Albumin Binds COVID-19 Spike 1 Subunit and Predicts In-Hospital Survival of Infected Patients-Possible Alteration by Glucose.

(1) Background: This study aimed to analyze if the serum albumin levels of hospitalized SARS-CoV-2 (COVID-19) patients on admission could predict <30 days in-hospital all-cause mortality, and if glucose levels on admission affected this predictive ability. (2) Methods: A multicenter retrospective cohort of 1555 COVID-19-infected adult patients from public hospitals of the Madrid community were analyzed. (3) Results: Logistic regression analysis showed increased mortality for ages higher than 49 y. After adjusting for age, comorbidities and on-admission glucose levels, it was found that on-admission serum albumin ≥3.5 g/dL was significantly associated with reduced mortality (OR 0.48; 95%CI:0.36-0.62). There was an inverse concentration-dependent association between on-admission albumin levels and <30 days in-hospital all-cause mortality. However, when on-admission glucose levels were above 125 mg/dL, higher levels of serum albumin were needed to reach an association with survival. In vitro experiments showed that the spike protein S1 subunit of SARS-CoV-2 binds to native albumin. The binding ability of native albumin to the spike protein S1 subunit was decreased in the presence of an increasing concentration of glycated albumin. (4) Conclusions: On-admission serum albumin levels were inversely associated with <30 days in-hospital all-cause mortality. Native albumin binds the spike protein S1 subunit, suggesting that native albumin may act as a scavenger of the SARS-CoV-2 virus.

Platelet Apoptotic Response May Be Associated With the Capacity of Aspirin to Inhibit Platelets.

An inadequate platelet response to aspirin (ASA) has been identified in some patients under chronic ASA treatment. The aim of this study was to analyze if ASA-sensitive and ASA-resistant platelets have differences in their apoptotic capability. Clinically stable ischemic coronary patients who had been taking ASA (100 mg/d) for at least 9 months before inclusion were divided into ASA-resistant (n = 11) and ASA-sensitive (n = 13) groups as defined by the PFA-100 test. Platelets from ASA-sensitive patients showed higher expression of the proapoptotic proteins Bak and Bax than those from ASA-resistant patients, although only Bak protein remained different when the results were adjusted by age. In resting platelets, neither caspase-3 activity nor cytosolic cytochrome C levels were different between both experimental groups. Stimulation of platelets with calcium ionophore (10 nmol/L, A23187) increased caspase-3 activity (1.91-fold higher; P < 0.05) and cytosolic cytochrome C levels (1.84-fold higher; P < 0.05) to a higher degree in ASA-sensitive than in ASA-resistant platelets. In conclusion, ASA-sensitive platelets seem to be better prepared to undergo apoptosis during robust platelet activation.

Mitral valve navigator. A new diagnostic tool for effective regurgitant orifice quantification in mitral regurgitation.

INTRODUCTION: Mitral regurgitation severity assessment is usually carried out using qualitative, semiquantitative, and quantitative parameters. The mitral valve navigation (MVN) tool allows to measure the mitral effective regurgitant orifice (MERO) from 3D echo datasets. Our aim was to validate the MVN as a new tool to quantify MERO. A secondary aim was to assess the intra- and interobserver variability. METHODS: This is a retrospective study in which consecutive subjects undergoing a transoesophageal echocardiogram for more than mild mitral regurgitation evaluation were included. MERO measurement obtained by means of 3D color Doppler was used as the gold standard method for comparison. In every patient, MERO was also obtained using the MVN tool. RESULTS: Fifty-nine consecutive patients were analyzed (47.5% female; mean age 50.8 years). Mitral regurgitation was moderate in 23 (39%) and severe in 36 (61%) patients. Forty patients (67.8%) had a primary and 19 (32.2%) a secondary mitral regurgitation. The intraclass correlation coefficient (ICC) between 3D color Doppler and MVN was excellent (ICC: 0.95; 95% CI: 0.82 to 0.98; P < 0.001) in the total group and for patients with primary and secondary mitral regurgitation. Intra- and interobserver agreements were also good. CONCLUSIONS: Mitral valve navigator shows an excellent accuracy for measuring MERO when the transoesophageal 3D color Doppler is used as the reference method, either primary or secondary mitral regurgitation. Intraobserver reproducibility and interobserver reproducibility are also excellent. These findings make this software a good alternative method to measure mitral regurgitation severity.

