Heart failure patients with improved ejection fraction: Insights from the MECKI score database

AIMS

Improvement of left ventricular ejection fraction is a major goal of heart failure (HF) treatment. However, data on clinical characteristics, exercise performance and prognosis in HF patients who improved ejection fraction (HFimpEF) are scarce. The study aimed to determine whether HFimpEF patients have a distinct clinical phenotype, biology and prognosis than HF patients with persistently reduced ejection fraction (pHFrEF).

METHODS AND RESULTS

A total of 7948 patients enrolled in the Metabolic Exercise Cardiac Kidney Indexes (MECKI) score database were evaluated (median follow-up of 1490 days). We analysed clinical, laboratory, electrocardiographic, echocardiographic, exercise, and survival data from HFimpEF (n = 1504) and pHFrEF (n = 6017) patients. The primary endpoint of the study was the composite of cardiovascular death, left ventricular assist device implantation, and urgent heart transplantation. HFimpEF patients had lower HF severity: left ventricular ejection fraction 44.0 [41.0-47.0] versus 29.7 [24.1-34.5]%, B-type natriuretic peptide 122 [65-296] versus 373 [152-888] pg/ml, haemoglobin 13.5 [12.2-14.6] versus 13.7 [12.5-14.7] g/dl, renal function by the Modification of Diet in Renal Disease equation 72.0 [56.7-89.3] versus 70.4 [54.5-85.3] ml/min, peak oxygen uptake 62.2 [50.7-74.1] versus 52.6 [41.8-64.3]% predicted, minute ventilation-to-carbon dioxide output slope 30.0 [26.9-34.4] versus 32.1 [28.0-38.0] in HFimpEF and pHFrEF, respectively (p < 0.001 for all). Cardiovascular mortality rates were 26.6 and 46.9 per 1000 person-years for HFimpEF and pHFrEF, respectively (p < 0.001). Kaplan-Meier analysis showed that HFimpEF had better a long-term prognosis compared with pHFrEF patients. After adjustment for variables differentiating HFimpEF from pHFrEF, except echocardiographic parameters, the Kaplan-Meier curves showed the same prognosis.

CONCLUSIONS

Heart failure with improved ejection fraction represents a peculiar group of HF patients whose clinical, laboratory, electrocardiographic, echocardiographic, and exercise characteristics parallel the recovery of systolic function. Nonetheless, these patients remain at risk for adverse outcome.

Exercise oscillatory ventilation: the past, present, and future

Exercise oscillatory ventilation (EOV) is a fascinating event that can be appreciated in the cardiopulmonary exercise test and is characterized by a cyclic fluctuation of minute ventilation, tidal volume, oxygen uptake, carbon dioxide production, and end-tidal pressure for oxygen and carbon dioxide. Its mechanisms stem from a dysregulation of the normal control feedback of ventilation involving one or more of its components, namely, chemoreflex delay, chemoreflex gain, plant delay, and plant gain. In this review, we intend to breakdown therapeutic targets according to pathophysiology and revise the prognostic value of exercise oscillatory ventilation in the setting of heart failure and other diagnoses.

Determinants of exercise performance in heart failure patients with extremely reduced cardiac output and left ventricular assist device

The evaluation of exercise capacity and cardiac output (QC) is fundamental in the management of patients with advanced heart failure (AdHF). QC and peak oxygen uptake (VO2) have a pivotal role in the prognostic stratification and in the definition of therapeutic interventions, including medical therapies and devices, but also specific treatments such as heart transplantation and left ventricular assist device (LVAD) implantation. Due to the intertwined relationship between exercise capacity and daily activities, exercise intolerance dramatically has impact on the quality of life of patients. It is a multifactorial process that includes alterations in central and peripheral haemodynamic regulation, anaemia and iron deficiency, pulmonary congestion, pulmonary hypertension, and peripheral O2 extraction. This paper aims to review the pathophysiological background of exercise limitations in HF patients and to examine the complex physiology of exercise in LVAD recipients, analysing the interactions between the cardiopulmonary system, the musculoskeletal system, the autonomic nervous system, and the pump. We performed a literature review to highlight the current knowledge on this topic and possible interventions that can be implemented to increase exercise capacity in AdHF patients-including administration of levosimendan, rehabilitation, and the intriguing field of LVAD speed changes. The present paper confirms the role of CPET in the follow-up of this peculiar population and the impact of exercise capacity on the quality of life of AdHF patients.

Beyond VO2: the complex cardiopulmonary exercise test

Cardiopulmonary exercise test (CPET) is a valuable diagnostic tool with a specific application in heart failure (HF) thanks to the strong prognostic value of its parameters. The most important value provided by CPET is the peak oxygen uptake (peak VO2), the maximum rate of oxygen consumption attainable during physical exertion. According to the Fick principle, VO2 equals cardiac output (Qc) times the arteriovenous content difference [C(a-v)O2], where Ca is the arterial oxygen and Cv is the mixed venous oxygen content, respectively; therefore, VO2 can be reduced both by impaired O2 delivery (reduced Qc) or extraction (reduced arteriovenous O2 content). However, standard CPET is not capable of discriminating between these different impairments, leading to the need for 'complex' CPET technologies. Among non-invasive methods for Qc measurement during CPET, inert gas rebreathing and thoracic impedance cardiography are the most used techniques, both validated in healthy subjects and patients with HF, at rest and during exercise. On the other hand, the non-invasive assessment of peripheral muscle perfusion is possible with the application of near-infrared spectroscopy, capable of measuring tissue oxygenation. Measuring Qc allows, by having haemoglobin values available, to discriminate how much any VO2 deficit depends on the muscle, anaemia or heart.

International validation of the Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score in heart failure

AIMS

Current European heart failure (HF) guidelines suggest the use of risk score: among them, the Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score has demonstrated to be one of the most accurate. However, the risk scores are still poorly implemented in clinical practice, also due to the lack of strong evidence regarding their external validation in different populations. Thus, the current study was designed as an external validation test of the MECKI score in an international multicentre setting.

