Exercise Oscillatory Breathing and NT-proBNP Levels in Stable Heart Failure Provide the Strongest Prediction of Cardiac Outcome When Combining Biomarkers With Cardiopulmonary Exercise Testing

Combining cardiopulmonary exercise testing with echocardiography: a multiparametric approach to the cardiovascular and cardiopulmonary systems

Exercise intolerance is a prominent feature of several cardiovascular conditions. However, the physical effort requires the intertwined adaptation of several factors, namely the cardiovascular system, the lungs, and peripheral muscles. Several abnormalities in each domain may be present in a given patient. Cardiopulmonary exercise testing (CPET) has been used to investigate metabolic and ventilatory alterations responsible for exercise intolerance but does not allow for direct evaluation of cardiovascular function. However, this can readily be obtained by concomitant exercise-stress echocardiography (ESE). The combined CPET-ESE approach allows for precise and thorough phenotyping of the pathophysiologic mechanisms underpinning exercise intolerance. Thus, it can be used to refine the diagnostic workup of patients with dyspnoea of unknown origin, as well as improve risk stratification and potentially guide the therapeutic approach in specific conditions, including left and right heart failure or valvular heart disease. However, given its hitherto sporadic use, both the conceptual and technical aspects of CPET-ESE are often poorly known by the clinician. Improving knowledge in this field could significantly aid in anticipating individual disease trajectories and tailoring treatment strategies accordingly. Therefore, we designed this review to revise the pathophysiologic correlates of exercise intolerance, the practical principles of the combined CPET-ESE examination, and its main applications according to current literature.

Characterisation of haemodynamic and metabolic abnormalities in the heart failure spectrum: the role of combined cardiopulmonary and exercise echocardiography stress test

Heart failure (HF) is a complex clinical syndrome characterised by different etiologies and a broad spectrum of cardiac structural and functional abnormalities. Current guidelines suggest a classification based on left ventricular ejection fraction (LVEF), distinguishing HF with reduced (HFrEF) from preserved (HFpEF) LVEF. HF should also be thought of as a continuous range of conditions, from asymptomatic stages to clinically manifest syndrome. The transition from one stage to the next is associated with a worse prognosis. While the rate of HF-related hospitalisation is similar in HFrEF and HFpEF once clinical manifestations occur, accurate knowledge of the steps and risk factors leading to HF progression is still lacking, especially in HFpEF. Precise hemodynamic and metabolic characterisation of patients with or at risk of HF may help identify different disease trajectories and risk factors, with the potential to identify specific treatment targets that might offset the slippery slope towards overt clinical manifestations. Exercise can unravel early metabolic and haemodynamic alterations that might be silent at rest, potentially leading to improved risk stratification and more effective treatment strategies. Cardiopulmonary exercise testing (CPET) offers valuable aid to investigate functional alterations in subjects with or at risk of HF, while echocardiography can assess cardiac structure and function objectively, both at rest and during exercise (exercise stress echocardiography, ESE). The purpose of this narrative review is to summarise the potential advantages of using an integrated CPET-ESE evaluation in the characterisation of both subjects at risk of developing HF and patients with stable HF.

Predicting the transition to and progression of heart failure with preserved ejection fraction: a weighted risk score using bio-humoural, cardiopulmonary, and echocardiographic stress testing

AIMS 

Risk stratification of heart failure (HF) patients with preserved ejection fraction (HFpEF) can promote a more personalized treatment. We tested the prognostic value of a multi-parametric evaluation, including biomarkers, cardiopulmonary exercise testing-exercise stress echocardiography (CPET-ESE), and lung ultrasound, in HFpEF patients and subjects at risk of developing HF (HF Stages A and B).

BACKGROUND 

Risk stratification of heart failure (HF) patients with preserved ejection fraction (HFpEF) can promote a more personalized treatment.

DESIGN 

We tested the prognostic value of a multi-parametric evaluation, including biomarkers, cardiopulmonary exercise testing-exercise stress echocardiography (CPET-ESE), and lung ultrasound, in HFpEF patients and subjects at risk of developing HF (HF Stages A and B).

