Timing of cardiac transplantation in patients with heart failure receiving β-adrenergic blockers

The cardiopulmonary exercise test in the prognostic evaluation of patients with heart failure and cardiomyopathies: the long history of making a one-size-fits-all suit

Cardiopulmonary exercise test (CPET) has become pivotal in the functional evaluation of patients with chronic heart failure (HF), supplying a holistic evaluation both in terms of exercise impairment degree and possible underlying mechanisms. Conversely, there is growing interest in investigating possible multiparametric approaches in order to improve the overall HF risk stratification. In such a context, in 2013, a group of 13 Italian centres skilled in HF management and CPET analysis built the Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score, based on the dynamic assessment of HF patients and on some other instrumental and laboratory parameters. Subsequently, the MECKI score, initially developed on a cohort of 2716 HF patients, has been extensively validated as well as challenged with the other multiparametric scores, achieving optimal results. Meanwhile, the MECKI score research group has grown over time, involving up to now a total of 27 centres with an available database accounting for nearly 8000 HF patients. This exciting joint effort from multiple HF Italian centres allowed to investigate different HF research field in order to deepen the mechanisms underlying HF, to improve the ability to identify patients at the highest risk as well as to analyse particular HF categories. Most recently, some of the participants of the MECKI score group started to join the forces in investigating a possible additive role of CPET assessment in the cardiomyopathy setting too. The present study tells the ten-year history of the MECKI score presenting the most important results achieved as well as those projects in the pipeline, this exciting journey being far to be concluded.

Cardiopulmonary Exercise Testing in Patients with Heart Failure: Impact of Gender in Predictive Value for Heart Transplantation Listing

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 β-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.

Age Differences in Cardiopulmonary Exercise Testing Parameters in Heart Failure with Reduced Ejection Fraction

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 β-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.

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.

Beta-Adrenergic Receptor Blockade Effects on Cardio-Pulmonary Exercise Testing in Healthy Young Adults: A Randomized, Placebo-Controlled Trial

BACKGROUND

Beta-blockers are increasingly prescribed while the effects of beta-adrenergic receptor blockade on cardio-pulmonary exercise test (CPET)-derived parameters remain under-studied.

METHODS

Twenty-one young healthy adults repeated three CPET at the same time with an interval of 7 days between each test. The tests were performed 3 h after a random, double-blind, cross-over single-dose intake of placebo, 2.5 mg or 5.0 mg bisoprolol, a cardio-selective beta1-adrenoreceptor antagonist. Gas exchange, heart rate (HR) and blood pressure (BP) were measured at rest and during cyclo-ergometric incremental CPET.

RESULTS

Maximal workload and VO₂max were unaffected by the treatment, with maximal respiratory exchange ratio > 1.15 in all tests. A beta-blocker dose-dependent effect reduced resting and maximal BP and HR and the chronotropic response to exercise, evaluated by the HR/VO₂ slope (placebo: 2.9 ± 0.4 beat/ml/kg; 2.5 mg bisoprolol: 2.4 ± 0.5 beat/ml/kg; 5.0 mg bisoprolol: 2.3 ± 0.4 beat/ml/kg, p < 0.001). Ventilation efficiency measured by the VE/VCO₂ slope and the ventilatory equivalent for CO₂ at the ventilatory threshold were not affected by beta1-receptor blockade. Post-exercise chronotropic recovery measured after 1 min was enhanced under beta1-blocker (placebo: 26 ± 7 bpm; 2.5 mg bisoprolol: 32 ± 6 bpm; 5.0 mg bisoprolol: 33 ± 6 bpm, p < 0.01).

CONCLUSION

The present results suggest that a single dose of bisoprolol does not affect metabolism, respiratory response and exercise capacity. However, beta-adrenergic blockade dose dependently reduces exercise hemodynamic response by lowering BP and the chronotropic response.

Left Ventricular Assist Devices: A Primer For the General Cardiologist

Durable implantable left ventricular assist devices (LVADs) have been shown to improve survival and quality of life for patients with stage D heart failure. Even though LVADs remain underused overall, the number of patients with heart failure supported with LVADs is steadily increasing. Therefore, general cardiologists will increasingly encounter these patients. In this review, we provide an overview of the field of durable LVADs. We discuss which patients should be referred for consideration of advanced heart failure therapies. We summarize the basic principles of LVAD care, including medical and surgical considerations. We also discuss the common complications associated with LVAD therapy, including bleeding, infections, thrombotic issues, and neurologic events. Our goal is to provide a primer for the general cardiologist in the recognition of patients who could benefit from LVADs and in the principles of managing patients with LVAD. Our hope is to "demystify" LVADs for the general cardiologist.

Optimizing exercise testing‐based risk stratification to predict poor prognosis after acute heart failure

AIMS

The timely selection of severe heart failure (HF) patients for cardiac transplantation and advanced HF therapy is challenging. Peak oxygen consumption (VO₂ ) values obtained by the cardiopulmonary exercise testing are used to determine the transplant recipient list. This study reassessed the prognostic predictability of peak VO₂ and compared it with the Heart Failure Survival Score (HFSS) in the modern optimized guideline-directed medical therapy (GDMT) era.

