Cardiopulmonary Imaging Utilization and Findings among Hospitalized COVID-19 Patients in Latin America: (From "RIMAC: Registry IMAging Cardiopulmonary among Hospitalized COVID-19 Patients in LATAM").

Objectives: Describe the use and findings of cardiopulmonary imaging-chest X-ray (cX-ray), echocardiography (cEcho), chest CT (cCT), lung ultrasound (LUS), and/or cardiac magnetic resonance imaging (cMRI)-in COVID-19 hospitalizations in Latin America (LATAM). Background: There is a lack of information on the images used and their findings during the SARS-CoV-2 pandemic in LATAM. Methods: Multicenter, prospective, observational study of COVID-19 inpatients, conducted from March to December 2020, from 12 high-complexity centers, in nine LATAM countries. Adults (>18 years) with at least one imaging modality performed, followed from admission until discharge and/or in-hospital death, were included. Results: We studied 1,435 hospitalized patients (64% males) with a median age of 58 years classified into three regions: Mexico (Mx), 262; Central America and Caribbean (CAC), 428; and South America (SAm), 745. More frequent comorbidities were overweight/obesity, hypertension, and diabetes. During hospitalization, 58% were admitted to the ICU. The in-hospital mortality was 28%, and it was highest in Mx (37%).The most frequent images performed were cCT (61%), mostly in Mx and SAm, and cX-ray (46%), significant in CAC. The cEcho was carried out in 18%, similarly among regions, and LUS was carried out in 7%, with a higher frequently in Mx. Abnormal findings on the cX-ray were peripheral or basal infiltrates, and in cCT abnormal findings were the ground glass infiltrates, more commonly in Mx. In LUS, interstitial syndrome was the most abnormal finding, predominantly in Mx and CAC.Renal failure was the most prevalent complication (20%), predominant in Mx and SAm. Heart failure developed in 13%, predominant in Mx and CAC. Lung thromboembolism was higher in Mx while myocardial infarction was in CAC.Logistic regression showed associations of abnormal imaging findings and their severity, with comorbidities, complications, and evolution. Conclusions: The use and findings of cardiopulmonary imaging in LATAM varied between regions and had a great impact on diagnosis and prognosis.

Left atrial volume changes during exercise stress echocardiography in heart failure and hypertrophic cardiomyopathy.

OBJECTIVE: We aimed to assess feasibility and functional correlates of left atrial volume index (LAVI) changes during exercise stress echocardiography (ESE). METHODS: ESE on a bike or treadmill was performed in 363 patients with heart failure with preserved ejection fraction (HFpEF, n = 173), reduced ejection fraction (HFrEF, n = 59), or hypertrophic cardiomyopathy (HCM, n = 131). The LAVI stress-rest increase ≥6.8 ml/m2 was defined as dilation. RESULTS: LAVI measurements were feasible in 100%. LAVI did not change in HFrEF being at rest 32 (25-45) vs at stress 36 (24-54) ml/m2, P = NS and in HCM at rest 35 (26-48) vs at stress 38 (28-48) ml/m2, P = NS, whereas it decreased in HFpEF from 30 (24-40) to 29 (21-37) ml/m2 at stress, P = 0.007. LA dilation occurred in 107 (30%) patients (27% with treadmill vs 33% with bike ESE, P = NS): 26 with HFpEF (15%), 26 with HFrEF (44%), and 55 with HCM (42%) with P < 0.001 for HFrEF and HCM vs HFpEF. A multivariate analysis revealed as the predictors for LAVI dilation E/e' > 14 at rest with odds ratio (OR) 4.4, LVEF <50% with OR 2.9, and LAVI at rest <35 ml/m2 with OR 2.7. CONCLUSION: The LAVI assessment during ESE was highly feasible and dilation equally frequent with a treadmill or bike. LA dilation was three-fold more frequent in HCM and HFrEF and could be predicted by increased resting E/e' and impaired EF as well as smaller baseline LAVI.

Feasibility and value of two-dimensional volumetric stress echocardiography.

BACKGROUND: Stroke volume response during stress is a major determinant of functional status in heart failure and can be measured by two-dimensional (2-D) volumetric stress echocardiography (SE). The present study hypothesis is that SE may identify mechanisms underlying the change in stroke volume by measuring preload reserve through end-diastolic volume (EDV) and left ventricular contractile reserve (LVCR) with systolic blood pressure and end-systolic volume (ESV). METHODS: We enrolled 4735 patients (age 63.6±11.3 years, 2800 male) referred to SE for known or suspected coronary artery disease (CAD) and/or heart failure (HF) in 21 SE laboratories in 8 countries. In addition to regional wall motion abnormalities (RWMA), force was measured at rest and peak stress as the ratio of systolic blood pressure by cuff sphygmomanometer/ESV by 2D with Simpson's or linear method. Abnormal values of LVCR (peak/rest) based on force were ≤1.10 for dipyridamole (N.=1992 patients) and adenosine (N.=18); ≤2.0 for exercise (N.=2087) or dobutamine (N.=638). RESULTS: Force-based LVCR was obtained in all 4735 patients. Lack of stroke volume increase during stress was due to either abnormal LVCR and/or blunted preload reserve, and 57% of patients with abnormal LVCR nevertheless showed increase in stroke volume. CONCLUSIONS: Volumetric SE is highly feasible with all stresses, and more frequently impaired in presence of ischemic RWMA, absence of viability and reduced coronary flow velocity reserve. It identifies an altered stroke volume response due to reduced preload and/or contractile reserve.

