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Background and Objectives: Cardiopulmonary exercise testing (CPET) is a cornerstone of risk stratification in heart failure with reduced ejection fraction (HFrEF). However, there is a paucity of evidence on its predictive power in older patients. The aim of this study was to evaluate the prognostic power of current heart transplantation (HTx) listing criteria in HFrEF stratified according to age groups. Materials and Methods: Consecutive patients with HFrEF undergoing CPET between 2009 and 2018 were followed-up for cardiac death and urgent HTx. Results: CPET was performed in 458 patients with HFrEF. The composite endpoint occurred in 16.8% of patients ≤50 years vs. 14.1% of patients ≥50 years in a 36-month follow-up. Peak VO2 (pVO2), VE/VCO2 slope and percentage of predicted pVO2 were strong independent predictors of outcomes. The International Society for Heart and Lung Transplantation thresholds of pVO2 ≤ 12 mL/kg/min (≤14 if intolerant to ß-blockers), VE/VCO2 slope > 35 and percentage of predicted pVO2 ≤ 50% presented a higher overall diagnostic effectiveness in younger patients (≤50 years). Specific thresholds for each age subgroup outperformed the traditional cut-offs. Conclusions: Personalized age-specific thresholds may contribute to an accurate risk stratification in HFrEF. Further studies are needed to address the gap in evidence between younger and older patients.
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Insuficiencia Cardíaca , Trasplante de Corazón , Humanos , Anciano , Prueba de Esfuerzo , Volumen Sistólico , CorazónRESUMEN
BACKGROUND: Data on the impact of sacubitril/valsartan (SV) therapy on phasic left atrial (LA) and left ventricular (LV) strain in heart failure with reduced ejection fraction (HFrEF) are limited. The aim of this study was to evaluate changes in two-dimensional speckle tracking (2D-STE) parameters with SV therapy in HFrEF patients. METHODS: Prospective evaluation of HFrEF patients receiving optimized medical therapy. Two-dimensional speckle tracking (2D-STE) parameters were assessed at baseline and after 6 months of SV therapy. LA strain and strain rate (SR) in reservoir, conduit, and contraction phases were compared with LV longitudinal, radial, and circumferential strain and SR and stratified according to heart rhythm and HFrEF etiology. RESULTS: A total of 35 patients completed the 6-month follow-up, with a mean age of 59 ± 11 years, 40% in atrial fibrillation, 43% with ischemic etiology, and LVEF of 29 ± 6%. There were significant improvements in LA reservoir, conduit, and contractile strain and SR following SV therapy, particularly among patients in sinus rhythm. There were significant improvements in longitudinal, radial, and circumferential LV function indices. CONCLUSION: SV therapy in HFrEF was associated with improved longitudinal, radial, and circumferential function, particularly among patients in sinus rhythm. These findings can provide insights into the mechanisms underlying the improvement of cardiac function and help assess subclinical responses to the treatment.
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BACKGROUND: Exercise testing is key in the risk stratification of patients with heart failure (HF). There are scarce data on its prognostic power in women. Our aim was to assess the predictive value of the heart transplantation (HTx) thresholds in HF in women and in men. METHODS: Prospective evaluation of HF patients who underwent cardiopulmonary exercise testing (CPET) from 2009 to 2018 for the composite endpoint of cardiovascular mortality and urgent HTx. RESULTS: A total of 458 patients underwent CPET, with a composite endpoint frequency of 10.5% in females vs. 16.0% in males in 36-month follow-up. Peak VO2 (pVO2), VE/VCO2 slope and percent of predicted pVO2 were independent discriminators of the composite endpoint, particularly in women. The International Society for Heart Lung Transplantation recommended values of pVO2 ≤ 12 mL/kg/min or ≤14 if the patient is intolerant to ß-blockers, VE/VCO2 slope > 35, and percent of predicted pVO2 ≤ 50% showed a higher diagnostic effectiveness in women. Specific pVO2, VE/VCO2 slope and percent of predicted pVO2 cut-offs in each sex group presented a higher prognostic power than the recommended thresholds. CONCLUSION: Individualized sex-specific thresholds may improve patient selection for HTx. More evidence is needed to address sex differences in HF risk stratification.