FXa inhibition by rivaroxaban modifies mechanisms associated with the pathogenesis of human abdominal aortic aneurysms.

AIMS: To evaluate if rivaroxaban, an oral factor Xa (FXa) inhibitor, could modify the expression in vitro of inflammatory and oxidative stress biomarkers in abdominal aortic aneurysmal (AAA) sites showing intraluminal thrombus. METHODS: AAA sites with intraluminal mural thrombus were obtained from six patients undergoing elective AAA repair. In addition, control abdominal aortic samples were obtained from six organ donors. AAA sites were incubated in the presence and absence of 50 nmol l-1 rivaroxaban. RESULTS: AAA sites showing thrombus demonstrated higher content of FXa than control. Interleukin-6 levels released from AAA [Control: median: 23.45 (interquartile range: 16.17-37.15) vs. AAA: median: 153.07 (interquartile range: 100.80-210.69) pg ml-1  mg tissue-1 , P < 0.05] and the expression levels of nitric oxide synthase 2 were significantly higher in AAA than in control. The protein expression level of NADPH oxidase subunits gp67-and gp91-phox, but did not gp47-phox, were also significantly higher in the AAA sites than in control. Addition of rivaroxaban to AAA sites explants significantly reduced the release of interleukin-6 [median: 51.61 (interquartile range: 30.87-74.03) pg ml-1  mg tissue-1 , P < 0.05 with respect to AAA alone] and the content of nitric oxide synthase 2, gp67 and gp91-phox NADPH subunits. The content of matrix metallopeptidase 9 was significantly higher in the AAA sites as compared to control. Rivaroxaban also reduced matrix metallopeptidase 9 content in AAA sites to similar levels to control. CONCLUSIONS: FXa inhibition by rivaroxaban exerted anti-inflammatory and antioxidative stress properties in human AAA sites, suggesting a role of FXa in these mechanisms associated with the pathogenesis of AAA.

Integración de la imagen multimodal en la práctica clínica: la importancia del trabajo multidisciplinario / Integrating multimodal imaging in clinical practice: the importance of a multidisciplinary approach

No disponible

Dosimetric Characteristics of an EMF Delivery System Based on a Real-Time Impedance Measurement Device.

In this paper, the dosimetric characterization of an EMF exposure setup compatible with real-time impedance measurements of adherent biological cells is proposed. The EMF are directly delivered to the 16-well format plate used by the commercial xCELLigence apparatus. Experiments and numerical simulations were carried out for the dosimetric analysis. The reflection coefficient was less than -10 dB up to 180 MHz and this exposure system can be matched at higher frequencies up to 900 and 1800 MHz. The specific absorption rate (SAR) distribution within the wells containing the biological medium was calculated by numerical finite-difference time domain simulations and results were verified by temperature measurements at 13.56 MHz. Numerical SAR values were obtained at the microelectrode level where the biological cells were exposed to EMF including 13.56, 900, and 1800 MHz. At 13.56 MHz, the SAR values, within the cell layer and the 270-µL volume of medium, are 1.9e3 and 3.5 W/kg/incident mW, respectively.

Thromboembolic risk in atrial fibrillation: association between left atrium mechanics and risk scores. A study based on 3D wall-motion tracking technology.

BACKGROUND/OBJECTIVES: Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with a significantly high risk of stroke and systemic embolism. The aim of our study was to assess the association between left atrium (LA) mechanics measured by 3D wall-motion tracking (3DWMT) technology and the most common thromboembolic risk scores (CHADS2, CHA2DS2-VASc). METHODS: A total of 101 consecutive patients with permanent AF referred were included. Conventional bidimensional (2D) LA parameters, and LA mechanics by means of 3DWMT were studied. Association between LA 2D and 3DWMT parameters and both risk scores was evaluated as well as its correlation with every component of the score individually. RESULTS: Mean age was 78 ± 10 years. Mean CHADS2 was 2.7 ± 1.3 and mean CHA2DS2-VASc was 4.4 ± 1.7. Values of 2D and 3DWTM LA parameters were: 2D area 26.4 ± 9.7 cm(2) , 2D volume index 49.4 ± 10.1 mL/m(2) , 3DWMT left atrial emptying fraction (LAEF) 15.9 ± 8.4%, longitudinal strain 9.1 ± 4.5% and area strain 14.9 ± 8.8%. Linear regression analysis showed statistically significant correlation between LA longitudinal strain and LAEF with CHADS2 and CHA2DS2-VASc scores. For each 10% variation in longitudinal strain, CHADS2 and CHA2DS2-VASc scores change in 0.7 and 0.8 points, respectively. CONCLUSIONS: Left atrial longitudinal strain and emptying fraction assessed by 3D WMT technology have correlation with both CHADS2 and CHA2DS2-VASc scores. Each 10% of variation in longitudinal strain represents a 0.7 and 0.8 points change in those risk scores. LA mechanics evaluation might provide additional value to risk scores and could be considered to be a predictor of stroke in patients with AF.

