Update in systemic sclerosis-associated pulmonary arterial hypertension

Pulmonary Hypertension in Systemic Sclerosis

Systemic sclerosis is a multisystem connective tissue disease that is associated with substantial morbidity and mortality. Visceral organ involvement is common in patients with systemic sclerosis and occurs independently of skin manifestations. Pulmonary hypertension (PH) is an important and prevalent complication of systemic sclerosis. The clinical classification of PH cohorts conditions with similar pathophysiological mechanisms into one of five groups. While patients with systemic sclerosis can manifest with a spectrum of pulmonary vascular disease, notable clinical groups include group 1 pulmonary arterial hypertension (PAH) associated with connective tissues disease, PAH with features of capillary/venous involvement, group 2 PH associated with left heart disease, and group 3 PH associated with interstitial lung disease. Considerable efforts have been made to advance screening methods for PH in systemic sclerosis including the DETECT and ASIG (Australian Scleroderma Interest Group) composite algorithms. Current guidelines recommend annual assessment of the risk of PAH as early recognition may result in attenuated hemodynamic impairment and improved survival. The treatment of PAH associated with systemic sclerosis requires a multidisciplinary team including a PH specialist and a rheumatologist to optimize immunomodulatory and PAH-specific therapies. Several potential biomarkers have been identified and there are several promising PAH therapies on the horizon such as the novel fusion protein sotatercept. This chapter provides an overview of PH in systemic sclerosis, with a specific focus on group 1 PAH.

Effects of bergapten on the pharmacokinetics of macitentan in rats both in vitro and in vivo

Macitentan was approved by the United States Food and Drug Administration (FDA) in 2013 for the treatment of pulmonary arterial hypertension (PAH). Bergapten is a furanocoumarin that is abundant in Umbelliferae and Rutaceae plants and is widely used in many Chinese medicine prescriptions. Considering the possible combination of these two compounds, this study is aimed to investigate the effects of bergapten on the pharmacokinetics of macitentan both in vitro and in vivo. Rat liver microsomes (RLMs), human liver microsomes (HLMs), and recombinant human CYP3A4 (rCYP3A4) were used to investigate the inhibitory effects and mechanisms of bergapten on macitentan in vitro. In addition, pharmacokinetic parameters were also studied in vivo. Rats were randomly divided into two groups (six rats per group), with or without bergapten (10 mg/kg), and pretreated for 7 days. An oral dose of 20 mg/kg macitentan was administered to each group 30 min after bergapten or 0.5% CMC-Na administration on day 7. Blood was collected from the tail veins, and the plasma concentrations of macitentan and its metabolites were assessed by ultra-performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS). Finally, we analyzed the binding force of the enzyme and two small ligands by in silico molecular docking to verify the inhibitory effects of bergapten on macitentan. The in vitro results revealed that the IC₅₀ values for RLMs, HLMs, and rCYP3A4 were 3.84, 17.82 and 12.81 μM, respectively. In vivo pharmacokinetic experiments showed that the AUC_(0-t), AUC_(0-∞), and C_max of macitentan in the experimental group (20,263.67 μg/L*h, 20,378.31 μg/L*h and 2,999.69 μg/L, respectively) increased significantly compared with the control group (7,873.97 μg/L*h, 7,897.83 μg/L*h and 1,339.44 μg/L, respectively), while the CL_z/F (1.07 L/h/kg) of macitentan and the metabolite-parent ratio (MR) displayed a significant decrease. Bergapten competitively inhibited macitentan metabolism in vitro and altered its pharmacokinetic characteristics in vivo. Further molecular docking analysis was also consistent with the experimental results. This study provides a reference for the combined use of bergapten and macitentan in clinical practice.

Metabolomic Profiles Differentiate Scleroderma-PAH From Idiopathic PAH and Correspond With Worsened Functional Capacity

BACKGROUND

The prognosis and therapeutic responses are worse for pulmonary arterial hypertension associated with systemic sclerosis (SSc-PAH) compared with idiopathic pulmonary arterial hypertension (IPAH). This discrepancy could be driven by divergence in underlying metabolic determinants of disease.