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BACKGROUND: New therapies with prognostic benefits have been recently introduced in heart failure with reduced ejection fraction (HFrEF) management. The aim of this study was to evaluate the prognostic power of current listing criteria for heart transplantation (HT) in an HFrEF cohort submitted to cardiopulmonary exercise testing (CPET) between 2009 and 2014 (group A) and between 2015 and 2018 (group B). METHODS: Consecutive patients with HFrEF who underwent CPET were followed-up for cardiac death and urgent HT. RESULTS: CPET was performed in 487 patients. The composite endpoint occurred in 19.4% of group A vs. 7.4% of group B in a 36-month follow-up. Peak VO2 (pVO2) and VE/VCO2 slope were the strongest independent predictors of mortality. International Society for Heart and Lung Transplantation (ISHLT) thresholds of pVO2 ≤ 12 mL/kg/min (≤14 if intolerant to ß-blockers) and VE/VCO2 slope > 35 presented a similar and lower Youden index, respectively, in group B compared to group A, and a lower positive predictive value. pVO2 ≤ 10 mL/kg/min and VE/VCO2 slope > 40 outperformed the traditional cut-offs. An ischemic etiology subanalysis showed similar results. CONCLUSION: ISHLT thresholds showed a lower overall prognostic effectiveness in a contemporary HFrEF population. Novel parameters may be needed to improve risk stratification.
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BACKGROUND: There is evidence suggesting that a peak oxygen uptake (pVO2) cut-off of 10ml/kg/min provides a more precise risk stratification in cardiac resynchronization therapy (CRT) patients. OBJECTIVE: To compare the prognostic power of several cardiopulmonary exercise testing (CPET) parameters in this population and assess the discriminative ability of the guideline-recommended pVO2cut-off values. METHODS: Prospective evaluation of consecutive heart failure (HF) patients with left ventricular ejection fraction ≤40%. The primary endpoint was a composite of cardiac death and urgent heart transplantation (HT) in the first 24 follow-up months, and was analysed by several CPET parameters for the highest area under the curve (AUC) in the CRT group. A survival analysis was performed to evaluate the risk stratification provided by several different cut-offs. p values <0.05 were considered significant. RESULTS: A total of 450 HF patients, of which 114 had a CRT device. These patients had a higher baseline risk profile, but there was no difference regarding the primary outcome (13.2% vs 11.6%, p =0.660). End-tidal carbon dioxide pressure at anaerobic threshold (PETCO2AT)had the highest AUC value, which was significantly higher than that of pVO2in the CRT group (0.951 vs 0.778, p =0.046). The currently recommended pVO2cut-off provided accurate risk stratification in this setting (p <0.001), and the suggested cut-off value of 10 ml/min/kg did not improve risk discrimination in device patients (p =0.772). CONCLUSION: PETCO2ATmay outperform pVO2's prognostic power for adverse events in CRT patients. The current guideline-recommended pVO2 cut-off can precisely risk-stratify this population.
FUNDAMENTO: Há evidências sugerindo que um corte do pico de consumo de oxigênio (pVO2) de 10ml/kg/min fornece uma estratificação de risco mais precisa em pacientes com Terapia de Ressincronização Cardíaca (TRC). OBJETIVO: Comparar o poder prognóstico de vários parâmetros do teste cardiopulmonar de exercício (TCPE) nesta população e avaliar a capacidade discriminativa dos valores de corte de pVO2 recomendados pelas diretrizes. MÉTODOS: Avaliação prospectiva de uma série consecutiva de pacientes com insuficiência cardíaca (IC) com fração de ejeção do ventrículo esquerdo ≤40%. O desfecho primário foi um composto de morte cardíaca e transplante cardíaco urgente (TC) nos primeiros 24 meses de acompanhamento, e foi analisado por vários parâmetros do TCPE para a maior área sob a curva (AUC) no grupo TRC. Uma análise de sobrevida foi realizada para avaliar a estratificação de risco fornecida por vários pontos de corte diferentes. Valores de p < 0,05 foram considerados significativos. RESULTADOS: Um total de 450 pacientes com IC, dos quais 114 possuíam aparelho de TRC. Esses pacientes apresentaram um perfil de risco basal mais alto, mas não houve diferença em relação ao desfecho primário (13,2% vs 11,6%, p = 0,660). A pressão expiratória de dióxido de carbono no limiar anaeróbico (PETCO2AT) teve o maior valor de AUC, que foi significativamente maior do que o de pVO2 no grupo TRC (0,951 vs 0,778, p = 0,046). O valor de corte de pVO2 atualmente recomendado forneceu uma estratificação de risco precisa nesse cenário (p <0,001), e o valor de corte sugerido de 10 ml/min/kg não melhorou a discriminação de risco em pacientes com dispositivos (p = 0,772). CONCLUSÃO: A PETCO2AT pode superar o poder prognóstico do pVO2 para eventos adversos em pacientes com TRC. O ponto de corte de pVO2 recomendado pelas diretrizes atuais pode estratificar precisamente o risco dessa população.
