Prognostic role of traditional cardiovascular risk factors in patients with idiopathic pulmonary arterial hypertension

Prognostic value of atherogenic index of plasma in pulmonary hypertension

Background

The atherogenic index of plasma (AIP) is a brand-new lipid parameter that has been used to assess various cardiovascular events. This study aimed to investigate the prognostic value of AIP in patients with pulmonary hypertension (PH).

Methods

This retrospective study was conducted at Shanghai Jiao Tong University School of Medicine affiliated Renji Hospital, and included data from 125 PH patients treated during 2014-2018. The endpoint events of this study were clinical worsening outcomes. PH patients include those from group 1 and group 4. AIP was determined as the logarithm of the blood triglycerides ratio to high-density lipoprotein cholesterol.

Results

The 1-year, 3-year, and 5-year incidence rates of clinical worsening outcomes in PH patients in this study were 20.0, 44.8, and 54.4%, respectively. The median age of the PH patients was 38.00 years, with females accounting for 90.4%. After controlling for multivariable factors, the results of Cox regression analysis indicated that AIP was an independent predictor of adverse outcomes with a hazard ratio and 95% confident interval (CI) of 2.426 (1.021-5.763). The positive linear relationship of AIP was evaluated using restricted cubic spline analysis. Kaplan-Meier curves showed a significantly higher events rate in patients with AIP ≥ 0.144 compared to those with AIP < 0.144 (p = 0.002). Four potential prognostic variables, including AIP, were identified by LASSO regression to construct a nomogram. Compared to the model minus AIP, the AUC of the nomogram displayed a non-significant improvement (0.749 vs. 0.788, p = 0.298). In contrast, the results of net reclassification improvement (0.306, 95% CI: 0.039-0.459, p < 0.001) and integrated discrimination improvement (0.049, 95% CI: 0.006-0.097, p = 0.020) demonstrated significant enhancements in the predictive ability of the model when AIP was added to the clinical model.

Conclusion

AIP is an independent predictor of long-term clinical worsening in PH patients, and its inclusion in prognostic models could improve risk stratification and management.

Impact of reduced apolipoprotein A-I levels on pulmonary arterial hypertension

OBJECTIVE

The significance of apolipoprotein A-I (ApoA-I) is the anti-inflammatory functional component of high-density lipoprotein, which needs to be further studied in relation to pulmonary arterial hypertension (PAH). This study aimed to identify the predictive value of ApoA-1 on the risk and prognosis of PAH, as well as the underlying anti-inflammatory mechanism.

METHODS

Proteomic analysis was conducted on lung tissue from 6 PAH patients and 4 lung donors. Prediction of risk and mortality risk factors associated with PAH in 343 patients used logistic analysis and Cox regression analysis, respectively. The protective function of ApoA-I was assessed in human pulmonary arterial endothelial cells (HPAEC), while its anti-inflammatory function was evaluated in THP-1 macrophages.

RESULTS

In the lung tissues of patients with PAH, 168 differentially expressed proteins were associated with lipid metabolism according to GO and KEGG enrichment analysis. A protein-protein interaction network identified ApoA-I as a key protein associated with PAH. Lower ApoA-I levels were independent risk factors for PAH and displayed a stronger predictive value for PAH mortality. Plasma interleukin 6 (IL-6) levels were positively correlated with risk stratification and were higher in PAH patients with lower ApoA-I levels. ApoA-I was downregulated in the lung tissues of monocrotaline (MCT) -induced rats. ApoA-I could reduce the IL-6-induced pro-proliferative and pro-migratory abilities of HPAEC and inhibit the secretion of IL-6 from macrophages, which is compromised under hypoxic conditions.

CONCLUSION

Our study identified the significance of ApoA-I as a biomarker for predicting the survival outcome of PAH patients, which might relate to its altered anti-inflammatory properties.

Is pulmonary vascular remodeling an intermediate link between hyperglycemia and adverse outcomes in patients with idiopathic pulmonary arterial hypertension? Insights from a multi-center cohort study

BACKGROUND

Hyperglycemia upon admission is associated with poor prognosis of many cardiovascular diseases. However, the relationship of stress hyperglycemia ratio (SHR), admission blood glucose (ABG), and hemoglobin A1c (HbA1c) with pulmonary hypertension has not been reported. This study aimed to explore the association of hyperglycemia indices with disease severity and long-term adverse outcomes in patients with idiopathic pulmonary arterial hypertension (IPAH).