Functional mitral regurgitation after a first non-ST segment elevation acute coronary syndrome: very-long-term follow-up, prognosis and contribution to left ventricular enlargement and atrial fibrillation development.

OBJECTIVE: To assess the relationship between functional mitral regurgitation (MR) after a non-ST segment elevation acute coronary syndrome (NSTSEACS) and long-term prognosis, ventricular remodelling and further development of atrial fibrillation (AF), since functional MR is common after myocardial infarction. DESIGN AND SETTING: Prospective cohort study conducted in a tertiary referral centre. PATIENTS: We prospectively studied 237 patients consecutively discharged in New York Heart Association class I-II (74% men; mean age 66.1 years) after a first NSTSEACS. All underwent an ECG the first week after admission and were echocardiographically and clinically followed-up (median 6.95 years). RESULTS: MR was detected in 95 cases (40.1%) and became an independent risk factor for the development of heart failure (HF) and major adverse cardiovascular events (MACE) (per MR degree, HRHF 1.71, 95% CI 1.138 to 2.588, p=0.01; HRMACE 1.49, 95% CI 1.158 to 1.921, p=0.002). Left ventricular diastolic (grade I 12.7±40.7; grade II 26.8±12.4; grade III 46.3±50.9 mL, p=0.01) and systolic (grade I 10.4±37.3; grade II 10.12±12.7; grade III 36.8±46.0 mL, p=0.02) mean volumes were higher after follow-up in patients with MR, in proportion to the initial degree of MR. In the rhythm analysis (126 patients; previously excluding those with any history of AF) during follow-up, 11.4% of patients with degree I MR, 14.3% with degree II MR and 75% with degree III MR developed AF, while only 5.1% of those with degree 0 developed AF, p<0.001. CONCLUSIONS: MR is common after an NSTSEACS. The presence and greater degree of MR confers a worse long-term prognosis after a first NSTSEACS. This can in part be explained by increased negative ventricular remodelling and increased occurrence of AF.

Validez y utilidad del péptido ventricular natriurético tipo B (BNP) en la detección de disfunción ventricular izquierda en pacientes de alto riesgo en atención primaria / Validity and usefulness of B-type natriuretic peptide (BNP) for early detection of left ventricular dysfunction in high-risk patients in Primary Care

Objetivo: Determinar la validez y utilidad del BNP en atención primaria para detectar la disfunción ventricular en pacientes asintomáticos con alto riesgo de insuficiencia cardiaca (IC). Diseño: Estudio descriptivo prospectivo y multicéntrico de validación de prueba diagnóstica. Emplazamiento: Consultas de atención primaria de 7 centros de salud de la comunidad de Madrid. Participantes: Muestra consecutiva de 204 pacientes asintomáticos con riesgo elevado de presentar IC (estadios A y B de la American Heart Association). Mediciones principales: Se recogieron datos de la anamnesis, exploración física, electrocardiograma, factores de riesgo de IC y tratamiento actual. Se determinó el BNP en sangre venosa en la propia consulta mediante Triage BNP Test® (Biosite®) realizándose en las siguientes 72h un ecocardiograma (prueba de referencia). Comparamos los niveles de BNP según presencia o ausencia de disfunción ventricular, tipo (sistólica/diastólica) y grado. Se calcularon la sensibilidad, especificidad y los valores predictivos para el mejor punto de corte en la curva ROC. Resultados: Los valores de BNP fueron más altos (p<0,001) en pacientes con disfunción sistólica ventricular izquierda (DSVI). No se hallaron diferencias significativas para la disfunción diastólica. El mejor punto de corte para la detección de DSVI fue 71,00 pg/ml, siendo el área bajo la curva de 0,757 (IC 95%: 0,64-0,87). La sensibilidad fue del 75% (IC 95%: 50,66-99,34), especificidad 70,19% (62,81-77,57), valor predictivo positivo 20% (IC 95%: 9,05-30,95) y valor predictivo negativo 96,58% (IC 95%: 92,86-100), siendo la prevalencia de DSVI en esta población del 9,04%. Conclusiones: El BNP puede tener utilidad en el diagnóstico precoz de DSVI en pacientes de alto riesgo de IC en consultas de atención primaria debido a su alto VPN (> 96%)(AU)