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Terapia de Resincronización Cardíaca , Insuficiencia Cardíaca , Prueba de Esfuerzo , Humanos , Volumen Sistólico , Resultado del Tratamiento , Función Ventricular IzquierdaRESUMEN
UNLABELLED: Cardiopulmonary exercise testing (CPET) is an objective method for assessment of functional capacity and for prognostic stratification of patients with chronic heart failure (CHF). In this study, we analyzed the prognostic value of a recently described CPET-derived parameter, the minute ventilation to carbon dioxide production slope normalized for peak oxygen consumption (VE/VCO2 slope/pVO2). METHODS: We prospectively studied 157 patients with stable CHF and dilated cardiomyopathy who performed maximal CPET using the modified Bruce protocol. The prognostic value of VE/VCO2 slope/pVO2 was determined and compared with traditional CPET parameters. RESULTS: During follow-up 37 patients died and 12 were transplanted. Mean follow-up in surviving patients was 29.7 months (12-36). Cox multivariate analysis revealed that VE/VCO2 slope/pVO2 had the greatest prognostic power of all the parameters studied. A VE/VCO2 slope/pVO2 of > or = 2.2 signaled cases at higher risk. CONCLUSION: Normalization of the ventilatory response to exercise for peak oxygen consumption appears to increase the prognostic value of CPET in patients with CHF.
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Prueba de Esfuerzo , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/metabolismo , Consumo de Oxígeno , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad Crónica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Adulto JovenRESUMEN
AIMS: Myocardial work is a new transthoracic echocardiogram (TTE) parameter that enhances the information provided through left ventricular (LV) global longitudinal strain (GLS). Nothing is known about the impact of sacubitril/valsartan (LCZ696) therapy on myocardial work parameters. The aim of this study was to evaluate the effects of LCZ696 on LV myocardial work in heart failure patients. METHODS: Prospective evaluation of chronic heart failure patients with LV ejection fraction of 40% or less despite optimized standard of care therapy, in which LCZ696 therapy was started and no other heart failure treatment was expected to change. TTE study was performed before and 6 months after LCZ696 therapy. A semiautomated analysis of LV GLS was made and myocardial work estimated using custom software of the GE Vivid E95 ultrasound system. RESULTS: Of the 42 patients, 35 (83.3%) completed the 6 months, follow-up, since 2 (4.8%) patients died and 5 (11.9%) discontinued treatment due to adverse events. Mean age was 58.6â±â11.1 years. TTE data showed a significant reduction in LV dimensions and atrial volumes, as well as an improvement in LV ejection fraction (29.3 vs. 35.2%, Pâ=â0.001) and GLS (-7.0 vs. -8.9%, Pâ=â0.001). Myocardial work had a significant increase in global constructive work (720.2 vs. 900.6âmmHg%, Pâ=â0.016) and global work efficiency (78.6 vs. 86.6%, Pâ=â0.027), with a nonsignificant decrease in global wasted work (150.2 vs. 136.8âmmHg%, Pâ=â0.441) at 6 months. CONCLUSION: LCZ696 therapy was associated with signs of reverse remodelling by usual TTE parameters and LV myocardial work at 6 months, including an increase in global constructive work and work efficiency.