METHODS AND RESULTS

We retrospectively selected 377 acute HF patients discharged from the hospital. The primary outcome was a composite of all-cause mortality, or urgent cardiac transplantation. We divided these patients into the more GDMT (two or more types of GDMT) and less GDMT groups (fewer than two types of GDMT) and compared the performance of their peak VO₂ and HFSS in predicting primary outcomes. The median follow-up period was 3.3 years. The primary outcome occurred in 57 participants. Peak VO₂ outperformed HFSS when predicting 1 year (0.81 vs. 0.61; P = 0.017) and 2 year (0.78 vs. 0.58; P < 0.001) major outcomes. The cutoff peak VO₂ for predicting a 20% risk of a major outcome within 2 years was 10.2 (11.8-7.0) for the total cohort. Multivariate Cox regression analyses showed that peak VO₂ , sodium, previous implantable cardioverter defibrillator (ICD) implantation, and estimated glomerular filtration rate were significant predictors of major outcomes.

CONCLUSIONS

Optimizing the cutoff value of peak VO₂ is required in the current GDMT era for advanced HF therapy. Other clinical factors such as ICD use, hyponatraemia, and chronic kidney disease could also be used to predict poor prognosis. The improvement of resource allocation and patient outcomes could be achieved by careful selection of appropriate patients for advanced HF therapies, such as cardiac transplantation.

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.

Melhora no Consumo Máximo de Oxigênio e na Ventilação após Tratamento com Sacubitril-Valsartana

Fundamento

O tratamento com sacubitril-valsartana teve seu benefício prognóstico confirmado no ensaio PARADIGM-HF. No entanto, dados sobre alterações no teste de esforço cardiopulmonar (TECP) com o uso de sacubitril-valsartana são escassos.

Objetivo

O objetivo deste estudo foi comparar os parâmetros do TECP antes e depois do tratamento com sacubitril-valsartana.

Métodos

Avaliação prospectiva de pacientes com insuficiência cardíaca (IC) crônica e fração de ejeção do ventrículo esquerdo ≤40%, mesmo sob terapia padrão otimizada, que iniciaram tratamento com sacubitril-valsartana, sem expectativa de tratamentos adicionais para a IC. Os dados do TECP foram coletados na semana anterior e 6 meses depois do tratamento com sacubitril-valsartana. Diferenças estatísticas com valor p <0,05 foram consideradas significativas.

Resultados

De 42 pacientes, 35 (83,3%) completaram o seguimento de 6 meses, uma vez que 2 (4,8%) morreram e 5 (11,9%) interromperam o tratamento devido a eventos adversos. A média de idade foi de 58,6±11,1 anos. A classe NYHA (classificação da New York Heart Association) melhorou em 26 (74,3%) pacientes. O consumo máximo de oxigênio (VO₂max) (14,4 vs. 18,3 ml/kg/min, p<0,001), a inclinação VE/VCO₂ (36,7 vs. 31,1, p<0,001) e a duração do exercício (487,8 vs. 640,3 s, p<0,001) também melhoraram com o uso de sacubitril-valsartana. O benefício foi mantido mesmo com a dose de 24/26 mg (13,5 vs. 19,2 ml/kg/min, p=0,018) de sacubitril-valsartana, desde que esta tenha sido a maior dose tolerada.

Conclusões

O tratamento com sacubitril-valsartana está associado a uma melhora acentuada do VO₂max, da inclinação VE/VCO₂ e da duração do exercício no TECP. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Catheter ablation for patients with end-stage complex congenital heart disease or cardiomyopathy considered for transplantation: Trials and tribulations

INTRODUCTION

Arrhythmia contributes significantly to morbidity and mortality of patients with congenital heart disease (CHD) or cardiomyopathy (CMP). It also has the potential to worsen symptoms and is particularly detrimental to patients with advanced heart failure awaiting cardiac transplantation. We report our experience using catheter ablation to treat recurrent arrhythmia in patients with CHD or CMP considered for transplantation.

METHODS

Five consecutive patients (3 female, mean age 47.8 ± 12.8 years) with complex CHD or CMP (tricuspid atresia, mitral atresia, double inlet left ventricle, arrhythmogenic right ventricular cardiomyopathy, left ventricular non-compaction) presented with either atrial (n = 3) or ventricular (n = 2) arrhythmias. All ablations were guided by three-dimensional (3D) electro-anatomical mapping, plus remote magnetic navigation in 3 patients.

RESULTS

Patients underwent a median of 2 ablation procedures for a total number of 26 tachycardias. None of the 5 patients experienced further arrhythmia at a median of 939 days (range 4-1375) from their last ablation. During a median follow up of 31 months (range 1-70), three patients underwent successful transplantation at 1375, 1062 and 321 days following their last ablation. One patient with a Fontan circulation died from hepatic cancer and one from end-stage heart failure despite urgent transplant listing.

CONCLUSIONS

Catheter ablation is feasible in complex cardiac patients considered for heart transplantation and should be offered for rhythm management and patient optimization until a suitable donor is found.

Cardiopulmonary Exercise Testing-A Valuable Tool, Not Gatekeeper When Referring Patients With Adult Congenital Heart Disease for Transplant Evaluation

INTRODUCTION

Treatment of patients with adult congenital heart disease (ACHD) with advanced therapies including heart transplant (HT) is often delayed due to paucity of objective prognostic markers for the severity of heart failure (HF). While the utility of Cardiopulmonary Exercise Testing (CPET) in non-ACHD patients has been well-defined as it relates to prognosis, CPET for this purpose in ACHD is still under investigation.

