Pulmonary arterial pressure during rest and exercise in healthy subjects: a systematic review

Raising the bar to ultradisciplinary collaborations in management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is an underdiagnosed and potentially fatal subgroup of pulmonary hypertension, if left untreated. Clinical signs include exertional dyspnea and non-specific symptoms. Diagnosis requires multimodality imaging and heart catheterization. Pulmonary endarterectomy, an open heart surgery, is the gold standard treatment of choice in selected patients in specialized centers. Targeted medical therapy and balloon pulmonary angioplasty can be effective in high-risk patients with significant comorbidities, distal pulmonary vascular obstructions, or recurrent/persistent pulmonary hypertension after pulmonary endarterectomy. Currently, there is a limited number of data regarding novel coronavirus-2019 infection in patients with chronic thromboembolic pulmonary hypertension and the changing spectrum of the disease during the pandemic. Challenging times during this outbreak due to healthcare crisis and relatively higher case-fatality rates require convergence; that is an ultradisciplinary collaboration, which crosses disciplinary and sectorial boundaries to develop integrated knowledge and new paradigms. Management strategies for the "new normal" such as virtual care, preparedness for further threats, redesigned standards and working conditions, reevaluation of specific recommendations, and online collaborations for optimal decisions for chronic thromboembolic pulmonary hypertension patients may change the poor outcomes.

Optimal Tricuspid Regurgitation Velocity to Screen for Pulmonary Hypertension in Tertiary Referral Centers

BACKGROUND

A mean pulmonary artery pressure >20 mmHg now defines pulmonary hypertension. We hypothesize that echocardiographic thresholds need to be adjusted.

RESEARCH QUESTION

Should TRV thresholds to screen for PH be revised given the new hemodynamic definition?

STUDY DESIGN AND METHODS

This multicenter retrospective study included 1,608 patients that underwent both echocardiography and right heart catherization within four weeks. The discovery cohort consisted of 1,081 individuals and the validation cohort included 527. Screening criteria for pulmonary hypertension were derived using receiver operating characteristic analysis and the Youden index assuming equal cost for false positive and negative classification. A lower threshold was calculated using a predefined sensitivity: 95%.

RESULTS

In the discovery cohort, echocardiographic tricuspid regurgitation velocity had a good discrimination for pulmonary hypertension, AUC 88.4 (95% CI, 85.3-91.5). A 3.4 m/s threshold provided a 78% sensitivity, 87% specificity, and 6.13 positive likelihood ratio to detect pulmonary hypertension. 2.7 m/s had a 95% sensitivity and 0.12 negative likelihood ratio to exclude pulmonary hypertension. In the validation cohort, the discovery threshold of 2.7 m/s provided a sensitivity and negative likelihood ratio of 80% and 0.34, respectively. Right cardiac size improved detection of pulmonary hypertension in the lower tricuspid regurgitation velocity groups.

INTERPRETATION

Our data support a lower tricuspid regurgitation velocity around 2.7 m/s for screening pulmonary hypertension with a high sensitivity in tertiary referral centers. Right heart chamber measurements improve the diagnostic yield of echocardiography.

Exercise intolerance in pulmonary arterial hypertension: insight into central and peripheral pathophysiological mechanisms

Exercise intolerance is a cardinal symptom of pulmonary arterial hypertension (PAH) and strongly impacts patients' quality of life (QoL). Although central cardiopulmonary impairments limit peak oxygen consumption (V' O2peak ) in patients with PAH, several peripheral abnormalities have been described over the recent decade as key determinants in exercise intolerance, including impaired skeletal muscle (SKM) morphology, convective O2 transport, capillarity and metabolism indicating that peripheral abnormalities play a greater role in limiting exercise capacity than previously thought. More recently, cerebrovascular alterations potentially contributing to exercise intolerance in patients with PAH were also documented. Currently, only cardiopulmonary rehabilitation has been shown to efficiently improve the peripheral components of exercise intolerance in patients with PAH. However, more extensive studies are needed to identify targeted interventions that would ultimately improve patients' exercise tolerance and QoL. The present review offers a broad and comprehensive analysis of the present literature about the complex mechanisms and their interactions limiting exercise in patients and suggests several gaps in knowledge that need to be addressed in the future for a better understanding of exercise intolerance in patients with PAH.

Pediatric Pulmonary Hypertension: Definitions, Mechanisms, Diagnosis, and Treatment

Pediatric pulmonary hypertension (PPH) is a multifactorial disease with diverse etiologies and presenting features. Pulmonary hypertension (PH), defined as elevated pulmonary artery pressure, is the presenting feature for several pulmonary vascular diseases. It is often a hidden component of other lung diseases, such as cystic fibrosis and bronchopulmonary dysplasia. Alterations in lung development and genetic conditions are an important contributor to pediatric pulmonary hypertensive disease, which is a distinct entity from adult PH. Many of the causes of pediatric PH have prenatal onset with altered lung development due to maternal and fetal conditions. Since lung growth is altered in several conditions that lead to PPH, therapy for PPH includes both pulmonary vasodilators and strategies to restore lung growth. These strategies include optimal alveolar recruitment, maintaining physiologic blood gas tension, nutritional support, and addressing contributing factors, such as airway disease and gastroesophageal reflux. The outcome for infants and children with PH is highly variable and largely dependent on the underlying cause. The best outcomes are for neonates with persistent pulmonary hypertension (PPHN) and reversible lung diseases, while some genetic conditions such as alveolar capillary dysplasia are lethal. © 2021 American Physiological Society. Compr Physiol 11:2135-2190, 2021.

Incidence of Swimming-Induced Pulmonary Edema: A Cohort Study Based on 47,600 Open-Water Swimming Distances

Background

Despite increasing awareness of swimming-induced pulmonary edema (SIPE), large population-based studies are lacking and the incidence is unknown.

Research Question

What is the incidence of SIPE in a mixed group of competitive and recreational swimmers during a large open-water swimming event?

Methods

In four consecutive years (2016-2019), a prospective cohort study was conducted during Sweden’s largest open-water swimming event, Vansbrosimningen. All swimmers seeking medical care with acute respiratory symptoms were eligible for the study. SIPE diagnosis was based on clinical findings in 2016 and 2017 and pulmonary edema assessed by lung ultrasound in 2018 and 2019. Data on patient characteristics, clinical findings, and information about the race were collected.

Results

Based on 47,573 consecutive swimming distances, 322 patients with acute respiratory symptoms (0.68%; CI, 0.61%-0.75%) were treated at the mobile medical unit. Of these, 211 patients (0.44%; CI, 0.39%-0.51%) received a diagnosis of SIPE. The annual incidence of SIPE was 0.34%, 0.47%, 0.41%, and 0.57%, respectively, from 2016 through 2019. Most patients diagnosed with SIPE were women (90%), despite about equal percentages of men and women participating (47% men and 53% women). The incidence of SIPE overall was 0.75% in women and 0.09% in men. The incidence increased with age, from 0.08% in the youngest age group (18-30 years) to 1.1% in the oldest age group (≥ 61 years). Based on multiple logistic regression analysis, the adjusted odds for SIPE occurring was 8.59 times higher for women compared with men and 12.74 times higher for the oldest age group compared with the youngest age group.

Interpretation

The incidence of SIPE over 4 years during a large open-water swimming event in Sweden was 0.44%. The incidence was higher in women than in men and increased with age.