METHODS AND RESULTS 

We performed a resting clinical/bio-humoural evaluation and a symptom-limited CPET-ESE in 274 patients (45 Stage A, 68 Stage B, and 161 Stage C-HFpEF) and 30 age- and sex-matched healthy controls. During a median follow-up of 18.5 months, we reported 71 HF hospitalizations and 10 cardiovascular deaths. Cox proportional-hazards regression identified five independent predictors and each was assigned a number of points proportional to its regression coefficient: stress-rest ΔB-lines >10 (3 points), peak oxygen consumption <16 mL/kg/min (2 points), minute ventilation/carbon dioxide production slope ≥36 (2 points), peak systolic pulmonary artery pressure ≥50 mmHg (1 point) and resting N-terminal pro-brain natriuretic peptide (NT-proBNP) >900 pg/mL (1 point). The event-free survival probability for low risk (<3 points), intermediate risk (3-6 points), and high risk (>6 points) were 93%, 52%, and 20%, respectively. The area under the curve (AUC) for the scoring system to predict events was 0.92 (95% CI 0.88-0.96), with an accuracy significantly higher than the individual components of the score (all P < 0.01 vs. individual AUCs).

CONCLUSION 

A weighted risk score including NT-proBNP, markers of cardiopulmonary dysfunction and indices of exercise-induced pulmonary congestion identifies HFpEF patients at increased risk for adverse events and Stage A and B subjects more likely to progress towards more advanced HF stages.

Exercise chronotropic incompetence phenotypes the level of cardiovascular risk and exercise gas exchange impairment in the general population. An analysis of the Euro-EX prevention trial

BACKGROUND

Chronotropic insufficiency (CI) is defined as the inability of the heart to increase its rate commensurate with increased demand. Exercise CI is an established predictor of major adverse cardiovascular events in patients with cardiovascular diseases.

AIM

The aim of this study was to evaluate how exercise CI phenotypes different levels of cardiovascular risk and how it may better perform in defining cardiovascular risk when analysed in the context of cardiopulmonary exercise test (CPET)-derived measures and standard echocardiography in a healthy population with variable cardiovascular risk profile.

METHODS

Apparently healthy individuals (N = 702, 53.8% females) with at least one major cardiovascular risk factor (MCVRF; hypertension, diabetes, tabagism, dyslipidaemia, body mass index > 25), enrolled in the Euro-EX prevention trial, underwent CPET. CI was defined as the inability to reach 80% of the chronotropic index, that is, the ratio of peak heart rate - rest heart rate/peak heart rate - age predicted maximal heart rate (AMPHR: 220 - age), they were divided into four groups according to the heart rate reserve (<80%>) and respiratory gas exchange ratio (RER; < 1.05>) as a marker of achieved maximal performance. Subjects with a RER < 1.05 (n = 103) were excluded and the final population (n = 599) was divided into CI group (n = 472) and no-CI group (n = 177).

RESULTS

Compared with no-CI, CI subjects were more frequently females with a history of hypertension in a high rate. CI subjects also exhibited a significantly lower peak oxygen uptake (VO₂) and circulatory power and an echocardiographic pattern indicative of higher left atrial volume index and left ventricular mass index. An inverse stepwise relationship between heart rate reserve and number of MCVRFs was observed (one MCVRF: 0.71 ± 0.23; two MCVRFs: 0.68 ± 0.24, three MCVRFs: 0.64 ± 0.20; four MCVRFs: 0.64 ± 0.23; five MCVRFs: 0.57 ± 18; p < 0.01). In multivariate analysis the only variable found predicting CI was peak VO₂ (p < 0.05; odds ratio 0.91; confidence interval 0.85-0.97).

CONCLUSIONS

In a population of apparently healthy subjects, exercise CI is common and phenotypes the progressive level of cardiovascular risk by a tight relationship with MCVRFs. CI patients exhibit some peculiar abnormal exercise gas exchange patterns (lower peak VO₂ and exercise oscillatory ventilation) and echo-derived measures (higher left atrium size and left ventricle mass) that may well anticipate evolution toward heart failure.