METHODS

We performed a retrospective cohort study of 20 consecutive patients with ACHD who underwent HT between March 2010 and February 2016. Only 12 of 20 patients underwent CPET prior to transplantation. Demographics, standard measures of CPET interpretation, and 30-day and 1-year post transplantation outcomes were collected.

RESULTS

Patient Characteristics. Twenty patients with ACHD were transplanted at a median of 40 years of age (range: 23-57 years). Of the 12 patients who underwent CPET, 4 had undergone Fontan procedures, 4 had tetralogy of Fallot, 3 had d-transposition of the great arteries, and 1 had Ebstein anomaly. Thirty-day and one-year survival was 100%. All tests included in the analysis had a peak respiratory quotient _1.0. The median peak oxygen consumption per unit time (_VO2) for all diagnoses was 18.2 mL/kg/min (46% predicted), ranging from 12.2 to 22.6.

CONCLUSION

There is a paucity of data to support best practices for patients with ACHD requiring transplantation. While it cannot be proven based on available data, it could be inferred that outcomes would have been worse or perhaps life sustaining options unavailable if providers delayed referral because of the lack of attainment of CPET-specific thresholds.

Heart failure prognosis over time: how the prognostic role of oxygen consumption and ventilatory efficiency during exercise has changed in the last 20 years

AIMS

Exercise-derived parameters, specifically peak exercise oxygen uptake (peak VO₂ ) and minute ventilation/carbon dioxide relationship slope (VE/VCO₂ slope), have a pivotal prognostic value in heart failure (HF). It is unknown how the prognostic threshold of peak VO₂ and VE/VCO₂ slope has changed over the last 20 years in parallel with HF prognosis improvement.

METHODS AND RESULTS

Data from 6083 HF patients (81% male, age 61 ± 13 years), enrolled in the MECKI score database between 1993 and 2015, were retrospectively analysed. By enrolment year, four groups were generated: group 1 1993-2000 (n = 440), group 2 2001-2005 (n = 1288), group 3 2006-2010 (n = 2368), and group 4 2011-2015 (n = 1987). We compared the 10-year survival of groups and analysed how the overall risk (cardiovascular death, urgent heart transplantation, or left ventricular assist device implantation) changed over time according to peak VO₂ and VE/VCO₂ slope and to major clinical and therapeutic variables. At 10 years, a progressively higher survival from group 1 to group 3 was observed, with no further improvement afterwards. A 20% risk for peak VO₂ 15 mL/min/kg (95% confidence interval 16-13), 9 (11-8), 4 (4-2) and 5 (7-4) was observed in group 1, 2, 3, and 4, respectively, while the VE/VCO₂ slope value for a 20% risk was 32 (37-29), 47 (51-43), 59 (64-55), and 57 (63-52), respectively.

CONCLUSIONS

Heart failure prognosis improved over time up to 2010 in a HF population followed by experienced centres. The peak VO₂ and VE/VCO₂ slope cut-offs identifying a definite risk progressively decreased and increased over time, respectively. The prognostic threshold of peak VO₂ and VE/VCO₂ slope must be updated whenever HF prognosis improves.

Dietary nitrate's effects on exercise performance in heart failure with reduced ejection fraction (HFrEF)

Heart failure with reduced ejection fraction (HFrEF) is a deadly and disabling disease. A key derangement contributing to impaired exercise performance in HFrEF is decreased nitric oxide (NO) bioavailability. Scientists recently discovered the inorganic nitrate pathway for increasing NO. This has advantages over organic nitrates and NO synthase production of NO. Small studies using beetroot juice as a source of inorganic nitrate demonstrate its power to improve exercise performance in HFrEF. A larger-scale trial is now underway to determine if inorganic nitrate may be a new arrow for physicians' quiver of HFrEF treatments.

Prognostic Role of Cardiopulmonary Exercise Testing in Clinical Practice

Risk stratification is a mainstay in the care of cardiac and pulmonary disorders, as the identification of adverse outcomes helps provide measures to improve survival and quality of life. The cardiopulmonary exercise test is a useful prognostic tool in the clinical evaluation of several pathological conditions, such as heart diseases, respiratory disorders, and pulmonary hypertension. If not contraindicated, a cardiopulmonary exercise test should always be performed and integrated with clinical, laboratory, and hemodynamic parameters to better stratify patient risk. In heart failure, the cardiopulmonary exercise test is important in all the stages of patient management, from diagnosis to risk assessment. Different exercise variables have been advocated as prognostic indicators in this condition, including peak oxygen uptake, ventilatory efficiency, respiratory patterns, and identification of the anaerobic threshold. The prognostic role of the cardiopulmonary exercise test in heart failure is amplified when included in multiparametric risk stratification methodology, currently considered the best method to assess patient outcome. In respiratory disorders and in pulmonary hypertension, cardiopulmonary exercise test parameters, focusing on ventilatory performance during exercise, may help evaluate the risk of adverse events. Finally, the cardiopulmonary exercise test may help define the presence of coexisting cardiac and respiratory disorders, a combination that leads to increased rates of disability and mortality.