METHODS AND RESULTS

The study cohort consisted of patients diagnosed with HF with reduced ejection fraction (HFrEF) across international centres (not Italian), retrospectively recruited. Collected data included demographics, HF aetiology, laboratory testing, electrocardiogram (ECG), echocardiographic findings, and cardiopulmonary exercise testing (CPET) results as described in the original MECKI score publication. A total of 1042 patients across 8 international centres (7 European and 1 Asian) were included and followed up from 1998 till 2019. Patients were divided according to the calculated MECKI scores into three subgroups: (i) MECKI score <10%, (ii) 10-20%, and (iii) ≥ 20%. Survival analysis comparison among the three MECKI score subgroups showed a worse prognosis in patients with higher MECKI score value: median event-free survival times were 4396 days for MECKI score <10%, 3457 days for 10-20%, and 1022 days for ≥20% (P < 0.0001). Receiver operating characteristic (ROC) curves and area under the ROC curves (AUC) were like those reported in the original internal validation studies.

CONCLUSION

In patients diagnosed with HFrEF, the power of the MECKI score was confirmed in terms of prognosis and risk stratification, supporting its implementation as advised by the HF guidelines.

Cardiopulmonary exercise testing and heart failure: a tale born from oxygen uptake

Since 50 years, cardiopulmonary exercise testing (CPET) plays a central role in heart failure (HF) assessment. Oxygen uptake (VO₂) is one of the main HF prognostic indicators, then paralleled by ventilation to carbon dioxide (VE/VCO₂) relationship slope. Also anaerobic threshold retains a strong prognostic power in severe HF, especially if expressed as a percent of maximal VO₂ predicted value. Moving beyond its absolute value, a modern approach is to consider the percentage of predicted value for peak VO₂ and VE/VCO₂ slope, thus allowing a better comparison between genders, ages, and races. Several VO₂ equations have been adopted to predict peak VO₂, built considering different populations. A step forward was made possible by the introduction of reliable non-invasive methods able to calculate cardiac output during exercise: the inert gas rebreathing method and the thoracic electrical bioimpedance. These techniques made possible to calculate the artero-venous oxygen content differences (ΔC(a-v)O₂), a value related to haemoglobin concentration, pO₂, muscle perfusion, and oxygen extraction. The role of haemoglobin, frequently neglected, is however essential being anaemia a frequent HF comorbidity. Finally, peak VO₂ is traditionally obtained in a laboratory setting while performing a standardized physical effort. Recently, different wearable ergo-spirometers have been developed to allow an accurate metabolic data collection during different activities that better reproduce HF patients' everyday life. The evaluation of exercise performance is now part of the holistic approach to the HF syndrome, with the inclusion of CPET data into multiparametric prognostic scores, such as the MECKI score.

The importance of re-evaluating the risk score in heart failure patients: An analysis from the Metabolic Exercise Cardiac Kidney Indexes (MECKI) score database

BACKGROUND

The role of risk scores in heart failure (HF) management has been highlighted by international guidelines. In contrast with HF, which is intrinsically a dynamic and unstable syndrome, all its prognostic studies have been based on a single evaluation. We investigated whether time-related changes of a well-recognized risk score, the MECKI score, added prognostic value. MECKI score is based on peak VO₂, VE/VCO₂ slope, Na⁺, LVEF, MDRD and Hb.

METHODS

A multi-centre retrospective study was conducted involving 660 patients who performed MECKI re-evaluation at least 6 months apart. Based on the difference between II and I evaluation of MECKI values (MECKI II - MECKI I = ∆ MECKI) the study population was divided in 2 groups: those presenting a score reduction (∆ MECKI <0, i.e. clinical improvement), vs. patients presenting an increase (∆ MECKI >0, clinical deterioration).

RESULTS

The prognostic value of MECKI score is confirmed also when re-assessed during follow-up. The group with improved MECKI (366 patients) showed a better prognosis compared to patients with worsened MECKI (294 patients) (p < 0.0001). At 1st evaluation, the two groups differentiated by LVEF, V_E/VCO₂ slope and blood Na⁺ concentration, while at 2nd evaluation they differentiated in all 6 parameters considered in the score. The patients who improved MECKI score, improved in all components of the score but hemoglobin, while patients who worsened the score, worsened all parameters.

CONCLUSIONS

This study shows that re-assessment of MECKI score identifies HF subjects at higher risk and that score improvement or deterioration regards several MECKI score generating parameters confirming the holistic background of HF.

Technology and Technique for left ventricular assist device optimization: A Bi-Tech solution

BACKGROUND

We investigated the synergistic effect of the new cone-bearing design of Jarvik 2000 (Jarvik Heart Inc., NY) together with a minimally-invasive approach on outcomes of LVAD patients.

METHODS

We retrospectively reviewed all patients from 5 institutions involved in the Jarvik 2000 Italian Registry, from October-2008 to October-2016. Patients were divided into three groups according to pump design and implantation technique: pin-bearing design and conventional approach (Group 1); cone-bearing and conventional approach (Group 2); cone-bearing and minimally-invasive implantation (Group 3).

RESULTS

A total of 150 adult patients with end-stage heart failure were enrolled: 26 subjects in Group 1, 74 in Group 2, and 50 in Group 3. Nineteen patients (73%) in Group 1, 51 (69%) in Group 2, and 36 (72%) in Group 3 were discharged. During follow-up, 22 patients underwent transplantation, while in 3 patients the LVAD was explanted. Overall 1-year survival was 58±10%, 64±6% and 74%±7% in Group 1, 2 and 3, respectively (p=0.034). The competing-risks-adjusted cumulative incidence rate for adverse events was 42.1 [27-62.7] per 100 patient-years in Group 1, 35.4 [25.3-48.2] in Group 2, and 22.1 [12.4-36.4] in Group 3 (p=0.046 for Group 1 vs 3).

CONCLUSIONS

The association of the modern cone-bearing configuration of Jarvik 2000 and minimally-invasive surgery improved survival and minimized the risk for cardiovascular events, as a result of combining technology and technique.

P330 A CASE OF SEVERE AORTIC STENOSIS IN A YOUNG PATIENT WITH BICUSPID AORTIC VALVE, FAMILIAL HYPERCHOLESTEROLEMIA AND CALCIFICATION AT THE SINOTUBULAR JUNCTION

Background

Familial hypercholesterolemia (FH) is a disorder characterized by elevated LDL–C and premature vascular calcifications. Aortic stenosis (AS) is the most frequent complication of bicuspid aortic valve (BAV), often requiring aortic valve replacement. Cardiac surgery in patients with severely calcified ascending aorta is challenging.

