Teste Cardiopulmonar em Pacientes Pós-COVID-19: De Onde vem a Intolerância ao Exercício? / Cardiopulmonary Exercise Testing in Post-COVID-19 Patients: Where Does Exercise Intolerance Come From?

Resumo Fundamento A intolerância ao exercício pós-COVID-19 não é bem entendida. O teste de esforço cardiopulmonar (TECP) pode identificar as limitações ao exercício subjacentes. Objetivos Avaliar a etiologia e a magnitude da intolerância ao exercício em sujeitos pós-COVID-19. Métodos Estudo de coorte que avaliou sujeitos com níveis de gravidades diferentes da doença COVID-19 e um grupo de controle selecionado por pareamento por escores de propensão. Em uma amostra seleta com TECP anterior à infecção viral disponível, foram realizadas comparações antes e depois. O nível de significância foi de 5% em toda a análise. Resultados Foram avaliados cento e quarenta e dois sujeitos com COVID-19 (idade mediana: 43 anos, 57% do sexo masculino), com níveis de gravidade de doença diferentes (60% leve, 21% moderada, 19% grave). O TECP foi realizado 11,5 (7,0, 21,2) semanas após o aparecimento da doença, com as limitações ao exercício sendo atribuídas aos sistemas muscular periférico (92%), pulmonar (6%), e cardiovascular (2%). Menor valor mediano do consumo de oxigênio pico percentual foi observado no subgrupo com níveis graves de doença (72,2%) em comparação com os controles (91,6%). O consumo de oxigênio foi diferente entre os grupos com diferentes níveis de gravidade de doença e o controle no pico e nos limiares ventilatórios. Inversamente, os equivalentes ventilatórios, a inclinação da eficiência do consumo de oxigênio, e o pico do pulso de oxigênio foram semelhantes. A análise do subgrupo de 42 sujeitos com TECP prévio revelou uma redução significativa no pico de velocidade da esteira no subgrupo com nível leve de doença, e no consumo de oxigênio no pico e nos limiares ventilatórios nos subgrupos com níveis moderado/grave. Por outro lado, os equivalentes ventilatórios, a inclinação da eficiência do consumo de oxigênio e o pico do pulso de oxigênio não apresentaram alterações significativas. Conclusões A fadiga do músculo periférico foi a etiologia de limitação de exercício mais comum em pacientes pós-COVID-19 independentemente da gravidade da doença. Os dados sugerem que o tratamento deve enfatizar programas de reabilitação abrangentes, incluindo componentes aeróbicos e de fortalecimento muscular.

Abstract Background Post-COVID-19 exercise intolerance is poorly understood. Cardiopulmonary exercise testing (CPET) can identify the underlying exercise limitations. Objectives To evaluate the source and magnitude of exercise intolerance in post-COVID-19 subjects. Methods Cohort study assessing subjects with different COVID-19 illness severities and a control group selected by propensity score matching. In a selected sample with CPET prior to viral infection, before and after comparisons were performed. Level of significance was 5% in the entire analysis. Results One hundred forty-four subjects with COVID-19 were assessed (median age: 43.0 years, 57% male), with different illness severities (60% mild, 21% moderate, 19% severe). CPET was performed 11.5 (7.0, 21.2) weeks after disease onset, with exercise limitations being attributed to the peripheral muscle (92%), and the pulmonary (6%), and cardiovascular (2%) systems. Lower median percent-predicted peak oxygen uptake was observed in the severe subgroup (72.2%) as compared to the controls (91.6%). Oxygen uptake differed among illness severities and controls at peak and ventilatory thresholds. Conversely, ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse were similar. Subgroup analysis of 42 subjects with prior CPET revealed significant reduction in only peak treadmill speed in the mild subgroup and in oxygen uptake at peak and ventilatory thresholds in the moderate/severe subgroup. By contrast, ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse did not change significantly. Conclusions Peripheral muscle fatigue was the most common exercise limitation etiology in post-COVID-19 patients regardless of the illness severity. Data suggest that treatment should emphasize comprehensive rehabilitation programs, including aerobic and muscle strengthening components.