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.

2020 KSC/KATRD guideline for the diagnosis and treatment of pulmonary hypertension: Executive summary

Pulmonary hypertension (PH) is a condition of increased blood pressure in the pulmonary arteries and is diagnosed with an increased a mean pulmonary artery pressure ≥25 mm Hg. This condition may be associated with multiple clinical situations. Based on pathophysiological mechanisms, clinical presentation, hemodynamic profiles, and treatment strategies, the patients were classified into five clinical groups. Although there have been major advances in the management of PH, it is still associated with significant morbidity and mortality. The diagnosis and treatment of PH have been performed mainly by following European guidelines, even in Korea because the country lacks localized PH guidelines. European treatment guidelines do not reflect the actual status of Korea. Therefore, the European diagnosis and treatment of PH have not been tailored well to suit the needs of Korean patients with PH. To address this issue, we developed this guideline to facilitate the diagnosis and treatment of PH appropriately in Korea, a country where the consensus for the diagnosis and treatment of PH remains insufficient. This is the first edition of the guidelines for the diagnosis and treatment of PH in Korea, and it is primarily based on the ‘2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension.’ with the acceptance and adaptation of recent publications of PH.

The role of imaging in pulmonary hypertension

Pulmonary hypertension (PH) is a debilitating and potentially life threatening condition in which increased pressure in the pulmonary arteries may result from a variety of pathological processes. These can include disease primarily involving the pulmonary vasculature, but more commonly PH may result from left-sided heart disease, including valvular heart disease. Chronic thromboembolic pulmonary hypertension (CTEPH) is an important disease to identify because it may be amenable to surgical pulmonary artery endarterectomy or balloon pulmonary angioplasty. Parenchymal lung diseases are also widespread in the community. Any of these disease processes may result in adverse remodeling of the right ventricle and progressive right heart (RH) failure as a common final pathway. Because of the breadth of pathological processes which cause PH, multiple imaging modalities play vital roles in ensuring accurate diagnosis and classification, which will lead to application of the most appropriate therapy. Multimodality imaging may also provide important prognostic information and has a role in the assessment of response to therapies which ultimately dictate clinical outcomes. This review provides an overview of the wide variety of established imaging techniques currently in use, but also examines many of the novel imaging techniques which may be increasingly utilized in the future to guide comprehensive care of patients with PH.

High Right Ventricular Afterload during Exercise in Patients with Pulmonary Arterial Hypertension

The right ventricle (RV) is more sensitive to an increase in afterload than the left ventricle (LV), and RV afterload during exercise increases more easily than LV afterload. Pulmonary arterial hypertension (PAH)-specific therapy has improved pulmonary hemodynamics at rest; however, the pulmonary hemodynamic response to exercise is still abnormal in most patients with PAH. In these patients, RV afterload during exercise could be higher, resulting in a greater increase in RV wall stress. Recently, an increasing number of studies have indicated the short-term efficacy of exercise training. However, considering the potential risk of promoting myocardial maladaptive remodeling, even low-intensity repetitive exercise training could lead to long-term clinical deterioration. Further studies investigating the long-term effects on the RV and pulmonary vasculature are warranted. Although the indications for exercise training for patients with PAH have been expanding, exercise training may be associated with various risks. Training programs along with risk stratification based on the pulmonary hemodynamic response to exercise may enhance the safety of patients with PAH.

How low should we go? Potential benefits and ramifications of the pulmonary hypertension hemodynamic definitions proposed by the 6th World Symposium

PURPOSE OF REVIEW

The 6th World Symposium on Pulmonary Hypertension (WSPH) proposed lowering the mean pulmonary artery pressure (mPAP) threshold that defines pulmonary hypertension from ≥ 25 to > 20 mmHg. The historical context and evolution of the pulmonary hypertension definition and the data used to rationalize recent changes are reviewed here.

RECENT FINDINGS

There are accumulating data on the clinical significance of mildly elevated mPAPs (21-24 mmHg). Studies have demonstrated lower exercise capacity and an increased risk of progression to overt pulmonary hypertension (mPAP ≥ 25 mmHg) in specific at-risk patient populations. Further, large registries across diverse pulmonary hypertension populations have identified increased mortality in patients with mPAPs 21-24 mmHg. Although the clinical sequelae of lowering the mPAP threshold remain unclear, this uncertainty has fueled recent debates within the pulmonary hypertension community.

SUMMARY

The changes to the pulmonary hypertension definition proposed by the 6th WSPH are supported by normative hemodynamic data in healthy individuals as well as studies demonstrating an association between mPAPs above this normal range and increased mortality. Whether the higher mortality observed in patients with mildly elevated mPAPs is directly attributable to pulmonary vascular disease that is amenable to therapeutic intervention remains to be determined.

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.

Validity of echocardiographic tricuspid regurgitation gradient to screen for new definition of pulmonary hypertension

BACKGROUND

Currently an echocardiographic threshold for the tricuspid regurgitation gradient (TRG) of > 31 mmHg is recommended for screening for pulmonary hypertension (PH). Invasively diagnosed PH was recently redefined as mean pulmonary arterial pressure (mPAP) > 20 mmHg instead of ≥ 25 mmHg. We investigated the ability of TRG to screen for the new PH-definition.

METHODS

Retrospective assessment of echocardiography and right heart catheterisation data from 1572 patients entering the Giessen PH-Registry during 2008-2018. Accuracy of different TRG thresholds and other echocardiographic parameters was evaluated using receiver operating characteristic curves.

FINDINGS

1264 patients fulfilled the new PH-definition. Positive (PPV) and negative predictive values and accuracy of TRG > 46 mmHg were 95%, 39%, and 73%, respectively, for the new PH-definition. Lowering the TRG cut-off to 31 mmHg and below worsened PPV to ≤ 89%. The PPV of TRG for pre-capillary PH (mPAP > 20 mmHg and pulmonary vascular resistance ≥ 3 Wood Units) was ≤ 85%. In patients with TRG ≤ 46 mmHg, tricuspid annular plane systolic excursion/TRG and TRG/right ventricular outflow tract acceleration time were superior to TRG in screening for newly defined pre-capillary PH.

INTERPRETATION

In patients with suspected PH referred to a tertiary care centre, the PPV of TRG to meet the new PH-definition depended strongly on the TRG cut-off used. Our data do not support lowering the TRG cut-off. Combining TRG with other echocardiographic parameters might improve the validity of echocardiographic screening for PH.

Invasive Hemodynamic and Metabolic Evaluation of HFpEF

Purpose of review

Heart failure with preserved ejection fraction (HFpEF) is a complex and heterogeneous condition of multiple causes, characterized by a clinical syndrome resulting from elevated left ventricular filling pressures, with an apparently unimpaired left ventricular systolic function. Although HFpEF has been long recognized as a distinct entity with significant morbidity for patients, its diagnosis remains challenging to this day. In recent years, few diagnostic algorithms have been postulated to aid in the identification of this condition. Invasive hemodynamic and metabolic evaluation is often warranted for the conclusive diagnosis and risk stratification of HFpEF, in patients presenting with undifferentiated DOE.