Case Presentation

A 28 year old male from Albania presented to the ED for dyspnea and low–threshold angina. The patient had family history for CAD and a sister with known FH treated with PCSK9–i. He had BAV, known hypercholesterolemia (max cholesterol 660 mg/dL), treated since 2015 with rosuvastatin plus ezetimibe, with reported irregular intake. He was treated with PCI and bioresorbable vascular scaffold on LAD coronary artery. He underwent surgical removal of limb xanthomas. At admission, the patient was asymptomatic at rest. Cardiac auscultatory findings included an ejection murmur in the aortic area. He presented upper and inferior eyelid xanthelasmas, bilateral calcaneal tendon thickening, elbows and knee xanthoma removal scars. Blood tests were unremarkable, except for lipid profile (LDL–C 443 mg/dL, HDL 36 mg/dL, TG 73 mg/dL). The echocardiography showed BAV, severe AS (Vmax 4,2 m/s, MPG 41 mmHg, AVA 0.46 cm2/m2), EF 60%. A coronary angiography excluded significant stenosis in the epicardial coronary vessels. An aortic CT scan showed sinotubular junction with preserved diameters and severe multiple parietal calcifications, ascending aorta with diffuse atheromatous disease. The patient underwent mechanical aortic valve replacement, ascending aorta thromboendarterectomy, non–coronary sinus enlargement patch, double CABG (SVG–OM, SVG–LAD) due to diffuse hypokinesia of the left ventricle after the interruption of extracorporeal circulation. At a 3–month outpatient re–evaluation, due to the unsatisfactory response to the regular intake of rosuvastatin plus ezetimibe (TC 309 mg/dL, TG 52 mg/dL, HDL 34 mg/dL, LDL–C 264 mg/dL), a PCSK9–i was prescribed. Genetic studies for FH are ongoing.

Discussion

This case underlines the importance of aortic evaluation before aortic valve replacement, even in young FH patients, in which severe aortic calcification can influence surgical approach.

Conclusion

We described the multidisciplinary management of a severe symptomatic AS in a young male with FH and sinotubular junction parietal calcifications, which represented a challenging substrate for valve replacement.

P251 PERIODIC BREATHING (EOV) ON CARDIORESPIRATORY STRESS TESTING: ARE THERE PROGNOSTIC DIFFERENCES BETWEEN PATIENTS WITH PERIODIC BREATHING THAT PERSISTS THROUGHOUT THE TEST AND PATIENTS TO WHOM IT DISAPPEARS?

Introduction

Oscillatory exercise ventilation (EOV) is frequently seen in patients with severe heart failure (HF) and has a ne:gative prognostic value in both patients with reduced HF and those with average ejection fraction. Two types of EOV have been described one that lasts throughout exercise and one that disappears before the end of exercise, Figure 1

Aim of the Study

It is currently unknown whether there are differences in prognosis and functional capacity between HF patients with EOV that persists or disappears during exercise.

Population

Male and female patients, aged≥18 years, diagnosed with HF and LVEF&lt;45% were enrolled.

Methods

The retrospective study enrolled patients who performed a cardiopulmonary exercise test (CPET) and presented with EOV during exercise (Monzino Heart Center Laboratory and patients included in the MECKI score registry, identified a total of 255 patients). A subset of 100 patients underwent measurement of maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) before and after exercise (Table 2). All patients were treated at the top of therapy for HF. CPETs were performed and analyzed with a standard approach using a customized ramp protocol. The main parameters obtained are reported and compared in Table 1. EOV was defined according to as a cyclic fluctuation in ventilation as proposed by Corrà et al. Statistical analysis:Data are reported as mean ± standard deviation or median and interquartile range as appropriate. The two groups of patients were compared by t test for unpaired data in the case of data with normal distribution. Mortality was analyzed by Kaplan Meier curves and Log Rank test. Survival was considered using the composite end–point of cardiovascular death, urgent cardiac transplantation, or implantation of a left ventricular assist device. The median MECKI score of the total population was 5.5% (2.5–13.7) with no significant differences between the 2 groups. Figure 1 shows the Kaplan Meyer describing the 5–year survival analysis in both groups.

Conclusions

Patients with disappearing EOV demonstrated better exercise performance but no significant difference in survival and major prognostic parameters.

Marginal donors and organ shortness: concomitant surgical procedures during heart transplantation: a literature review

Heart transplantation represents the gold standard for end-stage heart failure. However, due to the increasing demand and the shortage of available organs, donor supply remains the main limitation. Marginal donor hearts in high-risk candidates who do not meet standard listing criteria are the only alternative when life expectancy is limited, but their use is still debated. Surgical correction of detected coronary lesions or valvular heart defects allows further enlargement of the number of available organs. In this article, we offer a literature review on this topic and report two marginal donor hearts with angiography evidence of coronary stenosis and preserved ventricular function, which underwent concomitant myocardial revascularization during heart implantation.

Week to week variability of pulmonary capillary blood volume and alveolar membrane diffusing capacity in patients with heart failure

BACKGROUND

Alveolar-capillary membrane diffusing capacity for carbon monoxide (DMCO) and pulmonary capillary volume (Vcap) can be estimated by the multi-step Roughton and Foster (RF, original method from 1957) or the single-step NO-CO double diffusion technique (developed in the 1980s). The latter method implies inherent assumptions. We sought to determine which combination of the alveolar membrane diffusing capacity for nitric oxide (DMNO) to DMCO ratio, an specific conductance of the blood for NO (θ_NO) and CO (θ_CO) gave the lowest week-to-week variability in patients with heart failure.

METHODS

44 heart failure patients underwent DMCO and Vcap measurements on three occasions over a ten-week period using both RF and double dilution NO-CO techniques.

RESULTS

When using the double diffusing method and applying θ_NO = infinity, the smallest week-to-week coefficient of variation for DMCO was 10 %. Conversely, the RF method derived DMCO had a much greater week-to-week variability (2x higher coefficient of variation) than the DMCO derived via the NO-CO double dilution technique. The DMCO derived from the double diffusion technique most closely matched the DMCO from the RF method when θ_NO = infinity and DMCO = DLNO/2.42. The Vcap measured week-to-week was unreliable regardless of the method or constants used.

CONCLUSIONS

In heart failure patients, the week-to-week DMCO variability was lowest when using the single-step NO-CO technique. DMCO obtained from double diffusion most closely matched the RF DMCO when DMCO/2.42 and θ_NO = infinity. Vcap estimation was unreliable with either method.

