Prognostic impact of renal function in precapillary pulmonary hypertension

Pulmonary hypertension and chronic kidney disease: prevalence, pathophysiology and outcomes

Pulmonary hypertension (PH) is common in patients with chronic kidney disease (CKD) or kidney failure, with an estimated prevalence of up to 78% in those referred for right-heart catheterization. PH is independently associated with adverse outcomes in CKD, raising the possibility that early detection and appropriate management of PH might improve outcomes in at-risk patients. Among patients with PH, the prevalence of CKD stages 3 and 4 is estimated to be as high as 36%, and CKD is also independently associated with adverse outcomes. However, the complex, heterogenous pathophysiology and clinical profile of CKD-PH requires further characterization. CKD is often associated with elevated left ventricular filling pressure and volume overload, which presumably leads to pulmonary vascular stiffening and post-capillary PH. By contrast, a distinct subgroup of patients at high risk is characterized by elevated pulmonary vascular resistance and right ventricular dysfunction in the absence of pulmonary venous hypertension, which may represent a right-sided cardiorenal syndrome defined in principle by hypervolaemia, salt avidity, low cardiac output and normal left ventricular function. Current understanding of CKD-PH is limited, despite its potentially important ramifications for clinical decision making. In particular, whether PH should be considered when determining the suitability and timing of kidney replacement therapy or kidney transplantation is unclear. More research is urgently needed to address these knowledge gaps and improve the outcomes of patients with or at risk of CKD-PH.

Immature reticulocyte fraction: A novel biomarker of hemodynamic severity in pulmonary arterial hypertension

Various erythropoietic abnormalities are highly prevalent among patients with pulmonary arterial hypertension (PAH) and associated with worse disease severity. Given the poorly understood yet important roles of dysregulated erythropoiesis and iron metabolism in PAH, we sought to further characterize the hematologic and iron profiles in PAH and their relationship to PAH severity. We recruited 67 patients with PAH and 13 healthy controls. Hemodynamics attained within 1 year of blood sample collection were available for 36 patients. Multiple hematologic, iron, and inflammatory parameters were evaluated for their association with hemodynamics. The subset with hemodynamic data consisted of 29 females (81%). The most common etiologies were idiopathic PAH (47%) and connective tissue disease-related PAH (33%). 19 (53%) had functional class 3 or 4 symptomatology, and 12 (33%) were on triple pulmonary vasodilator therapy. Immature reticulocyte fraction (IRF) had significant positive correlations with mean pulmonary artery (PA) pressure (mPAP) (0.59, p < 0.001), pulmonary vascular resistance (0.52, p = 0.001), and right atrial pressure (0.46, p = 0.005), and significant negative correlations with cardiac index (-0.43, p = 0.009), PA compliance (PAC) (-0.60, p < 0.001), stroke volume index (SVI) (-0.57, p < 0.001), and mixed venous oxygen saturation (-0.51, p = 0.003). IRF correlated with markers of iron deficiency (ID) and erythropoiesis. On multivariable linear regression, IRF was associated with elevated mPAP and reduced SVI and PAC independent of EPO levels, transferrin saturation, and soluble transferrin receptor levels. We identified IRF as a novel and potent biomarker of PAH hemodynamic severity, possibly related to its associations with erythropoiesis, ID, and tissue hypoxia.

Blood urea nitrogen to serum albumin ratio as a new indicator of disease severity and prognosis in idiopathic pulmonary artery hypertension

BACKGROUND

Emerging evidence has shown that the blood urea nitrogen to serum albumin ratio (BAR) is associated with the severity and prognosis of heart failure. However, its role in idiopathic pulmonary arterial hypertension (IPAH) remains unclear. This study investigated the associations between BAR and functional status, echocardiographic findings, hemodynamics, and long-term outcomes among patients with IPAH.

METHODS

This study included consecutive patients who underwent right heart catheterization (RHC) and were diagnosed with IPAH between January 2013 and January 2018 at Fuwai Hospital. The primary outcome was the worsening of clinical symptoms. Spearman correlation coefficients were used to evaluate the association between the BAR and established markers of IPAH severity. Receiver operating characteristic (ROC) curve analysis was used to determine BAR's optimal cut-off and predictive performance. Kaplan-Meier analysis and Cox proportional hazard models assessed the relationship between BAR and clinical worsening.