METHODS

This multi-center cohort study included 625 consecutive patients diagnosed with or treated for IPAH between January 2015 and June 2023. SHR was calculated using the followings: ABG (mmol/L)/(1.59 × HbA1c [%] - 2.59). The primary endpoint was defined as clinical worsening events. Multivariable Cox regression and restricted cubic spline analyses were employed to evaluate the association of SHR, ABG, and HbA1c with endpoint events. The mediating effect of pulmonary hemodynamics was evaluated to investigate the potential mechanism between hyperglycemia and clinical outcomes.

RESULTS

During a mean follow-up period of 3.8 years, 219 (35.0%) patients experienced all-cause death or clinical worsening events. Hyperglycemia indices correlated with well-validated variables that reflected the severity of IPAH, such as the World Health Organization functional class, 6-min walk distance, and N-terminal pro-brain natriuretic peptide levels. Multivariable Cox regression analyses indicated that SHR (hazard ratio [HR] 1.328, 95% confidence intervals [CI]: 1.185, 1.489 per 0.1-unit increment, P < 0.001) and ABG (HR 1.317, 95% CI: 1.134, 1.529 per 1.0-unit increment, P < 0.001) were independent predictors of primary endpoint events. Mediation analysis indicated that pulmonary vascular resistance mediated 5.65% and 14.62% of the associations between SHR and ABG and clinical worsening events, respectively. The addition of SHR significantly improved reclassification, discrimination ability, and model fit beyond the clinical risk prediction model.

CONCLUSIONS

SHR is positively associated with clinical worsening in patients with IPAH. The association appeared to be partially mediated through the pathway of pulmonary vascular remodeling, indicating that SHR may serve as a valuable indicator for providing additional risk information.

Markuszewski M, Da̧browska-Kugacka A. Metabolomics Meets Clinics: A Multivariate Analysis of Plasma and Urine Metabolic Signatures in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe, multifactorial, and frequently misdiagnosed disorder. The aim of this observational study was to compare the plasma and urine metabolomic profiles of PAH patients and healthy control subjects. Plasma and urine metabolomic profiles were analyzed using the GC-MS technique. Correlations between metabolite levels and clinical parameters among PAH patients, as well as the between-group differences, were evaluated. The linear discriminant analysis model, which allows for subject classification in terms of PAH with the highest possible precision, was developed and proposed. Plasma pyruvic acid, cholesterol, threonine, urine 3-(3-hydroxyphenyl)-3-hydroxypropanoic acid, butyric acid, 1,2-benzenediol, glucoheptonic acid, and 2-oxo-glutaric acid were found to build a relatively accurate classification model for PAH patients. The model reached an accuracy of 91% and significantly improved subject classification (OR = 119 [95% CI: 20.3-698.3], p < 0.0001). Five metabolites were detected in urine that provide easily available and noninvasive tests as compared to right heart catheterization. The selected panel of metabolites has potential for early recognition of patients with dyspnea and faster referral to a reference center.

Association of non-insulin-based insulin resistance indices with disease severity and adverse outcome in idiopathic pulmonary arterial hypertension: a multi-center cohort study

BACKGROUND

Insulin resistance (IR) plays an important role in the pathophysiology of cardiovascular disease. Recent studies have shown that diabetes mellitus and impaired lipid metabolism are associated with the severity and prognosis of idiopathic pulmonary arterial hypertension (IPAH). However, the relationship between IR and pulmonary hypertension is poorly understood. This study explored the association between four IR indices and IPAH using data from a multicenter cohort.

METHODS

A total of 602 consecutive participants with IPAH were included in this study between January 2015 and December 2022. The metabolic score for IR (METS-IR), triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio, triglyceride and glucose (TyG) index, and triglyceride-glucose-body mass index (TyG-BMI) were used to quantify IR levels in patients with IPAH. The correlation between non-insulin-based IR indices and long-term adverse outcomes was determined using multivariate Cox regression models and restricted cubic splines.

