Ventilatory Efficiency and the Selection of Patients for Heart Transplantation

Relationship of red blood cell mass profiles and anemia type to outcomes and cardiopulmonary exercise performance in chronic heart failure

BACKGROUND

Blood volume analysis (BVA) allows direct measurement of red blood cell mass (RBCM) and differentiation of true and dilutional anemia in heart failure (HF). This study aimed to characterize the relationships of RBCM profiles and anemia types to HF outcomes and cardiopulmonary exercise test (CPET) parameters.

METHODS

Chronic stable HF patients were prospectively enrolled. All patients underwent BVA; a subset underwent supine invasive CPET within 24 hours of BVA. RBCM profiles were defined using RBCM %deviation (deficit: <-10%, normal: -10 to 10%, excess: >10%). Anemia defined by World Health Organization criteria alone was categorized using RBCM %deviation (<-10% true anemia, ≥-10% dilutional pseudo-anemia). HF hospitalization at 6 months and CPET parameters were compared among RBCM profiles and anemia types.

RESULTS

One-hundred twenty patients (58 years, 40% female, 41% Black, 63% HFrEF) were enrolled. Forty percent had RBCM deficit, 37.5% had normal RBCM, and 22.5% had excess RBCM. Fifty-eight patients (48%) were anemic: 60% true anemia and 40% dilutional pseudo-anemia. Patients with dilutional pseudo-anemia had a higher incidence of HF hospitalization (44.8%) compared to no anemia (22.7%) and true anemia (20.6%) (P = .040). There was no difference in HF hospitalization among RBCM profiles (P = .99). There was a nonsignificant trend toward worse peak VO2 in RBCM deficit and true anemia, with no differences in other CPET parameters.

CONCLUSIONS

Dilutional pseudo-anemia demonstrated higher HF hospitalizations compared to true anemia, while true anemia had a trend towards worse peak VO2. The implications of BVA-identified RBCM profiles and anemia types for clinical management warrant further investigation.

Cardiopulmonary Exercise Testing

AbstractBecause symptoms of cardiopulmonary disease often occur with exertion, cardiopulmonary exercise testing (CPET) has a unique role in the assessment of patient symptoms, disease severity, prognosis, and response to therapy. In addition to the evaluation of cardiovascular and pulmonary physiology, CPET provides an assessment of the interaction of the cardiovascular and pulmonary systems with the musculoskeletal, nervous, and hematological systems. In this article, we review key CPET variables, protocols, and clinical indications.

Prognostic value of cardiopulmonary exercise test in patients with acute myocardial infarction after percutaneous coronary intervention

To determine the independent risk factors of cardiopulmonary exercise test (CPET) parameters related to adverse prognostic events within 5 years in patients undergoing percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI), and establish a prediction model for the occurrence of adverse events within 5 years to provide a reference for cardiac rehabilitation training. From August 2015 to December 2021, patients who underwent PCI for AMI and completed CPET within 1-2 weeks after surgery before discharge from the Department of Cardiovascular Medicine of Zhengzhou Central Hospital Affiliated to Zhengzhou University, Henan Provincial Hospital of Traditional Chinese Medicine, and Anyang District Hospital were selected as participants. Univariate and multivariate analyses were used to screen for independent risk factors associated with 5-year adverse events. Feature importance was interpreted using SHapley Additive exPlanations (SHAP), and a logistic regression model was established for prediction. A receiver operating characteristic (ROC) curve was constructed to evaluate the performance of the prediction model. Calibration was assessed by the Hosmer-Lemeshow test and the calibration curve. In total, 375 patients met the inclusion criteria. Based on whether adverse events occurred during the 5-year follow-up period, the patients were divided into two groups: the event group (n = 53) and the non-event group (n = 322). Peak oxygen uptake (peakVO2), carbon dioxide ventilation equivalent slope (VE/VCO2slop), and peak end-tidal carbon dioxide partial pressure (PETCO2) were three independent risk factors for re-acute myocardial infarction (re-AMI), heart failure (HF), and even death after PCI for AMI (P < 0.05). The SHAP plots demonstrated that the significant contributors to model performance were related to peakVO2, VE/VCO2slop, and PETCO2. The risk of adverse events was significantly reduced when the peakVO2 was ≥ 20 mL/kg/min and the VE/VCO2slop was < 33. The ROC curves of the three models were drawn, including the no-event and event groups, re-AMI group, and HF group, which performed well, with AUC of 0.894, 0.760, and 0.883, respectively. The Hosmer-Lemeshow test showed that the three models were a good fit (P > 0.05). The calibration curve of the three models was close to the ideal diagonal lines. CPET parameters can predict the prognosis of adverse events within 5 years after PCI in patients with AMI and provide a theoretical basis for cardiac rehabilitation training.