Cardiopulmonary Exercise Measures of Men and Women with HFrEF Differ in Their Relationship to Prognosis: The Henry Ford Hospital Cardiopulmonary Exercise Testing (FIT-CPX) Project

BACKGROUND

This study evaluated if different prognostic characteristics exist for peak oxygen consumption (VO₂), percent predicted peak VO₂ (ppVO₂), and the slope of the change in minute ventilation to volume of carbon dioxide produced (V_E-VCO₂) slope between men and women with heart failure and reduced ejection fraction (HFrEF).

METHODS

Analysis of the Henry Ford Hospital Cardiopulmonary Exercise Testing database (n = 1085; 33% women, 55% black) of individuals with HFrEF who completed a physician-referred cardiopulmonary exercise testing (CPX) between 1997 and 2010. Primary outcome was a composite of all-cause death, left ventricular assist device placement, and orthotopic heart transplant . Logistic and Cox regressions were performed and Kaplan-Meier survival curves were developed to describe relationships of the CPX variables and the composite outcome within and between men and women.

RESULTS

All patients were followed-up for a minimum of 5 years, during which there were 643 combined events (62%; 499 deaths, 64 left ventricular assist device implants, 80 orthotopic heart transplant). Each CPX variable was significantly related to event-free survival among both men and women. Log-rank assessment of Kaplan-Meier curves noted survival differences for peak VO₂ and V_E-VCO₂ slope (p ≤ .002), but not ppVO₂ (P = .32), between men and women.

CONCLUSIONS

Prognostic values for peak VO₂ and the V_E-VCO₂ slope might be considered separately for men and women, whereas the ppVO₂ value corresponding to 1- and 3-year survival rates may not be different between the sexes.

Evaluation of a Heart Transplant Candidate

PURPOSE OF REVIEW

Heart transplantation is the best option for irreversible and critically advanced heart failure. However, limited donor pool, the risk of rejection, infection, and right ventricular dysfunction in short-term post-transplant period, as well as, the development of coronary allograft vasculopathy and malignancy in the long-term post-transplant period limits the utility of heart transplantation for all comers with advanced heart failure. Therefore, selection of appropriate candidates is very important for the best short and long-term prognosis. In this article, we discuss the principles of selection of candidates and compare to the recently updated International Society for Heart and Lung Transplantation (ISHLT) listing criteria with the goal of updating current clinical practice.

RECENT FINDINGS

We found that while most of the recommendations in the new listing criteria are continuous with the previous criteria, updated recommendations are made on the risk stratification models in choosing transplantation candidates. Recommendation on hepatic dysfunction is not directly included in the updated ISHLT listing criteria; however, adoption of the Model for End-stage Liver Disease (MELD) score and modified MELD scores in the evaluation of risk are suggested in recent studies. In conclusion, evaluation of patient selection for heart transplantation should be comprehensive and individualized with respect to indications and the risk of comorbidities of candidates. With the advancement of mechanical circulatory support (MCS), the selection of heart transplantation candidate is continuously evolving and widened. MCS as bridge to candidacy should be considered when the candidate has potentially reversible risk factors for transplantation.

Advanced Heart Failure: Prevalence, Natural History, and Prognosis

Heart failure is a complex clinical syndrome. The natural history of this syndrome is progressive. Advanced heart failure is present when a patient has signs and symptoms of heart failure that are refractory to therapy. Patients with the most advanced disease and worst prognosis can be identified using iterative, integrated clinical assessment of symptom burden, effort intolerance, and cardiac dysfunction. Recognizing the transition to advanced heart failure is necessary for referral to an advanced heart disease program. Advanced heart disease specialists can tailor medical therapies, perform risk stratification, and evaluate candidacy for mechanical support, transplantation, or end-of-life palliative treatment options.

Advanced (stage D) heart failure: a statement from the Heart Failure Society of America Guidelines Committee

We propose that stage D advanced heart failure be defined as the presence of progressive and/or persistent severe signs and symptoms of heart failure despite optimized medical, surgical, and device therapy. Importantly, the progressive decline should be primarily driven by the heart failure syndrome. Formally defining advanced heart failure and specifying when medical and device therapies have failed is challenging, but signs and symptoms, hemodynamics, exercise testing, biomarkers, and risk prediction models are useful in this process. Identification of patients in stage D is a clinically important task because treatments are inherently limited, morbidity is typically progressive, and survival is often short. Age, frailty, and psychosocial issues affect both outcomes and selection of therapy for stage D patients. Heart transplant and mechanical circulatory support devices are potential treatment options in select patients. In addition to considering indications, contraindications, clinical status, and comorbidities, treatment selection for stage D patients involves incorporating the patient's wishes for survival versus quality of life, and palliative and hospice care should be integrated into care plans. More research is needed to determine optimal strategies for patient selection and medical decision making, with the ultimate goal of improving clinical and patient centered outcomes in patients with stage D heart failure.

Patient selection for advanced heart failure therapy referral

Despite advances in medical therapy for chronic heart failure (HF), advanced HF carries a dismal prognosis. Options such as transplantation and durable mechanical circulatory support have greatly improved outcomes for these patients, but their introduction has introduced significant complexity to patient management. Although much of this management occurs at specialized heart transplant centers, it is the responsibility of the primary cardiologist of the patient with advanced HF to refer patients at the appropriate time and to help them navigate the difficult decisions related to the pursuit of advanced therapies. We present a unique pathway that incorporates guidelines, recent data, and expert opinion to help general cardiologists determine which patients should be referred for transplantation or durable mechanical circulatory support, and when they should be referred. Decision making on referral to the heart transplant center is also summarized.