RESEARCH QUESTION

Are circulating bioactive metabolites differentially altered in SSc-PAH vs IPAH, and can this alteration explain clinical disparity between these PAH subgroups?

STUDY DESIGN AND METHODS

Plasma biosamples from 400 patients with SSc-PAH and 1,082 patients with IPAH were included in the study. Another cohort of 100 patients with scleroderma with no PH and 44 patients with scleroderma with PH was included for external validation. More than 700 bioactive lipid metabolites, representing a range of vasoactive and immune-inflammatory pathways, were assayed in plasma samples from independent discovery and validation cohorts using liquid chromatography/high-resolution mass spectrometry-based approaches. Regression analyses were used to identify metabolites that exhibited differential levels between SSc-PAH and IPAH and associated with disease severity.

RESULTS

From hundreds of circulating bioactive lipid molecules, five metabolites were found to distinguish between SSc-PAH and IPAH, as well as associate with markers of disease severity. Relative to IPAH, patients with SSc-PAH carried increased levels of fatty acid metabolites, including lignoceric acid and nervonic acid, as well as eicosanoids/oxylipins and sex hormone metabolites.

INTERPRETATION

Patients with SSc-PAH are characterized by an unfavorable bioactive metabolic profile that may explain the poor and limited response to therapy. These data provide important metabolic insights into the molecular heterogeneity underlying differences between subgroups of PAH.

Immune Cells in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a complex and serious cardiopulmonary disease; it is characterised by increased pulmonary arterial pressure and pulmonary vascular remodelling accompanied by disordered endothelial and smooth muscle cell proliferation within pulmonary arterioles and arteries. Although recent reports have suggested that dysregulated immunity and inflammation are key players in PAH pathogenesis, their roles in PAH progression remain unclear. Intriguingly, altered host immune cell distribution, number, and polarisation within the lung arterial vasculature have been linked to disease development. This review mainly focusses on the roles of different immune cells in PAH and discusses the underlying mechanisms.

Systemic Sclerosis-Associated Pulmonary Hypertension: Spectrum and Impact

Systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH) is a catastrophic complication of one of the most common and devastating autoimmune diseases. Once diagnosed, it becomes the leading cause of mortality among this patient population. Screening modalities and risk assessments have been designed and validated by various organizations and societies in order to identify patients early in their disease course and promptly refer them to expert centers for a hemodynamic assessment and formal diagnosis. Moreover, several large multicenter clinical trials have now included patients with SSc-PAH to assess their response to therapy. Despite an improved understanding of the condition and significant advances in supportive and targeted therapy, outcomes have remained far from optimal. Therefore, rigorous phenotyping and search for novel therapies are desperately needed for this devastating condition.

Pulmonary arterial hypertension in Saudi patients with systemic sclerosis: Clinical and hemodynamic characteristics and mortality

BACKGROUND

Pulmonary arterial hypertension (PAH) is a major cause of morbidity and mortality in patients with systemic sclerosis (SSc). The objective of this study is to describe the clinical characteristics, mortality, and predictors of SSc-PAH in Saudi patients.

METHODS

Retrospective chart review study of SSc patients who were followed for at least 1 year in three tertiary care centers in Saudi Arabia was conducted. Clinical information, echocardiographic findings, and right heart catheterization (RHC) results were collected. Descriptive statistics were used for demographic and disease characteristics.

