The relationship between pericardial pressure and right atrial pressure: an intraoperative study

Nitroprusside Combined with Leg Raise at the Time of Right Heart Catheterization to Differentiate Precapillary from Other Hemodynamic Forms of Pulmonary Hypertension: A Single-Center Pilot Study

Pulmonary hypertension (PH) can arise from several distinct disease processes, with a percentage presenting with combined pre- and postcapillary pulmonary hypertension (cpcPH). Patients with cpcPH are unsuitable candidates for PH-directed therapies due to elevated pulmonary capillary wedge pressures (PCWPs); however, the PCWP is dynamic and is affected by both preload and afterload. Many patients that are diagnosed with cpcPH are hypertensive at the time of right heart catheterization which has the potential to increase the PCWP and, therefore, mimic a more postcapillary-predominant phenotype. In this small pilot study, we examine the effect of nitroprusside combined with dynamic preload augmentation with a passive leg raise maneuver in hypertensive cpcPH patients at the time of right heart catheterization to identify a more precapillary-dominant PH phenotype. Patients that met the criteria of PCWP ≤ 15 mmHg with nitroprusside infusion and PCWP ≤ 18 mmHg with nitroprusside infusion and simultaneous leg raise were started on pulmonary vascular-targeted therapy. Long-term PH therapy was well tolerated, with increased six-minute walk distance, improved WHO functional class, decreased NT-proBNP, and improved REVEAL 2.0 Lite Risk Score in this precapillary-dominant PH phenotype. This small study highlights the importance of characterizing patient physiology beyond resting conditions at the time of right heart catheterization.

Is Pulmonary Capillary Wedge Pressure a Reliable Indicator of Postcapillary Pulmonary Hypertension?

Although current pulmonary hypertension (PH) guidelines recommend a pulmonary capillary wedge pressure (PCWP) >15 mm Hg for the detection of a postcapillary component, the rationale of this recommendation may not be quite compatible with the peculiar hemodynamics of PH. We hypothesize that a high PCWP alone does not necessarily indicate left-sided disease, and this diagnosis can be improved using left ventricle transmural pressure difference (∆ PTM). In this 2-center, retrospective, observational study, we enrolled 1,070 patients with PH who underwent heart catheterization, with the final study population comprising 961 cases. ∆ PTM was calculated as PCWP minus right atrial pressure. The patients with group II PH had significantly higher ∆ PTM values (12.6 ± 6.6 mm Hg) compared with the other groups (1.1 ± 4.8 in group I, 12.4 ± 6.6 in group II, 2.5 ± 6.4 in group III, and 0.8 ± 8.0 in group IV, p <0.001) despite overlapping PCWP values. A ∆ PTM cutoff of 7 mm Hg identifies left heart disease when PCWP is >15 (area under curve 0.825, 95% confidence interval 0.784 to 0.866, p <0.001). Five-year mortality was significantly higher in patients with high ∆ PTM and PCWP subgroups compared with low ∆ PTM plus high PCWP (26.1% vs 18.5%, p = 0.027) and low ∆ PTM and PCWP subgroups (26.1% vs 15.6%, p <0.001). ∆ PTM has supplementary discriminatory power in distinguishing patients with and without postcapillary PH. In conclusion, a new approach utilizing ∆ PTM may improve our understanding of PH pathophysiology and may identify a subpopulation that may potentially benefit from PH-specific treatments.

Prognostic role of inferior vena collapsibility index in congenital heart disease: A validation study

BACKGROUND

A recent study showed that inferior vena cava collapsibility index (IVCCI) <60% had better prognostic performance as compared to the American Society of Echocardiogram (ASE) criteria for estimating right atrial pressure (RAP). However, this study was based on a selected cohort of adults with congenital heart disease (CHD) that underwent right heart catheterization and limiting the generalizability of the results. The purpose of this study was, therefore, to validate the prognostic performance of IVCCI in a more representative sample of adults with CHD, which would in turn, improve generalizability of the results.

METHODS

Retrospective cohort study of adults with CHD that underwent echocardiogram at Mayo Clinic (2003-2021). Elevated RAP was defined as RAP >10 mmHg, and was estimated using IVCCI <60% or the ASE criteria (maximum IVC diameter < 2.1 cm and IVCCI <50%). Cardiovascular event was defined as heart failure hospitalization, heart transplant or cardiovascular death.

RESULTS

Of the 4029 patients, 754 (19%) and 601 (15%) had elevated RAP (RAP >10 mmHg) based on IVCCI <60%, and the ASE criteria, respectively. Of the 4029 patients, 374 (9%) had cardiovascular events during 7.6 (4.4-10.5) years of follow-up. IVCCI <60% was independently associated with cardiovascular events (adjusted HR 2.08, 95% CI 1.75-2.42; C-statistic 0.708, 95%CI 0.688-0.728), and provided improved prognostic performance as compared to the ASE criteria (C-statistic difference 0.036, 95%CI 0.017-0.055, P = 0.008).

CONCLUSIONS

IVCCI had superior prognostic performance as compared to the ASE criteria.

Differential cardiopulmonary haemodynamic phenotypes in PASC-related exercise intolerance

Background

Post-acute sequelae of COVID-19 (PASC) affect a significant proportion of patients who have previously contracted SARS-CoV-2, with exertional intolerance being a prominent symptom. This study aimed to characterise the invasive haemodynamic abnormalities of PASC-related exertional intolerance using invasive cardiopulmonary exercise testing (iCPET).

Study design and intervention

55 patients were recruited from the Yale Post-COVID-19 Recovery Program, with most experiencing mild acute illness. Supine right heart catheterisation and iCPET were performed on all participants.

Main results

The majority (75%) of PASC patients exhibited impaired peak systemic oxygen extraction (pEO2) during iCPET in conjunction with supranormal cardiac output (CO) (i.e., PASC alone group). On average, the PASC alone group exhibited a "normal" peak exercise capacity, V'O2 (89±18% predicted). ∼25% of patients had evidence of central cardiopulmonary pathology (i.e., 12 with resting and exercise heart failure with preserved ejection fraction (HFpEF) and two with exercise pulmonary hypertension (PH)). PASC patients with HFpEF (i.e., PASC HFpEF group) exhibited similarly impaired pEO2 with well compensated PH (i.e., peak V'O2 and CO >80% respectively) despite aberrant central cardiopulmonary exercise haemodynamics. PASC patients with HFpEF also exhibited increased body mass index of 39±7 kg·m-2. To examine the relative contribution of obesity to exertional impairment in PASC HFpEF, a control group comprising obese non-PASC group (n=61) derived from a historical iCPET cohort was used. The non-PASC obese patients with preserved peak V'O2 (>80% predicted) exhibited a normal peak pulmonary artery wedge pressure (17±14 versus 25±6 mmHg; p=0.03) with similar maximal voluntary ventilation (90±12 versus 86±10% predicted; p=0.53) compared to PASC HFpEF patients. Impaired pEO2 was not significantly different between PASC patients who underwent supervised rehabilitation and those who did not (p=0.19).

Conclusions

This study highlights the importance of considering impaired pEO2 in PASC patients with persistent exertional intolerance unexplained by conventional investigative testing. Results of the current study also highlight the prevalence of a distinct high output HFpEF phenotype in PASC with a primary peripheral limitation to exercise.

Obesity-Related Differences in Pathomechanism and Outcomes in Patients With HFpEF: A CMR Study

Background

Clinical significance of an integrated evaluation of epicardial adipose tissue (EAT) and the right ventricle (RV) in heart failure with preserved ejection fraction (HFpEF) is unknown.

Objectives

The authors investigated the potential of EAT and RV quantification for obesity-related pathophysiology and risk stratification in obese HFpEF patients using cardiovascular magnetic resonance (CMR).

Methods

A total of 150 patients (obese, body mass index ≥30 kg/m2; n = 73, nonobese, body mass index <30 kg/m2; n = 77) with a clinical diagnosis of HFpEF undergoing CMR were retrospectively identified. EAT volume surrounding both ventricles were quantified with manual delineation on cine images. Total RV volume (TRVV) was calculated as the sum of RV cavity and mass at end-diastole. The endpoint was the composite of all-cause mortality and first HF hospitalization.

