LA volume by CMR distinguishes idiopathic from pulmonary hypertension due to HFpEF

Elucidating the Clinical Implications and Pathophysiology of Pulmonary Hypertension in Heart Failure With Preserved Ejection Fraction: A Call to Action: A Science Advisory From the American Heart Association

This science advisory focuses on the need to better understand the epidemiology, pathophysiology, and treatment of pulmonary hypertension in patients with heart failure with preserved ejection fraction. This clinical phenotype is important because it is common, is strongly associated with adverse outcomes, and lacks evidence-based therapies. Our goal is to clarify key knowledge gaps in pulmonary hypertension attributable to heart failure with preserved ejection fraction and to suggest specific, actionable scientific directions for addressing such gaps. Areas in need of additional investigation include refined disease definitions and interpretation of hemodynamics, as well as greater insights into noncardiac contributors to pulmonary hypertension risk, optimized animal models, and further molecular studies in patients with combined precapillary and postcapillary pulmonary hypertension. We highlight translational approaches that may provide important biological insight into pathophysiology and reveal new therapeutic targets. Last, we discuss the current and future landscape of potential therapies for patients with heart failure with preserved ejection fraction and pulmonary vascular dysfunction, including considerations of precision medicine, novel trial design, and device-based therapies, among other considerations. This science advisory provides a synthesis of important knowledge gaps, culminating in a collection of specific research priorities that we argue warrant investment from the scientific community.

The Role of the Left Atrium: From Multimodality Imaging to Clinical Practice: A Review

In recent years, new interest is growing in the left atrium (LA). LA functional analysis and measurement have an essential role in cardiac function evaluation. Left atrial size and function are key elements during the noninvasive analysis of diastolic function in several heart diseases. The LA represents a “neuroendocrine organ” with high sensitivity to the nervous, endocrine, and immune systems. New insights highlight the importance of left atrial structural, contractile, and/or electrophysiological changes, introducing the concept of “atrial cardiomyopathy”, which is closely linked to underlying heart disease, arrhythmias, and conditions such as aging. The diagnostic algorithm for atrial cardiomyopathy should follow a stepwise approach, combining risk factors, clinical characteristics, and imaging. Constant advances in imaging techniques offer superb opportunities for a comprehensive evaluation of LA function, underlying specific mechanisms, and patterns of progression. In this literature review, we aim to suggest a practical, stepwise algorithm with integrative multimodality imaging and a clinical approach for LA geometry and functional analysis. This integrates diastolic flow analysis with LA remodelling by the application of traditional and new diagnostic imaging techniques in several clinical settings such as heart failure (HF), atrial fibrillation (AF), coronary artery disease (CAD), and mitral regurgitation (MR).

Left atrial acceleration factor as a magnetic resonance 4D flow measure of mean pulmonary artery wedge pressure in pulmonary hypertension

Background

Mean pulmonary artery wedge pressure (PAWP) represents a right heart catheter (RHC) surrogate measure for mean left atrial (LA) pressure and is crucial for the clinical classification of pulmonary hypertension (PH). Hypothesizing that PAWP is related to acceleration of blood throughout the LA, we investigated whether an adequately introduced LA acceleration factor derived from magnetic resonance (MR) four-dimensional (4D) flow imaging could provide an estimate of PAWP in patients with known or suspected PH.

Methods

LA 4D flow data of 62 patients with known or suspected PH who underwent RHC and near-term 1.5 T cardiac MR (ClinicalTrials.gov identifier: NCT00575692) were retrospectively analyzed. Early diastolic LA peak outflow velocity (v_E) as well as systolic (v_S) and early diastolic (v_D) LA peak inflow velocities were determined with prototype software to calculate the LA acceleration factor (α) defined as α = v_E/[(v_S + v_D)/2]. Correlation, regression and Bland-Altman analysis were employed to investigate the relationship between α and PAWP, α-based diagnosis of elevated PAWP (>15 mmHg) was analyzed by receiver operating characteristic curve analysis.

Results

α correlated very strongly with PAWP (r = 0.94). Standard deviation of differences between RHC-derived PAWP and PAWP estimated from linear regression model (α = 0.61 + 0.10·PAWP) was 2.0 mmHg. Employing the linear-regression-derived cut-off α = 2.10, the α-based diagnosis of elevated PAWP revealed the area under the curve 0.97 with sensitivity/specificity 93%/92%.

Conclusions

The very close relationship between the LA acceleration factor α and RHC-derived PAWP suggests α as potential non-invasive parameter for the estimation of PAWP and the distinction between pre- and post-capillary PH.

MRI Feature Tracking Strain in Pulmonary Hypertension: Utility of Combined Left Atrial Volumetric and Deformation Assessment in Distinguishing Post- From Pre-capillary Physiology

Aims

Pulmonary hypertension (PH) is dichotomized into pre- and post-capillary physiology by invasive catheterization. Imaging, particularly strain assessment, may aid in classification and be helpful with ambiguous hemodynamics. We sought to define cardiac MRI (CMR) feature tracking biatrial peak reservoir and biventricular peak systolic strain in pre- and post-capillary PH and examine the performance of peak left atrial strain in distinguishing the 2 groups compared to TTE.

