Dynamic trend of lung fluid movement during exercise in heart failure: From lung imaging to alveolar-capillary membrane function

BACKGROUND

In chronic heart failure (HF), exercise-induced increase in pulmonary capillary pressure may cause an increase of pulmonary congestion, or the development of pulmonary oedema. We sought to assess in HF patients the exercise-induced intra-thoracic fluid movements, by measuring plasma brain natriuretic peptide (BNP), lung comets and lung diffusion for carbon monoxide (DLCO) and nitric oxide (DLNO), as markers of hemodynamic load changes, interstitial space and alveolar-capillary membrane fluids, respectively.

METHODS AND RESULTS

Twenty-four reduced ejection fraction HF patients underwent BNP, lung comets and DLCO/DLNO measurements before, at peak and 1 h after the end of a maximal cardiopulmonary exercise test. BNP significantly increased at peak from 549 (328-841) to 691 (382-1207, p < 0.0001) pg/mL and almost completely returned to baseline value 1 h after exercise. Comets number increased at peak from 9.4 ± 8.2 to 24.3 ± 16.7, returning to baseline (9.7 ± 7.4) after 1 h (p < 0.0001). DLCO did not change significantly at peak (from 18.01 ± 4.72 to 18.22 ± 4.73 mL/min/mmHg), but was significantly reduced at 1 h (16.97 ± 4.26 mL/min/mmHg) compared to both baseline (p = 0.0211) and peak (p = 0.0174). DLNO showed a not significant trend toward lower values 1 h post-exercise.

CONCLUSIONS

Moderate/severe HF patients have a 2-step intra-thoracic fluid movement with exercise: the first during active exercise, from the vascular space toward the interstitial space, as confirmed by comets increase, without any effect on diffusion, and the second, during recovery, toward the alveolar-capillary membrane, clearing the interstitial space but worsening gas diffusion.

Exploring the Prognostic Performance of MECKI Score in Heart Failure Patients with Non-Valvular Atrial Fibrillation Treated with Edoxaban

INTRODUCTION

Risk stratification in heart failure (HF) is essential for clinical and therapeutic management. The Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score is a validated prognostic model for assessing cardiovascular risk in HF patients with reduced ejection fraction (HFrEF). From the validation of the score, the prevalence of HF patients treated with direct oral anticoagulants (DOACs), such as edoxaban, for non-valvular atrial fibrillation (NVAF) has been increasing in recent years. This study aims to evaluate the reliability of the MECKI score in HFrEF patients treated with edoxaban for NVAF.

MATERIALS AND METHODS

This study included consecutive outpatients with HF and NVAF treated with edoxaban (n = 83) who underwent a cardiopulmonary exercise test (CPET). They were matched by propensity score with a retrospective group of HFrEF patients with NVAF treated with vitamin K antagonists (VKAs) from the MECKI score registry (n = 844). The study endpoint was the risk of cardiovascular mortality, urgent heart transplantation, or Left Ventricle Assist Device (LVAD) implantation.

RESULTS

Edoxaban patients were treated with a more optimized HF therapy and had different clinical characteristics, with a similar MECKI score. After propensity score, 77 patients treated with edoxaban were successfully matched with the MECKI-VKA control cohort. In both groups, MECKI accurately predicted the composite endpoint with similar area under the curves (AUC = 0.757 vs. 0.829 in the MECKI-VKA vs. edoxaban-treated group, respectively, p = 0.452). The two populations' survival appeared non-significantly different at the 2-year follow-up.

CONCLUSIONS

this study confirms the prognostic accuracy of the MECKI score in HFrEF patients with NVAF treated with edoxaban, showing improved predictive power compared to VKA-treated patients.

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.

Prognostic value of cardiopulmonary exercise testing repetition during follow-up of clinically stable patients with severe dilated cardiomyopathy. A preliminary study

BACKGROUND

Cardiopulmonary exercise testing (CPET) is a recognized tool for prognostic stratification in patients with dilated cardiomyopathy (DCM). Given the lack of data currently available, the aim of this study was to test the prognostic value of repeating CPET during the follow-up of patients with DCM.

METHODS

This multicenter, retrospective study, analyzed DCM patients who consecutively performed two echocardiographies and CPETs during clinical stability. The study end-point was a composite of death from all causes, heart transplantation, left ventricular assist device implantation, life-threatening ventricular arrhythmias or hospitalization for heart failure.

RESULTS

216 DCM patients were enrolled (52 years, 78% male, NYHA I-II 82%, LVEF 32%, 94% on ACE inhibitors/ARNI, 95% on beta-blockers). The interval between CPETs was 15 months. During a median follow-up of 38 months from the second CPET, 102 (47%) patients experienced the study end-point. Among them, there was stability of echocardiographic values but a significant worsening of functional capacity. Among the 173 patients (80%) who did not show echocardiographic left ventricular reverse remodeling (LVRR), the 1-year prevalence of the study-end point was higher in patients who worsened vs patients who maintained stable their functional capacity at CPET (38 vs. 15% respectively, p-value: 0.001). These results were consistent also when excluding life-threatening ventricular arrhythmias from the composite end-point.

CONCLUSION

In clinically stable DCM patients with important depression of LVEF, the repetition of combined echocardiography and CPET might be recommended. When LVRR fails, 1-year repetition of CPET could identify higher-risk 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.

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.

Intrapulmonary distribution of blood flow during exercise in pulmonary hypertension assessed by a new combination technique

Background

Hyperventilation and inadequate cardiac output (CO) increase are the main causes of exercise limitation in pulmonary hypertension (PH). Intrapulmonary blood flow partitioning between ventilated and unventilated lung zones is unknown. Thoracic impedance cardiography and inert gas rebreathing have been both validated in PH patients for non-invasive measurement of CO and pulmonary blood flow (PBF), respectively. This study sought to evaluate CO behaviour in PH patients during exercise and its partitioning between ventilated and unventilated lung areas, in parallel with ventilation partitioning between ventilated and unventilated lung zones.