Do optimal prognostic thresholds in continuous physiological variables really exist? Analysis of origin of apparent thresholds, with systematic review for peak oxygen consumption, ejection fraction and BNP

Background

Clinicians are sometimes advised to make decisions using thresholds in measured variables, derived from prognostic studies.

Objectives

We studied why there are conflicting apparently-optimal prognostic thresholds, for example in exercise peak oxygen uptake (pVO₂), ejection fraction (EF), and Brain Natriuretic Peptide (BNP) in heart failure (HF).

Data Sources and Eligibility Criteria

Studies testing pVO₂, EF or BNP prognostic thresholds in heart failure, published between 1990 and 2010, listed on Pubmed.

Methods

First, we examined studies testing pVO₂, EF or BNP prognostic thresholds. Second, we created repeated simulations of 1500 patients to identify whether an apparently-optimal prognostic threshold indicates step change in risk.

Results

33 studies (8946 patients) tested a pVO₂ threshold. 18 found it prognostically significant: the actual reported threshold ranged widely (10–18 ml/kg/min) but was overwhelmingly controlled by the individual study population's mean pVO₂ (r = 0.86, p<0.00001). In contrast, the 15 negative publications were testing thresholds 199% further from their means (p = 0.0001). Likewise, of 35 EF studies (10220 patients), the thresholds in the 22 positive reports were strongly determined by study means (r = 0.90, p<0.0001). Similarly, in the 19 positives of 20 BNP studies (9725 patients): r = 0.86 (p<0.0001).

Second, survival simulations always discovered a “most significant” threshold, even when there was definitely no step change in mortality. With linear increase in risk, the apparently-optimal threshold was always near the sample mean (r = 0.99, p<0.001).

Limitations

This study cannot report the best threshold for any of these variables; instead it explains how common clinical research procedures routinely produce false thresholds.

Key Findings

First, shifting (and/or disappearance) of an apparently-optimal prognostic threshold is strongly determined by studies' average pVO₂, EF or BNP. Second, apparently-optimal thresholds always appear, even with no step in prognosis.

Conclusions

Emphatic therapeutic guidance based on thresholds from observational studies may be ill-founded. We should not assume that optimal thresholds, or any thresholds, exist.

Comparison of usefulness of each of five predictors of mortality and urgent transplantation in patients with advanced heart failure

B-type natriuretic peptide (BNP), peak oxygen consumption (VO(2)), blood urea nitrogen (BUN), systolic blood pressure (SBP), and pulmonary capillary wedge pressure are all established predictors of mortality or urgent transplantation in patients with advanced heart failure (HF). However, their comparative predictive ability in estimating prognosis has not been well studied. We analyzed 1,215 patients with advanced systolic HF referred to a university center from 1999 to 2009. BUN, BNP, VO(2), SBP, and pulmonary capillary wedge pressure were measured as a part of the initial evaluation. The patients were divided into groups according to the best cutoffs for predicting both 1- and 2-year mortality from the analysis of the receiver operating characteristic curves (BNP > or =579 pg/ml, peak VO(2) <14 ml/kg/min, BUN > or =53 mg/dl, SBP <118 mm Hg, and pulmonary capillary wedge pressure > or =21 mm Hg). During a 2-year follow-up, 234 patients (19%) died, and 208 (17%) required urgent transplantation. BNP (odds ratio 4.3, 95% confidence interval 3.3 to 5.5) and peak VO(2) (odds ratio 4.5, 95% confidence interval 2.6 to 7.8) were the strongest predictors for death or urgent transplantation. On multivariate analyses, BNP and peak VO(2) were the strongest predictors for both death or urgent transplantation and all-cause mortality. The c-statistic was 0.756 for BNP, 0.701 for VO(2), 0.659 for BUN, 0.638 for SBP, and 0.650 for pulmonary capillary wedge pressure. In conclusion, of the 5 established predictors of outcomes in advanced HF, BNP was the most robust discriminator of risk and thus could be useful, along with other more traditional prognostic variables, in patient counseling regarding prognosis and determining the timing for heart transplantation.

Is there a difference between patients with peak oxygen consumption below 10 ml/kg/min versus between 10 and 14 ml/kg/min? Does the "Grey Zone" really exist?

BACKGROUND

Cardiopulmonary exercise testing is an important component of evaluation when orthotopic heart transplantation (OHT) is considered for chronic heart failure (CHF) patients. However there is a question about the accuracy of interpretations of peak oxygen consumption (VO(2)max) used at present.

MATERIALS AND METHODS

We analyzed 302 CHF patients stratified into 3 groups according to VO(2)max (mL/kg/min): group 1 = <10 (n = 37); group 2 = 10-14 (n = 121) and group 3 = >14 (n = 144). We compared the mortality rate, the OHT rate, time to OHT, time to death and pulmonary function tests (PFT) among the groups using ANOVA Kruskal-Wallis tests for analysis in Statistica 7.1.