Methods and Results

Retrospective cross-sectional study from 1 Jan 2015 to 31 Dec 2020; 48 patients (22 pre- and 26 post-capillary) were included with contemporaneous TTE, CMR and catheterization. Mean pulmonary artery pressures were higher in the pre-capillary cohort (55 ± 14 vs. 42 ± 9 mmHg; p < 0.001) as was pulmonary vascular resistance (median 11.7 vs. 3.7 WU; p < 0.001). Post-capillary patients had significantly larger left atria (60 ± 22 vs. 25 ± 9 ml/m2; p < 0.001). There was no difference in right atrial volumes between groups (60 ± 21 vs. 61 ± 29 ml/m2; p = 0.694), however peak RA strain was lower in post-capillary PH patients (8.9 ± 5.5 vs. 18.8 ± 7.0%; p < 0.001). In the post-capillary group, there was commensurately severe peak strain impairment in both atria (LA strain 9.0 ± 5.8%, RA strain 8.9 ± 5.5%). CMR LAVi and peak LA strain had a multivariate AUC of 0.98 (95% CI 0.89–1.00; p < 0.001) for post-capillary PH diagnosis which was superior to TTE.

Conclusion

CMR volumetric and deformation assessment of the left atrium can highly accurately distinguish post- from pre-capillary PH.

Diagnostic accuracy of automated 3D volumetry of cardiac chambers by CT pulmonary angiography for identification of pulmonary hypertension due to left heart disease

OBJECTIVES

To assess diagnostic accuracy of automated 3D volumetry of cardiac chambers based on computed tomography pulmonary angiography (CTPA) for the differentiation of pulmonary hypertension due to left heart disease (group 2 PH) from non-group 2 PH compared to manual diameter measurements.

METHODS

Patients with confirmed PH undergoing right heart catheterisation and CTPA within 100 days for diagnostic workup of PH between August 2013 and February 2016 were included in this retrospective, single-centre study. Automated 3D segmentation of left atrium, left ventricle, right atrium and right ventricle (LA/LV/RA/RV) was performed by two independent and blinded radiologists using commercial software. For comparison, axial diameters were manually measured. The ability to differentiate group 2 PH from non-group 2 PH was assessed by means of logistic regression.

RESULTS

Ninety-one patients (median 67.5 years, 44 women) were included, thereof 19 patients (20.9%) classified as group 2 PH. After adjustment for age, sex and mean pulmonary arterial pressure, group 2 PH was significantly associated with larger LA volume (p < 0.001), larger LV volume (p = 0.001), lower RV/LV volume ratio (p = 0.04) and lower RV/LA volume ratio (p = 0.003). LA volume demonstrated the highest discriminatory ability to identify group 2 PH (AUC, 0.908; 95% confidence interval, 0.835-0.981) and was significantly superior to LA diameter (p = 0.009). Intraobserver and interobserver agreements were excellent for all volume measurements (intraclass correlation coefficients 0.926-0.999, all p < 0.001).

CONCLUSIONS

LA volume quantified by automated, CTPA-based 3D volumetry can differentiate group 2 PH from other PH groups with good diagnostic accuracy and yields significantly higher diagnostic accuracy than left atrial diameter.

KEY POINTS

• Automated cardiac chamber volumetry using non-gated CT pulmonary angiography can differentiate pulmonary hypertension due to left heart disease from other causes with good diagnostic accuracy. • Left atrial volume yields significantly higher diagnostic accuracy than left atrial axial diameter for identification of pulmonary hypertension due to left heart disease without time-consuming manual processing.

Cardiovascular magnetic resonance predicts all-cause mortality in pulmonary hypertension associated with heart failure with preserved ejection fraction

This study aimed to determine the prognostic value of cardiovascular magnetic resonance (CMR) in patients with heart failure with preserved ejection fraction and associated pulmonary hypertension (pulmonary hypertension-HFpEF). Patients with pulmonary hypertension-HFpEF were recruited from the ASPIRE registry and underwent right heart catheterisation (RHC) and CMR. On RHC, the inclusion criteria was a mean pulmonary artery pressure (MPAP) ≥ 25 mmHg and pulmonary arterial wedge pressure > 15 mmHg and, on CMR, a left atrial volume > 41 ml/m² with left ventricular ejection fraction > 50%. Cox regression was performed to evaluate CMR against all-cause mortality. In this study, 116 patients with pulmonary hypertension-HFpEF were identified. Over a mean follow-up period of 3 ± 2 years, 61 patients with pulmonary hypertension-HFpEF died (53%). In univariate regression, 11 variables demonstrated association to mortality: indexed right ventricular (RV) volumes and stroke volume, right ventricular ejection fraction (RVEF), indexed RV mass, septal angle, pulmonary artery systolic/diastolic area and its relative area change. In multivariate regression, only three variables were independently associated with mortality: RVEF (HR 0.64, P < 0.001), indexed RV mass (HR 1.46, P < 0.001) and IV septal angle (HR 1.48, P < 0.001). Our CMR model had 0.76 area under the curve (P < 0.001) to predict mortality. This study confirms that pulmonary hypertension in patients with HFpEF is associated with a poor prognosis and we observe that CMR can risk stratify these patients and predict all-cause mortality. When patients with HFpEF develop pulmonary hypertension, CMR measures that reflect right ventricular afterload and function predict all-cause mortality.

Impact of the new definition of pulmonary hypertension according to world symposium of pulmonary hypertension 2018 on diagnosis of post-capillary pulmonary hypertension

BACKGROUND

The World Symposium on Pulmonary Hypertension (WSPH) in 2018 recommended new definitions of pulmonary hypertension (PH). We investigated the impact of the updated definition on prevalence of PH due to left heart disease (PH-LHD).