The value of a simplified approach to end-systolic volume measurement for assessment of left ventricular contractile reserve during stress-echocardiography.

The peak stress/rest ratio of left ventricular (LV) elastance, or LV force, is a load-independent index of left ventricular contractile reserve (LVCR) with stress echo (SE). To assess the accuracy of LVCR calculated during SE with approaches of different complexity. Two-hundred-forty patients were referred to SE for known or suspected coronary artery disease or heart failure and, of those, 200 patients, age 61 ± 15, 99 females, with interpretable volumetric SE were enrolled. All readers had passed the upstream quality control reading for regional wall motion abnormality (RWMA) and end-systolic volume (ESV) measurement. The employed stress was dipyridamole (0.84 mg, 6 min) in 86 (43%) and dobutamine (up to 40 mcg/kg/min) in 114 (57%) patients. All underwent SE with evaluation of RWMA and simultaneous LVCR assessment with stress/rest ratio of LV force (systolic blood pressure by cuff sphygmomanometer/ESV). ESV was calculated in each patient by two of three methods: biplane Simpson rule (S, in 100 patients), single plane area-length (AL, apical four-chamber area and length, in 100 patients), and Teichholz rule (T, from parasternal long axis and/or short axis view, in 200 patients). RMWA were observed in 54 patients. Success rate for ESV measurement was 76% (100/131) for S, 92% (100/109) for AL, and 100% (240/240) for T. There were 100 paired measurements (rest and stress) with S versus T, and 100 with AL versus T. The analysis time was the shortest for T (33 ± 8 s at rest, 34 ± 7 s at stress), intermediate for AL (70 ± 22 s at rest 67 ± 21 s at stress), and the longest for S (136 ± 24 at rest 129 ± 27 s at stress, p < 0.05 vs. T and AL). ESV absolute values were moderately correlated: T versus S (r rest = 0.746, p < 0.01, n = 100; r stress = 0.794, p < 0.01, n = 100); T vs. AL (r = 0.603 p < 0.01, n = 100, at rest and r = 0.820 p < 0.01 n = 100 at peak stress). LVCR values were tightly correlated independently of the method employed: T versus S (r = 0.899, p < 0.01, n = 100), and T versus AL (r = 0.845, p < 0.01, n = 100). LVCR can be accurately determined with all three methods used to extract the raw values of ESV necessary to generate the calculation of Force. Although S is known to be more precise in determining absolute ESV values, the relative (rest-stress) changes can be assessed, with comparable accuracy, with simpler and more feasible T and AL methods, characterized by higher success rate, shorter imaging and analysis time.

Chitosan-coated microvesicles: Effect of polysaccharide-phospholipid affinity on decafluorobutane dissolution.

The stability of perfluorinated microvesicles is mainly determined by the presence of interfacial materials and their ability to hinder the gas component diffusibility into the bloodstream. The goal of this study is to increase the persistence of the gaseous-core by introducing chitosan-coated 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) microvesicles, reducing gas diffusion from microvesicles, and increasing for a long time ultrasonic signals. Our hypothesis was based on the irreversible adhesion of chitosan towards DSPC head groups observed in thin-films models. This affinity enhanced the stabilization of gaseous-core microvesicles, in which the polysaccharide effectively reduced the phospholipid phase transition enthalpy from 383±5.5Jmg(-1) for plain to 150±9.7Jmg(-1) for chitosan-coated microvesicles, providing a more stable structure that diminished the gaseous component lost and provided the persistence of intense (19)F-NMR signals after 48h, twice as long compared to plain samples. As a result, stronger and long-lasting ultrasonic signals were produced by the more stable chitosan-containing microvesicles, thus, presenting great potential to increase the diagnostic and therapeutic applications of perfluorocarbon carries.