RESULTS

Fifty-seven patients with SSc were reviewed. PAH was confirmed by RHC in 40 patients (87.5%, females). Their mean age was 45.43 ± 13.48 years. The mean pulmonary artery pressure was 42.9 ± 12.7 mmHg, the pulmonary vascular resistance index was 19.4 ± 7.7 woods unit, and cardiac index was 2.43 ± 0.68 min/m². The median time from symptoms to first assessment was 42.8 ± 115.62 months. Most patients (77.5%) presented with functional Class III or IV and more than half (22.55%) were on dual combination therapy. Ten patients (25%) SSc PAH died over a follow up period of 37 ± 7 months. Compared to SSc patients without PAH, SSc-PAH patients had shorter 6-min walk distance (6MWD) (296.1 ± 116.5 vs. 399.59 ± 40.60 m, P < 0.0001), higher pro-brain natriuretic peptide (1755.8 ± 2123.4 vs. 69.8 ± 44.3 pg/ml P = 0.004), and more frequent Raynaud's phenomenon (RP) (90% vs. 35%, P < 0.0001). Logistic regression showed RP (odds ratio [OR] =48.58, 95% confidence interval [CI]; 3.73-633.10) and 6MWD (OR 1.02: 95% CI; 1.01-1.03) were associated with the development of PAH.

CONCLUSION

Our cohort of Saudi SSc-PAH patients has a younger disease onset and a lower mortality than what is described worldwide despite late presentation and requirement of combination therapy. The presence of RP and lower were associated with the development of SSc-PAH.

Prevalence of pulmonary hypertension in patients with systemic sclerosis and mixed connective tissue disease

Systemic sclerosis (SSc) and mixed connective tissue disease (MCTD) are 2 conditions in which pulmonary hypertension (PH) can develop.We retrospectively analyzed the probability of PH in case of 83 patients (69 SSc and 14 MCTD). The European Society of Cardiology/European Respiratory Society (ESC/ERS) echocardiographic guidelines of 2015 were used for the evaluation.On the basis of an echocardiography, the patients were divided into 2 subgroups: patients with elevated probability of PH (EP) (n = 16) versus the group with a low probability of PH (LP) (n = 67). Of the 16 patients in the EP group, 15 were SSc patients and 1 was an MCTD patient, respectively, that is, 21.7% and 7.1% of all patients. Of the 16 patients with EP, 10 with SSc had right-heart catheterization, which excluded PH in 7 patients; hence, PH was estimated to be 11.6% in the SSc group. The distribution of the individual causes of PH was arterial PH 2.9%, PH associated with interstitial lung disease 4.3%, PH associated with left ventricular disease 1.5%, and PH of unknown origin 2.9%. Further, there was a significant difference between EP and LP in the incidence of the right bundle branch block in standard electrocardiography, left atrial and right ventricular dimension, tricuspid annular plane systolic excursion, and Doppler-derived tricuspid lateral annular systolic velocity (S') in echocardiography.Echocardiography, particularly those evaluating the parameters included in the ESC/ERS guidelines of 2015, appears to be a useful tool in the detection of patients with a high PH probability. Additional tissue Doppler echocardiography seems to be a good option.

Echocardiographic assessment of regional right ventricular systolic function using two-dimensional strain echocardiography and evaluation of the predictive ability of longitudinal 2D-strain imaging for pulmonary arterial hypertension in systemic sclerosis patients

Systemic sclerosis (SSc) is a generalized connective tissue disorder, and SSc patients are at risk of developing pulmonary arterial hypertension (PAH). The aims of this study are to evaluate the right ventricular regional systolic function using two-dimensional speckle-tracking echocardiography (2D STE) and to determine the predictive ability of peak longitudinal systolic strain (PLSS) at the RV lateral wall for PAH in SSc patients. 80 SSc patients (mean age 51 ± 12 years) were included in the study. Echocardiography and 2D STE were performed at baseline and after 12 months. RHC was performed only in SSc patients with clinical indications. PLSS at the apical segment of the RV free wall was significantly impaired in PAH patients compared with non-PH patients (-14.6 ± 5.9 vs. - 22.2 ± 7.5%, p = 0.034). PLSS at the basal, mid, and apical segments of the RV free wall was lower in both groups at follow-up compared to baseline, but the drop in strain values was statistically significant only in the non-PH group (p < 0.05). Right atrial area (OR 1.758; p = 0.023), peak tricuspid regurgitation velocity (OR 24.23; p = 0.011) and PLSS at the apical segment of the RV lateral wall (OR 2.47; p = 0.005) were independent predictors of PAH. A cut-off value of - 14.48% PLSS at the apical segment of the RV lateral wall resulted in 100% specificity for predicting PAH in SSc patients. RV pressure overload affects RV systolic function as manifested by impaired RV longitudinal deformation. Evaluating RV regional systolic function with 2D STE could be useful as an additional echocardiographic parameter for screening PAH in SSc patients.