Cardiopulmonary Exercise Testing in the Age of New Heart Failure Therapies: Still a Powerful Tool?

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 β-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.

Capacidade Preditiva dos Parâmetros do Teste de Esforço Cardiopulmonar em Pacientes com Insuficiência Cardíaca em Terapia de Ressincronização Cardíaca

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 (P_ETCO_2AT) 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 P_ETCO_2AT 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.

2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" replaces the "2013 ACCF/AHA Guideline for the Management of Heart Failure" and the "2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure." The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.

METHODS

A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021. Structure: Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients' interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.

2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure

AIM

The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" replaces the "2013 ACCF/AHA Guideline for the Management of Heart Failure" and the "2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure." The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.

METHODS

A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021.

STRUCTURE

Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients' interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.

Impact of Exercise Modalities on Peripheral and Central Components of Cardiorespiratory Capacity in Heart Transplantation Patients: A Systematic Review and Meta-Analysis

Background and Objectives: To analyze the effects of aerobic, resistance, and combined training on peripheral and central components related to cardiorespiratory capacity after HTx. Materials and Methods: No time restriction was applied for study inclusion. MEDLINE/PubMed; EMBASE, CENTRAL, and PEDro databases were investigated. Studies reporting heart transplanted patients older than 19 years following aerobic, resistance, and combined training according. The outcomes included: V′O₂ peak, VE/V’CO₂ slope, heart rate (HR peak), systolic and diastolic blood pressure (SBP and DBP peak), maximum repetition test(1RM), sit-to-stand test, and flow-mediated dilation (FMD). The studies were selected by consensus. Four hundred ninety-two studies initially met the selection criteria. Cochrane handbook was used for abstracting data and assessing data quality and validity. Independent extraction by two observers was applied. Results: Isolated aerobic training leads to a greater increase in V′O₂ peak than combined training compared to the control group (p < 0.001, I2 = 0%). However, no significant differences were found in the subgroup comparison (p = 0.19, I2 = 42.1%). HR peak increased similarly after aerobic and combined training. High-intensity interval training (HIIT) was better than moderate continuous intensity to increase the V′O₂ after long term in HTx. Still, there is scarce evidence of HIIT on muscle strength and FMD. No change on VE/V’CO₂ slope, FMD, and SBP, DBP peak. 1RM and the sit-to-stand test increased after resistance training (p < 0.001, I2 = 70%) and CT (p < 0.001, I2 = 0%) when compared to control. Conclusions: Aerobic and combined training effectively improve VO₂ peak and muscle strength, respectively. HIIT seems the better choice for cardiorespiratory capacity improvements. More studies are needed to examine the impact of training modalities on VE/V’CO₂ slope and FMD.

Usefulness of ventilatory inefficiency in predicting prognosis across the heart failure spectrum

Aims

The minute ventilation–carbon dioxide production relationship (VE/VCO₂ slope) is widely used for prognostication in heart failure (HF) with reduced left ventricular ejection fraction (LVEF). This study explored the prognostic value of VE/VCO₂ slope across the spectrum of HF defined by ranges of LVEF.