Recent findings

Rest and provoked hemodynamics remain the golden-standard diagnostic tool to unequivocally confirm the diagnosis of both established and incipient HFpEF, respectively. Cycle exercise hemodynamics is the paramount provocative maneuver to unveil this condition. Rapid saline loading does not offer a significant benefit over that of cycle exercise. Vasoactive agents can also uncover and confirm incipient HFpEF disease. The role of metabolic evaluation in patients presenting with idiopathic dyspnea on exertion (DOE) is of unparalleled value for those who have expertise in cardiopulmonary exercise test (CPET) interpretation; however, the average clinician who focuses solely on oxygen consumption will find it underwhelming. Invasive CPET stands alone as the ultimate diagnostic tool to discriminate between pulmonary, cardiovascular, and skeletal muscle disorders, and their respective contribution to DOE and exercise intolerance.

Summary

Several hemodynamic and metabolic parameters have demonstrated not only strong diagnostic value, but also predictive power in HFpEF. Additionally, these diagnostic methods have given rise to several therapeutic interventions that are now part of our clinical armamentarium. Regrettably, due to the heterogeneity and multicausality of HFpEF, none of the targeted interventions have been so far successful in decreasing the mortality burden of this prevalent condition.

Mildly Elevated Pulmonary Arterial Pressure Is Associated With a High Risk of Progression to Pulmonary Hypertension and Increased Mortality: A Systematic Review and Meta-Analysis

Background

Pulmonary hypertension (PH) is defined as a mean pulmonary arterial pressure (PAP) ≥25 mm Hg measured by right heart catheterization. However, the upper limit of a normal mean PAP is 20 mm Hg. There is a gap between the upper limit of normal and the threshold for diagnosing PH. Therefore, we aimed to investigate whether individuals with a mildly elevated PAP, defined as 20 mm Hg < mean PAP <25 mm Hg, are at an increased risk of progression to PH or mortality than those with a normal PAP.

Methods and Results

We reviewed studies evaluating the risk of progression to PH and/or mortality in individuals with a mildly elevated PAP versus those with a normal PAP. The mean PAP value of each participant was confirmed by right heart catheterization. We reviewed 1213 studies and 8 fulfilled our inclusion criteria. Our results indicated that individuals with a mildly elevated PAP were 1.81 to 2.45 times more likely to progress to PH than individuals with a normal PAP. There was a statistically significant difference in mortality between the mildly elevated PAP and normal PAP groups (hazard ratio, 2.48; 95% CI, 1.69–3.64). We also pooled survival probabilities in each arm to obtain a summary survival curve for each group, and the pooled survival rates in the mildly elevated PAP group were numerically lower than those in the normal PAP group.

Conclusions

Our study revealed that individuals with a mildly elevated PAP were at an increased risk of progression to PH and mortality than those with a normal PAP.

Potassium (K+) channels in the pulmonary vasculature: Implications in pulmonary hypertension Physiological, pathophysiological and pharmacological regulation

The large K⁺ channel functional diversity in the pulmonary vasculature results from the multitude of genes expressed encoding K⁺ channels, alternative RNA splicing, the post-transcriptional modifications, the presence of homomeric or heteromeric assemblies of the pore-forming α-subunits and the existence of accessory β-subunits modulating the functional properties of the channel. K⁺ channels can also be regulated at multiple levels by different factors controlling channel activity, trafficking, recycling and degradation. The activity of these channels is the primary determinant of membrane potential (Em) in pulmonary artery smooth muscle cells (PASMC), providing an essential regulatory mechanism to dilate or contract pulmonary arteries (PA). K⁺ channels are also expressed in pulmonary artery endothelial cells (PAEC) where they control resting Em, Ca²⁺ entry and the production of different vasoactive factors. The activity of K⁺ channels is also important in regulating the population and phenotype of PASMC in the pulmonary vasculature, since they are involved in cell apoptosis, survival and proliferation. Notably, K⁺ channels play a major role in the development of pulmonary hypertension (PH). Impaired K⁺ channel activity in PH results from: 1) loss of function mutations, 2) downregulation of its expression, which involves transcription factors and microRNAs, or 3) decreased channel current as a result of increased vasoactive factors (e.g., hypoxia, 5-HT, endothelin-1 or thromboxane), exposure to drugs with channel-blocking properties, or by a reduction in factors that positively regulate K⁺ channel activity (e.g., NO and prostacyclin). Restoring K⁺ channel expression, its intracellular trafficking and the channel activity is an attractive therapeutic strategy in PH.

Combined pre- and post-capillary pulmonary hypertension: The clinical implications for patients with heart failure

BACKGROUND

The prognostic implications of combined pre- and post-capillary pulmonary hypertension (Cpc-PH) in patients with pulmonary hypertension due to left heart disease (PH-LHD) remain controversial. The aim of this retrospective study was to evaluate the new PH-LHD criteria, recommended by the 6th World Symposium on Pulmonary Hypertension and to determine the prognostic value of Cpc-PH.

METHODS

A total of 701 patients with symptomatic heart failure who had undergone right-heart catheterization were divided into the following four groups: (i) Isolated post-capillary PH (Ipc-PH) group; mean pulmonary artery pressure (mPAP) >20 mmHg, pulmonary artery wedge pressure (PAWP) >15 mmHg, and pulmonary vascular resistance (PVR) <3 Wood units (WU) (ii) Cpc-PH group; mPAP >20 mmHg, PAWP >15 mmHg, and PVR ≥3 WU (iii) borderline-PH group; mPAP >20 mmHg and PAWP ≤15 mmHg (iv) non-PH group; mPAP ≤20 mmHg. Multivariate Cox hazard analysis was used to investigate whether Cpc-PH was associated with cardiac outcomes.

RESULTS

The study subjects were allocated into the Ipc-PH (n = 268), Cpc-PH (n = 54), borderline-PH (n = 112), or non-PH (n = 267) groups. The Cpc-PH group was associated significantly with adverse cardiac events even after adjustment for clinically relevant confounding factors for heart failure prognosis (vs. non-PH group: HR 2.98 [95% CI 1.81-4.90], P <0.001; vs. Ipc-PH group: HR: 1.92 [95% CI 1.19-3.08], P = 0.007).

CONCLUSIONS

The new definitions of PH-LHD stratified patients into 4 categories. Long-term clinical outcomes were significantly different between the four categories, with Cpc-PH having the worst cardiac outcomes.

Cardiopulmonary Hemodynamics in Pulmonary Hypertension and Heart Failure: JACC Review Topic of the Week

Pulmonary hypertension (PH) is an independent risk factor for adverse clinical outcome, particularly in left heart disease (LHD) patients. Recent advances have clarified the mean pulmonary artery pressure (mPAP) range that is above normal and is associated with clinical events, including mortality. This progress has for the first time resulted in a new clinical definition of PH that is evidenced-based, is inclusive of mPAP >20 mm Hg, and emphasizes early diagnosis. Additionally, pulmonary vascular resistance (PVR) 2.2 to 3.0 WU, considered previously to be normal, appears to associate with elevated clinical risk. A revised approach to classifying PH patients as pre-capillary, isolated post-capillary, or combined pre-/post-capillary PH now guides point-of-care diagnosis, risk stratification, and treatment. Exercise hemodynamic or confrontational fluid challenge studies may also aid decision-making for patients with PH-LHD or otherwise unexplained dyspnea. This collective progress in pulmonary vascular and heart failure medicine reinforces the critical importance of accurate hemodynamic assessment.