Methods

Eighteen PH patients (group 1 or 4) underwent a cardiopulmonary exercise test (CPET) with a three-step loaded workload protocol. The steps occurred at 0%, 20%, 40%, and 60% of peak workload reached during a preliminary maximum CPET. Ventilatory parameters, arterial blood gases, CO, PBF, and intrapulmonary shunt (calculated as the difference between CO and PBF) were obtained at each step, combining thoracic impedance cardiography and an inert gas rebreathing technique.

Results

Dead space ventilation observed throughout the exercise was about 40% of total ventilation. A progressive increase of CO from 4.86 ± 1.24 L/min (rest) to 9.41 ± 2.63 L/min (last step), PBF from 3.81 ± 1.41 L/min to 7.21 ± 2.93 L/min, and intrapulmonary shunt from 1.05 ± 0.96 L/min to 2.21 ± 2.28 L/min was observed. Intrapulmonary shunt was approximately 20% of CO at each exercise step.

Conclusions

Although the study population was small, the combined non-invasive CO measurement seems a promising tool for deepening our knowledge of lung exercise haemodynamics in PH patients. This technique could be applied in future studies to evaluate PH treatment influences on CO partitioning, since a secondary increase of intrapulmonary shunt is undesirable.

The Current Role of Cardiopulmonary Exercise Test in the Diagnosis and Management of Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease with a poor prognosis if left untreated. Despite remarkable achievements in understanding disease pathophysiology, specific treatments, and therapeutic strategies, we are still far from a definitive cure for the disease, and numerous evidences have underlined the importance of early diagnosis and treatment to improve the prognosis. Cardiopulmonary exercise testing (CPET) is the gold standard for assessing functional capacity and evaluating the pathophysiological mechanisms underlying exercise limitation. As effort dyspnea is the earliest and one of the main clinical manifestations of PAH, CPET has been shown to provide valid support in early detection, differential diagnosis, and prognostic stratification of PAH patients, being a useful tool in both the first approach to patients and follow-up. The purpose of this review is to present the current applications of CPET in pulmonary hypertension and to propose possible future utilization to be further investigated.

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.

Is red distribution width a valid tool to predict impaired iron transport in heart failure?

Background

Impaired iron transport (IIT) is a form of iron deficiency (ID) defined as transferrin saturation (TSAT) < 20% irrespective of serum ferritin levels. It is frequently observed in heart failure (HF) where it negatively affects prognosis irrespective of anaemia.

Objectives

In this retrospective study we searched for a surrogate biomarker of IIT.

Methods

We tested the predictive power of red distribution width (RDW), mean corpuscular volume (MCV) and mean corpuscular haemoglobin concentration (MCHC) to detect IIT in 797 non-anaemic HF patients.

Results

At ROC analysis, RDW provided the best AUC (0.6928). An RDW cut-off value of 14.2% identified patients with IIT, with positive and negative predictive values of 48 and 80%, respectively. Comparison between the true and false negative groups showed that estimated glomerular filtration rate (eGFR) was significantly higher (p = 0.0092) in the true negative vs. false negative group. Therefore, we divided the study population according to eGFR value: 109 patients with eGFR ≥ 90 ml/min/1.73 m², 318 patients with eGFR 60-89 ml/min/1.73 m², 308 patients with eGFR 30-59 ml/min/1.73 m² and 62 patients with eGFR < 30 ml/min/1.73 m². In the first group, positive and negative predictive values were 48 and 81% respectively, 51 and 85% in the second group, 48 and 73% in the third group and 43 and 67% in the fourth group.

Conclusion

RDW may be seen as a reliable marker to exclude IIT in non-anaemic HF patients with eGFR ≥60 ml/min/1.73 m².

472 PROGNOSTIC VALUE OF CPET REPETITION DURING FOLLOW-UP OF DILATED CARDIOMYOPATHY

Background

although cardiopulmonary exercise testing (CPET) is a recognized tool for prognostic stratification in patients with dilated cardiomyopathy (DCM), there are no data about the prognostic value of its repetition during follow-up in this setting. The aim of this study was to test the prognostic value of repeating CPET during follow-up, among a large cohort of DCM patients.

Methods

in this multicenter, retrospective study, we analyzed DCM patients who consecutively performed at least two CPET during a clinical stable phase of disease. All patients performed CPET and echocardiogram within 10 days. The study end-point was a composite of death from all causes, heart transplantation, implantation of durable left ventricular assist device, life-threatening ventricular arrhythmias or hospitalization for HF.

Results

216 DCM patients were enrolled (52±12 years, 78% male, NYHA I-II 82%, LVEF 32±9%, 94% on ACE inhibitors, 95% on beta-blockers); the duration of the disease at the time of first CPET was 68 months. The interval between the two CPETs was 15 (11;23) months. During a median follow-up of 38 months from the second CPET, 108 (47%) patients went through the end-point. Time-dependent ROC curves revealed that to repeat during a follow-up of 12 months both CPET and echocardiogram gives a more accurate prognostic stratification than basal echocardiography + basal CPET. Despite an higher AUC (0.91 vs 0.85) there were no significant different accuracies (95% CI: 83.6 - 98 vs 75.5–96.5; p-value: 0.2) between the repetition of CPET plus echocardiogram vs. the repetition of the echocardiogram alone. Among patients who experienced the study outcome, there was a substantial stability of echocardiographic values (relative variation of LVEF +2.7%, LVEDV +1.3%) but a significant worsening of functional capacity (relative variation of percentage predicted VO2 peak +6%, p-value: 0.002). Conversely, there were a significant improvement in echocardiographic values and CPET values in events-free patients (LVEF relative variation -8.6% p-value: 0.002; ppVO2 peak relative variation -6.8%, p-value: 0.002).