Methods and results

In this single‐centre retrospective observational study of 1347 patients with HF referred for cardiopulmonary exercise testing, patients with HF were categorized into HF with reduced (HFrEF, LVEF < 40%, n = 598), mid‐range (HFmrEF, 40% ≤ LVEF < 50%, n = 164), and preserved (HFpEF, LVEF ≥ 50%, n = 585) LVEF. Four ventilatory efficiency categories (VC) were defined: VC‐I, VE/VCO₂ slope ≤ 29; VC‐II, 29 < VE/VCO₂ slope < 36; VC‐III, 36 ≤ VE/VCO₂ slope < 45; and VC‐IV, VE/VCO₂ slope ≥ 45. The associations of these VE/VCO₂ slope categories with a composite outcome of all‐cause mortality or HF hospitalization were evaluated for each category of LVEF. Over a median follow‐up of 2.0 (interquartile range: 1.9, 2.0) years, 201 patients experienced the composite outcome. Compared with patients in VC‐I, those in VC‐II, III, and IV demonstrated three‐fold, five‐fold, and eight‐fold increased risk for the composite outcome. This incremental risk was observed across HFrEF, HFmrEF, and HFpEF cohorts.

Conclusions

Higher VE/VCO₂ slope is associated with incremental risk of 2 year all‐cause mortality and HF hospitalization across the spectrum of HF defined by LVEF. A multilevel categorical approach to the interpretation of VE/VCO₂ slope may offer more refined risk stratification than the current binary approach employed in clinical practice.

Listing Criteria for Heart Transplant: Role of Cardiopulmonary Exercise Test and of Prognostic Scores

Patients with advanced heart failure (AdHF) have a reduced quality of life and poor prognosis. A heart transplant (HT) is an effective treatment for such patients. Still, because of a shortage of donor organs, the final decision to place a patient without contraindications on the HT waiting list is based on detailed risk-benefit analysis. Cardiopulmonary exercise tests (CPETs) play a pivotal role in guiding selection in patients with AdHF considered for an HT. Furthermore, several validated multivariable predicting scores obtained through various techniques, including the CPETs, are available and part of the decision-making process for HT listing.

Discordance Between Severity of Heart Failure as Determined by Patient Report Versus Cardiopulmonary Exercise Testing

Background

Patient‐reported outcomes may be discordant to severity of illness as assessed by objective parameters. The frequency of this discordance and its influence on clinical outcomes in patients with heart failure is unknown.

Methods and Results

In HF‐ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training), participants (N=2062) had baseline assessment of health‐related quality of life via the Kansas City Cardiomyopathy Clinical Summary score (KCCQ‐CS) and objective severity by cardiopulmonary stress testing (minute ventilation [V_E]/carbon dioxide production [VCO₂] slope). We defined 4 groups by median values: 2 concordant (lower severity: high KCCQ‐CS and low V_E/VCO₂ slope; higher severity: low KCCQ‐CS and high V_E/VCO₂ slope) and 2 discordant (symptom minimizer: high KCCQ‐CS and high V_E/VCO₂ slope; symptom magnifier: low KCCQ‐CS and low V_E/VCO₂ slope). The association of group assignment with mortality was assessed in adjusted Cox models. Symptom magnification (23%) and symptom minimization (23%) were common. Despite comparable KCCQ‐CS scores, the risk of all‐cause mortality in symptom minimizers versus concordant–lower severity participants was increased significantly (hazard ratio [HR], 1.79; 95% CI, 1.27–2.50; P<0.001). Furthermore, despite symptom magnifiers having a KCCQ‐CS score 28 points lower (poorer QOL) than symptom minimizers, their risk of mortality was not increased (HR, 0.79; 95% CI, 0.57–1.1; P=0.18, respectively).

Conclusions

Severity of illness by patient report versus cardiopulmonary exercise testing was frequently discordant. Mortality tracked more closely with the objective data, highlighting the importance of relying not only on patient report, but also objective data when risk stratifying patients with heart failure.

Longitudinal Changes in Exercise Capacity in Patients Who Underwent Ross Procedure and Mechanical Aortic Valve Replacement: Does the Type of Surgery Matter?