Results

During a median follow-up of 46 months, 39 nonobese patients (51%) and 32 obese patients (44%) experienced the endpoint. EAT was a prognostic biomarker regardless of obesity and was independently correlated with TRVV. In obese HFpEF, EAT correlated with RV longitudinal strain (r = 0.32, P = 0.006), and increased amount of EAT and TRVV was associated with greater left ventricular end-diastolic eccentric index (r = 0.36, P = 0.002). The integration of RV quantification into EAT provided improved risk stratification with a C-statistic increase from 0.70 to 0.79 in obese HFpEF. Obese patients with EAT<130 ml and TRVV<180 ml had low risk (annual event rate 3.2%), while those with increased EAT ≥130 ml and TRVV ≥180 ml had significantly higher risk (annual event rate 11.8%; P < 0.001).

Conclusions

CMR quantification of EAT and RV structure provides additive risk stratification for adverse outcomes in obese HFpEF.

Right Heart Failure in the Intensive Care Unit: Etiology, Pathogenesis, Diagnosis, and Treatment

Right heart (RH) failure carries a high rate of morbidity and mortality. Patients who present with RH failure often exhibit complex aberrant cardio-pulmonary physiology with varying presentations. The treatment of RH failure almost always requires care and management from an intensivist. Treatment options for RH failure patients continue to evolve rapidly with multiple options available, including different pharmacotherapies and mechanical circulatory support devices that target various components of the RH circulatory system. An understanding of the normal RH circulatory physiology, treatment, and support options for the RH failure patients is necessary for all intensivists to improve outcomes. The purpose of this review is to provide clinical guidance on the diagnosis and management of RH failure within the intensive care unit setting, and to highlight the different pathophysiological manifestations of RH failure, its hemodynamics, and treatment options available at the disposal of the intensivist.

Epicardial Fat in Heart Failure with Preserved Ejection Fraction: Bad Actor or Just Lying Around?

Heart failure with preserved ejection fraction (HFpEF) is increasingly recognised to be strongly associated with obesity and abnormalities in fat distribution. Epicardial fat has been associated with abnormal haemodynamics in HFpEF, with potential for direct mechanical effects on the heart causing constriction-like physiology and local myocardial remodelling effects from secretion of inflammatory and profibrotic mediators. However, patients with epicardial fat generally have more systemic and visceral adipose tissue making determination of causality between epicardial fat and HFpEF complex. In this review, we will summarise the evidence for epicardial fat being either directly causal in HFpEF pathogenesis or merely being a correlate of worse systemic inflammatory and generalised adiposity. We will also discuss therapies that directly target epicardial fat and may have potential for treating HFpEF and elucidating the independent role of epicardial fat in its pathogenesis.

Challenging the Hemodynamic Hypothesis in Heart Failure With Preserved Ejection Fraction: Is Exercise Capacity Limited by Elevated Pulmonary Capillary Wedge Pressure?

BACKGROUND

Exercise intolerance is a defining characteristic of heart failure with preserved ejection fraction (HFpEF). A marked rise in pulmonary capillary wedge pressure (PCWP) during exertion is pathognomonic for HFpEF and is thought to be a key cause of exercise intolerance. If true, acutely lowering PCWP should improve exercise capacity. To test this hypothesis, we evaluated peak exercise capacity with and without nitroglycerin to acutely lower PCWP during exercise in patients with HFpEF.

METHODS

Thirty patients with HFpEF (70±6 years of age; 63% female) underwent 2 bouts of upright, seated cycle exercise dosed with sublingual nitroglycerin or placebo control every 15 minutes in a single-blind, randomized, crossover design. PCWP (right heart catheterization), oxygen uptake (breath × breath gas exchange), and cardiac output (direct Fick) were assessed at rest, 20 Watts (W), and peak exercise during both placebo and nitroglycerin conditions.

RESULTS

PCWP increased from 8±4 to 35±9 mm Hg from rest to peak exercise with placebo. With nitroglycerin, there was a graded decrease in PCWP compared with placebo at rest (-1±2 mm Hg), 20W (-5±5 mm Hg), and peak exercise (-7±6 mm Hg; drug × exercise stage P=0.004). Nitroglycerin did not affect oxygen uptake at rest, 20W, or peak (placebo, 1.34±0.48 versus nitroglycerin, 1.32±0.46 L/min; drug × exercise P=0.984). Compared with placebo, nitroglycerin lowered stroke volume at rest (-8±13 mL) and 20W (-7±11 mL), but not peak exercise (0±10 mL).

CONCLUSIONS

Sublingual nitroglycerin lowered PCWP during submaximal and maximal exercise. Despite reduction in PCWP, peak oxygen uptake was not changed. These results suggest that acute reductions in PCWP are insufficient to improve exercise capacity, and further argue that high PCWP during exercise is not by itself a limiting factor for exercise performance in patients with HFpEF.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04068844.

Dynamic aspects of ventricular interaction during exercise in HFpEF and in pre-capillary pulmonary hypertension

AIMS

The contribution of adverse ventricular interdependence remains undervalued in heart failure or pulmonary vascular disease, and not much is known about its dynamic nature during exercise and respiration. In this study, we evaluated ventricular interaction during exercise in patients with heart failure with preserved ejection fraction (HFpEF) and patients with chronic thromboembolic pulmonary hypertension (CTEPH) as compared with healthy controls.

METHODS AND RESULTS

Forty-six subjects (10 controls, 19 CTEPH patients, and 17 HFpEF patients) underwent cardiac magnetic resonance imaging during exercise. Ventricular interaction was determined through analysis of the septal curvature (SC) of a mid-ventricular short-axis slice at end-diastole, end-systole, and early-diastole, both in expiration and inspiration. Exercise amplified ventricular interaction in CTEPH patients and to a lesser extent in HFpEF patients (P < 0.05 for decrease in SC with exercise). Adverse interaction was most profound in early-diastole and most pronounced in CTEPH patients (P < 0.05 interaction group * exercise) because of a disproportionate increase RV afterload (P < 0.05 to both controls and HFpEF) and diastolic pericardial restraint (P < 0.001 for interaction group * exercise) during exercise. Inspiration enhanced diastolic interdependence in CTEPH and HFpEF patients (P < 0.05 vs. expiration). Both at rest and during exercise, SC strongly correlated with RV volumes and pulmonary artery pressures (all P < 0.05).

CONCLUSIONS

Exercise amplifies adverse right-left ventricular interactions in CTEPH, while a more moderate effect is observed in isolated post-capillary HFpEF. Given the strong link with RV function and pulmonary hemodynamic, assessing ventricular interaction with exCMR might be valuable from a diagnostic or therapeutic perspective.

Hemodynamic Assessment in Heart Failure with Preserved Ejection Fraction

Heart failure (HF) with preserved ejection fraction (HFpEF) is characterized by an inability of the heart to perfuse the body without pathologic increases in filling pressure at rest or during exertion. Right heart catheterization provides direct assessment for HF, providing the most robust and direct method to evaluate the central hemodynamic abnormalities, and serves as the gold standard to confirm or refute the presence of HFpEF. This article reviews current understanding of the best practices in the performance and interpretation of hemodynamic assessment, relates important pathophysiologic concepts to clinical care, and discusses current and evidence-based applications of hemodynamics in HFpEF.

Role of Inferior Vena Cava Dynamics for Estimating Right Atrial Pressure in Congenital Heart Disease

BACKGROUND

Inferior vena cava (IVC) size and collapsibility (IVC dynamics) are used for estimating right atrial pressure (RAP). However, the diagnostic performance of the American Society of Echocardiography IVC criteria for estimating RAP in patients with congenital heart disease are unknown. The purpose of this study was to assess the role of IVC dynamics for estimating RAP in adults with congenital heart disease.

METHODS

We conducted a retrospective study of adults with congenital heart disease that underwent cardiac catheterization and echocardiogram at Mayo Clinic (2003-2019). IVC diameter was measured at inspiration (IVCmin) and end-expiration (IVCmax), and IVC collapsibility index (IVCCI) was calculated.

RESULTS

Based on 918 patients, we observed a good correlation between IVCmax and invasive RAP (r=0.56, P<0.001); IVCmin and RAP (r=0.58, P<0.001); and IVCCI (r=-0.72, P<0.001). There was excellent correlation between invasive RAP and estimated RAP using IVCCI (r=0.80, P<0.001). We observed that IVCCI <60% had superior diagnostic performance as compared with American Society of Echocardiography criteria (IVCmax >2.1 cm, area under the curve difference 0.15, P<0.001; IVCCI <50%, area under the curve difference 0.09, P=0.008; combination of IVCmax >2.1 cm; and IVCCI <50%, area under the curve difference 0.06, P=0.02). Estimated RAP >10 mm Hg based on IVCCI had comparable prognostic performance as invasive RAP but superior prognostic performance as the American Society of Echocardiography criteria.