Objective: The aim of this study was to determine the accuracy of BNP test for early diagnosis of left ventricular dysfunction in patients at high-risk for heart failure. Design: Cross-sectional descriptive study. Setting: 7 Primary Care Centres in Madrid (Spain). Participants: A consecutive sample of 204 consecutive asymptomatic patients with high risk for heart failure (Stages A-B, AHA/ACC Classification). Main measurements: BNP plasma levels were measured in the clinical setting using Triage BNP Test® (Biosite®) and an echocardiography was performed in the following 3 days in a single hospital unit as a reference standard. Plasma BNP levels were compared depending on the presence/absence of left ventricular dysfunction (LVD), type and severity degree. Sensitivity, specificity, positive and negative predictive values, and Área under the receiver operating characteristic curve (ROC) for BNP assay were calculated. Results: BNP values were significantly higher (P<.001) in patients with left ventricular systolic dysfunction (LVSD). No significant differences were found for diastolic dysfunction. The best cut-off value to discriminate the patients with LVSD was 71.00 pg/ml, with an Área under the ROC curve of 0.757 (95% CI 0.64-0.87). Sensitivity for LVD diagnosis was 75% (95% CI 50.66-99.34), specificity 70.19% (95% CI 62.81-77.57), positive predictive value (PPV) 20% (95% CI 9.05-30.95), and negative predictive value (NPV) 96.58% (95% CI 92.86-100), with LVSD prevalence of 9.04% in this population. Conclusions: BNP determinations are of value in diagnosing LVSD in a primary care setting, with similar sensitivities and specificities. Due to the high NPV is useful to rule-out patients for echocardiography(AU)

[Validity and usefulness of B-type natriuretic peptide (BNP) for early detection of left ventricular dysfunction in high-risk patients in primary care]. / Validez y utilidad del péptido ventricular natriurético tipo B (BNP) en la detección de disfunción ventricular izquierda en pacientes de alto riesgo en atención primaria.

OBJECTIVE: The aim of this study was to determine the accuracy of BNP test for early diagnosis of left ventricular dysfunction in patients at high-risk for heart failure. DESIGN: Cross-sectional descriptive study. SETTING: 7 Primary Care Centres in Madrid (Spain). PARTICIPANTS: A consecutive sample of 204 consecutive asymptomatic patients with high risk for heart failure (Stages A-B, AHA/ACC Classification). MAIN MEASUREMENTS: BNP plasma levels were measured in the clinical setting using Triage BNP Test(®) (Biosite(®)) and an echocardiography was performed in the following 3 days in a single hospital unit as a reference standard. Plasma BNP levels were compared depending on the presence/absence of left ventricular dysfunction (LVD), type and severity degree. Sensitivity, specificity, positive and negative predictive values, and Área under the receiver operating characteristic curve (ROC) for BNP assay were calculated. RESULTS: BNP values were significantly higher (P<.001) in patients with left ventricular systolic dysfunction (LVSD). No significant differences were found for diastolic dysfunction. The best cut-off value to discriminate the patients with LVSD was 71.00 pg/ml, with an Área under the ROC curve of 0.757 (95% CI 0.64-0.87). Sensitivity for LVD diagnosis was 75% (95% CI 50.66-99.34), specificity 70.19% (95% CI 62.81-77.57), positive predictive value (PPV) 20% (95% CI 9.05-30.95), and negative predictive value (NPV) 96.58% (95% CI 92.86-100), with LVSD prevalence of 9.04% in this population. CONCLUSIONS: BNP determinations are of value in diagnosing LVSD in a primary care setting, with similar sensitivities and specificities. Due to the high NPV is useful to rule-out patients for echocardiography.