RESULTS

During a mean of 3.6 years' follow-up, 214 participants experienced all-cause death or worsening condition. Compared with in low to intermediate-low risk patients, the TG/HDL-C ratio (2.9 ± 1.7 vs. 3.3 ± 2.1, P = 0.003) and METS-IR (34.5 ± 6.7 vs. 36.4 ± 7.5, P < 0.001) were significantly increased in high to intermediate-high risk patients. IR indices correlated with well-validated variables that reflected the severity of IPAH, such as the cardiac index and stroke volume index. Multivariate Cox regression analyses indicated that the TyG-BMI index (hazard ratio [HR] 1.179, 95% confidence interval [CI] 1.020, 1.363 per 1.0-standard deviation [SD] increment, P = 0.026) and METS-IR (HR 1.169, 95% CI 1.016, 1.345 per 1.0-SD increment, P = 0.030) independently predicted adverse outcomes. Addition of the TG/HDL-C ratio and METS-IR significantly improved the reclassification and discrimination ability beyond the European Society of Cardiology (ESC) risk score.

CONCLUSIONS

IR is associated with the severity and long-term prognosis of IPAH. TyG-BMI and METS-IR can independently predict clinical worsening events, while METS-IR also provide incremental predictive performance beyond the ESC risk stratification.

Serum PM20D1 levels in patients with idiopathic pulmonary arterial hypertension and its clinical significance

OBJECTIVE

This study aimed to investigate the serum levels of Peptidase M20 domain containing 1 (PM20D1) in idiopathic pulmonary arterial hypertension (IPAH) patients and examine its association with lipid metabolism, echocardiography, and hemodynamic parameters.

METHODS

This prospective observational research enrolled 103 IPAH patients from January 2018 to January 2022. Enzyme-linked immunosorbent assay (ELISA) was used to measure the serum PM20D1 levels in all patients before treatment within 24 h of admission. Demographic data, echocardiography, hemodynamic parameters and serum biomarkers were also collected.

RESULTS

The IPAH patients in the deceased group had significantly elevated age, right atrial (RA), mean pulmonary arterial pressure (mPAP), mean right atrial pressure (mRAP), pulmonary capillary wedge pressure (PCWP), pulmonary vascular resistance (PVR) and significantly decreased 6 min walking distance (6MWD) and tricuspid annulus peak systolic velocity (TASPV). IPAH patients showed significant decreases in serum PM20D1, low-density lipoprotein cholesterol (LDL-C), and albumin (ALB). Additionally, PM20D1 was negatively correlated with RA, NT-proBNP and positively correlated with PVR, ALB, 6MWD, and TAPSV. Moreover, PM20D1 has the potential as a biomarker for predicting IPAH patients' prognosis. Finally, logistic regression analysis indicated that PM20D1, ALB, NT-proBNP, PVR, TASPV, RA and 6MWD were identified as risk factors for mortality in IPAH patients.

CONCLUSION

Our findings indicated that the serum levels of PM20D1 were significantly decreased in IPAH patients with poor prognosis. Moreover, PM20D1 was identified as a risk factor associated with mortality in IPAH patients.

Blood Cholesterol and Triglycerides Associate with Right Ventricular Function in Pulmonary Hypertension

Background

Blood lipids are dysregulated in pulmonary hypertension (PH). Lower high-density lipoproteins cholesterol (HDL-C) and low-density lipoproteins cholesterol (LDL-C) are associated with disease severity and death in PH. Right ventricle (RV) dysfunction and failure are the major determinants of morbidity and mortality in PH. This study aims to test the hypothesis that dyslipidemia is associated with RV dysfunction in PH.

Methods

We enrolled healthy control subjects (n=12) and individuals with PH (n=30) (age: 18-65 years old). Clinical characteristics, echocardiogram, 2-[18F] fluoro-2-deoxy-D-glucose positron emission tomography (PET) scan, blood lipids, including total cholesterol (TC), triglycerides (TG), lipoproteins (LDL-C and HDL-C), and N-terminal pro-B type Natriuretic Peptide (NT-proBNP) were determined.