Conclusion

in a large population of clinically stable DCM patients, the systematic repetition of echocardiography or both CPET and echocardiography showed no significant prognostic impact, in presence of stable or worsened echocardiogram. Nevertheless, when there is a clinical variation of symptoms or a failing in the reverse remodeling process, 1-year repetition of CPET can identify higher risk patients.

ROLE OF CARDIOPULMONARY EXERCISE TEST IN THE PREDICTION OF HEMODYNAMIC IMPAIRMENT IN PATIENTS WITH PULMONARY ARTERIAL HYPERTENSION

Periodic repetition of right heart catheterization (RHC) in pulmonary arterial hypertension (PAH) can be challenging. We evaluated the correlation between RHC and cardiopulmonary exercise test (CPET) aiming at CPET use as a potential noninvasive tool for hemodynamic burden evaluation. One hundred and forty‐four retrospective PAH patients who had performed CPET and RHC within 2 months were enrolled. The following analyses were performed: (a) CPET parameters in hemodynamic variables tertiles; (b) position of hemodynamic parameters in the peak end‐tidal carbon dioxide pressure (P_ETCO₂) versus ventilation/carbon dioxide output (VE/VCO₂) slope scatterplot, which is a specific hallmark of exercise respiratory abnormalities in PAH; (c) association between CPET and a hemodynamic burden score developed including mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), cardiac index, and right atrial pressure. VE/VCO₂ slope and peak P_ETCO₂ significantly varied in mPAP and PVR tertiles, while peak oxygen uptake (peak VO₂) and O₂ pulse varied in the tertiles of all hemodynamic parameters. P_ETCO₂ versus VE/VCO₂ slope showed a strong hyperbolic relationship (R² = 0.7627). Patients with peak P_ETCO₂ > median (26 mmHg) and VE/VCO₂ slope < median (44) presented lower mPAP and PVR (p < 0.005) than patients with peak P_ETCO₂ < median and VE/VCO₂ slope > median. Multivariate analysis individuated peak VO₂ (p = 0.0158) and peak P_ETCO₂ (p = 0.0089) as hemodynamic score independent predictors; the formula 11.584 − 0.0925 × peak VO₂ − 0.0811 × peak P_ETCO₂ best predicts the hemodynamic score value from CPET data. A significant correlation was found between estimated and calculated scores (p < 0.0001), with a precise match for patients with mild‐to‐moderate hemodynamic burden (76% of cases). The results of the present study suggest that CPET could allow to estimate the hemodynamic burden in PAH patients.

Comparison between PtCO2 and PaCO2 and Derived Parameters in Heart Failure Patients during Exercise: A Preliminary Study

Evaluation of arterial carbon dioxide pressure (PaCO2) and dead space to tidal volume ratio (VD/VT) during exercise is important for the identification of exercise limitation causes in heart failure (HF). However, repeated sampling of arterial or arterialized ear lobe capillary blood may be clumsy. The aim of our study was to estimate PaCO2 by means of a non-invasive technique, transcutaneous PCO2 (PtCO2), and to verify the correlation between PtCO2 and PaCO2 and between their derived parameters, such as VD/VT, during exercise in HF patients. 29 cardiopulmonary exercise tests (CPET) performed on a bike with a ramp protocol aimed at achieving maximal effort in ≈10 min were analyzed. PaCO2 and PtCO2 values were collected at rest and every 2 min during active pedaling. The uncertainty of PCO2 and VD/VT measurements were determined by analyzing the error between the two methods. The accuracy of PtCO2 measurements vs. PaCO2 decreases towards the end of exercise. Therefore, a correction to PtCO2 that keeps into account the time of the measurement was implemented with a multiple regression model. PtCO2 and VD/VT changes at 6, 8 and 10 min vs. 2 min data were evaluated before and after PtCO2 correction. PtCO2 overestimates PaCO2 for high timestamps (median error 2.45, IQR -0.635-5.405, at 10 min vs. 2 min, p-value = 0.011), while the error is negligible after correction (median error 0.50, IQR = -2.21-3.19, p-value > 0.05). The correction allows removing differences also in PCO2 and VD/VT changes. In HF patients PtCO2 is a reliable PaCO2 estimation at rest and at low exercise intensity. At high exercise intensity the overall response appears delayed but reproducible and the error can be overcome by mathematical modeling allowing an accurate estimation by PtCO2 of PaCO2 and VD/VT.

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.

Role of comorbidities in heart failure prognosis Part 2: Chronic kidney disease, elevated serum uric acid

Despite improvements in pharmacotherapy, morbidity and mortality rates in community-based populations with chronic heart failure still remain high. The increase in medical complexity among patients with heart failure may be reflected by an increase in concomitant non-cardiovascular comorbidities, which are recognized as independent prognostic factors in this population. Heart failure and chronic kidney disease share many risk factors, and often coexist. The presence of kidney failure is associated with incremented risk of cardiovascular and non-cardiovascular mortality in heart failure patients. Chronic kidney disease is also linked with underutilization of evidence-based heart failure therapy that may reduce morbidity and mortality. More targeted therapies would be important to improve the prognosis of patients with these diseases. In recent years, serum uric acid as a determinant of cardiovascular risk has gained interest. Epidemiological, experimental and clinical data show that patients with hyperuricaemia are at increased risk of cardiac, renal and vascular damage and cardiovascular events. Moreover, elevated serum uric acid predicts worse outcome in both acute and chronic heart failure. While studies have raised the possibility of preventing heart failure through the use of uric acid lowering agents, the literature is still inconclusive on whether the reduction in uric acid will result in a measurable clinical benefit. Available evidences suggest that chronic kidney disease and elevated uric acid could worsen heart failure patients' prognosis. The aim of this review is to analyse a possible utilization of these comorbidities in risk stratification and as a therapeutic target to get a prognostic improvement in heart failure patients.