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Aminobutiratos/uso terapéutico , Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Ecocardiografía , Insuficiencia Cardíaca/tratamiento farmacológico , Contracción Miocárdica/efectos de los fármacos , Inhibidores de Proteasas/uso terapéutico , Volumen Sistólico/efectos de los fármacos , Tetrazoles/uso terapéutico , Función Ventricular Izquierda/efectos de los fármacos , Anciano , Aminobutiratos/efectos adversos , Bloqueadores del Receptor Tipo 1 de Angiotensina II/efectos adversos , Compuestos de Bifenilo , Combinación de Medicamentos , Femenino , Insuficiencia Cardíaca/diagnóstico por imagen , Insuficiencia Cardíaca/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Neprilisina/antagonistas & inhibidores , Valor Predictivo de las Pruebas , Estudios Prospectivos , Inhibidores de Proteasas/efectos adversos , Recuperación de la Función , Tetrazoles/efectos adversos , Factores de Tiempo , Resultado del Tratamiento , Valsartán , Remodelación Ventricular/efectos de los fármacosRESUMEN
UNLABELLED: Left atrial enlargement is common in many cardiac diseases; a major determinant of this enlargement is left ventricular diastolic pressure. Left atrial volume (LAV) has recently been linked to adverse prognosis. The objective of our study was to assess LAV as a prognostic marker in patients with dilated cardiomyopathy (DCM) and to correlate LAV with other known prognostic factors such as maximum oxygen consumption (VO2 max) and pro-B-type natriuretic peptide (pro-BNP). METHODS: Our population consisted of 35 patients with DCM followed regularly in our hospital and with mean ejection fraction (EF) of 31+/-9.6%. All patients underwent routine 2D Doppler echocardiographic examination, TDI was used to obtain early peak velocity of the mitral annulus, and LAV was calculated using Simpson's method of disks. Pro-BNP was measured and cardiopulmonary exercise testing was also carried out. Mean follow-up was 24+/-4 months and new hospital admission due to heart failure, cardiac transplantation and death were considered cardiac events. RESULTS: All two-dimensional (left ventricular dimensions and volumes and EF) and conventional Doppler echocardiographic parameters (mitral inflow) were analyzed; mean LAV was 78.6+/-33 ml. Age and gender had no influence on LAV. LAV (and LAV indexed to body surface area [BSA]) showed an inverse correlation with VO2max (r=-0.48, p=0.008) and with pro-BNP (r=0.43, p=0.02). With regard to prognosis, LAV and LAV/BSA were associated with cardiac events (r=0.4, p=0.02), like other classic prognostic markers (EF, left ventricular volumes, mitral regurgitation and E/E'). The cut-off values of LAV and LAV/BSA for cardiac events on ROC curve analysis were 70 ml and 38 ml/m2 respectively. CONCLUSIONS: LAV (LAV/BSA) has incremental prognostic value in patients with dilated cardiomyopathy and correlates with exercise tolerance and pro-BNP.
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Cardiomiopatía Dilatada/diagnóstico por imagen , Cardiomiopatía Dilatada/patología , Atrios Cardíacos/diagnóstico por imagen , Atrios Cardíacos/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Pronóstico , Estudios Prospectivos , UltrasonografíaRESUMEN
AIM: The aim of the study was to compare functional capacity in different types of congenital heart disease (CHD), as assessed by cardiopulmonary exercise testing (CPET). METHODS: A retrospective analysis was performed of adult patients with CHD who had undergone CPET in a single tertiary center. Diagnoses were divided into repaired tetralogy of Fallot, transposition of the great arteries (TGA) after Senning or Mustard procedures or congenitally corrected TGA, complex defects, shunts, left heart valve disease and right ventricular outflow tract obstruction. RESULTS: We analyzed 154 CPET cases. There were significant differences between groups, with the lowest peak oxygen consumption (VO2) values seen in patients with cardiac shunts (39% with Eisenmenger physiology) (17.2±7.1ml/kg/min, compared to 26.2±7.0ml/kg/min in tetralogy of Fallot patients; p<0.001), the lowest percentage of predicted peak VO2 in complex heart defects (50.1±13.0%) and the highest minute ventilation/carbon dioxide production slope in cardiac shunts (38.4±13.4). Chronotropism was impaired in patients with complex defects. Eisenmenger syndrome (n=17) was associated with the lowest peak VO2 (16.9±4.8 vs. 23.6±7.8ml/kg/min; p=0.001) and the highest minute ventilation/carbon dioxide production slope (44.8±14.7 vs. 31.0± 8.5; p=0.002). Age, cyanosis, CPET duration, peak systolic blood pressure, time to anaerobic threshold and heart rate at anaerobic threshold were predictors of the combined outcome of all-cause mortality and hospitalization for cardiac cause. CONCLUSION: Across the spectrum of CHD, cardiac shunts (particularly in those with Eisenmenger syndrome) and complex defects were associated with lower functional capacity and attenuated chronotropic response to exercise.