Pulmonary hypertension in heart failure

PURPOSE OF REVIEW

Pulmonary hypertension (PH) occurs frequently in heart failure (HF) and confers worse prognosis. It becomes important to adequately identify these patients to optimize treatment. The purpose of this review is to inform about the updated classification of PH in left heart disease, in addition to current and upcoming trials regarding treatment.

RECENT FINDINGS

The updated classification of PH due to left heart disease now utilizes pulmonary vascular resistance instead of diastolic pulmonary gradient to differentiate between isolated postcapillary and combined pre and postcapillary PH. In regards to treatment, recent clinical trials continue to provide data that pulmonary vasodilators do not improve outcomes in this population.

SUMMARY

Management of underlying heart disease and optimal control of comorbidities continues to be the mainstay of treatment in PH due to HF. At this time, current data does not support the use of PH-directed therapies.

Pulmonary vasodilation by sildenafil in acute intermediate-high risk pulmonary embolism: a randomized explorative trial

BACKGROUND

To investigate if acute pulmonary vasodilation by sildenafil improves right ventricular function in patients with acute intermediate-high risk pulmonary embolism (PE).

METHODS

Single center, explorative trial. Patients with PE were randomized to a single oral dose of sildenafil 50 mg (n = 10) or placebo (n = 10) as add-on to conventional therapy. The time from hospital admission to study inclusion was 2.3 ± 0.7 days. Right ventricular function was evaluated immediately before and shortly after (0.5-1.5 h) randomization by right heart catheterization (RHC), trans-thoracic echocardiography (TTE), and cardiac magnetic resonance (CMR). The primary efficacy endpoint was cardiac index measured by CMR.

RESULTS

Patients had acute intermediate-high risk PE verified by computed tomography pulmonary angiography, systolic blood pressure of 135 ± 18 (mean ± SD) mmHg, increased right ventricular/left ventricular ratio 1.1 ± 0.09 and increased troponin T 167 ± 144 ng/L. Sildenafil treatment did not improve cardiac index compared to baseline (0.02 ± 0.36 l/min/m2, p = 0.89) and neither did placebo (0.00 ± 0.34 l/min/m2, p = 0.97). Sildenafil lowered mean arterial blood pressure (- 19 ± 10 mmHg, p < 0.001) which was not observed in the placebo group (0 ± 9 mmHg, p = 0.97).

CONCLUSION

A single oral dose of sildenafil 50 mg did not improve cardiac index but lowered systemic blood pressure in patients with acute intermediate-high risk PE. The time from PE to intervention, a small patient sample size and low pulmonary vascular resistance are limitations of this study that should be considered when interpreting the results.

TRIAL REGISTRATION

The trial was retrospectively registered at www.clinicaltrials.gov (NCT04283240) February 2nd 2020, https://clinicaltrials.gov/ct2/show/NCT04283240?term=NCT04283240&draw=2&rank=1 .

Update on Perioperative Pediatric Pulmonary Hypertension Management

Pediatric pulmonary hypertension is a disease that has many etiologies and can present anytime during childhood. Its newly revised hemodynamic definition follows that of adult pulmonary hypertension: a mean pulmonary artery pressure >20 mmHg. However, the pediatric definition stipulates that the elevated pressure must be present after the age of three months. The definition encompasses many different etiologies, and diagnosis often involves a combination of noninvasive and invasive testing. Treatment often is extrapolated from adult studies or based on expert opinion. Moreover, although general anesthesia may be required for pediatric patients with pulmonary hypertension, it poses certain risks. A thoughtful, multidisciplinary approach is needed to deliver excellent perioperative care.

Biventricular function in exercise during autonomic (thoracic epidural) block

BACKGROUND

Blockade of cardiac sympathetic fibers by thoracic epidural anesthesia (TEA) was previously shown to reduce right and left ventricular systolic function and effective pulmonary arterial elastance. At conditions of constant paced heart rate, cardiac output and systemic hemodynamics were unchanged. In this study, we further investigated the effect of cardiac sympathicolysis during physical stress and increased oxygen demand.

METHODS

In a cross-over design, 12 patients scheduled to undergo thoracic surgery performed dynamic ergometric exercise tests with and without TEA. Hemodynamics were monitored and biventricular function was measured by transthoracic two-dimensional and M-mode echocardiography, pulsed wave Doppler and tissue Doppler imaging.

RESULTS

TEA attenuated systolic RV function (TV S': - 21%, P < 0.001) and LV function (MV S': - 14%, P = 0.025), but biventricular diastolic function was not affected. HR (- 11%, P < 0.001), SVI (- 15%, P = 0.006), CI (- 21%, P < 0.001) and MAP (- 12%, P < 0.001) were decreased during TEA, but SVR was not affected. Exercise resulted in significant augmentation of systolic and diastolic biventricular function. During exercise HR, SVI, CI and MAP increased (respectively, + 86%, + 19%, + 124% and + 17%, all P < 0.001), whereas SVR decreased (- 49%, P < 0.001). No significant interactions between exercise and TEA were found, except for RPP (P = 0.024) and MV E DT (P = 0.035).

CONCLUSION

Cardiac sympathetic blockade by TEA reduced LV and RV systolic function but did not significantly blunt exercise-induced increases in LV and RV function. These data indicate that additional mechanisms besides those controlled by the cardiac sympathetic nervous system are involved in the regulation of cardiac function during dynamic exercise. Trial registration Clinical trial registration: Nederlands Trial Register, NTR 4880 http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4880 .

Goar F, Kaiser CA. First-in-Human Experience of Mechanical Preload Control in Patients With HFpEF During Exercise

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Heart failure patients demonstrate pulmonary hypertension during exertion that correlates with limitations in exercise capacity.

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Titrated partial occlusion of the IVC through balloon inflation (mechanical preload control) during exercise significantly reduced PA pressure by 25% (from 68 ± 7 mm Hg to 51 ± 7 mm Hg) with no significant reduction in peak VO₂ (from 16.4 ± 5.8 ml/kg/min to 16.2 ± 4.0 ml/kg/min) or cardiac output (14.4 ± 5.9 l/min to 12.8 ± 2.9 l/min).

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Mechanical preload control trended toward longer exercise times and significantly reduced respiratory rate at matched exercise, suggesting that pulmonary pressures directly contribute to exercise limitations and hyperventilation in heart failure patients.

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Mechanical preload control may serve as a novel research and treatment strategy for heart failure patients.

Exercise intolerance remains one of the major factors determining quality of life in heart failure patients. In 6 patients with heart failure with preserved ejection fraction (HFpEF) undergoing invasive cardiopulmonary exercise testing, balloon inflation within the inferior vena cava (IVC) was performed during exercise to reduce and maintain pulmonary arterial (PA) pressures. Partial IVC occlusion significantly reduced PA pressures without reducing cardiac output. Partial IVC occlusion significantly reduced respiratory rate at matched levels of exercise. These findings highlight the importance of pulmonary pressures in the pathophysiology of HFpEF and suggest that therapies targeting hemodynamics may improve symptoms and exercise capacity in these patients.

Exercise right ventricular ejection fraction predicts right ventricular contractile reserve

BACKGROUND

Right ventricular (RV) contractile reserve shows promise as an indicator of occult RV dysfunction in pulmonary vascular disease. We investigated which measure of RV contractile reserve during exercise best predicts occult RV dysfunction and clinical outcomes.