Right Ventricular Strain Curve Morphology and Outcome in Idiopathic Pulmonary Arterial Hypertension

OBJECTIVES

The purpose of this study was to explore speckle tracking echocardiographic right ventricular (RV) post-systolic strain patterns and their clinical relevance in idiopathic pulmonary arterial hypertension (PAH).

BACKGROUND

The imaging of RV diastolic function in PAH remains incompletely understood.

METHODS

Speckle tracking echocardiography of RV post-systolic strain recordings were examined in 108 consecutive idiopathic patients with PAH. Each of them underwent baseline clinical, hemodynamic, and complete echocardiographic evaluation and follow-up.

RESULTS

In total, 3 post-systolic strain patterns derived from the mid-basal RV free wall segments were identified. Pattern 1 was characterized by prompt return of strain-time curves to baseline after peak systolic negativity, like in normal control subjects. Pattern 2 was characterized by persisting negativity of strain-time curves well into diastole, before an end-diastolic returning to baseline. Pattern 3 was characterized by a slow return of strain-time curves to baseline during diastole. The 3 patterns corresponded respectively to mild PH, more advanced PH but with still preserved RV function, and PH with obvious end-stage right heart failure. Patterns were characterized by optimal reproducibility when complementary to quantitative measurement of right ventricular longitudinal early diastolic strain rate (RVLSR-E), and right ventricular longitudinal late diastolic strain rate (RVLSR-A) (Cohen's κ = 0.88; p = 0.0001). Multivariable models for clinical worsening prediction demonstrated that the addition of RV post-systolic patterns to clinical and hemodynamic variables significantly increased their prognostic power (0.78 vs. 0.66; p < 0.001). Freedom from clinical worsening rates at 1 and 2 years from baseline were, respectively, 100% and 93% for Pattern 1; 80% and 55% for Pattern 2; and 60% and 33% for Pattern 3.

CONCLUSIONS

Speckle tracking echocardiography allows for the identification of 3 phenotypically distinct, reproducible, and clinically meaningful RV strain-derived post-systolic patterns.

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.’

Non-invasive estimation of stroke volume during exercise from oxygen in heart failure patients

AIMS

In heart failure, oxygen uptake and cardiac output measurements at peak and during exercise are important in defining heart failure severity and prognosis. Several cardiopulmonary exercise test-derived parameters have been proposed to estimate stroke volume during exercise, including the oxygen pulse (oxygen uptake/heart rate). Data comparing measured stroke volume and the oxygen pulse or stroke volume estimates from the oxygen pulse at different stages of exercise in a sizeable population of healthy individuals and heart failure patients are lacking.

METHODS

We analysed 1007 subjects, including 500 healthy and 507 heart failure patients, who underwent cardiopulmonary exercise testing with stroke volume determination by the inert gas rebreathing technique. Stroke volume measurements were made at rest, submaximal (∼50% of exercise) and peak exercise. At each stage of exercise, stroke volume estimates were obtained considering measured haemoglobin at rest, predicted exercise-induced haemoconcentration and peripheral oxygen extraction according to heart failure severity.

RESULTS

A strong relationship between oxygen pulse and measured stroke volume was observed in healthy and heart failure subjects at submaximal (R2 = 0.6437 and R2 = 0.6723, respectively), and peak exercise (R2 = 0.6614 and R2 = 0.5662) but not at rest. In healthy and heart failure subjects, agreement between estimated and measured stroke volume was observed at submaximal (-3 ± 37 and -11 ± 72 ml, respectively) and peak exercise (1 ± 31 and 6 ± 29 ml, respectively) but not at rest.

CONCLUSION

In heart failure patients, stroke volume estimation and oxygen pulse during exercise represent stroke volume, albeit with a relevant individual data dispersion so that both can be used for population studies but cannot be reliably applied to a single subject. Accordingly, whenever needed stroke volume must be measured directly.

Clinical implications of idiopathic pulmonary arterial hypertension phenotypes defined by cluster analysis

BACKGROUND

>Despite advances in drug development, life expectancy in idiopathic pulmonary arterial hypertension (IPAH) remains unacceptable. Contemporary IPAH characterization is based on criteria that may not adequately capture disease heterogeneity and may be proposed as a possible explanation for why patient outcome is still unfavorable. The aim of this study was to apply cluster analysis to improve phenotyping of patients with IPAH and analyze long-term clinical outcome of derived clusters.

METHODS

Patients with IPAH from 2 referral centers (n = 252) were evaluated with clinical, hemodynamic, and echocardiographic assessment and cardiopulmonary exercise test. Patients were classified according to cluster analysis and followed for clinical worsening occurrence.

RESULTS

The cluster analysis identified 4 IPAH phenotypes. Cluster 1 was characterized by young patients, mild pulmonary hypertension (PH), mild right ventricular (RV) dilation and high oxygen (O₂) pulse; Cluster 2 by severe PH and RV dilation and high O₂ pulse; and Cluster 3 by male patients, severe PH and RV dilation, and low O₂ pulse. Cluster 4 patients were older and overweight, with mild PH and RV dilation and low O₂ pulse. After a mean follow-up of 995 ± 623 days, 123 (48.8%) patients had clinical worsening. Cluster 1 patients presented the best prognosis, whereas Cluster 3 had the highest rates of clinical worsening. Compared with Cluster 1, risk of clinical worsening ranged from 4.12 (confidence interval [CI] 1.43-11.92; p = 0.009) for Cluster 4 to 7.38 (CI 2.80-19.40) for Cluster 2 and 13.8 (CI 5.60-34.0; p = 0.0001) for Cluster 3.