METHODS

The data of right heart catheterizations in patients with suspected PH-LHD between January 2008 and July 2015 was retrospectively analyzed applying different definitions. The number of patients diagnosed by the updated WSPH hemodynamic criteria of a mean pulmonary artery pressure (mPAP) > 20 mmHg was compared to the number of patients using mPAP ≥ 25 mmHg. The differentiation between patients with isolated post-capillary (Ipc) and combined post-capillary and pre-capillary (Cpc) PH was analyzed comparing the ESC/ERS guidelines, the recommendation of Cologne Consensus Conference (CCC) and WSPH.

RESULTS

Of the 726 patients with a suspected PH, 58 patients met the diagnostic criteria of the ESC/ERS guidelines for PH-LHD with 32.8% Ipc-cases, 34.4% Cpc-PH-cases and 32.8% unclassifiable cases. Overall, 58 patients were diagnosed by the CCC criteria, with 34.5% classified as Cpc-PH and 65.5% as Icp-PH. Using the criteria of WSPH, the number of PH-LHD rose by one patient. According to the new definition, 64.4% of the patients were classified as Cpc-PH and had a significantly higher right to left atrial area (RA/LA) ratio than Ipc-PH patients.

CONCLUSION

Applying the new recommendation, the number of diagnosed patients with PH-LHD increases marginally. There is, however, a relevant shift in the number of Cpc-PH cases. An elevated RA/LA ratio might help to identify patients for invasive diagnostic work-up.

Elevated Pulmonary Pressure Noted on Echocardiogram: A Simplified Approach to Next Steps

An elevated right ventricular/pulmonary artery systolic pressure suggestive of pulmonary hypertension (PH) is a common finding noted on echocardiography and is considered a marker for poor clinical outcomes, regardless of the cause. Even mild elevation of pulmonary pressure can be considered a modifiable risk factor, informing the trajectory of patients' clinical outcome. Although guidelines have been published detailing diagnostic and management algorithms, this echocardiographic finding is often underappreciated or not acted upon. Hence, patients with PH are often diagnosed in clinical practice when hemodynamic abnormalities are already moderate or severe. This results in delayed initiation of potentially effective therapies, referral to PH centers, and greater patient morbidity and mortality. This mini‐review presents a succinct, simplified case‐based approach to the “next steps” in the work‐up of PH, once elevated pulmonary pressures have been noted on an echocardiogram. Our goal is for clinicians to develop a good overview of diagnostic approach to PH and recognition of high‐risk features that may require early referral.

Cardiac Magnetic Resonance-Derived Indexed Volumes and Volume Ratios of the Cardiac Chambers Discriminating Group 2 Pulmonary Hypertension From Other World Health Organization Groups

OBJECTIVE

The aims of the study were to assess the performance of cardiac magnetic resonance (CMR)-derived cardiac chamber volumes and volume ratios to identify group 2 pulmonary hypertension (PH) patients and to determine their cutoff values with the highest sensitivity and specificity.

METHODS

One hundred six patients underwent CMR, 2 months after the diagnosis of PH by right heart catheterization. We classified patients with pulmonary capillary wedge pressure of greater than 15 mm Hg as group 2 PH. Cardiac chamber volumes indexed to the body surface area and volume ratios were correlated to the type of PH. Their sensitivity and specificity to detect group 2 PH were examined at various cutoff points.

RESULTS

The most appropriate cutoff values to designate group 2 PH patients with high sensitivity and specificity were as follows: left atrium volume index of 54.72 mL/m2 or greater, right ventricle volume/left atrium volume of 2.07 or less, and right atrium volume/left atrium volume of 1.61 or less.

CONCLUSIONS

Cardiac magnetic resonance-derived cardiac chamber volume indices and volume ratios can determine group 2 PH diagnosis with high sensitivity and specificity.

Underfilling decreases left ventricular function in pulmonary arterial hypertension

To evaluate the association between impaired left ventricular (LV) longitudinal function and LV underfilling in patients with pulmonary arterial hypertension (PAH). Thirty-nine patients with PAH and 18 age and sex-matched healthy controls were included. LV volume and left atrial volume (LAV) were delineated in short-axis cardiac magnetic resonance (CMR) cine images. LV longitudinal function was assessed from atrio-ventricular plane displacement (AVPD) and global longitudinal strain (GLS) was assessed using feature tracking in three long-axis views. LV filling was assessed by LAV and by pulmonary artery wedge pressure (PAWP) using right heart catheterisation. Patients had a smaller LAV, LV volume and stroke volume as well as a lower LV-AVPD and LV-GLS than controls. PAWP was 6 [IQR 5––9] mmHg in patients. LV ejection fraction did not differ between groups. LV stroke volume correlated with LV-AVPD (r = 0.445, p = .001), LV-GLS (r = − 0.549, p < 0.0001) and LAVmax (r = .585, p < 0.0001). Furthermore, LV-AVPD (r = .598) and LV-GLS (r = − 0.675) correlated with LAVmax (p < 0.0001 for both). Neither LV-AVPD, LV-GLS, LAVmax nor stroke volume correlated with PAWP. Impaired LV longitudinal function was associated with low stroke volume, low PAWP and a small LAV in PAH. Small stroke volumes and LAV, together with normal LA pressure, implies that the mechanism causing reduced LV longitudinal function is underfilling rather than an intrinsic LV dysfunction in PAH.

A machine learning cardiac magnetic resonance approach to extract disease features and automate pulmonary arterial hypertension diagnosis

AIMS

Pulmonary arterial hypertension (PAH) is a progressive condition with high mortality. Quantitative cardiovascular magnetic resonance (CMR) imaging metrics in PAH target individual cardiac structures and have diagnostic and prognostic utility but are challenging to acquire. The primary aim of this study was to develop and test a tensor-based machine learning approach to holistically identify diagnostic features in PAH using CMR, and secondarily, visualize and interpret key discriminative features associated with PAH.