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Prueba de Esfuerzo , Cardiopatías Congénitas/fisiopatología , Cardiopatías/congénito , Cardiopatías/fisiopatología , Adulto , Femenino , Cardiopatías Congénitas/diagnóstico , Cardiopatías/diagnóstico , Humanos , Masculino , Estudios RetrospectivosRESUMEN
OBJECTIVE: To assess the correlation between NT-proBNP values and Weber functional class as determined by cardiopulmonary exercise testing (CPET) in patients with chronic heart failure (CHF). METHODS: We studied 95 patients, 68 male, mean age 50.4 +/- 10.5 years, with CHF due to dilated cardiomyopathy (DCM), 65% of non-ischemic etiology, classified by symptom-limited treadmill CPET (modified Bruce protocol) as follows: 48 Weber class A, 27 class B, 16 class C and 4 class D. NT-proBNP values (pg/ml) were determined after 15 minutes rest immediately prior to CPET. There were no significant differences between the groups in gender, age or percentage of patients taking ACE inhibitors or ARBs and beta-blockers. Left ventricular ejection fraction was higher in class A and B (27.6+/-8.3%) than in class C and D (19.7+/-6.2%, p=0.001). Serum creatinine was lower in class A (0.97+/-0.22 mg/dl) than in classes C or D (1.16+/-0.26, p=0.006). RESULTS: NT-proBNP was: class A=1325.8+/-1500.3, class B=3473.0+/-2575.3 (p<0.001 vs. class A), class C=6193.1+/-2066.8 (p<0.001 vs. A and B), while in class D it was 11821.8+/-5489.7. There was an overall significant correlation between NT-proBNP and peak oxygen uptake (r=-0.66, p<0.001). On ROC curve analysis, an NT-proBNP value of 1766.5 pg/ml was found to be the best cut-off to discriminate class A vs. non-A (AUC=0.896, p<0.001, 95% CI 0.834 to 0.957, sensitivity=79%, specificity=83%), while a value of 5029.0 was the best discriminator of class B vs. class C or D (AUC=0.865, p<0.001, 95% CI 0.760 to 0.970, sensitivity=82%, specificity=80%). CONCLUSIONS: In patients with CHF due to DCM, NT-proBNP values correlate with Weber class as determined by CPET, and this study presents discriminative values.