Results

Individuals with PH had lower HDL-C [PH, 41±12; control, 56±16 mg/dL, p<0.01] and higher TG to HDL-C ratio [PH, 3.6±3.1; control, 2.2±2.2, p<0.01] as compared to controls. TC, TG, and LDL-C were similar between PH and controls. Lower TC and TG were associated with worse RV function measured by RV strain (R=-0.43, p=0.02 and R=-0.37, p=0.05 respectively), RV fractional area change (R=0.51, p<0.01 and R=0.48, p<0.01 respectively), RV end-systolic area (R=-0.63, p<0.001 and R=-0.48, p<0.01 respectively), RV end-diastolic area: R=-0.58, p<0.001 and R=-0.41, p=0.03 respectively), and RV glucose uptake by PET (R=-0.46, p=0.01 and R=-0.30, p=0.10 respectively). NT-proBNP was negatively correlated with TC (R=-0.61, p=0.01) and TG (R=-0.62, p<0.02) in PH.

Conclusion

These findings confirm dyslipidemia is associated with worse right ventricular function in PH.

The Impact of Abnormal Lipid Metabolism on the Occurrence Risk of Idiopathic Pulmonary Arterial Hypertension

The aim was to determine whether lipid molecules can be used as potential biomarkers for idiopathic pulmonary arterial hypertension (IPAH), providing important reference value for early diagnosis and treatment. Liquid chromatography-mass spectrometry-based lipidomic assays allow for the simultaneous detection of a large number of lipids. In this study, lipid profiling was performed on plasma samples from 69 IPAH patients and 30 healthy controls to compare the levels of lipid molecules in the 2 groups of patients, and Cox regression analysis was used to identify meaningful metrics, along with receiver operator characteristic curves to assess the ability of the lipid molecules to predict the risk of disease in patients. Among the 14 lipid subclasses tested, 12 lipid levels were significantly higher in IPAH patients than in healthy controls. Free fatty acids (FFA) and monoacylglycerol (MAG) were significantly different between IPAH patients and healthy controls. Logistic regression analysis showed that FFA (OR: 1.239, 95%CI: 1.101, 1.394, p < 0.0001) and MAG (OR: 3.711, 95%CI: 2.214, 6.221, p < 0.001) were independent predictors of IPAH development. Among the lipid subclasses, FFA and MAG have potential as biomarkers for predicting the pathogenesis of IPAH, which may improve the early diagnosis of IPAH.

Pulmonary Arterial Hypertension in the Elderly: Peculiar Features and Challenges for a Proper Phenotyping Approach

(1) Introduction. Although pulmonary arterial hypertension (PAH) usually affects young people with a low cardiovascular risk profile, progressive epidemiologic changes have been providing a codified phenotype of elderly subjects with PAH and increased risk predictors for left heart disease. We therefore conducted a systematic review to describe the current knowledge and characteristics of elderly individuals with PAH and further insights concerning their prognostic outcomes and therapeutic response. (2) Methods. A search was conducted in PubMed, Embase, and Cochrane Library for publications evaluating the epidemiology, diagnostic work-up, and treatment of PAH in elderly subjects. (3) Among the 74 publications initially retrieved, 16 full-text articles were selected for the present systematic review. Compared to their younger counterparts, elderly individuals with PAH showed greater clinical deterioration, reduced exercise capacity, and worse prognostic outcomes, as well as less response to PAH-targeted therapy and higher rates of PAH drug discontinuation. (4) Conclusions. Demographic changes over time contributed to define a peculiar PAH phenotype in elderly patients, with an increased burden of cardiovascular comorbidities and distinctive features compared to young patients. Further investigations are needed in order to better clarify the nosologic criteria, and management in this subset population.

Impact of diabetes mellitus on disease severity and patient survival in idiopathic pulmonary arterial hypertension: data from the Polish multicentre registry (BNP-PL)

BACKGROUND

Recent studies revealed that alterations in glucose and lipid metabolism in idiopathic pulmonary arterial hypertension (IPAH) are associated with disease severity and poor survival. However, data regarding the impact of diabetes mellitus (DM) on the prognosis of patients with IPAH remain scarce. The aim of our study was to determine that impact using data from a national multicentre prospective pulmonary hypertension registry.