METHODS AND RESULTS

Consecutive treatment naive patients with PAH or no evidence of pulmonary hypertension (PH), undergoing CMR and right heart catheterization within 48 h, were identified from the ASPIRE registry. A tensor-based machine learning approach, multilinear subspace learning, was developed and the diagnostic accuracy of this approach was compared with standard CMR measurements. Two hundred and twenty patients were identified: 150 with PAH and 70 with no PH. The diagnostic accuracy of the approach was high as assessed by area under the curve at receiver operating characteristic analysis (P < 0.001): 0.92 for PAH, slightly higher than standard CMR metrics. Moreover, establishing the diagnosis using the approach was less time-consuming, being achieved within 10 s. Learnt features were visualized in feature maps with correspondence to cardiac phases, confirming known and also identifying potentially new diagnostic features in PAH.

CONCLUSION

A tensor-based machine learning approach has been developed and applied to CMR. High diagnostic accuracy has been shown for PAH diagnosis and new learnt features were visualized with diagnostic potential.

Emerging role of cardiovascular magnetic resonance imaging in the management of pulmonary hypertension

Pulmonary hypertension (PH) is a clinical condition characterised by elevation of pulmonary arterial pressure (PAP) above normal range due to various aetiologies. While cardiac right-heart catheterisation (RHC) remains the gold standard and mandatory for establishing the diagnosis of PH, noninvasive imaging of the heart plays a central role in the diagnosis and management of all forms of PH. Although Doppler echocardiography (ECHO) can measure a range of haemodynamic and anatomical variables, it has limited utility for visualisation of the pulmonary artery and, oftentimes, the right ventricle. Cardiovascular magnetic resonance (CMR) provides comprehensive information about the anatomical and functional aspects of the pulmonary artery and right ventricle that are of prognostic significance for assessment of long-term outcomes in disease progression. CMR is suited for serial follow-up of patients with PH due to its noninvasive nature, high sensitivity to changes in anatomical and functional parameters, and high reproducibility. In recent years, there has been growing interest in the use of CMR derived parameters as surrogate endpoints for early-phase PH clinical trials. This review will discuss the role of CMR in the diagnosis and management of PH, including current applications and future developments, in comparison to other existing major imaging modalities.

Novel imaging techniques in pulmonary hypertension

PURPOSE OF REVIEW

Pulmonary hypertension is a life-shortening condition, which may be idiopathic but is more frequently seen in association with other conditions. Current guidelines recommend cardiac catheterization to confirm the diagnosis of pulmonary hypertension. Evidence suggests an increasing role for noninvasive imaging modalities in the initial diagnostic and prognostic assessment and evaluation of treatment response.

RECENT FINDINGS

In this review we examine the evidence for current noninvasive imaging methodologies: echocardiography computed tomography and MRI in the diagnostic and prognostic assessment of suspected pulmonary hypertension and explore the potential utility of modeling and machine-learning approaches.

SUMMARY

Noninvasive imaging allows a comprehensive assessment of patients with suspected pulmonary hypertension. It plays a key part in the initial diagnostic and prognostic assessment and machine-learning approaches show promise in the diagnosis of pulmonary hypertension.

Echocardiographic Detection of Occult Diastolic Dysfunction in Pulmonary Hypertension After Fluid Challenge

Background Identification of occult diastolic dysfunction often requires invasive right heart catheterization with provocative maneuvers such as fluid challenge. Non-invasive predictors of occult diastolic dysfunction have not been identified. We hypothesized that echocardiographic measures of diastolic function are associated with occult diastolic dysfunction identified at catheterization. Methods and Results We retrospectively examined hemodynamic and echocardiographic data from consecutive patients referred for right heart catheterization with fluid challenge from 2009 to 2017. A replication cohort of 52 patients who prospectively underwent simultaneous echocardiography and right heart catheterization before and after fluid challenge at Monaldi Hospital, Naples, Italy. In the retrospective cohort of 126 patients (83% female, 56+14 years), 27/126 (21%) had occult diastolic dysfunction. After adjusting for tricuspid regurgitant velocity and left atrial volume index, E velocity (odds ratio 1.8, 95% CI 1.1-2.9, P=0.01) and E/e' (odds ratio 1.9, 95% CI 1.1-3, P=0.005) were associated with occult diastolic dysfunction with an optimal threshold of E/e' >8.6 for occult diastolic dysfunction (sensitivity 70%, specificity 64%). In the prospective cohort, 5/52 (10%) patients had diastolic dysfunction after fluid challenge. Resting E/e' (odds ratio 8.75, 95% CI 2.3-33, P=0.001) and E velocity (odds ratio 7.7, 95% CI 2-29, P=0.003) remained associated with occult diastolic dysfunction with optimal threshold of E/e' >8 (sensitivity 73%, specificity 90%). Conclusions Among patients referred for right heart catheterization with fluid challenge, E velocity and E/e' are associated with occult diastolic dysfunction after fluid challenge. These findings suggest that routine echocardiographic measurements may help identify patients like to have occult diastolic dysfunction non-invasively.