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Insuficiencia Cardíaca/sangre , Insuficiencia Cardíaca/fisiopatología , Péptido Natriurético Encefálico/sangre , Fragmentos de Péptidos/sangre , Femenino , Insuficiencia Cardíaca/clasificación , Humanos , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
OBJECTIVE: We set out to evaluate whether changes in N-terminal pro-brain natriuretic peptide (proBNP) can predict changes in functional capacity, as determined by cardiopulmonary exercise testing (CPET), in patients with chronic heart failure (CHF) due to dilated cardiomyopathy (DCM). METHODS: We studied 37 patients with CHF due to DCM, 81% non-ischemic, 28 male, who performed symptom-limited treadmill CPET, with the modified Bruce protocol, in two consecutive evaluations, with determination of proBNP after 10 minutes rest prior to CPET. The time between evaluations was 9.6+/-5.5 months, and age at first evaluation was 41.1+/-13.9 years (21 to 67). RESULTS IN THE FIRST AND SECOND EVALUATIONS RESPECTIVELY WERE: NYHA functional class >II 51% and 16% (p<0.001), sinus rhythm 89% and 86.5% (NS), left ventricular ejection fraction 24.9+/-8.9% and 26.6+/-8.6% (NS), creatinine 1.03+/-0.25 and 1.09+/-0.42 mg/dl (NS), taking ACE inhibitors or ARBs 94.5% and 100% (NS), beta-blockers 73% and 97.3% (p<0.001), and spironolactone 89% and 89% (NS). We analyzed the absolute and percentage variation (AV and PV) in peak oxygen uptake (pVO2--ml/kg/min) and proBNP (pg/ml) between the two evaluations. RESULTS: (1) pVO2 AV: -17.4 to 15.2 (1.9+/-5.7); pVO2 PV: -56.1 to 84% (11.0+/-25.2); proBNP AV: -12850 to 5983 (-778.4+/-3332.5); proBNP PV: -99.0 to 379.5% (-8.8+/-86.3); (2) The correlations obtained--r value and p value [r (p)]--are shown in the table below; (3) We considered that a coefficient of variation of pVO2 PV of >10% represented a significant change in functional capacity. On ROC curve analysis, a proBNP PV value of 28% showed 80% sensitivity and 79% specificity for pVO2 PV of >10% (AUC=0.876, p=0.01, 95% CI 0.75 to 0.99). CONCLUSIONS: In patients with CHF due to DCM, changes in proBNP values correlate with variations in pVO2, as assessed by CPET. However, our results suggest that only a proBNP PV of >28% predicts a significant change in functional capacity.
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Insuficiencia Cardíaca/sangre , Insuficiencia Cardíaca/fisiopatología , Péptido Natriurético Encefálico/sangre , Fragmentos de Péptidos/sangre , Adulto , Anciano , Enfermedad Crónica , Insuficiencia Cardíaca/metabolismo , Humanos , Persona de Mediana Edad , Oxígeno/metabolismo , Estudios ProspectivosRESUMEN
Resumo Fundamento Há evidências sugerindo que um corte do pico de consumo de oxigênio (pVO2) de 10ml/kg/min fornece uma estratificação de risco mais precisa em pacientes com Terapia de Ressincronização Cardíaca (TRC). Objetivo Comparar o poder prognóstico de vários parâmetros do teste cardiopulmonar de exercício (TCPE) nesta população e avaliar a capacidade discriminativa dos valores de corte de pVO2 recomendados pelas diretrizes. Métodos Avaliação prospectiva de uma série consecutiva de pacientes com insuficiência cardíaca (IC) com fração de ejeção do ventrículo esquerdo ≤40%. O desfecho primário foi um composto de morte cardíaca e transplante cardíaco urgente (TC) nos primeiros 24 meses de acompanhamento, e foi analisado por vários parâmetros do TCPE para a maior área sob a curva (AUC) no grupo TRC. Uma análise de sobrevida foi realizada para avaliar a estratificação de risco fornecida por vários pontos de corte diferentes. Valores de p < 0,05 foram considerados significativos. Resultados Um total de 450 pacientes com IC, dos quais 114 possuíam aparelho de TRC. Esses pacientes apresentaram um perfil de risco basal mais alto, mas não houve diferença em relação ao desfecho primário (13,2% vs 11,6%, p = 0,660). A pressão expiratória de dióxido de carbono no limiar anaeróbico (PETCO2AT) teve o maior valor de AUC, que foi significativamente maior do que o de pVO2 no grupo TRC (0,951 vs 0,778, p = 0,046). O valor de corte de pVO2 atualmente recomendado forneceu uma estratificação de risco precisa nesse cenário (p <0,001), e o valor de corte sugerido de 10 ml/min/kg não melhorou a discriminação de risco em pacientes com dispositivos (p = 0,772). Conclusão A PETCO2AT pode superar o poder prognóstico do pVO2 para eventos adversos em pacientes com TRC. O ponto de corte de pVO2 recomendado pelas diretrizes atuais pode estratificar precisamente o risco dessa população.