The surgical options for significant aortic valve disease include either Ross procedure (RP) or aortic valve replacement (AVR). The exercise stress test is routinely performed in these patients to assess the objective functional capacity. This retrospective study was conducted to evaluate the differences and the longitudinal changes of exercise capacity in patients following the RP and AVR for aortic valve disease. This is an IRB approved retrospective study and included patients who had either RP or AVR performed for aortic valve disease and had at least one exercise stress test performed after the surgical procedure. Patients with other congenital heart disease, pacemaker or defibrillators, and those with inadequate data were excluded. Demographic data including age at surgery, type of surgery and type of aortic valve was collected. Data regarding treadmill cardiopulmonary exercise test (CPET) was also collected. A total of 47 patients met inclusion criteria and were equally represented in each group, i.e. RP [n = 23, 73.9% male, age at surgery 11.2 (4.5-15.9) years] vs. AVR [n = 24, 88% mechanical AVR, 60.9% male, age at surgery 15.1 (12.8-19.4) years]. There was a significant decline in predicted oxygen consumption (%VO₂) at time of first post-operative CPET in patients after AVR compared to RP (79 vs. 88%, p = 0.048) over a similar accrued median interval follow-up (4.6 vs. 6.2 years, p = 0.2). The longitudinal follow-up analysis of following AVR (n = 11, 54.5% male, median inter-test duration of 5 years) showed significant decline in peak exercise capacity or VO₂ (34.2 vs. 26.2 vs., p = 0.006). In contrast, after RP (n = 12 patients [58.3% male, median inter-test duration 7.1 of years], exercise capacity and other key parameters remained preserved. In this small sentinel study, we report a better initial exercise capacity among patients after RP compared to AVR over an intermediate follow-up. During longitudinal follow-up in a subset of patients, exercise capacity remained preserved amongst the RP group while it further declined in the AVR group.

Heart failure units: State of the art in disease management

The prevalence of heart failure has increased over the past decades and is a major social and economic burden on healthcare services. Patient quality of life is severely impaired and heart failure is one of the main causes of death in Portugal. The functional organization of multidisciplinary teams engaged in the treatment of these patients is essential to improve health care provision and outcomes, specifically reducing mortality, hospital admissions, and improving quality of life. We describe current approaches to heart failure management and discuss the organization of heart failure units and cooperation among these units and also with other healthcare professionals.

Ventilatory inefficiency adversely affects outcomes and longer-term survival after planned colorectal cancer surgery

BACKGROUND

Impaired cardiorespiratory reserve is an accepted risk factor for patients having major surgery. Ventilatory inefficiency, defined by an elevated ratio of minute ventilation to carbon dioxide excretion (VE/VCO₂), and measured by cardiopulmonary exercise testing (CPET), is a pathophysiological characteristic of patients with cardiorespiratory disease. We set out to evaluate the prevalence of ventilatory inefficiency in a colorectal cancer surgical population, and its influence on surgical outcomes and long-term cancer survival.

METHODS

In this retrospective study of 1375 patients who had undergone preoperative CPET followed by colorectal cancer surgery, we used receiver operating characteristic curve analysis to identify an optimal value of VE/VCO₂ associated with 90-day mortality. Binary logistic regression was used to evaluate whether this degree of ventilatory inefficiency was independently associated with decreased survival, both after surgery and in the longer term.

RESULTS

We identified an optimal VE/VCO₂ >39 cut-off for predicting 90-day mortality; 245 patients (17.8%) had VE/VCO₂ >39, of which 138 (10% of total cohort) had no known cardiorespiratory risk factors. Ventilatory inefficiency was independently associated with death at 90-days (8.2% mortality vs 1.9%; adjusted odds ratio [OR], 4.04; 95% confidence interval [CI], 2.09-7.84), with death after unplanned critical care admission (OR=4.45; 95% CI, 1.37-14.46) and with decreased survival at 2 yr (OR=2.21; 95%, 1.49-3.28) and 5 yr (OR=2.87; 95% CI, 1.54-5.37) after surgery.

CONCLUSIONS

A significant proportion of patients having colorectal cancer surgery have ventilatory inefficiency observed on CPET, the majority of whom have no history of cardiorespiratory risk factors. This group of patients has significantly decreased survival both after surgery and in the long-term, irrespective of cancer stage. Survival might be improved by formal medical evaluation and intervention in this group.

Contemporary Treatment of Heart Failure

Heart failure (HF) affects 2.4% of the adult population in the United States and is associated with high health care costs. Medical and device therapy delay disease progression and improve survival in HF with reduced ejection fraction. Stage D HF is characterized by significant functional limitation, frequent HF hospitalization for decompensation, intolerance of medical therapy, use of inotropes, and high diuretic requirement. Advanced therapies with left ventricular assist devices and cardiac transplantation reduce mortality and improve quality of life, and early referral to specialized centers is imperative for patient selection and success with these therapies.