CONCLUSIONS

IVCCI <60% was the best criterion to identify patients with elevated RAP. IVCCI was comparable to invasively measured RAP in its relation to prognosis. Further studies are required to determine whether the use of IVCCI in clinical decision-making will improve clinical outcomes in this population.

The nature of waves in the arteries in memoriam: Nico Westerhof and John Tyberg

This memorial remembers the lives of two distinguished researchers who made major contributions to cardiovascular physiology; Nico Westerhof (1937-2022) and John Tyberg (1938-2022). It is a joint memorial not because they collaborated closely but because they held very different views about the nature of waves in the arteries. Their papers and particularly their lively discussions at many scientific meetings stimulated interest in the subject. Both were thoughtful and articulate about their views and the debates were polite and dignified. They never resolved their differences and, after outlining what these differences were, we will suggest that perhaps there is no resolution. The authors of this memorial were close to one or the other protagonist; a son, a son-in-law and two close collaborators. We all have different views about the nature of waves in the arteries but we all share great respect for both men and felt that a joint memorial was a fitting way to remember them and their many contributions. All of the authors knew the subjects of this memorial as 'Nico' and 'John' and we will use these informal names throughout. This article is protected by copyright. All rights reserved.

Effect of positive end expiratory pressure on central venous pressure in closed and open thorax

OBJECTIVE

The magnitude and mechanism of the rise of central venous pressure (CVP) after positive end-expiratory pressure (PEEP) among patients with cardiac disease is poorly understood. Therefore, the study aimed to compare the magnitude of change in CVP after PEEP in patients with TR (tricuspid regurgitation), high CVP and high PCWP (pulmonary capillary wedge pressure) with no TR, low CVP and low PCWP. Additionally, we hypothesized that PEEP in the open thorax would also lead to a rise in CVP.

APPROACH

This prospective, quasi-experimental study was conducted in patients undergoing cardiac surgery. Three consecutive readings of variables were obtained at 1-minute intervals after PEEP (5 and 10 cm H2O) application in the closed and open thorax. Patients were stratified a priori into low CVP (<10 cm H2O) and high CVP (≥10 cm H2O), no TR and TR and low PCWP (<15 mm Hg) and high PCWP (≥15 mm Hg) in the closed and open thorax.

MAIN RESULTS

Sixty-two patients were eligible for final analysis. The mean difference (MD) in ∆CVP (CVP10 cm H2O of PEEP - CVP zero end-expiratory pressure) was 2.33±1.13 (95% CI, 2.04-2.62, P=0.000) and 1.02±0.77 (95% CI, 0.82-1.22, P=0.000) in the closed and open thorax, respectively. The increase in CVP was higher among patients who had a lower CVP (2.64 ± 0.9 mm Hg vs 1.45± 1.17 mm Hg; p=0.000), without TR (2.64 ± 0.97 mm Hg vs 2.14 ± 1.2 mm Hg, p=0.09) and lower PCWP (2.4 ± 0.9 mm Hg vs 2.3 ± 1.4 mm Hg, p=0.67) at 10 cm H2O PEEP in the closed thorax.

SIGNIFICANCE

The rise in CVP was higher among patients without TR, low CVP and low PCWP. Zero intrathoracic pressure in the open thorax did not abolish the effect of PEEP on CVP rise altogether.

Hemodynamic Response to Acute Volume Load and Endomyocardial NO-synthase Gene Expression in Heart Transplant Recipients

A pulmonary capillary wedge pressure (PCWP) >18 mm Hg following volume load has been proposed as a partition value for the detection of heart failure with preserved ejection fraction. As hemodynamic changes in filling pressures (FP) have been attributed to a nitric oxide (NO)-mediated rightward shift of the pressure-volume relationship, we investigated the hemodynamic response to volume load in heart transplant recipients (HTx) and examined the role of inducible NO synthase (iNOS) gene expression on diastolic function changes.

Mechanical Interaction of the Pericardium and Cardiac Function in the Normal and Hypertensive Rat Heart

The pericardium is a thin connective tissue membrane that surrounds the heart and is an integral regulatory component of cardiopulmonary performance. Pathological growth and remodeling of the right ventricle (RV) stemming from structural heart diseases are thought to include a significant role of the pericardium, but its exact role remains unclear. The objective of this study was to investigate potential biomechanical adaptations of the pericardium in response to pulmonary hypertension and their effects on heart behavior. Integrated computational-experimental modeling of the heart offers a robust platform to achieve this objective. We built upon our recently developed high-fidelity finite-element models of healthy and hypertensive rodent hearts via addition of the pericardial sac. In-silico experiments were performed to investigate changes in pericardium reserve elasticity and their effects on cardiac function in hypertensive hearts. Our results suggest that contractile forces would need to increase in the RV and decrease in the left ventricle (LV) in the hypertensive heart to compensate for reductions in pericardium reserve elasticity. The discrepancies between chamber responses to pericardium addition result, in part, from differences in the impact of pericardium on the RV and LV preload. We further demonstrated the capability of our platform to predict the effect of pericardiectomy on heart function. Consistent with previous results, the effect of pericardiectomy on the chamber pressure-volume loop was the largest in the hypertensive RV. These insights are expected to motivate further computational investigations of the effect of pericardiectomy on cardiac function which remains an important factor in surgical planning of constrictive pericarditis and coronary artery bypass grafting.

Effects of Metoprolol on Exercise Hemodynamics in Patients With Obstructive Hypertrophic Cardiomyopathy

BACKGROUND

The relationship between exercise hemodynamics, loading conditions, and medical treatment in patients with obstructive hypertrophic cardiomyopathy (HCM) is incompletely understood.

OBJECTIVES

This study aimed to investigate the effect of metoprolol on invasive hemodynamic parameters at rest and during exercise in patients with obstructive HCM.

METHODS

This randomized, double-blind, placebo-controlled crossover trial enrolled 28 patients with obstructive HCM and New York Heart Association functional class ≥II. Patients were randomized to initiate either metoprolol 150 mg or placebo for 2 consecutive 2-week periods. Right-heart catheterization and echocardiography were performed at rest and during exercise at the end of each treatment period. The primary outcome was the difference in pulmonary capillary wedge pressure (ΔPCWP) between peak exercise and rest.

RESULTS

No treatment effect on ΔPCWP was observed between metoprolol and placebo treatment (21 ± 9 mm Hg vs 23 ± 9 mm Hg; P = 0.12). At rest, metoprolol lowered heart rate (P < 0.0001), left ventricular outflow tract (LVOT) gradient (P = 0.01), and increased left ventricular end-diastolic volume (P = 0.02) and stroke volume (SV) (+6.4; 95% CI: 0.02-17.7; P = 0.049). During peak exercise, metoprolol was associated with a lower heart rate (P < 0.0001), a lower LVOT gradient (P = 0.0005), lesser degree of mitral regurgitation (P = 0.004), and increased SV (+9 mL; 95% CI: 2-15 mL; P = 0.008).

CONCLUSIONS

In patients with obstructive HCM, exercise was associated with an abnormal rise in PCWP, which was unaffected by metoprolol. However, metoprolol increased SV at rest and peak exercise following changes in end-diastolic volume, LVOT gradient, and degree of mitral regurgitation. (The Effect of Metoprolol in Patients With Hypertrophic Obstructive Cardiomyopathy [TEMPO]; NCT03532802).

The Value of Passive Leg Raise During Right Heart Catheterization in Diagnosing Heart Failure With Preserved Ejection Fraction

BACKGROUND

Because of limited accuracy of noninvasive tests, diastolic stress testing plays an important role in the diagnostic work-up of patients with heart failure with preserved ejection fraction (HFpEF). Exercise right heart catheterization is considered the gold standard and indicated when HFpEF is suspected but left ventricular filling pressures at rest are normal. However, performing exercise during right heart catheterization is not universally available. Here, we examined whether pulmonary capillary wedge pressure (PCWP) during a passive leg raise (PLR) could be used as simple and accurate method to diagnose or rule out occult-HFpEF.

METHODS

In our tertiary center for pulmonary hypertension and HFpEF, all patients who received a diagnostic right heart catheterization with PCWP-measurements at rest, PLR, and exercise were evaluated (2014-2020). The diagnostic value of PCWP_PLR was compared with the gold standard (PCWP_EXERCISE). Cut-offs derived from our cohort were subsequently validated in an external cohort (N=74).