CONCLUSIONS

Cluster analysis of clinical variables identified 4 distinct phenotypes of IPAH. Our findings underscore the high degree of disease heterogeneity that exists within patients with IPAH and the need for advanced clinical testing to define phenotypes to improve treatment strategy decision-making. CONDENSED ABSTRACT Idiopathic pulmonary arterial hypertension (IPAH) characterization is based on criteria that may not adequately capture disease heterogeneity. The aim of this study was to apply cluster analysis to improve phenotyping of IPAH. Patients with IPAH (n = 252) were evaluated with clinical, hemodynamic, and echocardiographic assessment and cardiopulmonary exercise test. Within the umbrella category of IPAH, it was the combination of mean pulmonary arterial pressure, right ventricular size, and oxygen pulse that further stratified patients into novel IPAH phenotypes that significantly associate with clinical worsening. These findings underscore the need for novel multidimensional IPAH phenotyping for improved patient care and trial quality.

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.

Decreased pulmonary vascular distensibility in adolescents conceived by in vitro fertilization

STUDY QUESTION

What is the functional relevance of decreased pulmonary vascular distensibility in adolescents conceived by IVF?

SUMMARY ANSWER

Children born by IVF have a slight decrease in pulmonary vascular distensibility observed during normoxic exercise that is not associated with altered right ventricular function and aerobic exercise capacity.

WHAT IS KNOWN ALREADY

General vascular dysfunction and increased hypoxic pulmonary hypertension have been reported in ART children as compared to controls. Pulmonary hypertension or decreased pulmonary vascular distensibility may affect right ventricular function and thereby possibly limit maximal cardiac output and aerobic exercise capacity.

STUDY DESIGN, SIZE, DURATION

This prospective case-control study enrolled 15 apparently healthy adolescents conceived by IVF/ICSI after fresh embryo transfer paired in a 2 to 1 ratio to 30 naturally conceived adolescents between March 2015 and May 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Fifteen IVF/ICSI adolescents and 30 controls from singleton gestations matched by age, gender, weight, height and physical activity underwent exercise echocardiography, lung diffusion capacity measurements and a cycloergometer cardiopulmonary exercise test. A pulmonary vascular distensibility coefficient α was determined from the pulmonary arterial pressure (PAP) versus cardiac output (Q) relationships. Pulmonary capillary volume (Vc) was calculated from single breath nitric oxide and carbon monoxide lung diffusion capacity measurements (DLCO and DLNO) at rest and during exercise (100 W). Eight of the IVF subjects and eight controls underwent a 30 min hypoxic challenge at rest with a fraction of inspired oxygen of 0.12 to assess hypoxic pulmonary vasoconstriction.

MAIN RESULTS AND THE ROLE OF CHANCE

In normoxia, oxygen uptake (VO2), blood pressure, DLCO, DLNO, echocardiographic indices of right ventricular function, Q and PAP at rest and during exercise were similar in both groups. However, IVF children had a lower pulmonary vascular distensibility coefficient α (1.2 ± 0.3 versus 1.5 ± 0.3%/mmHg, P = 0.02) and a blunted exercise-induced increase in Vc (24 versus 32%, P < 0.05). Hypoxic-induced increase in pulmonary vascular resistance in eight IVF subjects versus eight controls was similar.

LIMITATIONS, REASONS FOR CAUTION

The IVF cohort was small, and thus type I or II errors could have occurred in spite of careful matching of each case with two controls. ART evolved over the years, so that it is not certain that the presently reported subtle changes will be reproducible in the future. As the study was limited to singletons born after fresh embryo transfers, our observations cannot be extrapolated to singletons born after frozen embryo transfer.

WIDER IMPLICATIONS OF THE FINDINGS

The present study suggests that adolescents conceived by IVF have preserved right ventricular function and aerobic exercise capacity despite a slight alteration in pulmonary vascular distensibility as assessed by two entirely different methods, i.e. exercise echocardiography and lung diffusing capacity measurements. However, the long-term prognostic relevance of this slight decrease in pulmonary vascular distensibility needs to be evaluated in prospective large scale and long-term outcome studies.

STUDY FUNDING/COMPETING INTEREST(S)

Dr Caravita was supported by an ERS PAH short term research training fellowship (STRTF2014-5264). Dr Pezzuto was funded by an Italian Society of cardiology grant. Dr Motoji was supported by a grant from the Cardiac Surgery Funds, Belgium. All authors have no conflicts of interests to declare.

Do rebreathing manoeuvres for non-invasive measurement of cardiac output during maximum exercise test alter the main cardiopulmonary parameters?

Background

Inert gas rebreathing has been recently described as an emergent reliable non-invasive method for cardiac output determination during exercise, allowing a relevant improvement of cardiopulmonary exercise test clinical relevance. For cardiac output measurements by inert gas rebreathing, specific respiratory manoeuvres are needed which might affect pivotal cardiopulmonary exercise test parameters, such as exercise tolerance, oxygen uptake and ventilation vs carbon dioxide output (VE/VCO2) relationship slope.

Method

We retrospectively analysed cardiopulmonary exercise testing of 181 heart failure patients who underwent both cardiopulmonary exercise testing and cardiopulmonary exercise test+cardiac output within two months (average 16 ± 15 days). All patients were in stable clinical conditions (New York Heart Association I–III) and on optimal medical therapy.