Cardiopulmonary Exercise Test: Background, Applicability and Interpretation

Cardiopulmonary exercise test (CPET) has been gaining importance as a method of functional assessment in Brazil and worldwide. In its most frequent applications, CPET consists in applying a gradually increasing intensity exercise until exhaustion or until the appearance of limiting symptoms and/or signs. The following parameters are measured: ventilation; oxygen consumption (VO₂); carbon dioxide production (VCO₂); and the other variables of conventional exercise testing. In addition, in specific situations, pulse oximetry and flow-volume loops during and after exertion are measured. The CPET provides joint data analysis that allows complete assessment of the cardiovascular, respiratory, muscular and metabolic systems during exertion, being considered gold standard for cardiorespiratory functional assessment.^1-6

The CPET allows defining mechanisms related to low functional capacity that can cause symptoms, such as dyspnea, and correlate them with changes in the cardiovascular, pulmonary and skeletal muscle systems. Furthermore, it can be used to provide the prognostic assessment of patients with heart or lung diseases, and in the preoperative period, in addition to aiding in a more careful exercise prescription to healthy subjects, athletes and patients with heart or lung diseases.

Similarly to CPET clinical use, its research also increases, with the publication of several scientific contributions from Brazilian researchers in high-impact journals.

Therefore, this study aimed at providing a comprehensive review on the applicability of CPET to different clinical situations, in addition to serving as a practical guide for the interpretation of that test.

Changing our Approach to Stage D Heart Failure

Despite the tremendous progress made in the management of heart failure (HF), many patients reach advanced stages. This paper aims to present a practical approach to the stage D HF patient who is no longer responding to optimal medical therapy. We discuss all available therapies for this patient population. We also offer some important caveats with regard to identification, risk stratification, evaluation and treatment including early patient referral to a center with an advanced HF program. Given the changing landscape of heart transplantation and an impending change in the allocation system, we also intend to engage a discussion on the need for a paradigm shift towards left ventricular assist device therapy in this population.

Cardiac rehabilitation after acute coronary syndrome: Do all patients derive the same benefit?

INTRODUCTION

Cardiac rehabilitation (CR) has been demonstrated to improve exercise capacity in acute coronary syndrome (ACS), but not all patients derive the same benefit. Careful patient selection is crucial to maximize resources.

OBJECTIVE

To identify in a heterogeneous ACS population which patients would benefit the most with CR, in terms of functional capacity (FC), by using cardiopulmonary exercise testing (CPET).

METHODS

A retrospective analysis of consecutive ACS patients who underwent CR and CPET was undertaken. CPET was performed at baseline and after 36 sessions of exercise. Peak oxygen uptake (pVO₂), percentage of predicted pVO₂, minute ventilation/CO₂ production (VE/VCO₂) slope, VE/VCO₂ slope/pVO₂ and peak circulatory power (PCP) (pVO₂ times peak systolic blood pressure) were assessed in two moments. The differences in pVO₂ (ΔpVO₂), %pVO₂, PCP and exercise test duration were calculated. Patients were classified according to baseline pVO₂ (group 1, <20 ml/kg/min vs. group 2, ≥20 ml/kg/min) and left ventricular ejection fraction (group A, <50% vs. group B, ≥50%).

RESULTS

We analyzed 129 patients, 86% male, mean age 56.3±9.8 years. Both group 1 (n=31) and group 2 (n=98) showed significant improvement in FC after CR, with a more significant increase in pVO₂, in group 1 (ΔpVO₂ 4.4±7.3 vs. 1.6±5.4; p=0.018). Significant improvement was observed in CPET parameters in group A (n=34) and group B (n=95), particularly in pVO₂ and test duration.

CONCLUSION

Patients with lower baseline pVO₂ (<20 ml/kg/min) presented more significant improvement in FC after CR. CPET which is not routinely used in assessement before CR in context of ACS, could be a valuable tool to identify patients who will benefit the most.

Variables Measured During Cardiopulmonary Exercise Testing as Predictors of Mortality in Chronic Systolic Heart Failure

BACKGROUND

Data from a cardiopulmonary exercise (CPX) test are used to determine prognosis in patients with chronic heart failure (HF). However, few published studies have simultaneously compared the relative prognostic strength of multiple CPX variables.