RESULTS

Thirty-nine non-HFpEF, 33 occult-HFpEF, and 37 manifest-HFpEF patients were included (N=109). In patients with normal PCWP_REST (<15 mmHg), PCWP_PLR significantly improved diagnostic accuracy compared with PCWP_REST (AUC=0.82 versus 0.69, P=0.03). PCWP_PLR ≥19 mmHg (24% of cases) had a specificity of 100% for diagnosing occult-HFpEF, irrespective of diuretic use. PCWP_PLR ≥11 mmHg had a 100% sensitivity and negative predictive value for diagnosing occult-HFpEF. Both cut-offs retained a 100% specificity and 100% sensitivity in the external cohort. Absolute change in PCWP_PLR or V-wave derived parameters had no incremental value in diagnosing occult-HFpEF.

CONCLUSIONS

PCWP_PLR is a simple and powerful tool that can help to diagnose or rule out occult-HFpEF.

Multimodality imaging in patients with heart failure and preserved ejection fraction: an expert consensus document of the European Association of Cardiovascular Imaging

Nearly half of all patients with heart failure (HF) have a normal left ventricular (LV) ejection fraction (EF) and the condition is termed heart failure with preserved ejection fraction (HFpEF). It is assumed that in these patients HF is due primarily to LV diastolic dysfunction. The prognosis in HFpEF is almost as severe as in HF with reduced EF (HFrEF). In contrast to HFrEF where drugs and devices are proven to reduce mortality, in HFpEF there has been limited therapy available with documented effects on prognosis. This may reflect that HFpEF encompasses a wide range of different pathological processes, which multimodality imaging is well placed to differentiate. Progress in developing therapies for HFpEF has been hampered by a lack of uniform diagnostic criteria. The present expert consensus document from the European Association of Cardiovascular Imaging (EACVI) provides recommendations regarding how to determine elevated LV filling pressure in the setting of suspected HFpEF and how to use multimodality imaging to determine specific aetiologies in patients with HFpEF.

Uncoupling between intravascular and distending pressures leads to underestimation of circulatory congestion in obesity

AIMS

Patients with obesity frequently present with dyspnoea. Biomarkers that reflect wall stress are often used to evaluate circulatory congestion and help determine whether dyspnoea is of cardiac causes. Patients with obesity display greater external restraint on the heart, which may alter relationships between intravascular pressures and stress markers.

METHODS AND RESULTS

Subjects with unexplained dyspnoea (n = 212) underwent cardiac catheterization with simultaneous echocardiography. Blood sampling was performed in a subset (n = 58). Relationships between echocardiographic and blood biomarkers of circulatory congestion and directly-measured haemodynamics were compared between participants with severe obesity [body mass index (BMI) ≥35 kg/m² , Group B) and those without (BMI <35 kg/m² , Group A). Circulatory congestion was assessed by pulmonary capillary wedge pressure (PCWP), and vascular distending pressure was assessed by left ventricular transmural pressure (LVTMP). As compared to Group A, participants in Group B displayed higher PCWP relative to N-terminal pro-B-type natriuretic peptide, mid-regional pro-atrial natriuretic peptide (MR-proANP), troponin T, and growth differentiation factor-15 (all p < 0.01). In contrast, the relationships between LVTMP and the biomarkers were superimposable. Echocardiographic biomarkers revealed the same pattern: PCWP was higher for any E/e' ratio in Group B compared to Group A, but the relationship between LVTMP and E/e' was similar. In contrast, levels of C-terminal pro-endothelin-1 and MR-proADM were more robustly correlated with PCWP (r = 0.67 and r = 0.62, both p < 0.0001), with no differential relationship based upon BMI.

CONCLUSIONS

Non-invasive haemodynamic markers underestimate circulatory congestion in patients with obesity, an effect that appears related to uncoupling between cardiac wall stress and intravascular pressures. This may lead to systematic under-recognition of congestion in patients with obesity.

Left Atrial Myopathy in Heart Failure With Preserved Ejection Fraction

The left atrium (LA) plays an important role in facilitating left ventricular (LV) filling by acting as a reservoir, passive conduit, and active booster pump, as well as a regulator of blood volume through A-type natriuretic peptide secretion in response to stimulation by mechanical stretch of the cavity. LA myopathy has emerged as one of the most important non-LV contributors to disease progression in heart failure with preserved ejection fraction (HFpEF). LA dysfunction is common in HFpEF and is associated with more severe pulmonary vascular disease and right ventricular dysfunction, and increases the risk of incident atrial fibrillation or atrial functional mitral regurgitation, leading to limitations in cardiac output reserve and reduced exercise capacity. LA deformation assessed by 2-dimensional speckle-tracking echocardiography is useful for estimating abnormal hemodynamics or exercise capacity, discriminating HFpEF from non-cardiac dyspnea and is an independent predictor of adverse outcome in HFpEF. Thus, interventions directly targeting LA myopathy may improve outcomes in HFpEF with LA myopathy. This review provides information regarding the physiology of the LA in patients with HFpEF and discusses the importance of evaluation of LA function, management issues, and future directions through ongoing trials of medical interventions.

One-Year Committed Exercise Training Reverses Abnormal Left Ventricular Myocardial Stiffness in Patients With Stage B Heart Failure With Preserved Ejection Fraction

BACKGROUND

Individuals with left ventricular (LV) hypertrophy and elevated cardiac biomarkers in middle age are at increased risk for the development of heart failure with preserved ejection fraction. Prolonged exercise training reverses the LV stiffening associated with healthy but sedentary aging; however, whether it can also normalize LV myocardial stiffness in patients at high risk for heart failure with preserved ejection fraction is unknown. In a prospective, randomized controlled trial, we hypothesized that 1-year prolonged exercise training would reduce LV myocardial stiffness in patients with LV hypertrophy.

METHODS

Forty-six patients with LV hypertrophy (LV septum >11 mm) and elevated cardiac biomarkers (N-terminal pro-B-type natriuretic peptide [>40 pg/mL] or high-sensitivity troponin T [>0.6 pg/mL]) were randomly assigned to either 1 year of high-intensity exercise training (n=30) or attention control (n=16). Right-heart catheterization and 3-dimensional echocardiography were performed while preload was manipulated using both lower body negative pressure and rapid saline infusion to define the LV end-diastolic pressure-volume relationship. A constant representing LV myocardial stiffness was calculated from the following: P=S×[Exp {a (V-V₀)}-1], where "P" is transmural pressure (pulmonary capillary wedge pressure - right atrial pressure), "S" is the pressure asymptote of the curve, "V" is the LV end-diastolic volume index, "V₀" is equilibrium volume, and "a" is the constant that characterizes LV myocardial stiffness.

RESULTS

Thirty-one participants (exercise group [n=20]: 54±6 years, 65% male; and controls (n=11): 51±6 years, 55% male) completed the study. One year of exercise training increased max by 21% (baseline 26.0±5.3 to 1 year later 31.3±5.8 mL·min^-1·kg^-1, P<0.0001, interaction P=0.0004), whereas there was no significant change in max in controls (baseline 24.6±3.4 to 1 year later 24.2±4.1 mL·min^-1·kg^-1, P=0.986). LV myocardial stiffness was reduced (right and downward shift in the end-diastolic pressure-volume relationship; LV myocardial stiffness: baseline 0.062±0.020 to 1 year later 0.031±0.009), whereas there was no significant change in controls (baseline 0.061±0.033 to 1 year later 0.066±0.031, interaction P=0.001).

CONCLUSIONS

In patients with LV hypertrophy and elevated cardiac biomarkers (stage B heart failure with preserved ejection fraction), 1 year of exercise training reduced LV myocardial stiffness. Thus, exercise training may provide protection against the future risk of heart failure with preserved ejection fraction in such patients. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03476785.

Ischemic heart disease: Cellular and molecular immune contributions of the pericardium

Ischemic heart disease promotes complex inflammatory and remodeling pathways which contribute to the development of chronic heart failure. Although blood-derived and local cardiac mediators have traditionally been linked with these processes, the pericardial space has more recently been noted as alternative contributor to the injury response in the heart. The pericardial space contains fluid rich in physiologically active mediators, and immunologically active adipose tissue, which are altered during myocardial infarction. Key immune cells in the pericardial fluid and adipose tissue have been identified which act as mediators for cell recruitment and function after myocardial infarction have been identified in experimental models. Here, we provide an overview of the current understanding of the inflammatory mechanisms of the pericardial space and their role in post-myocardial infarction remodeling and the potential for the use of the pericardial space as a delivery vehicle for treatments to modulate heart healing.