METHODS

We analysed data of adult patients with IPAH from the Database of Pulmonary Hypertension in the Polish population (BNP‑PL) between March 1, 2018 and August 31, 2020. Upon admission, clinical, echocardiographic, and haemodynamic data were collected at 21 Polish IPAH reference centres. The all-cause mortality was assessed during a 30-month follow-up period. To adjust for differences in age, body mass index (BMI), and comorbidities between patients with and without DM, a 2-group propensity score matching was performed using a 1:1 pairing algorithm.

RESULTS

A total of 532 patients with IPAH were included in the study and 25.6% were diagnosed with DM. Further matched analysis was performed in 136 patients with DM and 136 without DM. DM was associated with older age, higher BMI, more advanced exertional dyspnea, increased levels of N-terminal pro-brain natriuretic peptide, larger right atrial area, increased mean right atrial pressure, mean pulmonary artery pressure, pulmonary vascular resistance, and all-cause mortality compared with no DM.

CONCLUSIONS

Patients with IPAH and DM present with more advanced pulmonary vascular disease and worse survival than counterparts without DM independently of age, BMI, and cardiovascular comorbidities.

Regular Risk Assessment in Pulmonary Arterial Hypertension - A Whistleblower for Hidden Disease Progression

Despite developments in the treatment of pulmonary arterial hypertension, timely treatment is seldom achieved, and hidden progression is not uncommonly disguised as a seemingly "stable" condition. Appropriate risk assessment tools facilitate goal-oriented treatment strategies. This article aimed to review the development of these risk assessment tools including early assessment equations/scores, European guidelines-based risk assessment scores, and tools derived from the United States nationwide registry. A stepwise and regular approach with these assessment tools in clinical practice is highly recommended for timely treatment escalation to stop disease progression early. In this review, a practical and recommended algorithm of these assessment tools is also provided.

Endothelin-1 gene and endothelin receptor A gene polymorphisms in severe pulmonary hypertension associated with rheumatic mitral valve disease

INTRODUCTION

Endothelin-1 (ET-1) gene polymorphisms are implicated in pathogenesis of idiopathic pulmonary arterial hypertension.

METHODS

We studied ET-1 (Lys198Asn and 3A/4A) and endothelin receptor A (ET_A) gene (His323His) polymorphisms in 123 subjects with pulmonary hypertension associated with rheumatic mitral valve disease (PH-MVD) and 123 healthy controls.

RESULTS

The mutant homozygous Asn/Asn genotype in Lys198Asn and T/T genotype in His323His polymorphism was more prevalent in the PH-MVD group. Presence of Asn/Asn genotype was significantly associated with an increased risk (odds ratio 3.9).

CONCLUSIONS

ET-1 and ET_A gene polymorphisms are prevalent in the PH-MVD group suggesting that they may predispose to the development of PH.

Increased serum PCSK9 in patients with idiopathic pulmonary arterial hypertension: insights from inflammatory cytokines

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an important and major player in the pathophysiology of hypercholesterolemia and atherosclerosis. Recently, PCSK9 has been implicated in the pathogenesis of inflammatory diseases. Whether PCSK9 is involved in idiopathic pulmonary arterial hypertension (IPAH) remains unclear. This study aimed to investigate the relationship between PCSK9 and IPAH. Serum PCSK9, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1 β (IL-1β), and monocyte chemotactic protein-1 (MCP-1) were measured by enzyme linked immunosorbent assay. Transthoracic echocardiography was performed among 40 IPAH patients and 20 control subjects. Hemodynamic data were collected via right heart catheterization in patients with IPAH. Serum PCSK9, TNF-α, IL-6, IL-1β, and MCP-1 levels were significantly higher in IPAH patients than in control subjects (p < 0.001). Among enrolled IPAH patients, PCSK9 levels were higher in WHO-FC III/IV patients compared with those in WHO-FC I/II (p < 0.05), and were positively correlated with TNF-α, IL-6, MCP-1, N-Terminal pro-brain natriuretic peptide, pulmonary arterial systolic pressure (r = 0.653, p < 0.001), pulmonary arterial diastolic pressure (r = 0.466, p = 0.002), mean pulmonary arterial pressure (mPAP, r = 0.730, <0.001), pulmonary vascular resistance (r = 0.488, p = 0.001), and right ventricle diameter (r = 0.563, p < 0.001). In multiple regression analysis, mPAP was strongly associated with serum PCSK9 (β = 0.694, p < 0.001), independent of other variables. Receiver operating characteristic curve analysis showed the optimal cutoff value of serum PCSK9 concentration for predicting IPAH was 90.67 ng/ml, with a sensitivity of 90.0% and a specificity of 85.0%. In conclusion, IPAH patients had elevated serum PCSK9 levels which correlated the presence and severity of pulmonary hypertension. PCSK9 may be a novel potential therapeutic target.