Non-invasive Multimodality Cardiovascular Imaging of the Right Heart and Pulmonary Circulation in Pulmonary Hypertension

Pulmonary hypertension (PH) is defined as resting mean pulmonary arterial pressure (mPAP) ≥25 millimeters of mercury (mmHg) via right heart (RH) catheterization (RHC), where increased afterload in the pulmonary arterial vasculature leads to alterations in RH structure and function. Mortality rates have remained high despite therapy, however non-invasive imaging holds the potential to expedite diagnosis and lead to earlier initiation of treatment, with the hope of improving prognosis. While historically the right ventricle (RV) had been considered a passive chamber with minimal role in the overall function of the heart, in recent years in the evaluation of PH and RH failure the anatomical and functional assessment of the RV has received increased attention regarding its performance and its relationship to other structures in the RH-pulmonary circulation. Today, the RV is the key determinant of patient survival. This review provides an overview and summary of non-invasive imaging methods to assess RV structure, function, flow, and tissue characterization in the setting of imaging's contribution to the diagnostic, severity stratification, prognostic risk, response of treatment management, and disease surveillance implications of PH's impact on RH dysfunction and clinical RH failure.

Diagnosis of Pulmonary Hypertension with Cardiac MRI: Derivation and Validation of Regression Models

Purpose To derive and test multiparametric cardiac MRI models for the diagnosis of pulmonary hypertension (PH). Materials and Methods Images and patient data from consecutive patients suspected of having PH who underwent cardiac MRI and right-sided heart catheterization (RHC) between 2012 and 2016 were retrospectively reviewed. Of 2437 MR images identified, 603 fit the inclusion criteria. The mean patient age was 61 years (range, 18-88 years; mean age of women, 60 years [range, 18-84 years]; mean age of men, 62 years [range, 22-88 years]). In the first 300 patients (derivation cohort), cardiac MRI metrics that showed correlation with mean pulmonary arterial pressure (mPAP) were used to create a regression algorithm. The performance of the model was assessed in the 303-patient validation cohort by using receiver operating characteristic (ROC) and χ2 analysis. Results In the derivation cohort, cardiac MRI mPAP model 1 (right ventricle and black blood) was defined as follows: -179 + loge interventricular septal angle × 42.7 + log10 ventricular mass index (right ventricular mass/left ventricular mass) × 7.57 + black blood slow flow score × 3.39. In the validation cohort, cardiac MRI mPAP model 1 had strong agreement with RHC-measured mPAP, an intraclass coefficient of 0.78, and high diagnostic accuracy (area under the ROC curve = 0.95; 95% confidence interval [CI]: 0.93, 0.98). The threshold of at least 25 mm Hg had a sensitivity of 93% (95% CI: 89%, 96%), specificity of 79% (95% CI: 65%, 89%), positive predictive value of 96% (95% CI: 93%, 98%), and negative predictive value of 67% (95% CI: 53%, 78%) in the validation cohort. A second model, cardiac MRI mPAP model 2 (right ventricle pulmonary artery), which excludes the black blood flow score, had equivalent diagnostic accuracy (ROC difference: P = .24). Conclusion Multiparametric cardiac MRI models have high diagnostic accuracy in patients suspected of having pulmonary hypertension. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Colletti in this issue.

Insights into the pulmonary vascular complications of heart failure with preserved ejection fraction

Pulmonary hypertension in the setting of heart failure with preserved ejection fraction (PH-HFpEF) is a growing public health problem that is increasing in prevalence. While PH-HFpEF is defined by a high mean pulmonary artery pressure, high left ventricular end-diastolic pressure and a normal ejection fraction, some HFpEF patients develop PH in the presence of pulmonary vascular remodelling with a high transpulmonary pressure gradient or pulmonary vascular resistance. Ageing, increased left atrial pressure and stiffness, mitral regurgitation, as well as features of metabolic syndrome, which include obesity, diabetes and hypertension, are recognized as risk factors for PH-HFpEF. Qualitative studies have documented that patients with PH-HFpEF develop more severe symptoms than those with HFpEF and are associated with more significant exercise intolerance, frequent hospitalizations, right heart failure and reduced survival. Currently, there are no effective therapies for PH-HFpEF, although a number of candidate drugs are being evaluated, including soluble guanylate cyclase stimulators, phosphodiesterase type 5 inhibitors, sodium nitrite and endothelin receptor antagonists. In this review we attempt to provide an updated overview of recent findings pertaining to the pulmonary vascular complications in HFpEF in terms of clinical definitions, epidemiology and pathophysiology. Mechanisms leading to pulmonary vascular remodelling in HFpEF, a summary of pre-clinical models of HFpEF and PH-HFpEF, and new candidate therapeutic strategies for the treatment of PH-HFpEF are summarized.

Identifying At-Risk Patients with Combined Pre- and Postcapillary Pulmonary Hypertension Using Interventricular Septal Angle at Cardiac MRI