High Central Venous Pressure and Right Ventricle Size Are Related to Non-decreased Left Ventricle Stroke Volume After Negative Fluid Balance in Critically Ill Patients: A Single Prospective Observational Study

Background: Optimal adjustment of cardiac preload is essential for improving left ventricle stroke volume (LVSV) and tissue perfusion. Changes in LVSV caused by central venous pressure (CVP) are the most important concerns in the treatment of critically ill patients. Objectives: This study aimed to clarify the changes in LVSV after negative fluid balance in patients with elevated CVP, and to elucidate the relationship between the parameters of right ventricle (RV) filling state and LVSV changes. Methods: This prospective cohort study included patients with high central venous pressure (CVP) (≥8 mmHg) within 24 h of ICU admission in the Critical Medicine Department of Peking Union Medical College Hospital. Patients were classified into two groups based on the LVSV changes after negative fluid balance. The cutoff value was 10%. The hemodynamic and echo parameters of the two groups were recorded at baseline and after negative fluid balance. Results: A total of 71 patients included in this study. Forty in VI Group (LVOT VTI increased ≥10%) and 31 in VNI Group (LVOT VTI increased <10%). Of all patients, 56.3% showed increased LVSV after negative fluid balance. In terms of hemodynamic parameters at T0, patients in VI Group had a higher CVP (p < 0.001) and P(v-a)CO₂ (p < 0.001) and lower ScVO₂ (p < 0.001) relative to VNI Group, regarding the echo parameters at T0, the RV_D/LV_D ratio (p < 0.001), DIVC _{end-expiratory} (p < 0.001), and ΔLVOT VTI (p < 0.001) were higher, while T0 LVOT VTI (p < 0.001) was lower, in VI Group patients. The multifactor logistic regression analysis suggested that a high CVP and RV_D/LV_D ratio ≥0.6 were significant associated with LVSV increase after negative fluid balance in critically patients. The AUC of CVP was 0.894. A CVP >10.5 mmHg provided a sensitivity of 87.5% and a specificity of 77.4%. The AUC of CVP combined with the RV_D/LV_D ratio ≥0.6 was 0.926, which provided a sensitivity of 92.6% and a specificity of 80.4%. Conclusion: High CVP and RV_D/LV_D ratio ≥0.6 were significant associated with RV stressed in critically patients. Negative fluid balance will not always lead to a decrease, even an increase, in LVSV in these patients.

Haemodynamic determinants of improved aerobic capacity after tricuspid valve surgery in Ebstein anomaly

BACKGROUND

Although tricuspid valve surgery improves functional capacity in patients with Ebstein anomaly, it is not always associated with improvement in aerobic capacity. The purpose of this study was to identify the determinants of improved aerobic capacity after tricuspid valve surgery in adults with Ebstein anomaly with severe tricuspid regurgitation.

METHODS

Retrospective study of patients with severe tricuspid regurgitation due to Ebstein anomaly that had tricuspid valve surgery at Mayo Clinic Rochester (2000-2019) and had preoperative and postoperative cardiopulmonary exercise tests and echocardiograms. The patients were divided into aerobic capacity(+) and aerobic capacity(-) groups depending on whether they had postoperative improvement in %-predicted peak oxygen consumption (VO2).

RESULTS

Of 76 patients with severe tricuspid regurgitation due to Ebstein anomaly, 28 (37%) and 48 (63%) were in aerobic capacity(+) and aerobic capacity(-) groups, respectively. The average improvement in peak VO2 was 2.1±1.4 mL/kg/min and -0.9±0.4 mL/kg/min in the in aerobic capacity(+) and aerobic capacity(-) groups, respectively. Although both groups had similar severity of residual tricuspid regurgitation, the aerobic capacity(+) group had more postoperative improvement in right atrial (RA) function, left atrial (LA) function and left ventricular preload and stroke volume. Of the preoperative variables analysed, RA reservoir strain (relative risk 1.12; 95% CI 1.06 to 1.18); LA reservoir strain (relative risk 1.09; 95% CI 1.04 to 1.14) and LV stroke volume index (OR 1.04; 95% CI 1.01 to 1.07) were predictors of postoperative improvement in peak VO2.

CONCLUSIONS

One-third of patients with severe tricuspid regurgitation due to Ebstein anomaly had postoperative improvement in aerobic capacity, and atrial function indices were the best predictors of postoperative improvement in aerobic capacity. These data provide new insight into the haemodynamic determinants of exercise capacity and lay the foundation for further studies to determine whether postoperative improvement in aerobic capacity translates to improved long-term survival, and whether timing of tricuspid valve surgery based on these echocardiographic indices will improve long-term outcomes.

Clinical performance and exercise hemodynamics in patients with severe secondary tricuspid regurgitation and chronic atrial fibrillation

Objective

The study aimed to investigate the functional capacity and hemodynamics at rest and during exercise in patients with chronic atrial fibrillation and severe functional symptomatic tricuspid regurgitation (AF-FTR).

Background

Symptoms and clinical performance of severe AF-FTR mimic the population of patients with heart failure with preserved ejection fraction (HFpEF). Severe AF-FTR is known to be associated with an adverse prognosis whereas less is reported about the clinical performance including exercise capacity and hemodynamics in patients symptomatic AF-FTR.

Methods

Right heart catheterization (RHC) at rest and during exercise was conducted in a group of patients with stable chronic AF-TR and compared with a group of patients with HFpEF diagnosed with cardiac amyloid cardiomyopathy (CA). All patients had preserved ejection fraction and no significant left-sided disease.

Results

Patients with AF-FTR demonstrated a low exercise capacity that was comparable to CA patients (TR 4.9 ± 1.2 METS vs. CA 4. 7 ± 1.5 METS; P = 0.78) with an average peak maximal oxygen consumption of 15 mL/min/kg. Right atrium pressure increased significantly more in the AF-FTR patients as compared to CA patients at peak exercise (25 ± 8 vs 19 ± 9, p < 0.01) whereas PCWP increased significantly to a similar extent in both groups (31 ± 4 vs 31 ± 8 mmHg, p = 0.88). Cardiac output (CO) was significantly lower among AF-FTR at rest as compared to CA patients (3.6 ± 0.9 vs 4.4 ± 1.3 l/min; p < 0.05) whereas both groups demonstrated a poor but comparable CO reserve at peak exercise (7.3 ± 2.9 vs 7.9 ± 3.8 l/min, p = 0.59).

Conclusions

AF-FTR contributes to the development of advanced heart failure symptoms and poor exercise capacity reflected in increased atrial filling pressures, reduced cardiac output at rest and during exercise sharing common features seen in HFpEF patients with other etiologies.

Atrial Dysfunction in Patients With Heart Failure With Preserved Ejection Fraction and Atrial Fibrillation

BACKGROUND

Paroxysmal and permanent atrial fibrillation (AF) are common in heart failure with preserved ejection fraction (HFpEF).

OBJECTIVES

This study sought to determine the implications of left atrial (LA) myopathy and dysrhythmia across the spectrum of AF burden in HFpEF.

METHODS

Consecutive patients with HFpEF (n = 285) and control subjects (n = 146) underwent invasive exercise testing and echocardiographic assessment of cardiac structure, function, and pericardial restraint.

RESULTS

Patients with HFpEF were categorized into stages of AF progression: 181 (65%) had no history of AF, 49 (18%) had paroxysmal AF, and 48 (17%) had permanent AF. Patients with permanent AF were more congested with greater pulmonary vascular disease and lower cardiac output. LA volumes increased, while LA compliance, LA reservoir strain, and right ventricular function decreased with increasing AF burden. The presence of permanent AF was characterized by a distinct pathophysiology, with greater total heart volume caused by atrial dilatation, leading to elevated filling pressures through heightened pericardial restraint. Survival decreased with increasing AF burden. Ten-year progression to permanent AF was common, particularly in paroxysmal AF (52%), and the likelihood of AF progression increased with higher AF stage, poorer LA compliance, and lower LA strain.

CONCLUSIONS

LA compliance and mechanics progressively decline with increasing AF burden in HFpEF, increasing risk for new onset AF and progressive AF. These changes promote development of a unique phenotype of HFpEF characterized by heightened ventricular interaction, right heart failure, and worsening pulmonary vascular disease. Further study is required to identify therapeutic interventions targeting LA myopathy to improve outcomes in HFpEF.

Sustained Improvement in Diastolic Reserve Following Percutaneous Pericardiotomy in a Porcine Model of Heart Failure With Preserved Ejection Fraction

BACKGROUND

Heart failure with preserved ejection fraction is increasing in prevalence, but few effective treatments are available. Elevated left ventricular (LV) diastolic filling pressures represent a key therapeutic target. Pericardial restraint contributes to elevated LV end-diastolic pressure, and acute studies have shown that pericardiotomy attenuates the rise in LV end-diastolic pressure with volume loading. However, whether these acute effects are sustained chronically remains unknown.