Successful Open Chest Epicardial Ablation for Refractory Ventricular Tachycardia in an LVAD Recipient

A patient with history of dilated cardiomyopathy, a cardiac resynchronization therapy defibrillator, and endocardial ablation presented for refractory ventricular tachycardia 3 years after implantation of a Jarvik 2000 left ventricular assist device (Jarvik Heart, Inc., New York, New York). Open-chest epicardial ablation safely and effectively terminated the arrhythmia, without ventricular tachycardia recurrence at 9-month follow-up and in the absence of complications during the hospital stay. (Level of Difficulty: Advanced.)

Minute ventilation/carbon dioxide production in chronic heart failure

In chronic heart failure, minute ventilation (V'_E) for a given carbon dioxide production (V'_CO2 ) might be abnormally high during exercise due to increased dead space ventilation, lung stiffness, chemo- and metaboreflex sensitivity, early metabolic acidosis and abnormal pulmonary haemodynamics. The V'_E versus V'_CO2 relationship, analysed either as ratio or as slope, enables us to evaluate the causes and entity of the V'_E/perfusion mismatch. Moreover, the V'_E axis intercept, i.e. when V'_CO2 is extrapolated to 0, embeds information on exercise-induced dead space changes, while the analysis of end-tidal and arterial CO₂ pressures provides knowledge about reflex activities. The V'_E versus V'_CO2 relationship has a relevant prognostic power either alone or, better, when included within prognostic scores. The V'_E versus V'_CO2 slope is reported as an absolute number with a recognised cut-off prognostic value of 35, except for specific diseases such as hypertrophic cardiomyopathy and idiopathic cardiomyopathy, where a lower cut-off has been suggested. However, nowadays, it is more appropriate to report V'_E versus V'_CO2 slope as percentage of the predicted value, due to age and gender interferences. Relevant attention is needed in V'_E versus V'_CO2 analysis in the presence of heart failure comorbidities. Finally, V'_E versus V'_CO2 abnormalities are relevant targets for treatment in heart failure.

Roles of periodic breathing and isocapnic buffering period during exercise in heart failure

In heart failure, exercise - induced periodic breathing and end tidal carbon dioxide pressure value during the isocapnic buffering period are two features identified at cardiopulmonary exercise testing strictly related to sympathetic activation. In the present review we analysed the physiology behind periodic breathing and the isocapnic buffering period and present the relevant prognostic value of both periodic breathing and the presence/absence of the identifiable isocapnic buffering period.

Cardiac patient care during a pandemic: how to reorganise a heart failure unit at the time of COVID-19

To date, the pandemic spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has involved over 100 countries in a matter of weeks, and Italy suffers from almost 1/3 of the dead cases worldwide.

In this report, we show the strategies adopted to face the emergency at Centro Cardiologico Monzino, a mono-specialist cardiology hospital sited in the region of Italy most affected by the pandemic, and specifically we describe how we have progressively modified in a few weeks the organization of our Heart Failure Unit in order to cope with the new COVID-19 outbreak. In fact, on the background of the pandemic, cardiovascular diseases still occur frequently in the general population, but we observed consistent reduction in hospital admissions for acute cardiovascular events and a dramatic increase of late presentation acute myocardial infarction. Despite a reduction of healthcare workers number, our ward has been rearranged in order to take care of both COVID-19 and cardiovascular patients. In particular according to a triple step procedure we divided admitted patients in confirmed, suspected and excluded cases (respectively allocated in “red”, “pink” and “green” separated areas).

Due to the absence of definite guidelines, our aim was to describe our strategy in facing the current emergency, in order to reorganize our hospital in a dynamic and proactive manner. To quote the famous Italian writer Alessandro Manzoni ‘It is less bad to be agitated in doubt than to rest in error.’

Effects of β2-receptor stimulation by indacaterol in chronic heart failure treated with selective or non-selective β-blockers: a randomized trial

Alveolar β₂-receptor blockade worsens lung diffusion in heart failure (HF). This effect could be mitigated by stimulating alveolar β₂-receptors. We investigated the safety and the effects of indacaterol on lung diffusion, lung mechanics, sleep respiratory behavior, cardiac rhythm, welfare, and exercise performance in HF patients treated with a selective (bisoprolol) or a non-selective (carvedilol) β-blocker. Study procedures were performed before and after indacaterol and placebo treatments according to a cross-over, randomized, double-blind protocol in forty-four patients (27 on bisoprolol and 17 on carvedilol). No differences between indacaterol and placebo were observed in the whole population except for a significantly higher VE/VCO₂ slope and lower maximal P_ETCO₂ during exercise with indacaterol, entirely due to the difference in the bisoprolol group (VE/VCO₂ 31.8 ± 5.9 vs. 28.5 ± 5.6, p < 0.0001 and maximal P_ETCO₂ 36.7 ± 5.5 vs. 37.7 ± 5.8 mmHg, p < 0.02 with indacaterol and placebo, respectively). In carvedilol, indacaterol was associated with a higher peak heart rate (119 ± 34 vs. 113 ± 30 bpm, with indacaterol and placebo) and a lower prevalence of hypopnea during sleep (3.8 [0.0;6.3] vs. 5.8 [2.9;10.5] events/hour, with indacaterol and placebo). Inhaled indacaterol is well tolerated in HF patients, it does not influence lung diffusion, and, in bisoprolol, it increases ventilation response to exercise.

Gender and age normalization and ventilation efficiency during exercise in heart failure with reduced ejection fraction

Aims

Ventilation vs. carbon dioxide production (VE/VCO₂) is among the strongest cardiopulmonary exercise testing prognostic parameters in heart failure (HF). It is usually reported as an absolute value. The current definition of normal VE/VCO₂ slope values is inadequate, since it was built from small groups of subjects with a particularly limited number of women and elderly. We aimed to define VE/VCO₂ slope prediction formulas in a sizable population and to test whether the prognostic power of VE/VCO₂ slope in HF was different if expressed as a percentage of the predicted value or as an absolute value.