Purpose To assess interventricular septal (IVS) angle in the identification of combined pre- and postcapillary pulmonary hypertension (Cpc-PH) in patients with pulmonary hypertension (PH) due to left-sided heart disease. Materials and Methods In this retrospective study, consecutive, incident patients suspected of having PH underwent same-day right-sided heart catheterization (RHC) and MRI at a PH referral center between April 2012 and April 2017. The diagnostic accuracy of the IVS angle to identify Cpc-PH in patients with pulmonary arterial wedge pressure (PAWP) greater than 15 mmHg was assessed by using receiver operator characteristic curves, sensitivity, specificity, and negative and positive predictive values. IVS angle also was assessed as a predictor of all-cause mortality by using Cox uni- and multivariable proportional hazards regression. Results A total of 708 patients underwent same-day MRI and RHC, and 171 patients had PAWP greater than 15 mmHg. Mean age was 70 years (range, 21-90 years) (women: mean age, 69 years; range, 21-88 years) (men: mean age, 71 years; range, 43-90 years). Systolic IVS angle correlated with diastolic pulmonary gradient (DPG) (r = 0.739, P < .001). Receiver operating characteristic curve analysis showed septal angle enabled identification of Cpc-PH (DPG ≥ 7), with an area under the receiver operating characteristic curve of 0.911 (P < .001). A 160° threshold, derived from the first half of patients with raised PAWP, enabled identification of a DPG of at least 7 mmHg with 67% sensitivity and 93% specificity (P < .001) in the second cohort of patients with raised PAWP. IVS angle was predictive of all-cause mortality (standardized univariable hazard ratio, 1.615; P < .01). Conclusion The systolic interventricular septal angle is elevated in patients with combined pre- and postcapillary pulmonary hypertension and enables one to predict those patients who have PH due to left-sided heart disease who have an increased risk of death. Published under a CC BY 4.0 license. Online supplemental material is available for this article.

CT derived left atrial size identifies left heart disease in suspected pulmonary hypertension: Derivation and validation of predictive thresholds

Background

Patients with pulmonary hypertension due to left heart disease (PH-LHD) have overlapping clinical features with pulmonary arterial hypertension making diagnosis reliant on right heart catheterization (RHC). This study aimed to investigate computed tomography pulmonary angiography (CTPA) derived cardiopulmonary structural metrics, in comparison to magnetic resonance imaging (MRI) for the diagnosis of left heart disease in patients with suspected pulmonary hypertension.

Methods

Patients with suspected pulmonary hypertension who underwent CTPA, MRI and RHC were identified. Measurements of the cardiac chambers and vessels were recorded from CTPA and MRI. The diagnostic thresholds of individual measurements to detect elevated pulmonary arterial wedge pressure (PAWP) were identified in a derivation cohort (n = 235). Individual CT and MRI derived metrics were tested in validation cohort (n = 211).

Results

446 patients, of which 88 had left heart disease. Left atrial area was a strong predictor of elevated PAWP>15 mm Hg and PAWP>18 mm Hg, area under curve (AUC) 0.854, and AUC 0.873 respectively. Similar accuracy was also identified for MRI derived LA volume, AUC 0.852 and AUC 0.878 for PAWP > 15 and 18 mm Hg, respectively. Left atrial area of 26.8 cm² and 30.0 cm² were optimal specific thresholds for identification of PAWP > 15 and 18 mm Hg, had sensitivity of 60%/53% and specificity 89%/94%, respectively in a validation cohort.

Conclusions

CTPA and MRI derived left atrial size identifies left heart disease in suspected pulmonary hypertension with high specificity. The proposed diagnostic thresholds for elevated left atrial area on routine CTPA may be a useful to indicate the diagnosis of left heart disease in suspected pulmonary hypertension.

•

Routine CTPA can diagnose left heart disease in suspected pulmonary hypertension.

•

Complex multiparameter models do not improve LHD diagnosis.

•

Highly specific thresholds have been derived and validated.

The importance of integrated left atrial evaluation: From hypertension to heart failure with preserved ejection fraction

AIM

Functional analysis and measurement of left atrium are an integral part of cardiac evaluation, and they represent a key element during non-invasive analysis of diastolic function in patients with hypertension (HT) and/or heart failure with preserved ejection fraction (HFpEF). However, diastolic dysfunction remains quite elusive regarding classification, and atrial size and function are two key factors for left ventricular (LV) filling evaluation. Chronic left atrial (LA) remodelling is the final step of chronic intra-cavitary pressure overload, and it accompanies increased neurohormonal, proarrhythmic and prothrombotic activities. In this systematic review, we aim to purpose a multi-modality approach for LA geometry and function analysis, which integrates diastolic flow with LA characteristics and remodelling through application of both traditional and new diagnostic tools.

METHODS

The most important studies published in the literature on LA size, function and diastolic dysfunction in patients with HFpEF, HT and/or atrial fibrillation (AF) are considered and discussed.

RESULTS

In HFpEF and HT, pulsed and tissue Doppler assessments are useful tools to estimate LV filling pressure, atrio-ventricular coupling and LV relaxation but they need to be enriched with LA evaluation in terms of morphology and function. An integrated evaluation should be also applied to patients with a high arrhythmic risk, in whom eccentric LA remodelling and higher LA stiffness are associated with a greater AF risk.

CONCLUSION

Evaluation of LA size, volume, function and structure are mandatory in the management of patients with HT, HFpEF and AF. A multi-modality approach could provide additional information, identifying subjects with more severe LA remodelling. Left atrium assessment deserves an accurate study inside the cardiac imaging approach and optimised measurement with established cut-offs need to be better recognised through multicenter studies.