Diagnostic Accuracy of NT-ProBNP for Heart Failure with Sepsis in Patients Younger than 18 Years

This clinical study investigated plasma NT-proBNP levels as a potential predictor of heart failure in pediatric patients with sepsis. Plasma NT-ProBNP levels of 211 pediatric patients with sepsis and 126 healthy children were measured. Patients were stratified as with heart failure (HF) or without heart failure (non-HF). Patients were graded as having sepsis, severe sepsis, or septic shock. The optimal cut-off values of plasma NT-ProBNP for heart failure were determined by analyzing the receiver operating characteristic (ROC). In the HF, non-HF and control groups, the median plasma NT-proBNP levels were 3640, 656, and 226 ng/L, respectively. For all patients with sepsis, the optimal diagnostic cut-off value was 1268 ng/L for differentiating heart failure. In the severe sepsis patients and septic shock patients, the optimal diagnostic cut-off values were 1368 ng/L and 1525 ng/L, respectively. This report is the first one to reveal that NT-proBNP may predict heart failure in children with sepsis. It provides an important clinical reference for the diagnosis of heart failure in pediatric patients with sepsis, and enables monitoring septic children for cardiac involvement.

An overview of the applied definitions and diagnostic methods to assess exercise oscillatory ventilation--a systematic review

The variable "exercise oscillatory ventilation" (EOV), assessed during cardiopulmonary exercise test (CPET), recently became a fundamental prognostic parameter in patients with heart failure. In literature, various definitions are suggested, but an uniformly accepted description to identify EOV still lacks. We performed a systematic review of the literature in order to determine the different definitions and diagnostic techniques to assess EOV. A systematic search strategy was established and executed in seven databases (PubMed, Google Scholar, Cochrane Clinical Trials, Science Direct, Pedro, Web Of Science library and Medline (Ovid)) resulting in 605 citations after de-duplication. Full-text articles (n=124) were assessed for eligibility, resulting in 75 citations. The review accounted 17,440 patients of whom 4,638 subjects presented EOV. Seven studies described EOV in a non-heart failure population accounting 168 EOV subjects. The definitions could be categorized in nine subdivisions of which four (n=43) referred to an original description. The other subdivisions were combinations of the original definitions (n=11), quantifications (n=4), computational (n=3), vaguely described (n=8) or not defined (n=6). Symptom limited maximal exercise tests were conducted to assess EOV, however the modes, protocols, software and data sampling were divers. Heterogeneity in the numerous definitions to identify EOV and the vaguely described assessment methods are hindering the evolution to a standardized uniformly accepted definition and technique to identify this abnormal breathing pattern. Unity in definition and international adopted assessment is warranted to strengthen its validity as a prognostic marker and could promote communication. It may facilitate clinical trials on pathophysiology and origin of EOV.

Management of pulmonary hypertension in left heart disease

Pulmonary hypertension (PH) due to left heart disease is classified as group II according to the Dana Point classification, which includes left ventricular systolic and/or diastolic left heart failure, and left-sided valvular disease. PH due to left heart disease is the most common cause and when present, especially with right ventricular dysfunction, is associated with a worse prognosis. Left heart disease with secondary PH is associated with increased left atrial pressure, which causes a passive increase in pulmonary pressure. Passive PH could be superimposed by an active protective, and in some patients by an ‘out of proportion’, elevated precapillary pulmonary vasoconstriction and vascular remodelling which leads to greater or lesser further increase of the pulmonary artery pressure. In this review, epidemiological and pathophysiologic mechanisms for the development of group II PH are summarized. The conflicting data about the haemodynamic and possible parameters to diagnose passive versus reactive and ‘out of proportion’ PH are presented. The different therapeutic concepts, along with novel treatment strategies, are reviewed in detail and critically discussed regarding their effectiveness and safety.

Exercise oscillatory ventilation in heart failure

Irregular breathing characterized by cyclic variation of ventilation with a period of approximately 1 min has been recognized in patients with heart failure for almost two centuries. Periodic breathing during exercise is a noninvasive parameter that is easily recognizable during submaximal cardiopulmonary exercise testing. Recent studies have established that periodic breathing during exercise not only signals significant impairment in resting and exercise hemodynamic parameters but also potently predicts adverse events in heart failure patients. This article reviews the mechanistic basis of periodic breathing and the clinical utility of discerning patterns of irregular breathing in patients with heart failure.