RESULTS

No important differences were observed between groups 1 and 2 (P > .05), but first in comparison with group 3 (P < .05) in terms of mortality (48.6% vs 33.1% vs 21.5%), number of OHT (24.3% vs 32.2% vs 14.6%), time to death (15.4 vs 16.6 vs 34.4 months) or PFT results (forced expiratory volume in the first second forced vital capacity and peak expiratory flow, all as direct or as percent of normal values). In contrast, time to OHT (4.6 vs 6.9 vs 10.9 months) and percent of normal vital capacity (72% vs 81% vs 91%) differed significantly among all groups (P < .05).

CONCLUSION

Patients with VO(2)max between 10 and 14 or <10 mL/kg/min are at similar risk of death.

New York Heart Association functional class predicts exercise parameters in the current era

BACKGROUND

The New York Heart Association (NYHA) functional class is a subjective estimate of a patient's functional ability based on symptoms that do not always correlate with the objective estimate of functional capacity, peak oxygen consumption (peak V(O2)). In addition, relationships between these 2 measurements have not been examined in the current medical era when patients are using beta-blockers, aldosterone antagonists, and cardiac resynchronization therapy (CRT). Using baseline data from the HF-ACTION (Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing) study, we examined this relationship.

METHODS

One thousand seven hundred fifty-eight patients underwent a symptom-limited metabolic stress test and stopped exercise due to dyspnea or fatigue. The relationship between NYHA functional class and peak V(O2) was examined. In addition, the effects of beta-blockers, aldosterone antagonists, and CRT therapy on these relationships were compared.

RESULTS

The NYHA II patients have a significantly higher peak Vo(2) (16.1 +/- 4.6 vs 13.0 +/- 4.2 mL/kg per minute), a lower ventilation (Ve)/V(CO2) slope (32.8 +/- 7.7 vs 36.8 +/- 10.4), and a longer duration of exercise (11.0 +/- 3.9 vs 8.0 +/- 3.4 minutes) than NYHA III/IV patients. Within each functional class, there was no difference in any of the exercise parameters between patients on or off of beta-blockers, aldosterone antagonists, or CRT therapy. Finally, with increasing age, a significant difference in peak Vo(2), Ve/V(CO2) slope, and exercise time was found.

CONCLUSION

For patients being treated with current medical therapy, there still is a difference in true functional capacity between NYHA functional class II and III/IV patients. However, within each NYHA functional class, the presence or absence or contemporary heart failure therapies does not alter exercise parameters.

Prognostic markers in heart failure--congestion, neurohormones, and the cardiorenal syndrome

There are several markers of poor prognosis in heart failure (HF). The most established markers of poor prognosis in HF include neurohormonal (NH) imbalance, low ejection fraction (EF), ventricular arrhythmias, intraventricular conduction delays, low functional capacity, low SBP, and renal failure. The relative importance of these factors is unknown, as they have never been studied together. We present a 74-year-old female with nonischemic cardiomyopathy and an EF<20% who over 24 years since diagnosis, never developed clinical or hemodynamic congestion, was never hospitalized for HF, and never required a loop diuretic. She had all of the clinical indicators of poor prognosis in HF except for severe NH imbalance and renal failure, illustrating their importance in HF prognosis. While NH activation in HF is initially an adaptive mechanism, an imbalance of NH effectors causes congestion leading to a vicious cycle of congestion, renal dysfunction, and worsening of HF. The combination of NH activation and renal failure in HF is a vasomotor nephropathy known as the cardiorenal syndrome (CRS) and portends a poor prognosis. Pharmacological disruption of NH pathways early in HF may prevent CRS and, therefore, improve outcomes.

Guidelines for heart transplantation

Based on the changes in the field of heart transplantation and the treatment and prognosis of patients with heart failure, these updated guidelines were composed by a committee under the supervision of both the Netherlands Society of Cardiology and the Netherlands Association for Cardiothoracic surgery (NVVC and NVT).THE INDICATION FOR HEART TRANSPLANTATION IS DEFINED AS: 'End-stage heart disease not remediable by more conservative measures'.CONTRAINDICATIONS ARE: irreversible pulmonary hypertension/elevated pulmonary vascular resistance; active systemic infection; active malignancy or history of malignancy with probability of recurrence; inability to comply with complex medical regimen; severe peripheral or cerebrovascular disease and irreversible dysfunction of another organ, including diseases that may limit prognosis after heart transplantation.Considering the difficulties in defining end-stage heart failure, estimating prognosis in the individual patient and the continuing evolution of available therapies, the present criteria are broadly defined. The final acceptance is done by the transplant team which has extensive knowledge of the treatment of patients with advanced heart failure on the one hand and thorough experience with heart transplantation and mechanical circulatory support on the other hand. (Neth Heart J 2008;16:79-87.).

Excessive ventilation during early phase of exercise: A new predictor of poor long-term outcome in patients with chronic heart failure

BACKGROUND

Studies demonstrating prognostic value of excessive exercise ventilation in chronic heart failure (CHF) have focused on data derived from the whole cardiopulmonary exercise test (CPET). Whether ventilatory response to early phase of exercise is useful for risk stratification in CHF is unknown.