Results

The majority of patients were in New York Heart Association Class I and II (78.8%), with a mean left ventricular ejection fraction of 31 ± 10%. No difference was found between the two tests in oxygen uptake at peak exercise (1101 (interquartile range 870–1418) ml/min at cardiopulmonary exercise test vs 1103 (844–1389) at cardiopulmonary exercise test-cardiac output) and at anaerobic threshold. However, anaerobic threshold and peak heart rate, peak workload (75 (58–101) watts and 64 (42–90), p < 0.01) and carbon dioxide output were significantly higher at cardiopulmonary exercise testing than at cardiopulmonary exercise test+cardiac output, whereas VE/VCO2 slope was higher at cardiopulmonary exercise test+cardiac output (30 (27–35) vs 33 (28–37), p < 0.01).

Conclusion

The similar anaerobic threshold and peak oxygen uptake in the two tests with a lower peak workload and higher VE/VCO2 slope at cardiopulmonary exercise test+cardiac output suggest a higher respiratory work and consequent demand for respiratory muscle blood flow secondary to the ventilatory manoeuvres. Accordingly, VE/VCO2 slope and peak workload must be evaluated with caution during cardiopulmonary exercise test+cardiac output.

Isocapnic buffering period: From physiology to clinics

Background

During cardiopulmonary exercise test, the isocapnic buffering period ranges between anaerobic threshold (AT) and respiratory compensation point (RCP). We investigated whether oxygen uptake (VO2) increase during the isocapnic buffering period (ΔVO2AT-RCP) is related to heart failure severity and prognosis.

Methods

We retrospectively analysed reduced ejection fraction heart failure patients who attained RCP at cardiopulmonary exercise test. The study endpoint was the composite of cardiovascular mortality and urgent heart transplantation/left ventricular assist device implantation. Hazard ratio was assessed to identify the increase of risk associated with ΔVO2AT-RCP (below and above the median of ΔVO2AT-RCP).

Results

AT and RCP were both identified in 782 (39.2%) out of 1995 reduced ejection fraction heart failure cases. Left ventricular ejection fraction and peak VO2 were 33 ± 9% and 16.5 ± 4.5 mL/kg per min (61 ± 16% of predicted value), suggesting moderate heart failure. At five years, endpoint did not vary between patients below and above the median ΔVO2AT-RCP (3.85 mL/min per kg (25–75th interquartile range = 2.69–5.46)). ΔVO2AT-RCP correlated with several parameters associated to heart failure prognosis, such as peak VO2, VE/VCO2 slope, brain natriuretic peptide and left ventricular ejection fraction. The ΔVO2AT-RCP value was associated with prognosis at univariate but not at multivariable analysis, where only VE/VCO2 slope endured.

Conclusion

ΔVO2AT-RCP correlates with several parameters linked to heart failure severity. Isocapnic buffering period stratifies heart failure patients, but not more than other prognostic indices.

The added value of cardiopulmonary exercise testing in the follow-up of pulmonary arterial hypertension

BACKGROUND

The added value of cardiopulmonary exercise testing (CPET) in the follow-up of patients with stable pulmonary arterial hypertension (PAH) remains undefined.

METHODS

Idiopathic, heritable, and drug-induced PAH patients free from clinical worsening (CW) after 1 year of treatment were enrolled in derivation (n = 80) and validation (n = 80) cohorts at an interval of 6 years and followed for 3 years. Prognostic models were constructed and validated in low-risk patients in World Health Organization (WHO) Functional Class I or II with cardiac index (CI) ≥2.5 liters/min/m² and right atrial pressure (RAP) <8 mm Hg. Discrimination and calibration were assessed.

RESULTS

Forty-one derivation cohort patients had CW (51.2%) during 722 ± 349 days. Changes (∆) in WHO classification and CI and absolute value of RAP were independent predictors of CW. With addition of CPET variables, peak oxygen uptake (VO₂ peak) and ∆CI independently improved the power of the prognostic model. Receiver operating characteristic (ROC)-derived cut-off values for ∆CI and VO₂ peak were 0.40 liter/min/m² and 15.7 ml/kg/min (≥60% predicted value), respectively. Twenty-nine validation cohort patients had CW (36.2%) during 710 ± 282 days. Different combinations of cut-off values of VO₂ peak and ∆CI defined 4 groups. The event-free survival rates at 1, 2, and 3 years were 100%, 100%, and 100%, respectively, for the high ∆CI with high VO₂ peak combination; 100%, 88%, and 71% for low ∆CI/high VO₂ peak; 80%, 54%, and 40% for high ∆CI/low VO₂ peak; and 72%, 54%, and 33% for low ∆CI/low VO₂ peak.

CONCLUSIONS

The combinations of baseline VO₂ peak and change in CI during follow-up is important in prognostication of low-risk patients with idiopathic, heritable, and drug-induced PAH.

The importance of right ventricular function in patients with pulmonary arterial hypertension

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a progressive, life-threatening, and incurable disease. Its prognosis is based on right ventricular (RV) function. Therefore, adequate assessment of RV function is mandatory. Areas covered: This article presents the case of a patient with PAH in which the traditional diagnostic approach did not provide a complete assessment of RV function. The authors show how the analysis of other parameters yielded additional information that improved the management of this patient. Expert commentary: Despite current treatments, PAH often worsens due to progressive RV dysfunction. Appropriate assessment of RV function may facilitate the early identification of patients at risk of RV function impairment. More aggressive treatment of PAH might delay progression of the disease. Traditional risk stratification, which is based on New York Heart Association/World Health Organization (NYHA/WHO) functional class evaluation, the 6-minute walk test, and right heart catheterization, proves insufficient in many PAH patients, as it does not provide complete information about RV function. Thus, further parameters are required. Analysis of RV function, in addition to echocardiography and cardiopulmonary exercise testing, may add relevant prognostic information and improve therapy.