Circulating Angiopoietin-1 Is Not a Biomarker of Disease Severity or Prognosis in Pulmonary Hypertension

Background

Circulating angiopoietin-1 (Ang-1) has been linked to pulmonary hypertension (PH) in experimental studies. However, the clinical relevance of Ang-1 as a biomarker in PH remains unknown. We aimed to investigate the prognostic and clinical significance of Ang-1 in PH using data from the prospectively recruiting Giessen PH Registry.

Methods

Patients with suspected PH (without previous specific pulmonary arterial hypertension [PAH] therapy) who underwent initial right heart catheterization (RHC) in our national referral center between July 2003 and May 2012 and who agreed to optional biomarker analysis were included if they were diagnosed with idiopathic PAH, connective tissue disease-associated PAH (CTD-PAH), PH due to left heart disease (PH-LHD), or chronic thromboembolic PH (CTEPH), or if PH was excluded by RHC (non-PH controls). The association of Ang-1 levels with disease severity (6-minute walk distance and pulmonary hemodynamics) was assessed using linear regression, and the impact of Ang-1 levels on transplant-free survival (primary endpoint) and clinical worsening was assessed using Kaplan—Meier curves, receiver operating characteristic (ROC) analyses, and Cox regression.

Results

151 patients (39, 39, 32, and 41 with idiopathic PAH, CTD-PAH, PH-LHD, and CTEPH, respectively) and 41 non-PH controls were included. Ang-1 levels showed no significant difference between groups (p = 0.8), and no significant associations with disease severity in PH subgroups (p ≥ 0.07). In Kaplan—Meier analyses, Ang-1 levels (stratified by quartile) had no significant impact on transplant-free survival (p ≥ 0.27) or clinical worsening (p ≥ 0.51) in PH subgroups. Regression models found no significant association between Ang-1 levels and outcomes (p ≥ 0.31). ROC analyses found no significant cut-off that would maximize sensitivity and specificity.

Conclusions

Despite a strong pathophysiological association in experimental studies, this first comprehensive analysis of Ang-1 in PH subgroups suggests that Ang-1 is not a predictive and clinically relevant biomarker in PH.

Left ventricular diastolic dysfunction and increased left ventricular mass index related to pulmonary hypertension in patients with systemic autoimmune disease without pericardial effusion

PURPOSE

We investigated the relationship of left ventricular (LV) diastolic dysfunction and LV mass index (LVMI) against pulmonary hypertension (PH) in systemic autoimmune disease (SAD).

METHODS

A total of 84 SAD patients (68 females; 53±17years; systemic lupus erythematosus, 27%; scleroderma, 17%; vasculitis, 16%; mixed connective tissue disease, 13% and polymyositis/dermatomyositis complex, 10%) without significant pericardial effusion (PE) on TTE (Vivid E9, GE) were analyzed. On TTE, PH was defined as peak tricuspid regurgitation velocity (TRV) of ≥2.9m/s based upon 2015 ESC guideline. Left atrial volume index (LAVI) and E/E' were measured as indicators of LV diastolic dysfunction. LVMI was also measured.