Methods and results

We calculated the linear regressions between age and VE/VCO₂ slope in 1136 healthy subjects (68% male, age 44.9 ± 14.5, range 13–83 years). We then applied age‐adjusted and sex‐adjusted formulas to predict VE/VCO₂ slope to HF patients included in the metabolic exercise test data combined with cardiac and kidney indexes score database, which counts 6112 patients (82% male, age 61.4 ± 12.8, left ventricular ejection fraction 33.2 ± 10.5%, peakVO₂ 14.8 ± 4.9, mL/min/kg, VE/VCO₂ slope 32.7 ± 7.7) from 24 HF centres. Finally, we evaluated whether the use of absolute values vs. percentages of predicted VE/VCO₂ affected HF prognosis prediction (composite of cardiovascular mortality + urgent transplant or left ventricular assist device). We did so in the entire cardiac and kidney indexes score population and separately in HF patients with severe (peakVO₂ < 14 mL/min/kg, n = 2919, 61.1 events/1000 pts/year) or moderate (peakVO₂ ≥ 14 mL/min/kg, n = 3183, 19.9 events/1000 pts/year) HF. In the healthy population, we obtained the following equations: female, VE/VCO₂ = 0.052 × Age + 23.808 (r = 0.192); male, VE/VCO₂ = 0.095 × Age + 20.227 (r = 0.371) (P = 0.007). We applied these formulas to calculate the percentages of predicted VE/VCO₂ values. The 2‐year survival prognostic power of VE/VCO₂ slope was strong, and it was similar if expressed as absolute value or as a percentage of predicted value (AUCs 0.686 and 0.690, respectively). In contrast, in severe HF patients, AUCs significantly differed between absolute values (0.637) and percentages of predicted values (0.650, P = 0.0026). Moreover, VE/VCO₂ slope expressed as a percentage of predicted value allowed to reclassify 6.6% of peakVO₂ < 14 mL/min/kg patients (net reclassification improvement = 0.066, P = 0.0015).

Conclusions

The percentage of predicted VE/VCO₂ slope value strengthens the prognostic power of VE/VCO₂ in severe HF patients, and it should be preferred over the absolute value for HF prognostication. Furthermore, the widespread use of VE/VCO₂ slope expressed as percentage of predicted value can improve our ability to identify HF patients at high risk, which is a goal of utmost clinical relevance.

Exercise physiology in pulmonary hypertension patients with and without congenital heart disease

Background

Cardiopulmonary exercise testing allows the assessment of integrative cardiopulmonary response to exercise.

Aims

The aim of the study was to better understand the exercise physiology in pulmonary arterial hypertension related to adult congenital heart disease compared to non-adult congenital heart disease patients by means of cardiopulmonary exercise testing parameters.

Methods

The present is a multicentre retrospective study which includes pulmonary hypertension group 1 and group 4 patients. All subjects underwent full clinical and instrumental evaluation, including cardiopulmonary exercise testing and right heart catheterization.

Results

One hundred and sixty-seven pulmonary hypertension patients (93 women and 74 men, 57 adult congenital heart disease and 110 non-adult congenital heart disease) were enrolled. Adult congenital heart disease patients had higher pulmonary pressure (mean pulmonary arterial pressure: 59.8 ± 19.5 mmHg vs 44.6 ± 16.5 mmHg, p < 0.001) and lower pulmonary blood flow (pulmonary blood flow: 3.3 (2.1–4.3) l/min vs 4.5 (3.8–5.4) l/min, p < 0.001). At cardiopulmonary exercise testing they had lower peak oxygen uptake/kg (12.8 ± 3.8 ml/kg/min vs 15.5 ± 4.2 ml/kg/min, p < 0.001) and higher ventilation/carbon dioxide elimination slope (53.2 (43.3–64.8) vs 44.0 (34.6–51.6), p < 0.001). When patients were paired for gender and peak oxygen uptake ( ± 1 ml/kg/min), obtaining 44 pairs, adult congenital heart disease patients had higher pulmonary pressure (mean pulmonary arterial pressure: 58.4 ± 20.2 mmHg vs 42.8 ± 16.8 mmHg, p < 0.001) and ventilation/carbon dioxide elimination slope (51.2 (43.4–63.6) vs 44.9 (35.4–55.1), p = 0.033).

Conclusions

In pulmonary arterial hypertension-adult congenital heart disease patients, pulmonary pressure and ventilation/carbon dioxide elimination slope are higher compared to non-adult congenital heart disease pulmonary hypertension patients, while pulmonary blood flow and peak oxygen uptake are lower. After matching patients for gender and peak oxygen uptake, pulmonary pressure and ventilation/carbon dioxide elimination remain higher in adult congenital heart disease patients suggesting that the long-term adaptation to high pulmonary pressure, hypoxia and low pulmonary blood flow, as well as a persisting shunt has, at least partially, preserved exercise performance of pulmonary arterial hypertension-adult congenital heart disease patients.

Mineralocorticoid receptor antagonists for heart failure: a real-life observational study

Aims

Mineralocorticoid receptor antagonists (MRAs) have been demonstrated to improve outcomes in reduced ejection fraction heart failure (HFrEF) patients. However, MRAs added to conventional treatment may lead to worsening of renal function and hyperkalaemia. We investigated, in a population‐based analysis, the long‐term effects of MRA treatment in HFrEF patients.

Methods and results

We analysed data of 6046 patients included in the Metabolic Exercise Cardiac Kidney Index score dataset. Analysis was performed in patients treated (n = 3163) and not treated (n = 2883) with MRA. The study endpoint was a composite of cardiovascular death, urgent heart transplantation, or left ventricular assist device implantation. Ten years' survival was analysed through Kaplan–Meier, compared by log‐rank test and propensity score matching.

At 10 years' follow‐up, the MRA‐untreated group had a significantly lower number of events than the MRA‐treated group (P < 0.001). MRA‐treated patients had more severe heart failure (higher New York Heart Association class and lower left ventricular ejection fraction, kidney function, and peak VO₂). At a propensity‐score‐matching analysis performed on 1587 patients, MRA‐treated and MRA‐untreated patients showed similar study endpoint values.

Conclusions

In conclusion, MRA treatment does not affect the composite of cardiovascular death, urgent heart transplantation or left ventricular assist device implantation in a real‐life setting. A meticulous patient follow‐up, as performed in trials, is likely needed to match the positive MRA‐related benefits observed in clinical trials.

Multiparametric prognostic scores in chronic heart failure with reduced ejection fraction: a long-term comparison

AIMS

Risk stratification in heart failure (HF) is crucial for clinical and therapeutic management. A multiparametric approach is the best method to stratify prognosis. In 2012, the Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score was proposed to assess the risk of cardiovascular mortality and urgent heart transplantation. The aim of the present study was to compare the prognostic accuracy of MECKI score to that of HF Survival Score (HFSS) and Seattle HF Model (SHFM) in a large, multicentre cohort of HF patients with reduced ejection fraction.