Non-invasive imaging of global and regional cardiac function in pulmonary hypertension

Pulmonary hypertension (PH) is a progressive illness characterized by elevated pulmonary artery pressure; however, the main cause of mortality in PH patients is right ventricular (RV) failure. Historically, improving the hemodynamics of pulmonary circulation was the focus of treatment; however, it is now evident that cardiac response to a given level of pulmonary hemodynamic overload is variable but plays an important role in the subsequent prognosis. Non-invasive tests of RV function to determine prognosis and response to treatment in patients with PH is essential. Although the right ventricle is the focus of attention, it is clear that cardiac interaction can cause left ventricular dysfunction, thus biventricular assessment is paramount. There is also focus on the atrial chambers in their contribution to cardiac function in PH. Furthermore, there is evidence of regional dysfunction of the two ventricles in PH, so it would be useful to understand both global and regional components of dysfunction. In order to understand global and regional cardiac function in PH, the most obvious non-invasive imaging techniques are echocardiography and cardiac magnetic resonance imaging (CMRI). Both techniques have their advantages and disadvantages. Echocardiography is widely available, relatively inexpensive, provides information regarding RV function, and can be used to estimate RV pressures. CMRI, although expensive and less accessible, is the gold standard of biventricular functional measurements. The advent of 3D echocardiography and techniques including strain analysis and stress echocardiography have improved the usefulness of echocardiography while new CMRI technology allows the measurement of strain and measuring cardiac function during stress including exercise. In this review, we have analyzed the advantages and disadvantages of the two techniques and discuss pre-existing and novel forms of analysis where echocardiography and CMRI can be used to examine atrial, ventricular, and interventricular function in patients with PH at rest and under stress.

A simple echocardiographic score for the diagnosis of pulmonary vascular disease in heart failure

AIMS

A simple echocardiographic score was designed for diagnosing precapillary vs postcapillary pulmonary hypertension and for discriminating between isolated postcapillary pulmonary hypertension (Ipc-PH) and combined precapillary and postcapillary pulmonary hypertension (Cpc-PH).

METHODS

The score comprised 7 points (2 for E/e' ratio ≤10, 2 for a dilated non-collapsible inferior vena cava, 1 for a left ventricular eccentricity index ≥1.2, 1 for a right-to-left heart chamber dimension ratio >1 and 1 for the right ventricle forming the heart apex) and was applied to 230 consecutive patients referred for evaluation of pulmonary hypertension.

RESULTS

Precapillary pulmonary hypertension and postcapillary pulmonary hypertension were diagnosed in 160 and 70 patients, respectively. In the latter, Ipc-PH was found in 51 and Cpc-PH in 19. The echo score was higher in precapillary vs postcapillary pulmonary hypertension patients (4.2 ± 1.7 vs 1.6 ± 1.7, P < 0.001) and in patients with Cpc-PH vs Ipc-PH (2.7 ± 2.1 vs 1.2 ± 1.3, P = 0.001). The sensitivity and specificity of the echo score at least 2 for precapillary pulmonary hypertension were 99 and 54%, respectively (area under the curve 0.85). In patients with postcapillary pulmonary hypertension, the sensitivity and specificity of the echo score at least 2 for Cpc-PH were 63 and 82% (area under the curve 0.73).

CONCLUSION

A simple echocardiographic score helps in the differential diagnosis between precapillary and postcapillary pulmonary hypertension, and between Ipc-PH and Cpc-PH.

Pulmonary hypertension

In 2015, more than 800 papers were published in the field of pulmonary hypertension. A Clinical Year in Review article cannot possibly incorporate all this work and needs to be selective. The recently published European guidelines for the diagnosis and treatment of pulmonary hypertension contain an inclusive summary of all published clinical studies conducted until very recently. Here, we provide an overview of papers published after the finalisation of the guideline. In addition, we summarise recent advances in pulmonary vasculature science. The selection we made from the enormous amount of published work undoubtedly reflects our personal views and may not include all papers with a significant impact in the near or more distant future. The focus of this paper is on the diagnosis of pulmonary arterial hypertension, understanding the success of combination therapy on the right ventricle and scientific breakthroughs.

Evolving Concepts of Pulmonary Hypertension Secondary to Left Heart Disease

Pulmonary hypertension associated with left heart disease is the most common form of pulmonary hypertension. Although its pathophysiology remains incompletely understood, it is now well recognized that the presence of pulmonary hypertension is associated with a worse prognosis. Right ventricular failure has independent and additive prognostic value over pulmonary hypertension for adverse outcomes in left heart disease. Recently, several new terminologies have been introduced to better define and characterize the nature and severity of pulmonary hypertension. Several new treatment options including the use of pulmonary arterial hypertension specific therapies are being considered, but there is lack of evidence. Here, we review the recent advances in this field and summarize the diagnostic and therapeutic modalities of use in the management of pulmonary hypertension associated with left heart disease.

CTA-derived left to right atrial size ratio distinguishes between pulmonary hypertension due to heart failure and idiopathic pulmonary arterial hypertension

BACKGROUND/OBJECTIVES

Assessing atrial sizes by routine non-gated CT-angiography (CTA) could be of value in discriminating between pulmonary hypertension (PH) due to heart failure with preserved ejection fraction (HFpEF) and idiopathic pulmonary arterial hypertension (IPAH). We aimed to determine how left (LA) and right atrial (RA) sizes on non-gated CTA can help discriminate between these patients.

METHODS AND RESULTS

In an initial study, CMR was used in 15 IPAH and 15 PH-HFpEF patients to determine LA- and RA size throughout the cardiac cycle. While significant variations were noted in LA size over the cardiac cycle, the calculated ratio of left over right atrial size (LA/RA ratio) remained stable in both groups and discriminated between PH-HFpEF and IPAH. In a second study, routine non-gated CTA was used to validate the diagnostic use of a LA/RA ratio in 95 consecutive treatment-naive patients with a final diagnosis of either IPAH (n=64) or PH-HFpEF (n=31). ROC analyses were conducted to determine the discriminative properties of atrial size parameters. On a transversal view, LA size was 19cm² (±5) in the IPAH group versus 27cm² (±6) in the PH-HFpEF group (p<0.001). CTA derived LA/RA ratio was significantly higher in PH-HFpEF patients compared to IPAH patients and had good discriminative abilities (AUC=0.833).