METHODS

We prospectively studied RV contractile reserve in 35 human subjects referred for right heart catheterization for known or suspected pulmonary hypertension. All underwent cardiac magnetic resonance imaging, echocardiography, and supine invasive cardiopulmonary exercise testing with concomitant RV pressure-volume catheterization. Event-free survival was prospectively adjudicated from time of right heart catheterization for a 4-year follow-up period.

RESULTS

RV contractile reserve during exercise, as measured by a positive change in end-systolic elastance (Ees) during exertion, was associated with elevation in pulmonary pressures but preservation of RV volumes. Lack of RV reserve, on the other hand, was tightly coupled with acute RV dilation during exertion (R² = 0.76, p< 0.001). RV Ees and dilation changes each predicted resting RV-PA dysfunction. RV ejection fraction during exercise, which captured exertional changes in both RV Ees and RV dilation, proved to be a robust surrogate for RV contractile reserve. Reduced exercise RV ejection fraction best predicted occult RV dysfunction among a variety of resting and exercise RV measures, and was also associated with clinical worsening.

CONCLUSIONS

RV ejection fraction during exercise, as an index of RV contractile reserve, allows for excellent identification of occult RV dysfunction, more so than resting measures of RV function, and may predict clinical outcomes as well.

Exercise Right Heart Catheterisation in Cardiovascular Diseases: A Guide to Interpretation and Considerations in the Management of Valvular Heart Disease

The use of exercise right heart catheterisation for the assessment of cardiovascular diseases has regained attention recently. Understanding physiologic haemodynamic exercise responses is key for the identification of abnormal haemodynamic patterns. Exercise total pulmonary resistance >3 Wood units identifies a deranged haemodynamic response and when total pulmonary resistance exceeds 3 Wood units, an exercise pulmonary artery wedge pressures/cardiac output slope >2 mmHg/l/min indicates the presence of underlying exercise-induced pulmonary hypertension related to left heart disease. In the evolving field of transcatheter interventions for valvular heart disease, exercise right heart catheterisation may objectively unmask symptoms and underlying haemodynamic abnormalities. Further studies are needed on the use of the procedure to inform the selection of patients who might receive the most benefit from transcatheter interventions for valvular heart diseases.

The Challenge to Decide between Pulmonary Hypertension Due to Chronic Lung Disease and PAH with Chronic Lung Disease

Chronic lung diseases are strongly associated with pulmonary hypertension (PH), and even mildly elevated pulmonary arterial pressures are associated with increased mortality. Chronic obstructive pulmonary disease (COPD) is the most common chronic lung disease, but few of these patients develop severe PH. Not all these pulmonary pressure elevations are due to COPD, although patients with severe PH due to COPD may represent the largest subgroup within patients with COPD and severe PH. There are also patients with left heart disease (group 2), chronic thromboembolic disease (group 4, CTEPH) and pulmonary arterial hypertension (group 1, PAH) who suffer from COPD or another chronic lung disease as co-morbidity. Because therapeutic consequences very much depend on the cause of pulmonary hypertension, it is important to complete the diagnostic procedures and to decide on the main cause of PH before any decision on PAH drugs is made. The World Symposia on Pulmonary Hypertension (WSPH) have provided guidance for these important decisions. Group 2 PH or complex developmental diseases with elevated postcapillary pressures are relatively easy to identify by means of elevated pulmonary arterial wedge pressures. Group 4 PH can be identified or excluded by perfusion lung scans in combination with chest CT. Group 1 PAH and Group 3 PH, although having quite different disease profiles, may be difficult to discern sometimes. The sixth WSPH suggests that severe pulmonary hypertension in combination with mild impairment in the pulmonary function test (FEV1 > 60 and FVC > 60%), mild parenchymal abnormalities in the high-resolution CT of the chest, and circulatory limitation in the cardiopulmonary exercise test speak in favor of Group 1 PAH. These patients are candidates for PAH therapy. If the patient suffers from group 3 PH, the only possible indication for PAH therapy is severe pulmonary hypertension (mPAP ≥ 35 mmHg or mPAP between 25 and 35 mmHg together with very low cardiac index (CI) < 2.0 L/min/m²), which can only be derived invasively. Right heart catheter investigation has been established nearly 100 years ago, but there are many important details to consider when reading pulmonary pressures in spontaneously breathing patients with severe lung disease. It is important that such diagnostic procedures and the therapeutic decisions are made in expert centers for both pulmonary hypertension and chronic lung disease.

[Differential Diagnosis of Pulmonary Hypertension Using the Example of Collagenosis-associated PAH in the Context of Chronic Lung and Left Heart Disease]

Pulmonary hypertension (PH) can be diagnosed in the context of connective tissue diseases (CTD) as well as in elderly patients with multiple comorbidities. A correct clinical differential diagnosis and classification is essential before adequate therapeutic decisions can be made. Differential diagnosis of PH in CTD comprises associated pulmonary arterial hypertension (APAH), group 2 or 3 PH (PH arising from left heart or chronic lung disease), chronic thromboembolic PH (PH) and group 5 (e. g. in the context of terminal renal insufficiency). This is also true of elderly patients in whom the decision has to be made if the increasing number of coincident diseases lead to PH or have to be interpreted as comorbidities. In this manuscript, the differential diagnosis of PH is elucidated, focusing on CTD, in the context of left heart disease and chronic lung disease. Furthermore, criteria are presented facilitating an objective approach in this context.

Risk Stratification in Acute Pulmonary Embolism: The Latest Algorithms

Pulmonary embolism (PE) is a common clinical entity, which most clinicians will encounter. Appropriate risk stratification of patients is key to identify those who may benefit from reperfusion therapy. The first step in risk assessment should be the identification of hemodynamic instability and, if present, urgent patient consideration for systemic thrombolytics. In the absence of shock, there is a plethora of imaging studies, biochemical markers, and clinical scores that can be used to further assess the patients' short-term mortality risk. Integrated prediction models incorporate more information toward an individualized and precise mortality prediction. Additionally, bleeding risk scores should be utilized prior to initiation of anticoagulation and/or reperfusion therapy administration. Here, we review the latest algorithms for a comprehensive risk stratification of the patient with acute PE.

Vital capacity and valvular dysfunction could serve as non-invasive predictors to screen for exercise pulmonary hypertension in the elderly based on a new diagnostic score

Introduction: Exercise pulmonary hypertension (exPH) has been defined as total pulmonary resistance (TPR) >3 mm Hg/L/min and mean pulmonary artery pressure (mPAP) >30 mm Hg, albeit with a considerable risk of false positives in elderly patients with lower cardiac output during exercise.

Methods: We retrospectively analysed patients with unclear dyspnea receiving right heart catheterisation at rest and exercise (n=244) between January 2015 and January 2020. Lung function testing, blood gas analysis, and echocardiography were performed. We elaborated a combinatorial score to advance the current definition of exPH in an elderly population (mean age 67.0 years±11.9). A stepwise regression model was calculated to non-invasively predict exPH.