Soluble ST2 protein as a new biomarker in patients with precapillary pulmonary hypertension

Introduction

Non-invasive tests that may improve clinical evaluation of pulmonary hypertension (PH) are needed. The purpose of this study was to assess the role of soluble ST2 (sST2) in patients with PH.

Material and methods

A total of 57 patients with chronic thromboembolic PH and 43 patients with idiopathic arterial PH were enrolled in this study. All patients were evaluated for World Health Organization (WHO) functional class (FC), N-terminal prohormone B-type natriuretic peptide (NT-proBNP), troponin T (TnT), and hemodynamics. Plasma sST2 was assessed by an immunofluorescent in vitro diagnostic assay. All patients were followed up from the date of blood sampling. The endpoint was all-cause death.

Results

The median sST2 concentration was 32.8 ng/ml (IQR: 21.6-48.5 ng/ml) in the whole study population. Significant differences were found between median sST2 in successive WHO FCs (FC II vs. FC III, p = 0.002; FC III vs. FC IV, p = 0.12; FC II vs. FC IV, p = 0.008). Significant correlations were found between sST2 and hemodynamic parameters: mean right atrial pressure (r = 0.56; p < 0.05), mean pulmonary artery pressure (r = 0.25; p < 0.05), cardiac index (r = -0.40; p < 0.05), pulmonary vascular resistance (r = 0.41; p < 0.05), and between sST2 and WHO FC (r = 0.36; p < 0.05), NT-proBNP (r = 0.55; p < 0.05), and TnT (r = 0.44; p < 0.05). sST2 concentration above the median was associated with worse clinical prognosis (p = 0.02, Kaplan-Meier).

Conclusions

sST2 seems to be a marker of poor clinical prognosis in patients with PH.

Characterization of Patients with Pulmonary Arterial Hypertension: Data from the Polish Registry of Pulmonary Hypertension (BNP-PL)

Current knowledge of pulmonary arterial hypertension (PAH) epidemiology is based mainly on data from Western populations, and therefore we aimed to characterize a large group of Caucasian PAH adults of Central-Eastern European origin. We analyzed data of incident and prevalent PAH adults enrolled in a prospective national registry involving all Polish PAH centers. The estimated prevalence and annual incidence of PAH were 30.8/mln adults and 5.2/mln adults, respectively and they were the highest in females ≥65 years old. The most frequent type of PAH was idiopathic (n = 444; 46%) followed by PAH associated with congenital heart diseases (CHD-PAH, n = 356; 36.7%), and PAH associated with connective tissue disease (CTD-PAH, n = 132; 13.6%). At enrollment, most incident cases (71.9%) were at intermediate mortality risk and the prevalent cases had most of their risk factors in the intermediate or high risk range. The use of triple combination therapy was rare (4.7%). A high prevalence of PAH among older population confirms the changing demographics of PAH found in the Western countries. In contrast, we found: a female predominance across all age groups, a high proportion of patients with CHD-PAH as compared to patients with CTD-PAH and a low use of triple combination therapy.

HDL Cholesterol as a Marker of Disease Severity and Prognosis in Patients with Pulmonary Arterial Hypertension

The impact of high-density lipoprotein (HDL) cholesterol on the development of atherosclerosis and diseases of systemic circulation has been well documented both in experimental and registry studies. Recent discoveries in pulmonary arterial hypertension (PAH) revealed a significant impact of HDL on pulmonary artery vasoreactivity and patients' prognosis. The vasoprotective activity of HDL primarily involves vascular endothelium that also plays a central role in pulmonary arterial hypertension (PAH) pathobiology. However, the exact mechanism in which this lipoprotein fraction exerts its effect in pulmonary circulation is still under investigation. This paper reviews potential vasoprotective mechanisms of HDL in pulmonary circulation and presents current clinical reports on the role of HDL in PAH patients.