression-related changes of heart rate variability (HRV) nonlinear dynamics. Alterations of the HRV have been recently shown to predict mortality in patients recovering from an acute myocardial infarction. In 52 patients > or =60 years (52% women) with recent (within 24 to 72 hours) unstable angina pectoris or myocardial infarction, we obtained conventional time- and frequency-domain HRV measurements, along with nonlinear HRV measurements, including SD of the instantaneous beat-to-beat variability (SD1), scaling exponent alpha1 (alpha1), and approximate entropy (ApEn) from 10-minute RR-interval recordings. We also evaluated the presence of clinical depression and measured its severity by means of a 21-item Hamilton Depression Scale. On admission to the coronary care unit, 19 patients (37%) were depressed; alpha1 was higher (1.23 +/- 0.21 vs 1.03 +/- 0.30, p <0.05), whereas SD1 (10.4 +/- 3.7 vs 14.4 +/- 7.3, p <0.05) and ApEn (0.98 +/- 0.22 vs 1.16 +/- 0.15, p <0.001) were lower in depressed patients. Also, alpha1 increased (r = 0.31, p <0.05) and both SD1 (r = -0.46, p <0.01) and ApEn (r = -0.28, p <0.05) decreased with worsening depressive symptoms. In our sample, depression was associated with increased correlation and decreased complexity of the interbeat interval time series in older adults who had recently developed an acute coronary syndrome.