METHODS

Minimally invasive pericardiotomy was performed percutaneously using a novel device in a porcine model of heart failure with preserved ejection fraction. Hemodynamics were assessed at baseline and following volume loading with pericardium intact, acutely following pericardiotomy, and then again chronically after 4 weeks. Cardiac structure was assessed by magnetic resonance imaging.

RESULTS

The increase in LV end-diastolic pressure with volume loading was mitigated by 41% (95% CI, 27%-45%, P<0.0001; ΔLV end-diastolic pressure reduced from +9±3 mm Hg to +5±3 mm Hg, P=0.0003, 95% CI, -2.2 to -5.5). The effect was sustained at 4 weeks (+5±2 mm Hg, P=0.28 versus acute). There was no statistically significant effect of pericardiotomy on ventricular remodeling compared with age-matched controls. None of the animals developed hemodynamic or pathological indicators of pericardial constriction or frank systolic dysfunction.

CONCLUSIONS

The acute hemodynamic benefits of pericardiotomy are sustained for at least 4 weeks in a swine model of heart failure with preserved ejection fraction, without excessive chamber remodeling, pericarditis, or clinically significant systolic dysfunction. These data support trials evaluating minimally invasive pericardiotomy as a novel treatment for heart failure with preserved ejection fraction in humans.

Hemodynamic function of the right ventricular-pulmonary vascular-left atrial unit: normal responses to exercise in healthy adults

With each heartbeat, the right ventricle (RV) inputs blood into the pulmonary vascular (PV) compartment, which conducts blood through the lungs at low pressure and concurrently fills the left atrium (LA) for output to the systemic circulation. This overall hemodynamic function of the integrated RV-PV-LA unit is determined by complex interactions between the components that vary over the cardiac cycle but are often assessed in terms of mean pressure and flow. Exercise challenges these hemodynamic interactions as cardiac filling increases, stroke volume augments, and cycle length decreases, with PV pressures ultimately increasing in association with cardiac output. Recent cardiopulmonary exercise hemodynamic studies have enriched the available data from healthy adults, yielded insight into the underlying mechanisms that modify the PV pressure-flow relationship, and better delineated the normal limits of healthy responses to exercise. This review will examine hemodynamic function of the RV-PV-LA unit using the two-element Windkessel model for the pulmonary circulation. It will focus on acute PV and LA responses that accommodate increased RV output during exercise, including PV recruitment and distension and LA reservoir expansion, and the integrated mean pressure-flow response to exercise in healthy adults. Finally, it will consider how these responses may be impacted by age-related remodeling and modified by sex-related cardiopulmonary differences. Studying the determinants and recognizing the normal limits of PV pressure-flow relations during exercise will improve our understanding of cardiopulmonary mechanisms that facilitate or limit exercise.

Acute Unloading Effects of Sildenafil Enhance Right Ventricular-Pulmonary Artery Coupling in Heart Failure

BACKGROUND

Phosphodiesterase-5A inhibitors (PDE5i) are sometimes used in patients with advanced heart failure with reduced ejection fraction before heart transplant or left ventricular assist device implantation to decrease right ventricular (RV) afterload and mitigate the risk of right heart failure. Conflicting evidence exists regarding the impact of these drugs on RV contractility. The aim of this study was to explore the acute effects of PDE5i on ventricular-vascular coupling and load-independent RV contractility.

METHODS

Twenty-two patients underwent right heart catheterization and gated equilibrium blood pool single photon emission computed tomography, before and after 20 mg intravenous sildenafil. Single photon emission computed tomography and right heart catheterization-derived data were used to calculate RV loading and contractility.

RESULTS

PDE5i induced a decrease in the right atrial pressure (-43%), pulmonary artery (PA) mean pressure (-26%), and PA wedge pressure (PAWP; -23%), with favorable reductions in pulmonary vascular resistance (-41%) and PA elastance (-40%), and increased cardiac output (+13%) (all P < 0.01). The RV ejection fraction increased with sildenafil (+20%), with no change of RV contractility (P = 0.74), indicating that the improvement in the RV ejection fraction was related to enhanced RV-PA coupling (r = 0.59, P = 0.004) by a decrease in the ventricular load. RV diastolic compliance increased with sildenafil. The decrease in the PAWP correlated with RV end-diastolic volume decrease; no relationship was observed with the change in LV transmural pressure, suggesting decreased pericardial constraint.

CONCLUSIONS

Acute PDE5i administration has profound RV afterload-reducing effects, improves the RVEF, decreases RV volumes, and decreases the PAWP, predominantly through relief of pericardial constraint, without effects on RV chamber contractility. These findings support further study of PDE5i in protection of RV function in advanced heart failure with reduced ejection fraction who are at risk of RV failure.

The Role of the Pericardium in Heart Failure: Implications for Pathophysiology and Treatment

The elastic pericardium exerts a compressive contact force on the surface of the myocardium that becomes more substantial when heart volume increases, as in patients with various forms of heart failure (HF). Pericardial restraint plays an important role in determining hemodynamics and ventricular function in both health and disease. This review discusses the physiology of pericardial restraint in HF and explores the question of whether it can be targeted indirectly through medical interventions or directly through a number of existing and future therapies.

Diastolic Ventricular Interaction in Heart Failure With Preserved Ejection Fraction

Background

Exercise‐induced pulmonary hypertension is common in heart failure with preserved ejection fraction (HFpEF). We hypothesized that this could result in pericardial constraint and diastolic ventricular interaction in some patients during exercise.

Methods and Results

Contrast stress echocardiography was performed in 30 HFpEF patients, 17 hypertensive controls, and 17 normotensive controls (healthy). Cardiac volumes, and normalized radius of curvature (NRC) of the interventricular septum at end‐diastole and end‐systole, were measured at rest and peak‐exercise, and compared between the groups. The septum was circular at rest in all 3 groups at end‐diastole. At peak‐exercise, end‐systolic NRC increased to 1.47±0.05 (P<0.001) in HFpEF patients, confirming development of pulmonary hypertension. End‐diastolic NRC also increased to 1.54±0.07 (P<0.001) in HFpEF patients, indicating septal flattening, and this correlated significantly with end‐systolic NRC (ρ=0.51, P=0.007). In hypertensive controls and healthy controls, peak‐exercise end‐systolic NRC increased, but this was significantly less than observed in HFpEF patients (HFpEF, P=0.02 versus hypertensive controls; P<0.001 versus healthy). There were also small, non‐significant increases in end‐diastolic NRC in both groups (hypertensive controls, +0.17±0.05, P=0.38; healthy, +0.06±0.03, P=0.93). In HFpEF patients, peak‐exercise end‐diastolic NRC also negatively correlated (r=−0.40, P<0.05) with the change in left ventricular end‐diastolic volume with exercise (ie, the Frank‐Starling mechanism), and a trend was noted towards a negative correlation with change in stroke volume (r=−0.36, P=0.08).

Conclusions

Exercise pulmonary hypertension causes substantial diastolic ventricular interaction on exercise in some patients with HFpEF, and this restriction to left ventricular filling by the right ventricle exacerbates the pre‐existing impaired Frank‐Starling response in these patients.

Hemodynamic and Functional Impact of Epicardial Adipose Tissue in Heart Failure With Preserved Ejection Fraction

OBJECTIVES

This study determined the impact of excess epicardial adipose tissue (EAT) in patients with the obese phenotype of heart failure with preserved ejection fraction (HFpEF).

BACKGROUND

Patients with HFpEF and an elevated body mass index differ from nonobese patients, but beyond generalized obesity, fat distribution may be more important. Increases in EAT are associated with excess visceral adiposity, inflammation, and cardiac fibrosis, and EAT has been speculated to play an important role in the pathophysiology of HFpEF, but no study has directly evaluated this question.

METHODS

Patients with HFpEF and obesity (n = 169) underwent invasive hemodynamic exercise testing with expired gas analysis and echocardiography. Increased EAT was defined by echocardiography (EAT thickness ≥9 mm).

RESULTS

Compared with obese patients without increased EAT (HFpEF_EAT-, n = 92), obese patients with HFpEF with increased EAT (HFpEF_EAT+; n = 77) displayed a higher left ventricular eccentricity index, indicating increased pericardial restraint, but similar resting biventricular structure and function. In contrast, hemodynamics were more abnormal in patients with HFpEF_EAT+, with higher right atrial, pulmonary artery, and pulmonary capillary wedge pressures at rest and during exercise compared with those of patients with HFpEF_EAT-. Peak oxygen consumption (VO₂) was reduced in both groups but was 20% lower in patients with HFpEF_EAT+ (p < 0.01).