Abstract Background There is evidence suggesting that a peak oxygen uptake (pVO2) cut-off of 10ml/kg/min provides a more precise risk stratification in cardiac resynchronization therapy (CRT) patients. Objective To compare the prognostic power of several cardiopulmonary exercise testing (CPET) parameters in this population and assess the discriminative ability of the guideline-recommended pVO2cut-off values. Methods Prospective evaluation of consecutive heart failure (HF) patients with left ventricular ejection fraction ≤40%. The primary endpoint was a composite of cardiac death and urgent heart transplantation (HT) in the first 24 follow-up months, and was analysed by several CPET parameters for the highest area under the curve (AUC) in the CRT group. A survival analysis was performed to evaluate the risk stratification provided by several different cut-offs. p values <0.05 were considered significant. Results A total of 450 HF patients, of which 114 had a CRT device. These patients had a higher baseline risk profile, but there was no difference regarding the primary outcome (13.2% vs 11.6%, p =0.660). End-tidal carbon dioxide pressure at anaerobic threshold (PETCO2AT)had the highest AUC value, which was significantly higher than that of pVO2in the CRT group (0.951 vs 0.778, p =0.046). The currently recommended pVO2cut-off provided accurate risk stratification in this setting (p <0.001), and the suggested cut-off value of 10 ml/min/kg did not improve risk discrimination in device patients (p =0.772). Conclusion PETCO2ATmay outperform pVO2's prognostic power for adverse events in CRT patients. The current guideline-recommended pVO2 cut-off can precisely risk-stratify this population.
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INTRODUCTION: Low-dose dobutamine stress echocardiography is a common and useful technique to assess myocardial viability in patients with ischemic cardiomyopathy. OBJECTIVE: To evaluate the use of low-dose dobutamine stress echocardiography in determining the functional status of patients with idiopathic dilated cardiomyopathy (IDCM). METHODS: Prospective study of 28 patients with IDCM by transthoracic echocardiography (2D), low-dose dobutamine stress echocardiography, cardiopulmonary exercise testing (CPET) and measurement of pro-BNP. RESULTS: The mean age of the population was 50.3 +/- 11.5 years, 9 female and 19 male. Mean ejection fraction was 32.1 +/- 9.8%. All were in sinus rhythm. The following parameters were analyzed in 2D echocardiography and after dobutamine: dimensions of left atrium (LA) and of left ventricle in diastole and systole, shortening fraction (%), left ventricular end-diastolic (EDV) and end-systolic volumes (ESV), ejection fraction (EF), and mitral inflow (E, A, E/A ratio and deceleration time). In CPET, we considered the following parameters: peak VO2 and % maximal peak VO2 attained. We compared echo results with CPET. There was a correlation between age and peak VO2 (r = -0.38 with p = 0.049). In 2D echo, there was a correlation between baseline EF and LA dimensions and peak VO2 (r = 0.45 / p = 0.004 and r = -0.49 / p = 0.014, respectively). After dobutamine echo, there was a correlation between some echo parameters and peak VO2: EF - r = 0.59 / p = 0.001, LA dimensions - r = 0.56 / p = 0.007, and ESV - r = -0.45 / p = 0.026. Percentage maximal peak VO2 attained correlated with LA dimensions measured in 2D echo and after dobutamine (r = -0.398 / p = 0.036 and r = -0.674 / p = 0.02 respectively) and EF after dobutamine (r = -0.389 / p = 0.04). The value of pro-BNP correlated with LA dimensions and baseline EF (r = 0.44 / p = 0.02 and r = -0.57 / p = 0.002, respectively), and the correlation was maintained after inotropic stimulation with dobutamine (r = 0.57 / p = 0.001 and r = -0.55 / p = 0.0039). CONCLUSION: Low-dose dobutamine stress echocardiography showed stronger correlations with cardiopulmonary exercise testing than the parameters evaluated by conventional echocardiography and could be used to determine the functional status of patients with dilated cardiomyopathy; patients with greater ejection fraction after inotropic stimulation had better cardiopulmonary tests.