Utilidad de la resonancia magnética cardiaca en el diagnóstico de los pacientes con síndrome coronario agudo y coronarias normales / The value of cardiac magnetic resonance in patients with acute coronary syndrome and normal coronary arteries

Introducción y objetivos. Diferentes enfermedades pueden presentar síntomas similares a los del síndrome coronario agudo (SCA): dolor torácico, cambios en el ECG y elevación de marcadores de daño miocárdico. Incluso después de realizar una coronariografía, a veces es difícil establecer el diagnóstico. El objetivo del estudio fue valorar la utilidad de la resonancia magnética cardiaca (RMC) en el diagnóstico de los procesos que se presentan como un SCA y tienen coronarias normales. Métodos. Estudiamos a 80 pacientes con sospecha de SCA y coronarias normales. La media de edad fue 48 ± 15 años. La troponina T media fue 1,8 ± 0,9 ng/ml. Realizamos un estudio de RMC incluyendo secuencias potenciadas en T2 para detectar edema y secuencia I-R de realce tardío (RT) a los 10 min de la administración de gadolinio. Resultados. El diagnóstico final fue miocarditis aguda en 51 pacientes (63%). En todos estos casos observamos RT localizado en el subepicardio y las porciones medias de miocardio. En 12 pacientes (15%) el diagnóstico final fue infarto agudo de miocardio, todos ellos con RT subendocárdico o transmural. En 9 pacientes (11%) con alteraciones de la contractilidad en el ecocardiograma basal y normalización posterior, el estudio con RMC no mostró RT de contraste y se les diagnosticó síndromes de tako-tsubo. En 4 pacientes el diagnóstico final fue pericarditis aguda y en 4 no se pudo establecer un diagnóstico. Conclusiones. La miocarditis aguda y el síndrome de tako-tsubo pueden presentarse en la clínica de forma similar al SCA. La presencia y el patrón de RT de contraste en el estudio de RMC nos ayudan de forma importante a establecer el diagnóstico (AU)

Introduction and objectives. A number of different conditions can present with symptoms similar to acute coronary syndrome (ACS): chest pain, electrocardiographic changes, and elevated levels of markers of myocardial damage. Even after coronary angiography has been performed, differential diagnosis can be challenging. The aim of this study was to evaluate the usefulness of cardiac magnetic resonance (CMR) for diagnosing conditions that present like ACS but in which the coronary arteries are normal. Methods. The study involved 80 patients with suspected ACS and normal coronary arteries. Their mean age was 48 (15) years and their mean troponin-T (TnT) level was 1.8 (0.9) ng/mL. A CMR study, which involved T2 weighted imaging to detect edema and delayed contrast-enhancement (DCE) imaging 10 minutes after gadolinium administration, was performed. Results. In 51 patients (63%), the final diagnosis was acute myocarditis. In all these cases, DCE was observed in subepicardial and middle segments of the myocardium. The final diagnosis was acute myocardial infarction in 12 patients (15%), all of whom exhibited subendocardial or transmural DCE. In the 9 (11%) who exhibited abnormal contractility on baseline echocardiography with subsequent normalization, CMR did not show DCE, a finding that is characteristic of Takotsubo cardiomyopathy. In addition, 4 patients had a final diagnosis of pericarditis, while no diagnosis could be established in another 4. Conclusions. The clinical presentation of acute myocarditis and Takotsubo syndrome can be similar to that of ACS. The presence and distribution of DCE on CMR are of great help in establishing a diagnosis (AU)

The value of cardiac magnetic resonance in patients with acute coronary syndrome and normal coronary arteries.