Impacto da COVID-19 nos Programas de Reabilitação Cardiovascular no Brasil: Um Estudo Transversal Baseado em uma Pesquisa Online / Impact of COVID-19's on Cardiovascular Rehabilitation Programs in Brazil: An Online Survey-Based Cross-Sectional Study

Resumo Fundamento A pandemia da COVID-19 teve um impacto sobre os programas de reabilitação cardiovasculares (RC) no Brasil. Objetivos Descrever características dos programas de RC no Brasil, os impactos da primeira onda epidemiológica da COVID-19 (primeiros 60 dias) sobre os programas, e apresentar as iniciativas usadas para superar esses impactos. Métodos Este estudo transversal e retrospectivo usou um questionário online específico. Os participantes eram coordenadores de programas de RC. As variáveis foram apresentadas por região geográfica do Brasil, como as seguintes categorias: característica demográficas, clínicas e operacionais. O nível de significância estatística foi definido em 5%. Resultados Cinquenta e nove programas de RC atendiam 5349 pacientes, dos quais somente 1817 eram pacientes após eventos cardiovasculares agudos, o que correspondia a 1,99% dos pacientes internados no mês anterior à pesquisa (n=91.231). O maior impacto foi a suspensão das atividades presenciais, o que ocorreu de maneira similar em áreas com as taxas mais altas e áreas com as taxas mais baixas de COVID-19 no período. Quarenta e quatro (75%) programas foram interrompidos de forma breve, e três (5%) foram encerrados. Todos os 42 programas que já utilizavam estratégias de reabilitação remota notaram aumento substancial nas atividades, baseadas principalmente no uso da mídia e chamadas por vídeo. Somente três (5%) consideraram seguro atender pacientes durante os primeiros 60 dias. Conclusões Houve redução no número de programas de RC devido a pandemia da COVID-19. Atividades de telerreabilitação aumentaram durante os primeiros dois meses da pandemia da COVID-19, mas que não foi suficiente para superar a redução nas atividades dos programas de RC no Brasil.

Abstract Background The COVID-19 pandemic had an impact on cardiovascular rehabilitation (CR) programs in Brazil. Objectives To describe the characteristics of CR programs in Brazil, the impacts of the first epidemiological wave of COVID-19 (first 60 days) on the programs and present the initiatives used to overcome the impacts. Method This cross-sectional and retrospective study utilized a specific online survey. Participants were coordinators of CR programs. Variables were presented by Brazilian geographic region and as the following categories: demographic, clinical and operational characteristics. The significance level for statistical analysis was set at 5%. Results Fifty-nine CR programs were responsible for 5,349 patients, of which only 1,817 were post-acute cardiovascular events, which corresponded to 1.99% of hospitalized patients in the month prior to the survey (n=91,231). The greatest impact was the suspension of on-site activities, which occurred similarly in areas with the highest and the lowest rates of COVID-19 in the period. Forty-five programs (75%) were shortly interrupted, while three (5%) were ended. All 42 programs that already used remote rehabilitation strategies noticed a substantial increase in activities, based primarily on the use of media and video calling. Only three (5%) considered safe to see patients during the first 60 days. Conclusions There was a reduction in the number of CR programs with the COVID-19 pandemic. Telerehabilitation activities increased during the first two months of the COVID-19 pandemic, but this was not enough to overcome the reduction in CR program activities across Brazil.

Factors associated with inspiratory muscle weakness in patients with HIV-1

Background: the impact of human immunodeficiency virus type 1 (HIV-1) on lung function is well known and associated with a reduction in pulmonary ventilation. Moreover, the use of highly active antiretroviral therapy has been associated with mitochondrial dysfunction and decreased muscle strength. However, there is scarce information about the factors associated with inspiratory muscle weakness in these patients. Objective: the purpose of the present study was to investigate the factors associated with inspiratory muscle weakness in patients with HIV-1. Methods: two-hundred fifty seven patients with HIV-1 were screened and categorized into two groups: (1) IMW+ (n = 142) and (2) IMW-(n = 115). Lung function (FEV1, FVC and FEV1 /FVC), maximum inspiratory pressure, distance on the six-minute walk test and CD4 cell count were assessed. Results: the mean duration of HIV infection was similar in the two groups. The following variables were significantly different between groups: mean duration of highly active antiretroviral therapy (81 ± 12 in IMW+ versus 38 ± 13 months in IMW-; p = 0.01), and CD4 cell count (327 ± 88 in IMW+ versus 637 ± 97 cells/mm3 in IMW-; p = 0.02). IMW+ presented reduced lung function (FEV1, FVC, FEV1/FVC). Conclusion: patients with IMW+ had lower distance on the six-minute walk test in comparison to the IMW- group. The duration of highly active antiretroviral therapy, distance traveled on the 6MWT and CD4 count were determinants of IMW in patients with HIV. .