A reologia microvascular das microesferas de perfluoropropano na presença da isquemia-reperfusão, diabetes e sepsis / The microvascular reology of ultrasound contrast in ischemia-reperfusion injury, diabetes and sepsis

Fundamentos: A adesão das microesferas aos leucócitos no tecido inflamado tem sido discutida, porém, pouco se sabe sobre seu comportamento nos capilares. A avaliação dos efeitos circulatórios desse agente pode trazer informações sobre sua ação no miocárdio. Objetivo: Avaliar o comportamento microvascular e hemodinâmico das microesferas nos seguintes grupos: controle, isquemia-reperfusão, diabetes tipo 2, diabetes com isquemia e sepsis. Métodos: Experimentalmente estudou-se a microcirculação da bolsa da bochecha de 65 hamsters machos, sendo separados por grupos conforme a indução da doença de base G-1 igual isquemia/reperfusão. GD igual diabetes, GDI igual diabetes com isquemia GS igual sepsis em relação ao GC (grupo controle). Dentro de cada grupo avaliou-se a pressão arterial...

Análise dos gradientes intraventricular e aórtico ao ecocardiograma de estresse com dobutamina: correlação entre hiperdinamia miocárdica e complicações / Analysis of intraventricular and aortic gradient during dobutamine stress echocardiogram: correlation with complications

Fundamento: A interpretação do ecocardiograma de estresse com dobutamina-atropina é baseada no aumento do espessamento sistólico, onde o contrário disto é considerado indicativo de doença arterial coronariana (DAC).Porém, a condição hiperdinâmica induzida pela dobutamina pode repercurtir em sintomas que não decorrem da DAC obstrutiva. Objetivo: Avaliar a associação entre o gradiente na via de saída do ventrículo esquerdo (VSVE) e aórtico)AO) e a presença de sintomas, durante a ecocardiografia de estresse com dobutamina (DOB), e as diferenças na hemodinâmica desses fluxos entre os protocolos precoce e padrão(PR e PD). Material e Métodos: Estudados 75 pt com função sistólica normal. Os pt foram randomizados aleatoriamente para PD(Atr em 40mcg de DOB) ou PR(Atr iniciando em 20mcg de DOB). Os gradientes na VSVE e AO foram obtidos em repouso e em cada estágio do teste e foram analisados evolutivamente. Presença de complicações foram consideradas e alterações hemodinâmicas registradas. O teste de Wilcoxon, t de Strudent e de Mann-Whitney foram utilizados para análise estatística. Resultados: Dos 75 pt estudados, a média de idade foi de 61 anos, 71 por cento tinham história de HAS e HVE foi identificada em 36 por cento dos casos. Variações dos gradientes entre os PD e PR não ocorreram junto ao basal, mas os gradientes foram maiores no PD a partir de 20mcg DOB, e em todos os estágios do teste os gradientes aumentam gradativa e significativamente (p menor 0,0001). No pico do teste dos gradientes foram maiores no PD em relação ao PR (p menor 0,05), considerando um delta (pico-basal) maior 20mmHg (p igual 0,022). Dor precordial ocorreu em 8,6 por cento (em testes negativos), arritmias em 15,5 por cento e hipotensão 5,2 por cento dos casos. A presença de complicações se relacionou mais com a elevação dos gradientes durante o teste, e mais no PD (60 por cento vezes 22 por cento) em relação ao PR, p igual 0,002. Conclusão: Os gradientes em VSVE e AO apresentaram aumentos...

The effects of beta-blockers on dobutamine-atropine stress echocardiography: early protocol versus standard protocol.

BACKGROUND: To study the effects of Beta-blockers during Dobutamine Stress Echocardiography (DSE) comparing the hemodynamic benefits of an early administration of atropine in patients taking or not Beta-blockers. METHODS: One hundred and twenty-one patients were submitted to dobutamine stress echocardiography for the investigation of myocardial ischemia. The administration of atropine was randomized into two groups: A or B (early protocol when atropine was administered at 10 and 20 mcg/kg/min of dobutamine, respectively) and C (standard protocol with atropine at 40 mcg/kg/min of dobutamine). Analysis of the effects of Beta-blockers was done regarding the behavior pattern of heart rate and blood pressure, test time, number of conclusive and inconclusive (negative sub-maximum test) results, total doses of atropine and dobutamine, and general complications. RESULTS: Beta-blocked patients who received early atropine (Group A&B) had a significantly lower double product (p = 0.008), a higher mean test time (p = 0.010) and required a higher dose of atropine (p = 0.0005) when compared to the patients in this group who were not Beta-blocked. The same findings occurred in the standard protocol (Group C), however the early administration of atropine reduced test time both in the presence and absence of this therapy (p = 0.0001). The patients with Beta-blockers in Group A&B had a lower rate of inconclusive tests (26%) compared to those in Group C (40%). Complications were similar in both groups. CONCLUSION: The chronotropic response during dobutamine stress echocardiography was significantly reduced with the use of Beta-blockers. The early administration of atropine optimized the hemodynamic response, reduced test time in patients with or without Beta-blockers and reduced the number of inconclusive tests in the early protocol.