METHODS AND RESULTS

We collected data on 6112 HF patients and compared the prognostic accuracy of MECKI score, HFSS, and SHFM at 2- and 4-year follow-up for the combined endpoint of cardiovascular death, urgent cardiac transplantation, or ventricular assist device implantation. Patients were followed up for a median of 3.67 years, and 931 cardiovascular deaths, 160 urgent heart transplantations, and 12 ventricular assist device implantations were recorded. At 2-year follow-up, the prognostic accuracy of MECKI score was significantly superior [area under the curve (AUC) 0.781] to that of SHFM (AUC 0.739) and HFSS (AUC 0.723), and this relationship was also confirmed at 4 years (AUC 0.764, 0.725, and 0.720, respectively).

CONCLUSION

In this cohort, the prognostic accuracy of the MECKI score was superior to that of HFSS and SHFM at 2- and 4-year follow-up in HF patients in stable clinical condition. The MECKI score may be useful to improve resource allocation and patient outcome, but prospective evaluation is needed.

Prognostic role of β-blocker selectivity and dosage regimens in heart failure patients. Insights from the MECKI score database

AIMS

The use of β-blockers represents a milestone in the treatment of heart failure with reduced ejection fraction (HFrEF). Few studies have compared β-blockers in HFrEF, and there is little data on the effects of different doses. The present study aimed to investigate in a large database of HFrEF patients (MECKI score database) the association of β-blocker treatment with a composite outcome of cardiovascular death, urgent heart transplantation or left ventricular assist device implantation, addressing the role of β-selectivity and dosage regimens.

METHODS AND RESULTS

In 5242 HFrEF patients, we investigated the role of: (i) β-blocker treatment vs. non-β-blocker treatment, (ii) β1-/β2-receptor-blockers vs. β1-selective blockers, and (iii) daily β-blocker dose. Patients were followed for 3.58 years, and 1101 events (18.3%) were observed; 4435 patients (86.8%) were on β-blockers, while 807 (13.2%) were not. At 5 years, β-blocker-patients showed a better outcome than non-β-blocker-subjects [hazard ratio (HR) 0.48, P < 0.0001], while also considering potential confounders. A comparable prognosis was observed at 5 years in the β1-/β2-receptor-blocker (n = 2219) vs. β1-selective group (n = 2216) (HR 0.95, P = ns). A better prognosis was observed in high-dose (>2 5 mg carvedilol equivalent daily dose, n = 1005) patients than in both medium dose (12.5-25 mg, n = 1431) and low dose (<12.5 mg, n = 1960) (HR 1.97, P < 0.001; HR 1.95, P = 0.001, respectively), with no differences between the last two groups (HR 0.84, P = ns).

CONCLUSION

In a large population of chronic HFrEF patients, β-blockers were associated with a more favourable prognosis without any difference between β1- and β2-receptor-blockers vs. β1-selective blockers. A better outcome was observed in subjects receiving a high daily dose.

Heart failure and anemia: Effects on prognostic variables

BACKGROUND

Anemia is frequent in heart failure (HF), and it is associated with higher mortality. The predictive power of established HF prognostic parameters in anemic HF patients is unknown.

METHODS

Clinical, laboratory, echocardiographic and cardiopulmonary-exercise-test (CPET) data were analyzed in 3913 HF patients grouped according to hemoglobin (Hb) values. 248 (6%), 857 (22%), 2160 (55%) and 648 (17%) patients had very low (<11g/dL), low (11-12 for females, 11-13 for males), normal (12-15 for females, 13-15 for males) and high (>15) Hb, respectively.

RESULTS

Median follow-up was 1363days (606-1883). CPETs were always performed safely. Hb was related to prognosis (Hazard ratio (HR)=0.864). No prognostic difference was observed between normal and high Hb groups. Peak oxygen consumption (VO₂), ventilatory efficiency (VE/VCO₂ slope), plasma sodium concentration, ejection fraction (LVEF), kidney function and Hb were independently related to prognosis in the entire population. Considering Hb groups separately, peakVO₂ (very low Hb HR=0.549, low Hb HR=0.613, normal Hb HR=0.618, high Hb HR=0.542) and LVEF (very low Hb HR=0.49, low Hb HR=0.692, normal Hb HR=0.697, high Hb HR=0.694) maintained their prognostic roles. High VE/VCO₂ slope was associated with poor prognosis only in patients with low and normal Hb.

CONCLUSIONS

Anemic HF patients have a worse prognosis, but CPET can be safely performed. PeakVO₂ and LVEF, but not VE/VCO₂ slope, maintain their prognostic power also in HF patients with Hb<11g/dL, suggesting CPET use and a multiparametric approach in HF patients with low Hb. However, the prognostic effect of an anemia-oriented follow-up is unknown.

Cardiopulmonary evidence of exercise-induced silent ischaemia

BACKGROUND

Exercise-induced ST changes, suggestive of cardiac ischaemia, are found in asymptomatic patients.

METHODS

Gas exchange kinetics were studied during exercise to help to separate patients affected by epicardial coronary disease from those without. Forty-eight patients, without angina symptoms and showing significant changes of ST during exercise, underwent a coronarography and maximal cardiopulmonary exercise test. Thirty-five healthy individuals of matched age and sex underwent a cardiopulmonary exercise test as controls.

RESULTS

Patients were grouped according to the presence (group 1, n = 35) or the absence (group 2, n = 13) of significant coronary lesions at angiography. When corrected for predicted oxygen consumption (VO2) at peak exercise and at anaerobic threshold, results showed a low VO2 at peak exercise and anaerobic threshold in group 1 (68 +/- 19 and 84 +/- 17% of predicted, respectively) compared with normal subjects (91 +/- 19 and 96 +/- 24% of predicted VO2) and group 2 patients (86 +/- 17 and 96 +/- 18%). Also the ischaemic threshold, when normalized for predicted workload at peak exercise, occurred earlier in group 1 (67 +/- 22%) than in group 2 (87 +/- 19%). The time-related (Delta)VO2/Deltawork relationship showed a significant flattening above the anaerobic threshold in group 1 (7.4+/-2.2 versus 9.4+/-1.4 ml/watt per minute, P < 0.01), but not in controls or in group 2. Also the DeltaVO2/Deltawork relationship, above the ischaemic threshold, flattened in group 1, but not in group 2.

CONCLUSION

The suggestion of major coronary disease in patients with exercise-induced ST changes is given by: (i) a flattening of the DeltaVO2/Deltawork relationship, above both the ischaemic and anaerobic thresholds; and (ii) low VO2 values at anaerobic and ischaemic thresholds.