Right ventricular dyssynchrony during hypoxic breathing but not during exercise in healthy subjects: a speckle tracking echocardiography study

NEW FINDINGS

What is the central question of this study? Right ventricular dyssynchrony in severe pulmonary hypertension is associated with a poor prognosis. However, it has recently been observed in patients with lung or connective tissue disease and pulmonary artery pressure at the upper limits of normal. The mechanisms of right ventricular dyssynchrony in pulmonary hypertension remain uncertain. What is the main finding and its importance? Acute hypoxic breathing, but not normoxic exercise, induces an increase in right ventricular dyssynchrony detected by speckle tracking echocardiography in healthy subjects. These results add new insights into the determinants of right ventricular dyssynchrony, suggesting a role for systemic factors added to afterload in the pathophysiology of right ventricular inhomogeneity of contraction.

ABSTRACT

Pulmonary hypertension (PH) has been shown to be associated with regional inhomogeneity (or dyssynchrony) of right ventricular (RV) contraction. Right ventricular dyssynchrony is an independent predictor of decreased survival in advanced PH, but has also been reported in patients with only mildly elevated pulmonary artery pressure (PAP). The mechanisms of RV dyssynchrony in PH remain uncertain. Our aim was to evaluate RV regional function in healthy subjects during acute hypoxia and during exercise. Seventeen healthy subjects (24 ± 6 years) underwent a speckle tracking echocardiography of the RV at rest in normoxia and every 15 min during a 60 min exposure to hypoxic breathing ( F I O 2 12%). Ten of the subjects also underwent an incremental cycle ergometry in normoxia to 100 W, with the same echocardiographic measurements. Dyssynchrony was measured as the SD of the times to peak systolic strain of the four basal and mid RV segments corrected for the heart rate (RV-SD4). RV-SD4 increased during hypoxia from 12 ± 7 to 22 ± 11 ms in spite of mild increases in mean PAP (mPAP) from 15 ± 2 to 20 ± 2 mmHg and pulmonary vascular resistance (PVR) from 1.18 ± 0.15 to 1.4 ± 0.15 Wood units (WU). During exercise RV-SD4 did not significantly change (from 12 ± 6 ms to 14 ± 6 ms), while mPAP increased to 25 ± 2 mmHg and PVR was unchanged. These data show that in healthy subjects, RV contraction is inhomogeneous in hypoxia but not during exercise. Since PAP increases more during exercise, RV dyssynchrony in hypoxia may be explained by a combination of mechanical (RV afterload) and systemic (hypoxia) factors.

[Oral combination therapy for the treatment of patients with pulmonary arterial hypertension: what evidence from long-term studies?]

The introduction of specific drugs for the treatment of pulmonary arterial hypertension over the last 20 years has led to an improvement of clinical and hemodynamic conditions and prognosis of affected patients. The use of combination therapy has made it possible to act simultaneously on several biological pathways involved in the etiopathogenesis of the disease. However, although the diagnosis and management have radically changed in recent years, the disease remains progressive and often fatal. The purpose of this paper is to review and discuss the results of the main clinical trials and the future perspectives of combination strategies for the treatment of pulmonary arterial hypertension.

Prognostic relevance of right heart reverse remodeling in idiopathic pulmonary arterial hypertension

BACKGROUND

Right ventricular (RV) failure is a major determinant of symptoms and shortened survival in pulmonary arterial hypertension (PAH). This study assessed the prognostic relevance of increased right heart (RH) dimensions determined by echocardiography and RH reverse remodeling (RHRR) with targeted therapies in idiopathic PAH (IPAH).

METHODS

The study prospectively monitored 102 therapy-naïve IPAH patients for the presence of clinical worsening. Baseline evaluation included RH catheterization and echocardiography. RHRR at the 1-year follow-up was defined by a decrease in RV end-diastolic area, right atrial area, and the left ventricular systolic eccentricity index.

RESULTS

At the 1-year follow-up, 18 of 102 patients (17.6%) presented with RHRR. A decrease in pulmonary vascular resistance was the only independent determinant of RHRR. The 94 surviving patients were monitored for 995 ± 529 days. RHRR was an independent prognostic factor and significantly improved the power of the prognostic model based on traditional clinical and hemodynamic parameters. The respective event-free survival rates at 1, 3, and 5 years were 94%, 94%, and 94% in patients with RHRR and 75%, 55%, and 24% in those without RHRR (p = 0.0001). Interestingly, RHRR was able to further stratify patients' risk assessment through the Registry to Evaluate Early And Long-term PAH Disease Management risk score.

CONCLUSIONS

RHRR after 1 year of treatment is an independent predictor of prognosis in IPAH. The likelihood of RHRR is proportional to decreased pulmonary vascular resistance.

Prognostic relevance of right heart reverse remodeling in idiopathic pulmonary arterial hypertension

BACKGROUND

Right ventricular (RV) failure is a major determinant of symptoms and shortened survival in pulmonary arterial hypertension (PAH). This study assessed the prognostic relevance of increased right heart (RH) dimensions determined by echocardiography and RH reverse remodeling (RHRR) with targeted therapies in idiopathic PAH (IPAH).

METHODS

The study prospectively monitored 102 therapy-naïve IPAH patients for the presence of clinical worsening. Baseline evaluation included RH catheterization and echocardiography. RHRR at the 1-year follow-up was defined by a decrease in RV end-diastolic area, right atrial area, and the left ventricular systolic eccentricity index.

RESULTS

At the 1-year follow-up, 18 of 102 patients (17.6%) presented with RHRR. A decrease in pulmonary vascular resistance was the only independent determinant of RHRR. The 94 surviving patients were monitored for 995 ± 529 days. RHRR was an independent prognostic factor and significantly improved the power of the prognostic model based on traditional clinical and hemodynamic parameters. The respective event-free survival rates at 1, 3, and 5 years were 94%, 94%, and 94% in patients with RHRR and 75%, 55%, and 24% in those without RHRR (p = 0.0001). Interestingly, RHRR was able to further stratify patients' risk assessment through the Registry to Evaluate Early And Long-term PAH Disease Management risk score.