CONCLUSIONS

Assessing LA/RA size ratio by non-gated CTA allows for accurate discrimination between PH-HFpEF and IPAH patients. Because CTA is often available in the early diagnostic work-up, a LA/RA size ratio may guide clinical and diagnostic decision-making, even before invasive hemodynamic measurements.

A Simple Derived Prediction Score for the Identification of an Elevated Pulmonary Artery Wedge Pressure Using Precatheterization Clinical Data in Patients Referred to a Pulmonary Hypertension Center

BACKGROUND

One of the foremost diagnostic challenges in clinical pulmonary hypertension is discriminating between pulmonary arterial hypertension (group 1) and heart failure with preserved ejection fraction (group 2.2). Group 2.2 is defined as a normal left ventricular ejection fraction (> 50%) and a pulmonary arterial wedge pressure (PAWP) > 15 mm Hg. We aimed to determine whether patient history, demographics, and noninvasive measures could predict PAWP before to right heart catheterization.

METHODS

Data were prospectively collected on 350 consecutive patients at a single tertiary care medical center; of these patients, 151 met criteria for entry into our study (88 in group 1 and 63 in group 2.2). Data included historical features, demographics, and results of a transthoracic echocardiogram. A multivariate regression model was developed to predict PAWP > 15 mm Hg.

RESULTS

Univariate predictors of PAWP > 15 mm Hg included older age, higher BMI and weight, systemic systolic BP and pulse pressure, more features of the metabolic syndrome, presence of hypertension and left atrial enlargement, absence of right ventricular enlargement, and lower glomerular filtration rate and 6-min walk distance. The optimal model for predicting PAWP > 15 mm Hg was composed of age (> 68 years), BMI (> 30 kg/m(2)), absence of right ventricular enlargement, and presence of left atrial enlargement (area under the curve, 0.779).

CONCLUSIONS

Clinical characteristics obtained before diagnostic right heart catheterization accurately predict the probability of elevation of PAWP > 15 mm Hg in patients with preserved ejection fraction. These combined clinical characteristics can be used a priori to predict the likelihood of group 2.2 pulmonary hypertension.

Imaging the heart in pulmonary hypertension: an update

Noninvasive imaging of the heart plays an important role in the diagnosis and management of pulmonary hypertension (PH), and several well-established techniques are available for assessing performance of the right ventricle, the key determinant of patient survival. While right heart catheterisation is mandatory for establishing a diagnosis of PH, echocardiography is the most important screening tool for early detection of PH. Cardiac magnetic resonance imaging (CMRI) is also a reliable and practical tool that can be used as part of the diagnostic work-up. Echocardiography can measure a range of haemodynamic and anatomical variables (e.g. pericardial effusion and pulmonary artery pressure), whereas CMRI provides complementary information to echocardiography via high-resolution, three-dimensional imaging. Together with echocardiography and CMRI, techniques such as high-resolution computed tomography and positron emission tomography may also be valuable for screening, monitoring and follow-up assessments of patients with PH, but their clinical relevance has yet to be established. Technological advances have produced new variants of echocardiography, CMRI and positron emission tomography, and these permit closer examination of myocardial architecture, motion and deformation. Integrating these new tools into clinical practice in the future may lead to more precise noninvasive determination of diagnosis, risk and prognosis for PH.

Management of pulmonary arterial hypertension

Pulmonary hypertension (PH) is common and may result from a number of disorders, including left heart disease, lung disease, and chronic thromboembolic disease. Pulmonary arterial hypertension (PAH) is an uncommon disease characterized by progressive remodeling of the distal pulmonary arteries, resulting in elevated pulmonary vascular resistance and, eventually, in right ventricular failure. Over the past decades, knowledge of the basic pathobiology of PAH and its natural history, prognostic indicators, and therapeutic options has exploded. A thorough evaluation of a patient is critical to correctly characterize the PH. Cardiac studies, including echocardiography and right heart catheterization, are key elements in the assessment. Given the multitude of treatment options currently available for PAH, assessment of risk and response to therapy is critical in long-term management. This review also underscores unique situations, including perioperative management, intensive care unit management, and pregnancy, and highlights the importance of collaborative care of the PAH patient through a multidisciplinary approach.

Noninvasive identification of left-sided heart failure in a population suspected of pulmonary arterial hypertension

Exclusion of pulmonary hypertension secondary to left-sided heart disease (left heart failure (LHF)) is pivotal in the diagnosis of pulmonary arterial hypertension (PAH). In case of doubt, invasive measurements are recommended. The aim of the present study was to investigate whether it is possible to diagnose LHF using noninvasive parameters in a population suspected of PAH.300 PAH and 80 LHF patients attended our pulmonary hypertension clinic before August 2010, and were used to build the predictive model. 79 PAH and 55 LHF patients attended our clinic from August 2010, and were used for prospective validation.A medical history of left heart disease, S deflection in V1 plus R deflection in V6 in millimetres on ECG, and left atrial dilation or left valvular heart disease that is worse than mild on echocardiography were independent predictors of LHF. The derived risk score system showed good predictive characteristics: R(2)=0.66 and area under the curve 0.93. In patients with a risk score ≥72, there is 100% certainty that the cause of pulmonary hypertension is LHF. Using this risk score system, the number of right heart catheterisations in LHF may be reduced by 20%.In a population referred under suspicion of PAH, a predictive model incorporating medical history, ECG and echocardiography data can diagnose LHF noninvasively in a substantial percentage of cases.