A non invasive estimate of dead space ventilation from exercise measurements

Rationale

During exercise, heart failure patients (HF) show an out-of-proportion ventilation increase, which in patients with COPD is blunted. When HF and COPD coexist, the ventilatory response to exercise is unpredictable.

Objectives

We evaluated a human model of respiratory impairment in 10 COPD-free HF patients and in 10 healthy subjects, tested with a progressive workload exercise with different added dead space. We hypothesized that increased serial dead space upshifts the VE vs. VCO₂ relationship and that the VE-axis intercept might be an index of dead space ventilation.

Measurements

All participants performed a cardiopulmonary exercise test with 0, 250 and 500 mL of additional dead space. Since DS does not contribute to gas exchange, ventilation relative to dead space is ventilation at VCO₂ = 0, i.e. VE-axis intercept. We compared dead space volume, estimated dividing VE-axis intercept by the intercept on respiratory rate axis of the respiratory rate vs. VCO₂ relationship with standard method measured DS.

Main results

In HF, adding dead space increased VE-axis intercept (+0 mL = 4.98±1.63 L; +250 mL = 9.69±2.91 L; +500 mL = 13.26±3.18 L; p<0.001) and upshifted the VE vs.VCO₂ relationship, with a minor slope rise (+0 mL = 27±4 L; +250 = 28±5; +500 = 29±4; p<0.05). In healthy, adding dead space increased VE-axis intercept (+0 mL = 4.9±1.4 L; +250 = 9.3±2.4; +500 = 13.1±3.04; p<0.001) without slope changes. Measured and estimated dead space volumes were similar both in HF and healthy subjects.

Conclusions

VE-axis intercept is related to dead space ventilation and dead space volume can be non-invasively estimated.

Acetazolamide and inhaled carbon dioxide reduce periodic breathing during exercise in patients with chronic heart failure

BACKGROUND

Periodic breathing (PB) during sleep and exercise in heart failure (HF) is related to respiratory acid-base status, CO2 chemosensitivity, and temporal dynamics of CO2 and O2 sensing. We studied inhaled CO2 and acetazolamide to alter these factors and reduce PB.

METHODS AND RESULTS

We measured expired and arterial gases and PB amplitude and duration in 20 HF patients during exercise before and after acetazolamide given acutely (500 mg intravenously) and prolonged (24 hours, 2 g orally), and we performed overnight polysomnography. We studied CO2 inhalation (1%-2%) during constant workload exercise. PB disappeared in 19/20 and 2/7 patients during 2% and 1% CO2. No changes in cardiorespiratory parameters were observed after acute acetazolamide. With prolonged acetazolamide at rest: ventilation +2.04 ± 4.0 L/min (P = .001), tidal volume +0.11 ± 1.13 L (P = .003), respiratory rate +1.24 ± 4.63 breaths/min (NS), end-tidal PO2 +4.62 ± 2.43 mm Hg (P = .001), and end-tidal PCO2 -2.59 ± 9.7 mm Hg (P < .001). At maximum exercise: Watts -10% (P < .02), VO2 -61 ± 109 mL/min (P = .04) and VCO2 101 ± 151 mL/min (P < .02). Among 20 patients, PB disappeared in 1 and 7 subjects after acute and prolonged acetazolamide, respectively. PB was present 80% ± 26, 65% ± 28, and 43% ± 39 of exercise time before and after acute and prolonged acetazolamide, respectively. Overnight apnea/hypopnea index decreased from 30.8 ± 83.8 to 21.1 ± 16.9 (P = .003).

CONCLUSIONS

In HF, inhaled CO2 and acetazolamide reduce exercise PB with additional benefits of acetazolamide on sleep PB.

Alveolar-capillary membrane diffusion measurement by nitric oxide inhalation in heart failure

BACKGROUND

In heart failure, lung diffusion is reduced, it correlates with prognosis and exercise capacity, and it is a therapy target.

DESIGN

Diffusion is measured as CO total diffusion (DL(CO)), which has two components: membrane diffusion (Dm) and capillary volume, the latter related to CO and O2 competition for hemoglobin. DL(CO) needs to be corrected for hemoglobin. Diffusion can also be measured with NO (DL(NO)), which has a very high affinity for hemoglobin, and thus, the resistance of hemoglobin being trivial, it directly represents Dm. Therefore, Dm is directly calculated from DL(NO) through a correction factor. DL(NO) has never been measured in heart failure. The study aims at determining, in heart failure, DL(NO), Dm correction factor, and whether Dm(NO) provides Dm estimates comparable to Dm(CO).

METHODS

We measured DL(CO), Dm(CO) by multi-maneuver Roughton-Forster method, and DL(CO) and DL(NO) by single-breath maneuver in 50 heart failure and 50 healthy subjects.

RESULTS

DL(CO) was 21.9 ± 4.8 ml/mmHg per min and 16.8 ± 5.1 in healthy subjects and heart failure subjects, respectively (p < 0.001). DL(NO) was 88.6 ± 20.5 ml/mmHg per min and 72.5 ± 22.3, respectively (p < 0.001). The correction factors to obtain Dm from DL(NO) were 2.68 (entire population), 2.63 (healthy subjects) and 2.75 (heart failure subjects). Dm(CO) and Dm(NO) were 34.7 ± 10.9 ml/mmHg per min and 33.8 ± 7.6 in healthy subjects and 25.9 ± 2.0 and 26.4 ± 8.1 in heart failure subjects.

CONCLUSIONS

DL(NO) and Dm(NO) measurements are feasible in heart failure. Dm(CO) and Dm(NO) provide comparable results. The correction factor to calculate Dm from DL(NO) in heart failure is 2.75, which is little different from the 2.63 value we observed in healthy subjects.

Multiparametric comparison of CARvedilol, vs. NEbivolol, vs. BIsoprolol in moderate heart failure: the CARNEBI trial

BACKGROUND

Several β-blockers, with different pharmacological characteristics, are available for heart failure (HF) treatment. We compared Carvedilol (β1-β2-α-blocker), Bisoprolol (β1-blocker), and Nebivolol (β1-blocker, NO-releasing activity).

METHODS

Sixty-one moderate HF patients completed a cross-over randomized trial, receiving, for 2 months each, Carvedilol, Nebivolol, Bisoprolol (25.6 ± 12.6, 5.0 ± 2.4 and 5.0 ± 2.4 mg daily, respectively). At the end of each period, patients underwent: clinical evaluation, laboratory testing, echocardiography, spirometry (including total DLCO and membrane diffusion), O2/CO2 chemoreceptor sensitivity, constant workload, in normoxia and hypoxia (FiO2=16%), and maximal cardiopulmonary exercise test.