Results: Analysis of variables across the achieved peak power allowed the creation of a model for defining exPH, where three out of four criteria needed to be fulfilled: Peak power ≤100 Watt, pulmonary capillary wedge pressure ≥18 mm Hg, pulmonary vascular resistance >3 Wood Units, and mPAP ≥35 mm Hg. The new scoring model resulted in a lower number of exPH diagnoses than the current suggestion (63.1% vs. 78.3%). We present a combinatorial model with vital capacity (VC_max) and valvular dysfunction to predict exPH (sensitivity 93.2%; specificity 44.2%, area under the curve 0.73) based on our suggested criteria. The odds of the presence of exPH were 2.1 for a 1 l loss in VC_max and 3.6 for having valvular dysfunction.

Conclusion: We advance a revised definition of exPH in elderly patients in order to overcome current limitations. We establish a new non-invasive approach to predict exPH by assessing VC_max and valvular dysfunction for early risk stratification in elderly patients.

Echocardiographic predictors of exercise induced pulmonary hypertension in patients with asymptomatic moderate to severe mitral regurgitation and preserved left ventricular ejection fraction

BACKGROUND

The significant role of mitral regurgitation (MR) in development of pulmonary hypertension (PH) has been proved in previous studies. Experts suggest systolic pulmonary arterial pressure (SPAP) ⩾60 mmHg during exercise as a significant threshold of negative prognostic value in patients with MR.

PURPOSE

The aim of this study was to evaluate the changes of SPAP and to ascertain the determinants of exercise induced pulmonary hypertension (EIPH) in patients with asymptomatic primary MR.

METHODS

We performed a prospective study that included 50 patients with asymptomatic primary moderate to severe MR with preserved left ventricular ejection fraction (LV EF ⩾60%) at rest. They were divided into two groups according to the presence (PH group; n = 13) or absence (non-PH group; n = 37) of EIPH. Rest and stress (bicycle ergometry) echocardiography and speckle-tracking offline analysis were performed.

RESULTS

An increment of SPAP from rest to peak stress was higher in PH group (p < 0.001). Multivariate regression analysis showed that MR effective regurgitation orifice area (EROA; p = 0.008) and regurgitant volume (RVol; p = 0.006) contributed significantly to SPAP at rest. Higher increment of MR EROA during stress and worse parameters of LV diastolic function at rest (E, A, E/e') correlated significantly with higher SPAP during peak stress and they had a major role in predicting EIPH according to univariate logistic regression analysis. In ROC analysis SPAP >33.1 mmHg at rest could predict EIPH with 84.6% sensitivity and 87.1% specificity (95%CI 0.849-1.000; p < 0.001).

CONCLUSIONS

Parameters of MR severity (EROA and RVol) were significant determinants of SPAP at rest, while the increment of MR EROA during stress and parameters of resting LV diastolic function were the best predictors of significant EIPH.

Response to exercise in patients with pulmonary arterial hypertension treated with combination therapy

Pulmonary arterial hypertension (PAH)-specific combination therapy improves pulmonary haemodynamics at rest in patients with PAH; nevertheless, exertional dyspnoea remains. We investigated pulmonary haemodynamic response to exercise, and the relationship to ventilatory efficiency and hypoxaemia in patients with PAH treated with combination therapy. 32 clinically stable patients with PAH undergoing combination therapy underwent cardiopulmonary exercise testing with right heart catheterisation. Haemodynamic impairment was moderate to severe before treatment. However, after treatment it was significantly improved, and the mean pulmonary arterial pressure (mPAP) at rest was <25 mmHg in 13 patients. The mPAP increased significantly from 27.9±10.7 to 45.9±16.7 mmHg (p<0.01) during exercise. The cardiac index increased inadequately, and the total pulmonary resistance (TPR) increased significantly from 5.74±3.42 to 6.58±3.82 Wood units (p<0.01). The mPAP/cardiac output (CO) slope was steep (10.0±6.7 mmHg·min·L⁻¹). It significantly correlated with both the minute ventilation/carbon dioxide output slope (r=0.51, p<0.01) and peripheral arterial oxygen saturation/workload slope (r=−0.41, p=0.02). In addition, the mPAP/CO slope correlated significantly with mPAP at rest (r=0.73, p<0.01) and TPR at rest (r=0.64, p<0.01). Even after pulmonary haemodynamics at rest was significantly improved in PAH patients with PAH-specific combination therapy, the mPAP/CO slope was steep and the steep mPAP/CO slope related to decreased ventilatory efficiency and the severity of hypoxaemia. The mPAP/CO slope was steeper in patients with higher mPAP and TPR at rest.

Even after pulmonary haemodynamics at rest are improved in PAH patients with combination therapy, pulmonary haemodynamic response to exercise is abnormal, and related to abnormal respiratory response and the severity of hypoxaemiahttps://bit.ly/2HGS0TX

The Evolution in Nomenclature, Diagnosis, and Classification of Pulmonary Hypertension

The current description of pulmonary hypertension is a testament to the physicians and scientists who dedicated their lives to furthering understanding of the pulmonary circulation. This has spanned a millennium, from ancient Egyptian descriptions of human anatomy to the current molecular and hemodynamic phenotyping of pulmonary hypertension. The recent Sixth World Symposium on Pulmonary Hypertension is a direct result of these discoveries and reflects an evolution in a classification scheme that has spanned half a century. This provides a framework for future directions related to therapeutics and mechanisms of disease.

Sex-Related Differences in Dynamic Right Ventricular-Pulmonary Vascular Coupling in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Right ventricular (RV) dysfunction is associated with poorer outcomes in heart failure with preserved ejection fraction (HFpEF). Although female subjects are more likely to have HFpEF, male subjects have worse prognosis and resting RV function. The contribution of dynamic RV-pulmonary arterial (RV-PA) coupling between sex and its impact on peak exercise capacity (VO₂) in HFpEF is not known.

RESEARCH QUESTION

The goal of this study was to investigate the differential effects of sex on RV-PA coupling during maximum incremental exercise in patients with HFpEF.

STUDY DESIGN AND METHODS

This study examined rest and exercise invasive pulmonary hemodynamics in 22 male patients with HFpEF and 27 female patients with HFpEF. To further investigate the discrepancy in RV-PA response between sex, 26 age-matched control subjects (11 male subjects and 15 female subjects) were included. Single beat analysis of RV pressure waveforms was used to determine the end-systolic elastance (Ees) and pulmonary arterial elastance. RV-PA coupling was determined as the ratio of end-systolic elastance/PA elastance.

RESULTS

Both HFpEF groups experienced decreased peak VO₂ (% predicted). However, male patients with HFpEF experienced a greater decrement in peak VO₂ compared with female patients (58 ± 16% vs 70 ± 15%; P < .05). Male patients with HFpEF had a more pronounced increase in RV afterload, Ea (1.8 ± 0.6 mm Hg/mL/m² vs 1.3 ± 0.4 mm Hg/mL/m²; P < .05) and failed to increase RV contractility during exercise, resulting in dynamic RV-PA uncoupling (0.9 ± 0.4 vs 1.2 ± 0.4; P < .05) and subsequent reduced stroke volume index augmentation. In contrast, female patients with HFpEF were able to augment RV contractility in the face of increasing afterload, preserving RV-PA coupling during exercise.

INTERPRETATION

Male patients with HFpEF were more compromised regarding dynamic RV-PA uncoupling and reduced peak VO₂ compared with female patients. This finding was driven by both RV contractile impairment and afterload mismatch. In contrast, female patients with HFpEF had preserved RV-PA coupling during exercise and better peak exercise VO₂ compared with male patients with HFpEF.