CONCLUSIONS

Among patients with the obese phenotype of HFpEF, the presence of increased EAT is associated with more profound hemodynamic derangements at rest and exercise, including greater elevation in cardiac filling pressures, more severe pulmonary hypertension, and greater pericardial restraint, culminating in poorer exercise capacity. Further study is needed to understand the biology and treatment of excessive EAT in patients with HFpEF.

Determinants and Prognostic Implications of Left-Heart Filling Pressures in Tetralogy of Fallot

BACKGROUND

Elevated pulmonary artery wedge pressure (PAWP) is the hallmark of left-heart failure and is responsible for heart failure symptoms and mortality. Although PAWP typically correlates with right atrial pressure (RAP), it is primarily dependent on left-heart myocardial properties and volume status. As right-heart disease can occur in the absence of left-heart disease in patients with tetralogy of Fallot (TOF), we hypothesized that RAP was the primary determinant of PAWP in this population.

METHODS

A cohort study of adults with TOF that underwent right-heart catheterization at Mayo Clinic Rochester (1990 to 2017) to determine the relationship among RAP, PAWP, and mortality.

RESULTS

Among 213 patients (male 105; age 37 ± 14 years), the mean PAWP was 14 ± 5 mm Hg, and RAP was 11 ± 5 mm Hg. RAP was the strongest predictor of PAWP (β = 0.68, standard error = 0.06, P < 0.001), independent of left-heart disease and atherosclerotic cardiovascular risk factors. The patients with high PAWP also had normal tissue Doppler velocities, suggesting normal left-ventricular myocardial properties. PAWP was an independent predictor of death/transplant (hazard ration [HR] 1.11, 95% confidence interval [CI], 1.03-1.20, P = 0.004). However, when RAP was incorporated into the regression model, RAP (and not PAWP) became the independent predictor of outcomes (HR 1.14, 95% CI, 1.06-1.22, P = 0.001).

CONCLUSIONS

The current study showed that RAP was the primary determinant of PAWP and accounts, to some extent, for the mortality in patients with TOF and high PAWP. The data provide new insight in the pathophysiology of disease progression for symptomatic patients with TOF.

Heightened Dependence of Left-Heart Filling Pressures on Right-Heart Failure in Congenital Heart Disease

BACKGROUND

Pulmonary artery wedge pressure (PAWP) is often elevated in patients with right-sided congenital heart disease (CHD), raising the possibility of coexisting left-heart disease, but pressure-volume relationships in the left and right sides of the heart influence one another through interdependence, which may be amplified in patients with CHD.

METHODS

We hypothesized that increases in PAWP in patients with CHD would be more strongly related to ventricular interdependence compared with patients who have isolated left-heart disease such as heart failure with preserved ejection fraction (HFpEF). Ventricular interdependence was assessed by the relationship between PAWP and right-atrial pressure (RAP), RAP/PAWP ratio, and the left-ventricular (LV) eccentricity index.

RESULTS

PAWP was elevated (≥15 mm Hg) in 49% of patients with CHD (n = 449). There was a very strong correlation between RAP and PAWP in CHD (r = 0.81, P < 0.001) that greatly exceeded the respective correlation in HFpEF (n = 160; r = 0.58, P < 0.001; P < 0.001 between groups). RAP/PAWP ratio and LV eccentricity index were higher in CHD than HFpEF (1.26 ± 0.18 vs 1.05 ± 0.14, P = 0.007) and (0.80 ± 0.21 vs 0.59 ± 0.19, P < 0.001), respectively. RAP (but not PAWP) was an independent predictor of death/transplant (hazard ratio 1.86 per 5 mm Hg, 95% confidence interval, 1.39-2.45, P = 0.002).

CONCLUSIONS

Left-heart filling pressures are commonly elevated in right-sided CHD, but this is related predominantly to right-heart failure and enhanced ventricular interdependence rather than left-heart disease. These data provide new insight into the basis of abnormal left-heart hemodynamics in patients with CHD and reinforce the importance of therapeutic interventions targeted to the right heart.

Increased Myocardial Stiffness in Patients With High-Risk Left Ventricular Hypertrophy: The Hallmark of Stage-B Heart Failure With Preserved Ejection Fraction

BACKGROUND

Individuals with left ventricular hypertrophy (LVH) and elevated cardiac biomarkers in middle age are at high risk for the development of heart failure with preserved ejection fraction (HFpEF). However, it is unknown what the pathophysiological underpinnings of this high-risk state may be. We tested the hypothesis that patients with LVH and elevated cardiac biomarkers would demonstrate elevated left ventricular (LV) myocardial stiffness in comparison with healthy controls as a key marker for future HFpEF.

METHODS

Forty-six patients with LVH (LV septum >11 mm) and elevated cardiac biomarkers (N-terminal pro-B-type natriuretic peptide [>40 pg/mL] or troponin T [>0.6 pg/mL]) were recruited, along with 61 age- and sex-matched (by cohort) healthy controls. To define LV pressure-volume relationships, right heart catheterization and 3-dimensional echocardiography were performed while preload was manipulated using lower body negative pressure and rapid saline infusion.

RESULTS

There were significant differences in body size, blood pressure, and baseline pulmonary capillary wedge pressure between groups (eg, pulmonary capillary wedge pressure: LVH, 13.4±2.7 versus control, 11.7±1.7 mm Hg, P<0.0001). The LV was less distensible in LVH than in controls (smaller volume for the same filling pressure). When preload was expressed as transmural filling pressure (pulmonary capillary wedge pressure - right atrial pressure), LV myocardial stiffness was nearly 30% greater in LVH than in controls (LVH stiffness constant, 0.053±0.027 versus controls, 0.042±0.020, P=0.028).

CONCLUSIONS

LV myocardial stiffness in patients with LVH and elevated biomarkers (stage-B HFpEF) is greater than in age- and sex-matched controls and thus appears to represent a transitional state from a normal healthy heart to HFpEF. Although the LV myocardial stiffness of patients with LVH is greater than that of healthy controls at this early stage, further studies are required to clarify whether interventions such as exercise training to improve LV compliance may prevent the full manifestation of the HFpEF syndrome in these high-risk individuals.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifiers: NCT03476785 and NCT02039154.

The β-Adrenergic Agonist Albuterol Improves Pulmonary Vascular Reserve in Heart Failure With Preserved Ejection Fraction

RATIONALE

Pulmonary vascular resistance fails to decrease appropriately during exercise in patients with heart failure with preserved ejection fraction (HFpEF). Interventions that enhance pulmonary vasodilation might be beneficial in this cohort but could also worsen left atrial hypertension, exacerbating lung congestion. Intravenous β-agonists reduce pulmonary vascular resistance but are not suitable for chronic use.

OBJECTIVE

We hypothesized that the inhaled β-adrenergic agonist albuterol would improve pulmonary vasodilation during exercise in patients with HFpEF, without increasing left heart filling pressures.

METHODS AND RESULTS

We performed a randomized, double-blind, placebo-controlled trial testing the effects of inhaled albuterol on resting and exercise hemodynamics in subjects with HFpEF using high-fidelity micromanometer catheters and expired gas analysis. The primary end point was pulmonary vascular resistance during exercise. Subjects with HFpEF (n=30) underwent resting and exercise hemodynamic assessment and were then randomized 1:1 to inhaled, nebulized albuterol or placebo. Rest and exercise hemodynamic testing was then repeated. Albuterol improved the primary end point of exercise pulmonary vascular resistance as compared with placebo (-0.6±0.5 versus +0.1±0.7 WU; P=0.003). Albuterol enhanced cardiac output reserve and right ventricular pulmonary artery coupling, reduced right atrial and pulmonary artery pressures, improved pulmonary artery compliance, and enhanced left ventricular transmural distending pressure (all P <0.01), with no increase in pulmonary capillary hydrostatic pressures.

CONCLUSIONS

Albuterol improves pulmonary vascular reserve in patients with HFpEF without worsening left heart congestion. Further study is warranted to evaluate the chronic efficacy of β-agonists in HFpEF and other forms of pulmonary hypertension.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov . Unique identifier: NCT02885636.

Pathophysiologic and Prognostic Implications of Right Atrial Hypertension in Adults With Tetralogy of Fallot

Background

Right atrial pressure (RAP), a composite metric of right ventricular diastolic function, volume status, and right heart compliance, is a predictor of mortality in patients with heart failure due to acquired heart disease. Because patients with tetralogy of Fallot (TOF) might have abnormal right atrial and ventricular mechanics caused by myocardial injury and remodeling, we hypothesized that RAP would be associated with disease severity and cardiovascular adverse events in this population.