RESULTS

No significant differences were observed for clinical evaluation (NYHA classification, Minnesota questionnaire), laboratory findings (including kidney function and BNP), echocardiography, and lung mechanics. DLCO was lower on Carvedilol (18.3 ± 4.8*mL/min/mmHg) compared to Nebivolol (19.9 ± 5.1) and Bisoprolol (20.0 ± 5.0) due to membrane diffusion 20% reduction (*=p<0.0001). Constant workload exercise showed in hypoxia a faster VO2 kinetic and a lower ventilation with Carvedilol. Peripheral and central sensitivity to CO2 was lower in Carvedilol while response to hypoxia was higher in Bisoprolol. Ventilation efficiency (VE/VCO2 slope) was 26.9 ± 4.1* (Carvedilol), 28.8 ± 4.0 (Nebivolol), and 29.0 ± 4.4 (Bisoprolol). Peak VO2 was 15.8 ± 3.6*mL/kg/min (Carvedilol), 16.9 ± 4.1 (Nebivolol), and 16.9 ± 3.6 (Bisoprolol).

CONCLUSIONS

β-Blockers differently affect several cardiopulmonary functions. Lung diffusion and exercise performance, the former likely due to lower interference with β2-mediated alveolar fluid clearance, were higher in Nebivolol and Bisoprolol. On the other hand, Carvedilol allowed a better ventilation efficiency during exercise, likely via a different chemoreceptor modulation. Results from this study represent the basis for identifying the best match between a specific β-blocker and a specific HF patient.

Effects of carvedilol on oxygen uptake and heart rate kinetics in patients with chronic heart failure at simulated altitude

Background: The response to moderate exercise at altitude in heart failure (HF) is unknown.

Methods and results: We evaluated 30 HF patients, (NYHA I-III, 25 M/5 F; 59 ± 10 years; LVEF = 39.6 ± 7.1%), in stable clinical conditions, treated with carvedilol at the maximal tolerated dose. We performed a maximal cardiopulmonary exercise test (CPET) with ramp protocol at sea level to evaluate patients’ performance and two moderate intensity constant workload CPETs (50% of peak workload) at sea level (normoxia) and simulated altitude (hypoxia). Oxygen uptake ([Formula: see text]) and heart rate (HR) on-kinetics at constant workload were assessed calculating the time constant (τ) with a monoexponential equation. [Formula: see text] and HR were higher in hypoxia (0.944 ± 0.233 vs 1.031 ± 0.264 l/min; 100 ± 23 vs 108 ± 22 bpm; p < 0.001). On-kinetics showed a different behavior of τ being [Formula: see text] faster in hypoxia (67.1 ± 23.0 vs. 56.3 ± 19.7 s; p = 0.026) and HR faster in normoxia (49.3 ± 19.4 vs. 62.2 ± 22.5 s; p = 0.018). Ten patients, who lowered oxygen kinetics in hypoxia, had greater HR increase during maximal CPET suggesting lower functional betablockade. The higher τ of [Formula: see text] in hypoxia is likely to be due to a peripheral effect of carvedilol mediated either by β- or α-receptor.

Conclusion: HF patients performing moderate exercise at 2000 m simulated altitude have 20% [Formula: see text] increase without trouble at the beginning of exercise when treated with carvedilol.

Chronotropic incompentence and functional capacity in chronic heart failure: no role of β-blockers and β-blocker dose

AIM

To assess the effect of chronotropic incompetence on functional capacity in chronic heart failure (CHF) patients, as evaluated as NYHA and peak oxygen consumption (pVO(2) ), focusing on the presence and dose of β-blocker treatment.

METHODS

Nine hundred and sixty-seven consecutive CHF patients were evaluated, 328 of whom were discarded because they failed to meet the study criteria. Of the 639 analyzed, 90 were not treated with β-blockers whereas the other 549 were. The latter were further subdivided in high (n = 184) and low (n = 365) β-blockers daily dose group in accordance with an arbitrary cut-off of 25 mg for carvedilol and of 5 mg for bisoprolol. Failure to achieve 80% of the percentage of maximum age predicted peak heart rate (%Max PHR) or of HR reserve (%HRR) constituted chronotropic incompetence.

RESULTS

No differences were found in NYHA or pVO2 between patients with and without β-blockers and, similarly, between high and low β-blocker dose groups. Twenty and sixty-nine percent of not β-blocked patients showed chronotropic incompetence according to %Max PHR and %HRR, respectively, whereas this prevalence rose to 61% and 84% in those on β-blocker therapy. Patients taking β-blockers without chronotropic incompetence, as inferable from both %Max PHR and %HRR, showed higher NYHA and pVO2 regardless of drug dose, whereas, in not β-blocked patients, only %HRR revealed a difference in functional capacity. At multivariable analysis, HR increase during exercise (ΔHR) was the variable most strongly associated to pVO2 (β: 0.572; SE: 0.008; P < 0.0001) and NYHA class (β: -0.499; SE: 0.001; P < 0.0001).

CONCLUSIONS

ΔHR is a powerful predictor of CHF severity regardless of the presence of β-blocker therapy and of β-blocker daily dose.

Relationship of resting hemoglobin concentration to peak oxygen uptake in heart failure patients

Anemia is frequent in chronic heart failure (HF). To calculate what change in peak oxygen uptake ( VO(2)) should be expected in the event of changes in hemoglobin concentration, we studied the correlation between peak VO(2) and hemoglobin concentration in a large HF population. We carried out retrospective analysis of all cardiopulmonary exercise tests (CPET) performed in our HF Clinic between June 2001 and March 2009 in HF patients who had a resting hemoglobin concentration measurement taken within 7 days of the CPET. We collected 967 CPETs, 704 tests were considered maximal and analyzed. We identified 181 patients (26%) as anemic. Peak VO(2) was lower (P < 0.001) in anemic patients (971 +/- 23 ml/min) compared with nonanemic (1243 +/- 18 ml/min). The slope of the VO(2) vs. hemoglobin ratio was 109 ml/min/g/dl at peak exercise. This correlation remained significant also when several confounding variables were analyzed by multivariate analysis. As an average, each gram of hemoglobin accounts, at peak exercise, for 109 ml/min change in VO(2) which is equivalent to 0.97 ml/min/kg. Therefore, in HF patients anemia treatment should increase VO(2) by 109 ml/min for each g/dl of hemoglobin increase.