OBJECTIVES

The study sought to describe the strength of the association among variables measured during a CPX test and all-cause mortality in patients with HF with reduced ejection fraction (HFrEF), including the influence of sex and patient effort, as measured by respiratory exchange ratio (RER).

METHODS

Among patients (n = 2,100, 29% women) enrolled in the HF-ACTION (HF-A Controlled Trial Investigating Outcomes of exercise traiNing) trial, 10 CPX test variables measured at baseline (e.g., peak oxygen uptake [Vo2], exercise duration, percent predicted peak Vo2 [%ppVo2], ventilatory efficiency) were examined.

RESULTS

Over a median follow-up of 32 months, there were 357 deaths. All CPX variables, except RER, were related to all-cause mortality (all p < 0.0001). Both %ppVo2 and exercise duration were equally able to predict (Wald chi-square: ∼141) and discriminate (c-index: 0.69) mortality. Peak Vo2 (ml·kg(-1)·min(-1)) was the strongest predictor of mortality among men (Wald chi-square: 129) and exercise duration among women (Wald chi-square: 41). Multivariable analyses showed that %ppVo2, exercise duration, and peak Vo2 (ml·kg(-1)·min(-1)) were similarly able to predict and discriminate mortality. In men, a 10% 1-year mortality rate corresponded to a peak Vo2 of 10.9 ml·kg(-1)·min(-1) versus 5.3 ml·kg(-1)·min(-1) in women.

CONCLUSIONS

Peak Vo2, exercise duration, and % ppVo2 carried the strongest ability to predict and discriminate the likelihood of death in patients with HFrEF. The prognosis associated with a given peak Vo2 differed by sex. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure; NCT00047437).

Exercise oscillatory ventilation in patients with Fontan physiology

BACKGROUND

Exercise oscillatory ventilation (EOV) refers to regular oscillations in minute ventilation (VE) during exercise. Its presence correlates with heart failure severity and worse prognosis in adults with acquired heart failure. We evaluated the prevalence and predictive value of EOV in patients with single ventricle Fontan physiology.

METHODS AND RESULTS

We performed a cross-sectional analysis and prospective survival analysis of patients who had undergone a Fontan procedure and subsequent cardiopulmonary exercise test. Data were reviewed for baseline characteristics and incident mortality, heart transplant, or nonelective cardiovascular hospitalization. EOV was defined as regular oscillations for >60% of exercise duration with amplitude >15% of average VE. Survival analysis was performed using Cox regression. Among 253 subjects, EOV was present in 37.5%. Patients with EOV were younger (18.8±9.0 versus 21.7±10.1 years; P=0.02). EOV was associated with higher New York Heart Association functional class (P=0.02) and VE/VCO2 slope (36.8±6.9 versus 33.7±5.7; P=0.0002), but not with peak VO2 (59.7±14.3 versus 61.0±16.0% predicted; P=0.52) or noninvasive measures of cardiac function. The presence of EOV was associated with slightly lower mean cardiac index but other invasive hemodynamic variables were similar. During a median follow-up of 5.5 years, 22 patients underwent transplant or died (n=19 primary deaths, 3 transplants with 2 subsequent deaths). EOV was associated with increased risk of death or transplant (hazard ratio, 3.9; 95% confidence interval, 1.5-10.0; P=0.002) and also predicted the combined outcome of death, transplant, or nonelective cardiovascular hospitalization after adjusting for New York Heart Association functional class, peak VO2, and other covariates (multivariable hazard ratio, 2.0; 95% confidence interval, 1.2-3.6; P=0.01).

CONCLUSIONS

EOV is common in the Fontan population and strongly predicts lower transplant-free survival.