Oxidative damage induced by cigarette smoke exposure in mice: impact on lung tissue and diaphragm muscle, / Dano oxidativo induzido por exposição a fumaça de cigarro em camundongos: impacto sobre o pulmão e o músculo diafragma

OBJECTIVE: To evaluate oxidative damage (lipid oxidation, protein oxidation, thiobarbituric acid-reactive substances [TBARS], and carbonylation) and inflammation (expression of phosphorylated AMP-activated protein kinase and mammalian target of rapamycin [p-AMPK and p-mTOR, respectively]) in the lung parenchyma and diaphragm muscles of male C57BL-6 mice exposed to cigarette smoke (CS) for 7, 15, 30, 45, or 60 days. METHODS: Thirty-six male C57BL-6 mice were divided into six groups (n = 6/group): a control group; and five groups exposed to CS for 7, 15, 30, 45, and 60 days, respectively. RESULTS: Compared with control mice, CS-exposed mice presented lower body weights at 30 days. In CS-exposed mice (compared with control mice), the greatest differences (increases) in TBARS levels were observed on day 7 in diaphragm-muscle, compared with day 45 in lung tissue; the greatest differences (increases) in carbonyl levels were observed on day 7 in both tissue types; and sulfhydryl levels were lower, in both tissue types, at all time points. In lung tissue and diaphragm muscle, p-AMPK expression exhibited behavior similar to that of TBARS. Expression of p-mTOR was higher than the control value on days 7 and 15 in lung tissue, as it was on day 45 in diaphragm muscle. CONCLUSION: Our data demonstrate that CS exposure produces oxidative damage, not only in lung tissue but also (primarily) in muscle tissue, having an additional effect on respiratory muscle, as is frequently observed in smokers with COPD. .

OBJETIVO: Avaliar o dano oxidativo (oxidação lipídica, oxidação proteica, thiobarbituric acid-reactive substances [TBARS, substâncias reativas ao ácido tiobarbitúrico], e carbonilação) e inflamação (expressão de phosphorylated AMP-activated protein kinase e de phosphorylated mammalian target of rapamycin (p-AMPK e p-mTOR, respectivamente) em tecido pulmonar e músculos do diafragma em camundongos C57BL/6 machos expostos à fumaça de cigarro (FC) por 7, 15, 30, 45 ou 60 dias. MÉTODOS: Trinta e seis camundongos machos da espécie C57BL/6 foram divididos em seis grupos (n = 6/grupo): grupo controle e 5 grupos expostos a FC por 7, 15, 30, 45 e 60 dias, respectivamente. RESULTADOS: Comparados aos camundongos controle, os camundongos expostos à FC apresentaram menor peso corporal em 30 dias. Nos camundongos expostos à FC (comparados aos controle) as maiores diferenças (aumentos) nos níveis de TBARS foram observados no dia 7 no músculo diafragma, comparado ao dia 45 em tecido pulmonar; as maiores diferenças (aumentos) nos níveis de carbonilas foram observados no dia 7 em ambos os tipos de tecido; e os níveis de sulfidrilas foram menores, nos dois tipos de tecidos, em todos os tempos. No tecido pulmonar e no músculo diafragma, a expressão de p-AMPK exibiu um comportamento semelhante ao dos níveis de TBARS. A expressão de p-mTOR foi maior que o valor controle nos dias 7 e 15 no tecido pulmonar, assim como no dia 45 no músculo diafragma. CONCLUSÕES: Nossos dados demonstram que a exposição à FC produz dano oxidativo tanto no tecido pulmonar quanto (primariamente) no tecido muscular, tendo um efeito adicional no músculo respiratório, como é frequentemente observado em fumantes com DPOC. .

Interferential electrical stimulation improves peripheral vasodilatation in healthy individuals

BACKGROUND: Interferential electrical stimulation (IES), which may be linked to greater penetration of deep tissue, may restore blood flow by sympathetic nervous modulation; however, studies have found no association between the frequency and duration of the application and blood flow. We hypothesized that 30 min of IES applied to the ganglion stellate region might improve blood flow redistribution. OBJECTIVES: The purpose of this study was to determine the effect of IES on metaboreflex activation in healthy individuals. METHOD: Interferential electrical stimulation or a placebo stimulus (same protocol without electrical output) was applied to the stellate ganglion region in eleven healthy subjects (age 25±1.3 years) prior to exercise. Mean blood pressure (MBP), heart rate (HR), calf blood flow (CBF) and calf vascular resistance (CVR) were measured throughout exercise protocols (submaximal static handgrip exercise) and with recovery periods with or without postexercise circulatory occlusion (PECO+ and PECO -, respectively). Muscle metaboreflex control of calf vascular resistance was estimated by subtracting the area under the curve when circulation was occluded from the area under the curve from the AUC without circulatory occlusion. RESULTS: At peak exercise, increases in mean blood pressure were attenuated by IES (p<0.05), and the effect persisted under both the PECO+ and PECO- treatments. IES promoted higher CBF and lower CVR during exercise and recovery. Likewise, IES induced a reduction in the estimated muscle metaboreflex control (placebo, 21±5 units vs. IES, 6±3, p<0.01). CONCLUSION: Acute application of IES prior to exercise attenuates the increase in blood pressure and vasoconstriction during exercise and metaboreflex activation in healthy subjects. .