INTRODUCTION AND OBJECTIVES: A number of different conditions can present with symptoms similar to acute coronary syndrome (ACS): chest pain, electrocardiographic changes and elevated levels of markers of myocardial damage. Even after coronary angiography has been performed, differential diagnosis can be challenging. The aim of this study was to evaluate the usefulness of cardiac magnetic resonance (CMR) for diagnosing conditions that present like ACS but in which the coronary arteries are normal. METHODS: The study involved 80 patients with suspected ACS and normal coronary arteries. Their mean age was 48+/-15 years and their mean troponin-T (TnT) level was 1.8+/-0.9 ng/ml. A CMR study, which involved T2-weighted imaging to detect edema and delayed contrast-enhancement (DCE) imaging 10 minutes after gadolinium administration, was performed. RESULTS: In 51 patients (63%), the final diagnosis was acute myocarditis. In all these cases, DCE was observed in subepicardial and middle segments of the myocardium. The final diagnosis was acute myocardial infarction in 12 patients (15%), all of whom exhibited subendocardial or transmural DCE. In the 9 (11%) who exhibited abnormal contractility on baseline echocardiography with subsequent normalization, CMR did not show DCE, a finding that is characteristic of Takotsubo cardiomyopathy. In addition, 4 patients had a final diagnosis of pericarditis, while no diagnosis could be established in another 4. CONCLUSIONS: The clinical presentation of acute myocarditis and Takotsubo syndrome can be similar to that of ACS. The presence and distribution of DCE on CMR are of great help in establishing a diagnosis.

[Percutaneous aortic valve implantation: initial experience in Spain]. / Implantación percutánea de prótesis valvular aórtica: experiencia inicial en España.

Patients with symptomatic aortic stenosis have a very poor prognosis on medical treatment. In those with contraindications to surgery, percutaneous valve replacement has been proposed as an alternative. We report on physicians' initial experience in Spain with percutaneous aortic valve replacement. We analyzed inhospital and short-to-medium-term findings in four patients who underwent percutaneous implantation of a Cribier-Edwards prosthetic aortic valve. In all four cases, the Cribier-Edwards prosthetic valves were successfully implanted via the femoral artery. The procedures were guided by angiography and transesophageal echocardiography. Patients were discharged 3 to 5 days after the procedure and were still in a satisfactory clinical condition 3 months later. In summary, early experience in Spain with the percutaneous implantation of Cribier-Edwards prosthetic aortic valves indicates that it is a suitable alternative for patients for whom replacement surgery is contraindicated or would place them at a high risk.

Implantación percutánea de prótesis valvular aórtica: experiencia inicial en España / Percutaneous aortic valve implantation: initial experience in Spain

Los pacientes con estenosis aórtica sintomática tienen un pronóstico ominoso con tratamiento médico. En pacientes con contraindicación quirúrgica, se ha propuesto la implantación percutánea como alternativa. Presentamos la experiencia inicial en España de la implantación percutánea de prótesis valvular aórtica. Analizamos los resultados hospitalarios y a corto-medio plazo de 4 pacientes a quienes se implantó, de forma percutánea, una prótesis valvular aórtica de Cribier-Edwards. Las cuatro prótesis valvulares se implantaron con éxito por vía percutánea a través de la arteria femoral. El procedimiento fue guiado por angiografía y ecocardiografía transesofágica. Los pacientes fueron dados de alta entre 3 y 5 días después del procedimiento y siguen en buena situación clínica a los 3 meses. En conclusión, la experiencia inicial en España de implantación percutánea de prótesis valvular aórtica de Cribier-Edwards apunta en la dirección de una alternativa válida en pacientes con contraindicación o alto riesgo para la sustitución quirúrgica (AU)

Patients with symptomatic aortic stenosis have a very poor prognosis on medical treatment. In those with contraindications to surgery, percutaneous valve replacement has been proposed as an alternative. We report on physicians' initial experience in Spain with percutaneous aortic valve replacement. We analyzed inhospital and short-to-medium-term findings in 4 patients who underwent percutaneous implantation of a Cribier-Edwards prosthetic aortic valve. In all four cases, the Cribier-Edwards prosthetic valves were successfully implanted via the femoral artery. The procedures were guided by angiography and transesophageal echocardiography. Patients were discharged 3 to 5 days after the procedure and were still in a satisfactory clinical condition 3 months later. In summary, early experience in Spain with the percutaneous implantation of Cribier-Edwards prosthetic aortic valves indicates that it is a suitable alternative for patients for whom replacement surgery is contraindicated or would place them at a high risk (AU)

Objective quantification of global and regional left ventricular systolic function by endocardial tracking of contrast echocardiographic sequences.