METHODS AND RESULTS

We evaluated 216 patients with systolic CHF who underwent CPET (age: 60+/-11 years, NYHA class [I/II/III/IV]: 18/104/77/17). Ventilatory response to exercise (slope of regression line relating ventilation to carbon dioxide production) was calculated from the whole exercise test (VE-VCO(2)-all) and from the first 3 min of exercise (early phase - VE-VCO(2)-3 min). During follow-up (mean: 40+/-20 months, >3 years in survivors), 89 (41%) CHF patients died. High VE-VCO(2)-all and VE-VCO(2)-3 min predicted poor outcome in single predictor analyses, and in multivariable models when adjusted for prognosticators (age, NYHA class, ejection fraction, peak VO(2)) (P<0.0001). In receiver operating characteristic curve analysis, areas under curve for 3-year follow-up were similar for VE-VCO(2)-all and VE-VCO(2)-3 min. VE-VCO(2)-3 min maintained its prognostic value in patients taking beta-blockers (P<0.0001) and those unable to perform maximal CPET (P=0.0009).

CONCLUSIONS

In CHF patients, excessive ventilation assessed over the first 3 min predicts poor outcome. Assessment of ventilatory response to exercise for prognostic stratification may be extended to patients unable to perform maximal CPET.

The Prognostic Value of Ventilatory Efficiency with Beta-Blocker Therapy in Heart Failure

PURPOSE

Beta-blockade (BB) has been shown to improve outcomes among patients with heart failure (HF). The impact this pharmacological approach has on the prognostic information gained from cardiopulmonary exercise testing (CPX) is, however, unclear.

METHODS

Four hundred seventeen subjects diagnosed with HF underwent CPX. The numbers of subjects prescribed and not prescribed a BB agent were 167 and 250, respectively. Subjects were tracked for cardiac-related mortality after CPX.

RESULTS

Values are reported for the no-BB versus the BB group throughout. Age (57.9 +/- 13.3 vs 55.6 +/- 12.5), peak VO2 (16.2 +/- 5.7 vs 16.5 +/- 5.5 mL x kg(-1) x min(-1)), VE/VCO2 slope (34.2 +/- 9.0 vs 33.2 +/- 7.4), and peak RER (1.07 +/- 0.16 vs 1.05 +/- 0.14) were similar between groups (P > 0.05). Multivariate Cox regression analysis revealed that the VE/VCO2 slope was the superior predictor of death in both groups (chi-square: 71.9, P < 0.001; and 18.4, P < 0.001). The optimal threshold values for VE/VCO2 slope in the no-BB and BB groups were 36.0 and 34.3, respectively.

CONCLUSIONS

The results of the present study indicate that BB does not alter the prognostic value/characteristics of the VE/VCO2 slope. Findings from previous investigations examining the prognostic significance of CPX predominantly using HF groups not receiving a BB agent may, therefore, still be applicable in modern-day clinical practice.

Comparison of the prognostic value of cardiopulmonary exercise testing between male and female patients with heart failure

BACKGROUND

Cardiopulmonary exercise testing (CPX) clearly holds prognostic value in the heart failure (HF) population. Studies investigating the prognostic value of CPX in individuals with HF have consistently examined predominantly male groups. The purpose of the present study was to examine the prognostic value of CPX in a female HF group.

METHODS

Seventy-five female and 337 male subjects diagnosed with HF participated in this study. The ability of peak oxygen consumption (VO(2)) and the minute ventilation/carbon dioxide production (VE/VCO(2)) slope to predict cardiac-related events were assessed.

RESULTS

In the year following CPX, the female group suffered 26 cardiac-related events (8 deaths/18 hospitalizations), while the male group suffered 89 cardiac-related events (20 deaths/69 hospitalizations). The hazard ratios for peak VO(2) and the VE/VCO(2) slope were 4.0 (95% confidence interval: 2.6-6.1, p<0.001) and 4.2 (95% confidence interval: 2.7-6.6, p<0.001) in the male group and 3.8 (95% confidence interval: 1.7-8.5, p<0.001) and 4.3 (95% confidence interval: 1.8-9.8, p<0.001) in the female group. In both the male and female groups, Cox multivariate analysis revealed VE/VCO(2) slope was the strongest predictor of cardiac-related events while peak VO(2) added significant predictive value and was retained in the regression.

CONCLUSION

The results of the present study indicate that the prognostic value of peak VO(2) and the VE/VCO(2) slope are similar in men and women diagnosed with HF. In both men and women, the prognostic power of the VE/VCO(2) slope is greater than that of peak VO(2).

Prognostic value of cardiopulmonary exercise variables in chronic heart failure patients with or without beta-blocker therapy

The prognostic value of exercise-derived variables in the prediction of mortality in patients with chronic heart failure treated by beta blockers continues to be debated. A total of 402 patients with chronic heart failure, including 255 treated with beta blockers, were included and followed for 26 +/- 20 months after the exercise test. On univariate analysis, and in contrast to peak exercise oxygen consumption, the prognostic value of the minute ventilation/carbon dioxide production slope was increased in patients receiving beta-blocker therapy. On multivariate analysis, no independent prognostic variable emerged in patients not on beta-blocker therapy. However, the model that included the circulatory power (peak oxygen uptake x systolic blood pressure), in addition to age, New York Heart Association class, and left ventricular ejection fraction, was the best 1 for patients on beta-blocker therapy. In conclusion, in patients with chronic heart failure, the circulatory power is the exercise variable with the greatest independent prognostic value, compared with the peak exercise oxygen consumption and minute ventilation/carbon dioxide production slope.