CONCLUSIONS

RHRR after 1 year of treatment is an independent predictor of prognosis in IPAH. The likelihood of RHRR is proportional to decreased pulmonary vascular resistance.

Right ventricular dyssynchrony and exercise capacity in idiopathic pulmonary arterial hypertension

Survival in patients with pulmonary arterial hypertension (PAH) is determined by right ventricular (RV) function adaptation to afterload. How altered RV function impacts on exercise capacity in PAH is not exactly known.

104 idiopathic PAH (IPAH) patients aged 52±14 years underwent a diagnostic right heart catheterisation, a comprehensive echocardiography including two-dimensional speckle tracking for RV dyssynchrony evaluation and a cardiopulmonary exercise test. Multivariate analyses were performed to identify independent predictors of peak oxygen uptake (peakV′O2).

A first multivariate analysis of only resting haemodynamic variables identified cardiac index, right atrial (RA) pressure and pulmonary arterial compliance as independent predictors, with low predictive capacity (r2=0.31; p<0.001). A second multivariate analysis model which considered only echocardiographic parameters but without RV dyssynchrony, identified RV fractional area change (FAC) and RA area as independent predictors with still low predictivity (r2=0.35; p<0.001). Adding RV dyssynchrony to the second model increased its predictivity (r2=0.48; p<0.001). Repetition of the three multivariate analyses in patients with preserved RVFAC confirmed that inclusion of RV dyssynchrony results in the highest predictive capability of peakV′O2(r2=0.53; p=0.001).

A comprehensive echocardiography with speckle tracking-derived assessment of the heterogeneity of RV contraction improves the prediction of aerobic exercise capacity in IPAH.

Echocardiography Combined With Cardiopulmonary Exercise Testing for the Prediction of Outcome in Idiopathic Pulmonary Arterial Hypertension

BACKGROUND

Right ventricular (RV) function is a major determinant of exercise intolerance and outcome in idiopathic pulmonary arterial hypertension. The aim of the study was to evaluate the incremental prognostic value of echocardiography of the right ventricle and cardiopulmonary exercise testing (CPET) on long-term prognosis in these patients.

METHODS

One hundred and thirty treatment-naïve patients with idiopathic pulmonary arterial hypertension were enrolled and prospectively followed. Clinical worsening (CW) was defined by a reduction in 6-min walk distance plus an increase in functional class, or nonelective hospitalization for PAH, or death. Baseline evaluation included clinical, hemodynamic, echocardiographic, and CPET variables. Cox regression modeling with c-statistic and bootstrapping validation methods were done.

RESULTS

During a mean period of 528 ± 304 days, 54 patients experienced CW (53%). Among demographic, clinical, and hemodynamic variables at catheterization, functional class and cardiac index were independent predictors of CW (model 1). With addition of echocardiographic and CPET variables (model 2), peak O₂ pulse (peak V˙o₂/heart rate) and RV fractional area change (RVFAC) independently improved the power of the prognostic model (area under the curve, 0.81 vs 0.66, respectively; P = .005). Patients with low RVFAC and low O₂ pulse (low RVFAC + low O₂ pulse) and high RVFAC + low O₂ pulse showed a 99.8 and 29.4 increase in the hazard ratio, respectively (relative risk, 41.1 and 25.3, respectively), compared with high RVFAC + high O₂ pulse (P = .0001).

CONCLUSIONS

Echocardiography combined with CPET provides relevant clinical and prognostic information. A combination of low RVFAC and low O₂ pulse identifies patients at a particularly high risk of clinical deterioration.

Right ventricular dyssynchrony in idiopathic pulmonary arterial hypertension: determinants and impact on pump function

BACKGROUND

Right ventricular (RV) dyssynchrony has been described in pulmonary arterial hypertension (PAH), but no evidence is available on its morphologic determinants and its effect on systolic function. The aim of this study was to evaluate the morphologic determinants of RV dyssynchrony by echocardiographic and cardiac magnetic resonance imaging and its effect on systolic function.

METHODS

In 60 consecutive idiopathic PAH (IPAH) patients with narrow QRS, RV dyssynchrony was evaluated by 2D speckle-tracking echocardiography, calculating the standard deviation of the times to peak systolic strain for the four mid-basal RV segments (RV-SD4). Patients were grouped by the median value of RV-SD4 (19 milliseconds) and compared for RV remodeling and systolic function parameters, WHO class, pulmonary hemodynamics and 6-minute walk test (6MWT).

RESULTS

Despite similar pulmonary vascular resistance and mean pulmonary arterial pressure, patients with RV-SD4 at >19 milliseconds had advanced WHO class and worse 6MWT, RV hemodynamics, RV remodeling and systolic function parameters compared with patients at ≤19 milliseconds. The morphologic determinants of RV dyssynchrony resulted RV end-diastolic area, LV diastolic eccentricity index and RV mass volume ratio (r = 0.69, r(2) = 0.47, p < 0.0001). Finally, we found a significant inverse correlation between RV mid-basal segments post-systolic shortening time and cardiac index (r = -0.64, r(2) = 0.41, p = 0.001), accounting for the significant correlation between RV-SD4 and cardiac index (r = 0.57, r(2) = 0.32, p = 0.003).

CONCLUSIONS

In IPAH with narrow QRS, RV dyssynchrony is associated with RV dilation and eccentric hypertrophy pattern, suggesting a role of segmental wall stress heterogeneity as the major determinant of mechanical delay. Post-systolic shortening, as inefficient contraction, contributes to pump dysfunction.