Characteristics and outcomes of patients with heart failure and discordant findings by right-sided heart catheterization and cardiopulmonary exercise testing

There are limited data integrating findings on right-sided cardiac catheterization and cardiopulmonary exercise testing in ambulatory patients with heart failure. In this study, 187 outpatients with HF referred to the Duke Medical Center for consideration of advanced HF therapies were retrospectively evaluated. All patients had undergone right-sided cardiac catheterization and cardiopulmonary exercise testing; the median cardiac index (CI) was 2.0 L/min/m2 (interquartile range 1.7 to 2.3), and the median peak oxygen consumption was 11.3 ml/kg/min (interquartile range 9.2 to 13.8). Despite aggressive medical therapy, medical management had failed in 97 patients (52%) at 18 months, defined as left ventricular assist device implantation, cardiac transplantation, or death. After multivariate adjustment, factors associated with failure of optimal medical management included percentage achieved of predicted peak oxygen consumption, low CI (i.e., <2 L/min/m2), left ventricular size, and exercise time. Patients with discordant findings on right-sided cardiac catheterization and cardiopulmonary exercise testing were common, occurring in 88 patients (47%). The most common profile was preserved CI but reduced functional capacity, and these patients remained at high risk for requiring advanced therapies, whereas patients with reduced CIs but preserved exercise capacity were uncommon. In conclusion, low CI was independently associated with higher rates of death, transplantation, and left ventricular assist device implantation in this study. Also, patients with preserved CIs at rest but poor functional capacity, so-called cardiac insufficiency, were commonly encountered and had poor outcomes with medical management.

Adult heart transplant: indications and outcomes

Cardiac transplantation is the treatment of choice for many patients with end-stage heart failure (HF) who remain symptomatic despite optimal medical therapy. For carefully selected patients, heart transplantation offers markedly improved survival and quality of life. Risk stratification of the large group of patients with end-stage HF is essential for identifying patients who are most likely to benefit, particularly as the number of suitable donors is insufficient to meet demand. The indications for heart transplant and review components of the pre-transplant evaluation, including the role for exercise testing and risk scores such as the Heart Failure Survival Score (HFSS) and Seattle Heart Failure Model (SHFM) are summarized. Common contraindications are also discussed. Outcomes, including survival and common complications such as coronary allograft vasculopathy are reviewed.

Systolic blood pressure influences the interpretation of cardiopulmonary exercise tests and helps identify a very high-risk cohort of heart failure patients

BACKGROUND

Ventilatory inefficiency (high volume of expired air/volume of carbon dioxide eliminated [Ve/Vco2] slope), and impaired exercise tolerance (low peak volume of oxygen consumption) obtained from cardiopulmonary exercise testing (CPX) strongly predict mortality in heart failure (HF) patients; however, other CPX variables may also contain prognostic information. Therefore, the purpose of this study was to determine the prognostic power of the aggregate of CPX data.

METHODS

The study prospectively monitored 390 patients referred for cardiac transplantation evaluation for 10 years for events (death, urgent transplant, left ventricular assist devices). Cox regression was used to analyze 18 CPX variables to identify the best survival model.

RESULTS

Ve/Vco2 slope was the most powerful mortality predictor, and only resting systolic blood pressure (SBP) added additional independent prognostic power when expressed at its threshold effect value as SBP ≤ 100 mm Hg. Patients with low SBP had a greater risk than those who were within the next higher quartile of Ve/Vco2 slope with SBP > 100 mm Hg. A very high-risk cohort included 9% of the population that had a Ve/Vco2 slope > 41 and SBP ≤ 100 mm Hg and an associated 2-year event rate of 67%; conversely, a low-risk cohort had a Ve/Vco2 slope ≤ 30 and SBP >100 mm Hg and associated 2-, 5-, and 10-year event rates of 5%, 12%, and 30%, respectively.

CONCLUSIONS

Ve/Vco2 slope was the best individual predictive CPX variable and its interpretation was significantly altered by the presence of hypotension. An algorithm combining these CPX variables identifies a HF population at very high risk of early death and warranting advanced therapies.

Evaluation of patients with heart failure

Heart failure is one of the most prevalent cardiovascular diseases in the United States, and is associated with significant morbidity, mortality, and costs. Prompt diagnosis may help decrease mortality, hospital stay, and costs related to treatment. A complete heart failure evaluation comprises a comprehensive history and physical examination, echocardiogram, and diagnostic tools that provide information regarding the etiology of heart failure, related complications, and prognosis in order to prescribe appropriate therapy, monitor response to therapy, and transition expeditiously to advanced therapies when needed. Emerging technologies and biomarkers may provide better risk stratification and more accurate determination of cause and progression.