RESULTS

Seven patients (8%) had PH. PH patients had greater LAVI (p<0.001), E/E' (p=0.004), LVMI (p=0.009) than non-PH patients. LAVI (R=0.458), E/E' (R=0.337), and LVMI (R=0.313) significantly and positively correlated with TRV (all p<0.05). Multiple regression analysis was performed to explore determinants of TRV. Age, female sex, and brain natriuretic peptide (BNP) were included in all the models. Three multiple regression models were generated using 1) LAVI, 2) E/E', and 3) LVMI and included LAVI, E/E', LVMI, and BNP as significant variables influencing TRV. Multi logistic regression analysis for predicting TRV of ≥2.9m/s showed that LAVI, and E/E' were significant predictors (Odds ratio, 1.296, and 1.370, respectively).

CONCLUSION

In SAD patients without PE, LV diastolic dysfunction and increment of LVMI was closely associated with PH based upon TRV. LAVI and E/E' were independent predictors for PH. Measuring LAVI and E/E' may be a key to determine the mechanism of PH in these patients.

Aberrant immune response with consequent vascular and connective tissue remodeling - causal to scleroderma and associated syndromes such as Raynaud phenomenon and other fibrosing syndromes?

PURPOSE OF REVIEW

Scleroderma and other autoimmune-induced connective tissue diseases are characterized by dysfunctions in the immune system, connective tissue and the vasculature. We are focusing on systemic sclerosis (SSc)-associated pulmonary hypertension, which remains a leading cause of death with only a 50-60% of 2-year survival rate.

RECENT FINDINGS

Much research and translational efforts have been directed at understanding the immune response that causes SSc and the networked interactions with the connective tissue and the vasculature. One of the unexpected findings was that in some cases the pathogenic immune response in SSc resembles the immune response to helminth parasites. During coevolution, means of communication were developed which protect the host from over-colonization with parasites and which protect the parasite from excessive host responses. One explanation for the geographically clustered occurrence of SSc is that environmental exposures combined with genetic predisposition turn on triggers of molecular and cellular modules that were once initiated by parasites.

SUMMARY

Future research is needed to further understand the parasite-derived signals that dampen the host response. Therapeutic helminth infection or treatment with parasite-derived response modifiers could be promising new management tools for autoimmune connective tissue diseases.

Monitoring of Lung Involvement in Rheumatologic Disease

The monitoring of lung involvement in patients with connective tissue diseases is central to optimal long-term management and is directed towards: (a) the detection of supervening lung involvement not present at presentation and (b) the identification of disease progression in established lung disease. For both goals, accurate surveillance requires multi-disciplinary evaluation with the integration of symptomatic change, serial pulmonary function trends and imaging data. Evaluated in isolation, each of these monitoring domains has significant limitations. Symptomatic change may be confounded by a wide variety of systemic factors. Pulmonary function tests provide the most reliable data, but are limited by measurement variability, the heterogeneity of functional patterns and the confounding effects of non-pulmonary factors. Chest radiography is insensitive to change but may provide rapid confirmation of major disease progression or alert the clinician to respiratory co-morbidities. Although high-resolution computed tomography has a central role in assessing disease severity, it should be used very selectively as a monitoring tool due to the associated radiation burden. Ancillary tests include echocardiography and exercise testing to proactively identify cases of pulmonary hypertension and worsening of oxygenation. In summary, a multi-disciplinary approach is essential for the identification of disease progression and prompt treatment of comorbidities that severely impact on the morbidity and mortality of disease.

Clinical pharmacokinetics and pharmacodynamics of the endothelin receptor antagonist macitentan

Pulmonary arterial hypertension (PAH) is a progressive disease of the lung vascular system, which leads to right-sided heart failure and ultimately death if untreated. Treatments to regulate the pulmonary vascular pressure target the prostacyclin, nitric oxide, and endothelin (ET) pathways. Macitentan, an oral, once-daily, dual ET_A and ET_B receptor antagonist with high affinity and sustained receptor binding is the first ET receptor antagonist to show significant reduction of the risk of morbidity and mortality in PAH patients in a large-scale phase III study with a long-term outcome. Here we present a review of the available clinical pharmacokinetic, pharmacodynamic, pharmacokinetic/pharmacodynamic relationship, and drug–drug interaction data of macitentan in healthy subjects, patients with PAH, and in special populations.