Prognostic value of end-tidal carbon dioxide during exercise testing in heart failure

BACKGROUND

The partial pressure of end-tidal carbon dioxide production (P(ET)CO2) at ventilatory threshold (VT) has been shown to be strongly correlated with cardiac output during exercise in patients with heart failure (HF), but few data are available regarding its prognostic utility.

AIMS

The purpose of this study was to assess the ability of P(ET)CO2 to predict cardiac-related events in a group of subjects with HF.

METHODS

One hundred and thirty subjects diagnosed with compensated HF underwent cardiopulmonary exercise testing (CPX). Peak oxygen consumption (VO2), the minute ventilation-carbon dioxide production (VE/VCO2) slope and P(ET)CO2 were determined.

RESULTS

Receiver operating characteristic (ROC) curve analysis revealed that P(ET)CO2 at the ventilatory threshold (VT) was a significant predictor of cardiac-related events (ROC area=0.82, p<0.001). The optimal P(ET)CO2 at a VT threshold value for separating high (< or =) and low (>) risk groups was 36.1 mm Hg (77% sensitivity, 69% specificity). In a multivariate Cox regression analysis, P(ET)CO2 at VT added significant predictive value to the VE/VCO2 slope and peak VO2.

CONCLUSION

These results indicate that P(ET)CO2 during CPX is a significant predictor of cardiac-related events in patients with HF. Clinical assessment of this variable in patients with HF undergoing CPX may therefore be warranted.

Effects of Gender on Peak Oxygen Consumption and the Timing of Cardiac Transplantation

OBJECTIVES

This study examines the gender effects on peak exercise oxygen consumption (VO2) and survival in heart failure (HF) patients and their implications for cardiac transplantation.

BACKGROUND

The predictive value of peak VO2 in women HF patients is poorly established but is one of the indicators used to optimally time cardiac transplantation in women.

METHODS

A total of 594 ambulatory HF patients (mean age 52 +/- 12 years, 28% women, mean left ventricular ejection fraction 26 +/- 12%, 73% on beta-blocker) underwent symptom-limited exercise tests with breath-by-breath expired gas analyses using ramped treadmill protocols. Kaplan-Meier survival curves were generated for each gender and compared using log-rank tests.

RESULTS

Women had a significantly lower peak VO2 than men (14.0 +/- 4.9 ml/kg/min vs. 16.6 +/- 7.1 ml/kg/min; p < 0.0001), despite being younger (48.9 +/- 11.5 years vs. 53.2 +/- 12.4 years; p < 0.0001) and having a higher left ventricular ejection fraction (29 +/- 13% vs. 25 +/- 11%; p < 0.0003). However, the one-year transplant-free survival was significantly lower for men than for women (81% vs. 94%, p < 0.0001), a finding seen across each Weber class. Cox regression analyses confirmed the protective effects of female gender on transplant-free survival when controlling for peak VO2, age, race, beta-blocker use, and type of cardiomyopathy. The peak VO2 associated with 85% one-year transplant-free survival was significantly higher in men than in women (11.5 vs. 10.0 ml/kg/min).

CONCLUSIONS

Women had a significantly lower peak Vo(2) than men, but had better survival at all levels of exercise capacity. The current practice of uniform application of peak VO2 as an aid to determine cardiac transplantation timing should be re-examined.

Prospective comparison of ventilatory equivalent versus peak oxygen consumption in predicting outcomes of patients with heart failure

In patients with heart failure (HF), peak exercise oxygen consumption (VO2) is an important prognostic tool on which critical clinical decisions are made. However, recent retrospective data have suggested that ventilatory equivalent (VE = ventilation [liters per minute]/VO2 [liters per minute]) may be a stronger predictor of outcomes than VO2 in patients with HF on modern medical therapies. We prospectively collected baseline demographics, cardiovascular history, hemodynamics, and exercise ventilatory data from 221 consecutive patients with HF who underwent treadmill exercise VO2 testing. The composite primary end point was death or heart transplantation. Mean follow-up was 508 days, during which 27 events occurred (13 deaths and 14 transplantations). One-year event-free survival was 88% (n = 104 with 1-year follow-up). Mean age was 49 years, 68% were men, 84% were taking beta blockers, 82% were taking angiotensin-converting enzyme inhibitors, and 21% had an implantable cardioverter-defibrillator. Mean VO2 was 16 +/- 5 ml/kg/min. Mean VE was 47.4 +/- 15.2. Univariate predictors of events included lower VO2 (p <0.0001), higher heart rate at rest (p = 0.05), and presence of an implantable cardioverter-defibrillator (p = 0.024). Higher VE (p = 0.10) and lower maximum systolic blood pressure (p = 0.09) were of borderline significance. Age, gender, HF etiology or severity, and other ventilatory parameters were not significant predictors. Multivariate models that incorporated VE, VO2, or their combination confirmed VO2 as an independent predictor of event-free survival (p < or =0.0002); VE did not independently predict outcomes. Other independent predictors were higher heart rate at rest (p < or =0.02) and presence of an implantable cardioverter-defibrillator (p < or =0.04). In conclusion, peak VO2, but not VE, predicts clinical outcomes of patients with HF who are treated with contemporary medical therapies.