Chronic Thromboembolic Pulmonary Hypertension: the Bedside

PURPOSE OF REVIEW

Chronic thromboembolic pulmonary hypertension (CTEPH), included in group 4 PH, is an uncommon complication of acute pulmonary embolism (PE), in which emboli in the pulmonary vasculature do not resolve but rather form into an organized scar-like obstruction which can result in right ventricular (RV) failure. Here we provide an overview of current diagnosis and management of CTEPH.

RECENT FINDINGS

CTEPH management is complex with treatments that range from surgery, percutaneous interventions, to medical therapies. Current CTEPH medical therapies have largely been repurposed from pulmonary arterial hypertension (PAH). The diagnosis of CTEPH can be challenging, requiring a multimodality approach to differentiate from disease mimics. While these treatments improve symptoms, they may not reverse the underlying pathology of CTEPH.

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.

[Current Aspects of Definition and Diagnosis of Pulmonary Hypertension]

At the 6th World Symposium on Pulmonary Hypertension (WSPH), which took place from February 27 until March 1, 2018 in Nice, scientific progress over the past 5 years in the field of pulmonary hypertension (PH) was presented by 13 working groups. The results of the discussion were published as proceedings towards the end of 2018. One of the major changes suggested by the WSPH was the lowering of the diagnostic threshold for PH from ≥ 25 to > 20 mmHg mean pulmonary arterial pressure, measured by right heart catheterization at rest. In addition, the pulmonary vascular resistance was introduced into the definition of PH, which underlines the importance of cardiac output determination at the diagnostic right heart catheterization.In this article, we discuss the rationale and possible consequences of a changed PH definition in the context of the current literature. Further, we provide a current overview on non-invasive and invasive methods for diagnosis, differential diagnosis, and prognosis of PH, including exercise tests.

Experimental investigation of right-left flow balance concepts for a total artificial heart

A total artificial heart (TAH) must be designed to autonomously balance the flows of the systemic and pulmonary circulation to prevent potentially lethal lung damage. The flow difference between the systemic and pulmonary circulation is mainly caused by the bronchial (arteries) shunt flow and can change dynamically. The ReinHeart TAH consists of only one actuator that ejects blood alternately from the right and left pump chamber. This design entails a coupling of the right and left stroke and thus, complicates the independent adaptation of the right and left flow. In this experimental study on the ReinHeart TAH, four concepts to keep the flows well balanced were investigated using an active mock circulation loop for data acquisition. Three concepts are based on mechanical design changes (variation of pusher plate shape, flexible right pump chamber housing, and reduced right stroke volume) to achieve a static flow difference. In combination with these static concepts, a concept influencing the ratio of systole and diastole duration to respond to dynamic changes was studied. In total, four measurement series, each with 270 operating points, to investigate the influence of circulatory filling volume, heart rate, bronchial shunt flow, and lung resistance were recorded. In the course of this study, we introduce a concept deviation indicator, providing information about the efficiency of the concepts to balance the flows based on changes in lung's blood pressures. Furthermore, the distribution of the measured data was evaluated based on bubble plot visualizations. The investigated variation of the right pusher plate shape results in high lung pressures which will cause lethal lung damage. In comparison, a flexible right pump chamber housing shows lower lung pressures, but it still has the potential to damage the lungs. Reducing the stroke volume of the right pump chamber results in proper lung pressures. The flow balance can dynamically be influenced with a positive effect on the lung pressures by choosing a suitable systole-diastole-ratio. The results of this study suggest that an adequate right-left flow balance can be achieved by combining the mechanical concept of a reduced right stroke volume with an active control of the systole-diastole-ratio.

Right Atrial Pressure During Exercise Predicts Survival in Patients With Pulmonary Hypertension

Background We investigated changes in right atrial pressure (RAP) during exercise and their prognostic significance in patients assessed for pulmonary hypertension (PH). Methods and Results Consecutive right heart catheterization data, including RAP recorded during supine, stepwise cycle exercise in 270 patients evaluated for PH, were analyzed retrospectively and compared among groups of patients with PH (mean pulmonary artery pressure [mPAP] ≥25 mm Hg), exercise-induced PH (exPH; resting mPAP <25 mm Hg, exercise mPAP >30 mm Hg, and mPAP/cardiac output >3 Wood Units (WU)), and without PH (noPH). We investigated RAP changes during exercise and survival over a median (quartiles) observation period of 3.7 (2.8-5.6) years. In 152 patients with PH, 58 with exPH, and 60 with noPH, median (quartiles) resting RAP was 8 (6-11), 6 (4-8), and 6 (4-8) mm Hg (P<0.005 for noPH and exPH versus PH). Corresponding peak changes (95% CI) in RAP during exercise were 5 (4-6), 3 (2-4), and -1 (-2 to 0) mm Hg (noPH versus PH P<0.001, noPH versus exPH P=0.027). RAP increase during exercise correlated with mPAP/cardiac output increase (r=0.528, P<0.001). The risk of death or lung transplantation was higher in patients with exercise-induced RAP increase (hazard ratio, 4.24; 95% CI, 1.69-10.64; P=0.002) compared with patients with unaltered or decreasing RAP during exercise. Conclusions In patients evaluated for PH, RAP during exercise should not be assumed as constant. RAP increase during exercise, as observed in exPH and PH, reflects hemodynamic impairment and poor prognosis. Therefore, our data suggest that changes in RAP during exercise right heart catheterization are clinically important indexes of the cardiovascular function.

Pulmonary Hypertension Due to Left Heart Disease-A Practical Approach to Diagnosis and Management

Pulmonary hypertension (PH) due to left heart disease (LHD) is a frequent complication of heart failure (HF) and is associated with exercise intolerance, poor quality of life, increased risk of hospitalisations, and reduced overall survival. Since the recent Sixth World Symposium on Pulmonary Hypertension in 2018, there have been significant changes in the hemodynamic definitions and clinical classification of PH-LHD. PH-LHD can be subdivided into (1) isolated postcapillary PH (IpcPH) and (2) combined precapillary and postcapillary PH (CpcPH). This categorisation of PH-LHD is important because CpcPH shares certain pathophysiologic, clinical, and hemodynamic characteristics with pulmonary arterial hypertension and is associated with worse outcomes compared with IpcPH. A systematic approach using clinical history and noninvasive investigations is required in the diagnosis of PH-LHD. Right heart catheterisation with and without provocative testing is performed in expert centres and is indicated in selected individuals. Although the definition of IpcPH and CpcPH is based on measurements made with right heart catheterisation, distinguishing between these two entities is not always necessary. Despite strong evidence for medical therapy in patients with pulmonary arterial hypertension, those options have limited benefit in PH-LHD. Expert PH centres in Canada have been established to provide ongoing care for the more complex patient subgroups.

Prevalence and characteristics of portopulmonary hypertension in cirrhotic patients who underwent both hepatic vein and pulmonary artery catheterization

Portopulmonary hypertension (PoPH) is a well-known complication of liver cirrhosis. The aim of this study was to clarify the pulmonary hemodynamics and the prevalence and characteristics of PoPH in patients with portal hypertension.

METHODS

The subjects were 335 patients with portal hypertension diagnosed by hepatic vein pressure gradient (HVPG). Among them, 186 patients received measurements of pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP) and pulmonary vascular resistance (PVR). PoPH was diagnosed by PAP >20 mmHg, PVR ≥3 Wood units (WU) and PAWP ≤15 mmHg.