Methods and Results

We performed a cohort study of adults with TOF who underwent right heart catheterization at the Mayo Clinic Rochester between 1990 and 2017. The objective was to determine the association between RAP and multiple domains of disease severity in TOF (percentage of predicted peak oxygen consumption, atrial or ventricular arrhythmia, and heart failure hospitalization), as well as cardiovascular adverse events, defined as sustained ventricular tachycardia, resuscitated or aborted sudden death, heart transplantation, or death. Among 225 patients (113 male; mean age: 39±14 years), mean RAP was 10.7±5.2 mm Hg and median was 10 mm Hg (interquartile range: 7–13 mm Hg). Increasing RAP was associated with atrial or ventricular arrhythmias (odds ratio: 5.01; 95% CI, 1.22–23.49; P<0.001), heart failure hospitalization (odds ratio: 1.47; 95% CI, 1.10–2.39; P=0.033) per 5 mm Hg, and worsening exercise capacity (peak oxygen consumption; R²=0.74, r=−0.86, P<0.001). RAP was a predictor of cardiovascular adverse events (hazard ratio: 1.28; 95% CI, 1.10–1.47; P=0.028) per 5 mm Hg.

Conclusions

In symptomatic patients with TOF, increasing RAP correlates with multiple domains of disease severity (risk stratification) and predicts future cardiovascular events (prognostication). These data have potential clinical implications in the target population of symptomatic TOF patients.

Intraoperative Management to Prevent Cardiac Collapse in a Patient With a Recurrent, Large-volume Pericardial Effusion and Paroxysmal Atrial Fibrillation During Liver Transplantation: A Case Report

BACKGROUND

Pericardial effusion is a common feature of end-stage liver disease. In this case report we describe the intraoperative management of recurrent pericardial effusion, without re-pericardiocentesis, to prevent circulatory collapse during a critical surgical time-point; that is, during manipulation of the major vessels and graft reperfusion.

METHODS

A 47-year-old woman with hepatitis B was scheduled to undergo deceased donor liver transplantation (LT). A large pericardial effusion was preoperatively identified using transthoracic echocardiography (TTE). The patient also had paroxysmal atrial fibrillation. Two days before surgery, preemptive pericardiocentesis was performed and the 1150-mL effusion was drained. Intraoperatively, recurrence of the large pericardial effusion was identified using transesophageal echocardiography (TEE). During inferior vena cava manipulation, the surgeon consulted the anesthesiologist to evaluate the hemodynamic changes in the patient. After 3 attempts, the transplant team was able to determine the most appropriate anastomosis site, defined as that with the least impact on cardiac function. To prevent the development of severe postreperfusion syndrome, 10% MgSO₄ (2 g) was gradually infused 20 minutes before portal vein declamping, and immediately before graft reperfusion a 100-μg bolus of epinephrine was administered.

RESULTS

During graft reperfusion, there was no evidence of heart chamber collapse or flow disturbance, as seen on the TEE findings. Postoperatively, the patient recovered completely and was discharged from the hospital. Six months after surgery, there was no sign of pericardial effusion on follow-up TTE.

CONCLUSION

Our intraoperative strategy may prevent cardiac collapse in patients with pericardial effusion detected during LT. Intraoperative TEE plays an important role in guiding hemodynamic management.

Invited Article: Emerging soft bioelectronics for cardiac health diagnosis and treatment

Cardiovascular diseases are among the leading causes of death worldwide. Conventional technologies for diagnosing and treating lack the compliance and comfort necessary for those living with life-threatening conditions. Soft electronics presents a promising outlet for conformal, flexible, and stretchable devices that can overcome the mechanical mismatch that is often associated with conventional technologies. Here, we review the various methods in which electronics have been made flexible and stretchable, to better interface with the human body, both externally with the skin and internally with the outer surface of the heart. Then, we review soft, wearable, noninvasive heart monitors designed to be attached to the chest or other parts of the body for mechano-acoustic and electrophysiological sensing. A common method of treatment for various abnormal heart rhythms involves catheter ablation procedures and we review the current soft bioelectronics that can be placed on the balloon or head of the catheter. Cardiac mapping is integral to determine the state of the heart; we discuss the various parameters for sensing aside from electrophysiological sensing, such as temperature, pH, strain, and tactile sensing. Finally, we review the soft devices that harvest energy from the natural and spontaneous beating of the heart by converting its mechanical motion into electrical energy to power implants.

Heart-lung interactions during mechanical ventilation: the basics

The hemodynamic effects of mechanical ventilation can be grouped into three clinically relevant concepts. First, since spontaneous ventilation is exercise. In patients increased work of breathing, initiation of mechanical ventilatory support may improve O₂ delivery because the work of breathing is reduced. Second, changes in lung volume alter autonomic tone, pulmonary vascular resistance, and at high lung volumes compress the heart in the cardiac fossa similarly to cardiac tamponade. As lung volume increases so does the pressure difference between airway and pleural pressure. When this pressure difference exceeds pulmonary artery pressure, pulmonary vessels collapse as they pass form the pulmonary arteries into the alveolar space increasing pulmonary vascular resistance. Hyperinflation increases pulmonary vascular resistance impeding right ventricular ejection. Anything that over distends lung units will increase their vascular resistance, and if occurring globally throughout the lung, increase pulmonary vascular resistance. Decreases in end-expiratory lung volume cause alveolar collapse increases pulmonary vasomotor tone by the process of hypoxic pulmonary vasoconstriction. Recruitment maneuvers that restore alveolar oxygenation without over distention will reduce pulmonary artery pressure. Third, positive-pressure ventilation increases intrathoracic pressure. Since diaphragmatic descent increases intra-abdominal pressure, the decrease in the pressure gradient for venous return is less than would otherwise occur if the only change were an increase in right atrial pressure. However, in hypovolemic states, it can induce profound decreases in venous return. Increases in intrathoracic pressure decreases left ventricular afterload and will augment left ventricular ejection. In patients with hypervolemic heart failure, this afterload reducing effect can result in improved left ventricular ejection, increased cardiac output and reduced myocardial O₂ demand. This brief review will focus primarily on mechanical ventilation and intrathoracic pressure as they affect right and left ventricular function and cardiac output.

Exercise unmasks distinct pathophysiologic features in heart failure with preserved ejection fraction and pulmonary vascular disease

Aims

Pulmonary hypertension (PH) and pulmonary vascular disease (PVD) are common and associated with adverse outcomes in heart failure with preserved ejection fraction (HFpEF). Little is known about the impact of PVD on the pathophysiology of exercise intolerance.

Methods and results

Heart failure with preserved ejection fraction patients (n = 161) with elevated pulmonary capillary wedge pressure (≥15 mmHg) at rest were classified into three groups: non-PH-HFpEF (n = 21); PH but no PVD (isolated post-capillary PH, IpcPH; n = 95); and PH with PVD (combined post- and pre-capillary PH, CpcPH; n = 45). At rest, CpcPH-HFpEF patients had more right ventricular (RV) dysfunction and lower pulmonary arterial (PA) compliance compared to all other groups. While right atrial pressure (RAP) and left ventricular transmural pressure (LVTMP) were similar in HFpEF with and without PH or PVD at rest, CpcPH-HFpEF patients demonstrated greater increase in RAP, enhanced ventricular interdependence, and paradoxical reduction in LVTMP during exercise, differing from all other groups (P < 0.05). Lower PA compliance was correlated with greater increase in RAP with exercise. During exercise, CpcPH-HFpEF patients displayed an inability to enhance cardiac output, reduction in forward stroke volume, and blunted augmentation in RV systolic performance, changes that were coupled with marked limitation in aerobic capacity.

Conclusion

Heart failure with preserved ejection fraction patients with PVD demonstrate unique haemodynamic limitations during exercise that constrain aerobic capacity, including impaired recruitment of LV preload due to excessive right heart congestion and blunted RV systolic reserve. Interventions targeted to this distinct pathophysiology require testing in patients with HFpEF and PVD.

Right heart dysfunction: from pathophysiologic insights to therapeutic options: a translational overview

: The right ventricle has become increasingly studied in cardiovascular research. In this article, we describe specific pathophysiological characteristics of the right ventricle, with special focus on functional and molecular modifications as well as therapeutic strategies in right ventricular dysfunction, underlining the differences with the left ventricle. Then we analyze the main imaging modalities to assess right ventricular function in different clinical settings. Finally, we acknowledge main therapeutic advances for treatment of right heart diseases.