BACKGROUND: Echocardiographic assessment of LV wall motion is still most frequently done visually. This study was designed to validate a new system for semi-automatic quantification of global and regional LV systolic function from contrast-enhanced cross-sectional echocardiograms. METHODS: Measurements of LV volumes were validated in 50 patients using magnetic resonance (MR) as reference. The regional identification of the endocardial boundary was validated frame-by-frame against the visually identified border in another 27 patients. Finally, the applicability of the system for quantifying stress-echocardiographic exams was assessed in 52 patients undergoing dobutamine interventions. Echocardiographic sequences were digitally processed using custom-built algorithms, based on local phase feature descriptors, deformable contour fitting, and prospective training. RESULTS: Compared to MR, the tracing system showed reasonable accuracy, with relative errors for end-diastolic volume, end-systolic volume, and EF of 21+/-20%, 27+/-33%, and--4+/-18%, respectively. Regional agreement of the instantaneous contours with visually traced borders was within the limits of visual reproducibility. The system was suitable for tracking stress-echo studies from all patients except two (96%). Quantification of regional radial shortening allowed to discriminate segments showing an abnormal regional wall motion with an overall area under the ROC curve of 0.87. CONCLUSIONS: A reliable and accurate quantification of LV systolic function can be obtained by processing contrast echocardiograms. Values of LV volumes, ejection fraction, and regional endocardial shortening adequately correlate with currently available reference methods. Readily applicable to baseline and stress studies, endocardial tracking techniques increase the reliability of echocardiography for the assessment of global and regional systolic function.

Noninvasive assessment of the right ventricular filling pressure gradient.

BACKGROUND: The physiological basis of right ventricular (RV) diastolic function remains incompletely studied in humans. The driving force responsible for RV filling, the pressure gradient along the RV inlet from the right atrium to the RV apex, has never been measured in the clinical setting. METHODS AND RESULTS: We validated a method for measuring the RV filling pressure difference (RVFPD) from color Doppler M-mode recordings in 12 pigs undergoing interventions on RV preload, afterload, and lusitropic states (error, -0.1+/-0.4 mm Hg compared with micromanometers; intraclass correlation coefficient, 0.88). Peak early RVFPD correlated directly with mean right atrial pressure and inversely with the time constant of RV relaxation. In 21 patients with dilated cardiomyopathy, the peak RVFPD was 1.0 mm Hg (95% CI, 0.8 to 1.2), significantly lower than in age-matched control subjects (1.4 mm Hg; 95% CI, 1.2 to 1.6). In another population of 19 young healthy volunteers, the peak RVFPD was 2.3 mm Hg (95% CI, 2.0 to 2.6), which was reduced by nitroglycerine and esmolol and was augmented by volume overload and atropine infusions. RVFPD was generated almost exclusively by inertial forces. CONCLUSIONS: For the first time, the RV driving filling force can be accurately measured noninvasively in the clinical setting, and the method is sensitive to detect the effects of preload, chronotropic, and lusitropic states. In patients with dilated cardiomyopathy, the RV filling force is markedly reduced, indicating severely impaired RV relaxation. These findings suggest that this is a useful tool for improving the clinical assessment of RV diastolic function.

Impact of image spatial, temporal, and velocity resolutions on cardiovascular indices derived from color-Doppler echocardiography.

Quantitative processing of color-Doppler echocardiographic images has substantially improved noninvasive assessment of cardiac physiology. Many indices are computed from the velocity fields derived either from color-Doppler tissue imaging (DTI), such as acceleration, strain and strain-rate, or from blood-flow color-Doppler, such as intracardiac pressure gradients (ICPG). All of these indices are dependent on the finite resolution of the ultrasound scanner. Therefore, we developed an image-dependent method for assessing the influence of temporal, spatial, and velocity resolutions, on cardiovascular parameters derived from velocity images. In order to focus our study on the spatial, temporal, and velocity resolutions of the digital image, we did not consider the effect of other sources of noise such as the interaction between ultrasound and tissue. A simple first-order Taylor's expansion was used to establish the functional relationship between the acquired image velocity and the calculated cardiac index. Resolutions were studied on: (a) myocardial acceleration, strain, and strain-rate from DTI, and (b) ICPG from blood-flow color-Doppler. The performance of Taylor's-based error bounds (TBEB) was demonstrated on simulated models and illustrated on clinical images. Velocity and temporal resolution were highly relevant for the accuracy of DTI-derived parameters and ICPGs. TBEB allow to assess the effects of ideal digital image resolution on quantitative cardiovascular indices derived from velocity measurements obtained by cardiac imaging techniques.