RESULTS

The Child-Pugh classification was class A in 53, B in 92 and C in 41 patients. Median (range) values of HVPG, PAP, PVR and PAWP were 18.4 (5.5-39.0) mmHg, 12.9 (6.6-40.8) mmHg, 0.8 (0.1-4.5) WU and 7.5 (2.2-15.4) mmHg, respectively. Of six patients with PAP >20 mmHg, four had autoimmune hepatitis or primary biliary cholangitis, with the prevalence being significantly higher than that in patients with PAP ≤20 mmHg. Meanwhile, no significant difference was noted in the hepatic functional reserve or HVPG between patients with PAP >20 mmHg and ≤20 mmHg. Only two patients met the diagnostic criteria of PoPH and both patients were Child-Pugh B. The Child-Pugh score and HVPG were not associated with PoPH.

CONCLUSIONS

Our study demonstrated that only two patients were complicated by PoPH. High PAP values were noted in patients with primary biliary cholangitis or autoimmune hepatitis. However, the presence of PoPH and high PAP were not associated with the degree of hepatic functional reserve or HVPG.

Impairment of right ventricular strain evaluated by cardiovascular magnetic resonance feature tracking in patients with interstitial lung disease

OBJECTIVES

The aims of this study were to investigate the relationship between pulmonary hypertension (PH) and right ventricular (RV) strain, and to evaluate the prognostic value of RV strain by cardiac magnetic resonance (CMR) feature tracking for patients with interstitial lung disease (ILD).

METHODS

A total of seventy ILD patients (mean age: 71 ± 8 years, 39 [56%] males) who underwent CMR and right heart catheterization (RHC) were studied. Using a 1.5T magnetic resonance (MR) scanner, steady-state free precession cine MR images encompassing the RV were acquired in all patients and 20 control subjects. RV longitudinal strain were calculated with a feature tracking algorithm. PH was defined as a mean pulmonary artery pressure of more than 20 mmHg at rest and a pulmonary vascular resistance ≥3 Woods unit.

RESULTS

The RV longitudinal strain was significantly impaired in the ILD patients with PH (n=18) than ILD patients without PH (n=52) (-13.3 ± 5.4% vs. -16.9±5.4%, p=0.048). The RV longitudinal strain differed significantly between the ILD patients without PH and the controls (n=20) (-16.9 ± 5.4% vs. -20.8 ± 6.2%, p=0.002). Five of 70 (7%) patients died within one-year after CMR scan. Area under receiver operating characteristics curve for predicting death was 0.900 (95%CI: 0.800 to 1.000) for RV strain, 0.643 (95%CI: 0.454 to 0.832) for RVEF.

CONCLUSIONS

Presence of PH was associated with impairment of RV strain, and RV strain could predict short-term mortality in patients with ILD. RV strain by feature tracking might be useful as a non-invasive prognostic marker for patients with ILD.

Right ventricular dysfunction in patients with non-severe idiopathic pulmonary fibrosis: a cross-sectional prospective single-center study

BACKGROUND

Little is known about right ventricular dysfunction in non-advanced idiopathic pulmonary fibrosis (IPF) patients without hypoxemia at rest. We evaluated it at rest and during exercise.

RESEARCH DESIGN AND METHODS

123 IPF patients were evaluated, and 27 met all the following criteria: Gender-Age-Physiology Index score ≤5, modified Medical Research Council dyspnea score ≤3, peripheral oxygen saturation ≥92% at rest, and no history of oxygen therapy. They were submitted to two-dimensional speckle-tracking echocardiography at rest and during cardiopulmonary exercise to analyze right ventricular global longitudinal strain.

RESULTS

Abnormal speckle-tracking echocardiography findings were identified in 10/27 patients (37%), indicating right ventricular (RV) dysfunction. No patients had abnormalities observed in conventional echocardiographic parameters. Significant differences in mPAP were observed between patients with RV dysfunction and those without dysfunction (at rest: 26.0 ± 4.8 vs. 19.1 ± 4.2 mmHg, p = 0.001; during exercise: 51.3 ± 6.4 vs. 36.9 ± 14.7 mmHg, p = 0.002).

CONCLUSIONS

RV dysfunction was detected in 37% of non-advanced IPF patients and early recognition was only possible using speckle-tracking echocardiography. Special attention should be given to these patients as RV dysfunction is suggestive of worse prognosis. These patients could benefit from new specific drugs or even oxygen therapy for transitory hypoxia.

Long-term changes of exercise hemodynamics and physical capacity in chronic thromboembolic pulmonary hypertension after pulmonary thromboendarterectomy

BACKGROUND

A substantial number of chronic thromboembolic pulmonary hypertension (CTEPH) patients experience dyspnea on exertion and limited exercise capacity despite surgically successful pulmonary endarterectomy (PEA). We sought to prospectively evaluate resting and peak exercise hemodynamics before, 3 and 12 months after PEA in consecutive CTEPH-patients and correlate it to physical functional capacity.

METHODS AND RESULTS

Twenty consecutive CTEPH-patients were examined. Twelve months after PEA, 75% of patients with severely increased pre-PEA mean pulmonary arterial pressure (mPAP) at rest had normal or mildly increased mPAP. However, mPAP reduction was less pronounced during exercise where only 45% had normal or mildly increased mPAP at 12 months. Hemodynamic changes during exercise were tested using the pressure-flow relationship (i.e. mPAP/cardiac output (CO) slope). The average mPAP/CO slope was 7.5 ± 4.2 mm Hg/L/min preoperatively and 3.9 ± 3.0 mm Hg/L/min at 12 months (p < .005). CO reserve (CO increase from rest to peak exercise) was increased (5.7 ± 2.9 L/min) 12 months after PEA compared with pre-PEA (2.5 ± 1.8 L/min), p < .0001. However, 12 months after PEA, the CO reserve was only 49% of that of healthy controls, p < .0001. Changes in cardiac output (∆CO), calculated as the difference between CO before PEA and 12 months later, were significantly correlated with six-minute-walk-test and peak oxygen uptake (VO2), both at rest and peak exercise.

CONCLUSION

Invasive exercise hemodynamic examination in CTEPH-patients demonstrates that after otherwise successful PEA surgery, >50% of patients have a significant increase in exercise mPAP, and the CO reserve remains compromised 12 months after PEA. Improvement in physical capacity is correlated with ∆CO.

Optimal Cut-Off of Tricuspid Regurgitation Velocity According to the New Definition of Pulmonary Hypertension ― Its Use in Predicting Pulmonary Hypertension ―

Background: The 6th World Symposium on Pulmonary Hypertension proposed that precapillary pulmonary hypertension (PH) be defined as mean pulmonary arterial pressure (mPAP) >20 mmHg instead of mPAP ≥25 mmHg. Peak tricuspid regurgitation velocity (TRV) >3.4 m/s is widely used to predict PH, but it is unclear whether this value remains reliable for the new definition of PH.

Methods and Results: We found that the optimal cut-off value of peak TRV for 511 PH patients was >2.8 m/s, with a sensitivity of 89.5%, specificity of 73.4%, and area under the curve of 0.89 (P<0.001).

Conclusions: Based on the new definition of PH, TRV >2.8 m/s can be considered to indicate a high probability of PH.