Perioperative management of patients with pulmonary hypertension for non-cardiac surgery

Pulmonary hypertension (PH) is associated with significant morbidity and mortality. While the advent of disease-modifying therapies in the treatment of PH has dramatically increased the life expectancy of these patients, they remain at high risk for perioperative complications. Outcome studies suggest that patients with PH undergoing non-cardiac surgery have higher morbidity and mortality than those without, independent of severity. Despite these risks, more and more of these patients are presenting for non-cardiac surgery. Patients with rheumatologic disorders in particular often have pulmonary arterial hypertension (PAH), a group that is associated with a poorer prognosis. Yet, these patients invariably develop debilitating joint diseases and not uncommonly present for elective surgery. Preoperatively, patients with PH should be appropriately risk stratified based on functional class, etiology, exercise capacity, pulmonary hemodynamics, and the risk of surgery. If the risks and benefits assessment proves favorable, they should undergo optimization prior to surgery, with any chronic therapy continuing without cessation through the perioperative period. A multidisciplinary approach involving all intraoperative physicians is imperative to forming a safe intraoperative plan based on the inherent physiology underlying the patient's disease. Finally, because complications in this patient population often occur postoperatively, patients should be monitored in an appropriate setting with a goal of preventing right ventricular dysfunction. In this review article, we focus on the evaluation, risk stratification, and optimization of patients with PH undergoing non-cardiac surgery.

2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension

Guidelines summarize and evaluate all available evidence on a particular issue at the time of the writing process, with the aim of assisting health professionals in selecting the best management strategies for an individual patient with a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines and recommendations should help health professionals to make decisions in their daily practice. However, the final decisions concerning an individual patient must be made by the responsible health professional(s) in consultation with the patient and caregiver as appropriate.

Cross-sectional study of soluble selectins, fractions of circulating microparticles and their relationship to lung and skin involvement in systemic sclerosis

Background

Endothelial damage and activation may play central roles in the pathogenesis of systemic sclerosis (SSc) and are reflected by microparticles (MPs) and soluble selectins. The objective of this study was to determine if these potential biomarkers are associated with specific organ involvements or cutaneous subgroups of SSc patients.

Method

MPs in platelet-poor plasma from 121 patients with SSc, 79 and 42 with limited and diffuse cutaneous disease, respectively, were characterized by flow cytometry for their capacity to bind annexin V in combination with surface markers of either platelets (PMPs), leukocytes (LMPs) or endothelial cells (EMPs). Soluble E- and P-selectin levels were determined in plasma. By correlation analyses, this was held against involvement of skin, lung function, lung fibrosis, pulmonary artery hypertension, and serology.

Results

None of the markers were associated with cutaneous subgroups of SSc. Concentrations of annexin V non-binding EMPs and annexin V non-binding LMPs were negatively correlated to pulmonary diffusing capacity (DL_CO) (r = -0.28; p = 0.003; r = -0.26; p = 0.005) and forced vital capacity (FVC) (r = -0.24; p = 0.009; r = -0.29; p = 0.002), driven by patients with limited and diffuse cutaneous disease, respectively. Soluble E-selectin levels correlated negatively to DL_CO (r = -0.21, p = 0.03) and FVC (r = -0.25; p = 0.007); and soluble P-selectin correlated negatively to DL_CO (r = -0.23, p = 0.01).

Conclusion

Negative correlations between annexin V non-binding EMP and LMP concentrations with lung function parameters (DL_CO and FVC) differed between limited and diffuse cutaneous subsets of SSc, indicative of various pathogeneses of lung involvement in SSc, possibly with a differential role of MPs.