RESULTS

A total of 340 patients with IPAH were included in this study. BAR correlated with well-validated variables that reflected the severity of IPAH, such as World Health Organization functional class, 6-min walk distance, N-terminal pro-brain natriuretic peptide (NT-proBNP) level, mixed venous oxygen saturation, and cardiac index. Kaplan-Meier curves indicated that patients with BAR＞3.80 had a significantly higher clinical worsening rate (log-rank test, P < 0.001) than those with BAR≤3.80. Multivariate Cox analysis showed that BAR could independently predict clinical worsening [hazard ratio(HR):2.642, 95 % confidence interval (CI):1.659-4.208, P < 0.001]. In addition, BAR provided additional predictive value for the European Society of Cardiology (ESC)/European Respiratory Society (ERS) risk assessment score.

CONCLUSIONS

BAR reflects disease severity and is independently associated with the prognosis of patients with IPAH.

The potential of cystatin C as a predictive biomarker in pulmonary hypertension

BACKGROUND

Cystatin C is a novel biomarker to identify renal dysfunction and cardiovascular risk.

OBJECTIVE

The aim of this study was to investigate the role of cystatin C in non-invasive risk prediction in a large cohort of patients with pre-capillary pulmonary hypertension (PH).

METHOD

We retrospectively analyzed pre-capillary PH patients with available cystatin C and hemodynamic data derived from right heart catheterization.

RESULTS

A total of 398 consecutive patients with confirmed pre-capillary PH were recruited from Fuwai Hospital between November 2020 and November 2021. Over a median duration of 282 days, 72 (18.1%) of these patients experienced clinical worsening. Cystatin C levels significantly correlated with cardiac index (r = -0.286, P < 0.001), mixed venous oxygen saturation (r = -0.216, P < 0.001), and tricuspid annular plane systolic excursion (r = -0.236, P < 0.001), and high cystatin C levels independently predicted a poor prognosis after adjusting potential confounders in different models (all P < 0.05). A three-group non-invasive risk model was constructed based on the combined assessment of the cystatin C and WHO-FC using dichotomous cut-off value. Those patients with higher cystatin C (≥ 1.0 mg/L) and a worse WHO-FC experienced the highest risk of endpoint occurrence. The predictive capacity of this model was comparable to that of an existing invasive risk stratification model (area under curve: 0.657 vs 0.643, P = 0.619).

CONCLUSIONS

Cystatin C levels were associated with disease severity and prognosis in patients with pre-capillary PH. A combination of high cystatin C and advanced WHO-FC identifies patients at particularly high risk of clinical deterioration.

Urine Output Is Associated With In-hospital Mortality in Intensive Care Patients With Septic Shock: A Propensity Score Matching Analysis

Background: The relationship between urine output (UO) and in-hospital mortality in intensive care patients with septic shock is currently inconclusive. Methods: The baseline data, UO, and in-hospital prognosis of intensive care patients with septic shock were retrieved from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. By drawing receiver operating characteristic (ROC) curves and comparing the areas under the ROC curves (AUC) to determine the predictive value of UO for in-hospital mortality, and by drawing the Kaplan-Meier curves to compare the difference in in-hospital mortality between different groups of UO. Results: Before and after the propensity score matching (PSM) analysis, UO was always a risk factor for in-hospital mortality in patients with septic shock. The AUC of UO was comparable to the Sequential Organ Failure Assessment (SOFA) scoring system, while the AUC of combining UO and SOFA was greater than that of SOFA. The median survival time of the high-UO group (UO > 0.39 ml/kg/h, before PSM; UO > 0.38 ml/kg/h, after PSM) was longer than that of the low-UO group. Compared with the high-UO group, the hazard ratios (HR) of the low-UO group were 2.6857 (before PSM) and 1.7879 (after PSM). Conclusions: UO is an independent risk factor for septic shock. Low levels of UO significantly increase the in-hospital mortality of intensive care patients with septic shock. The predictive value of UO is comparable to the SOFA scoring system, and the combined predictive value of the two surpasses SOFA alone.

Biological heterogeneity in idiopathic pulmonary arterial hypertension identified through unsupervised transcriptomic profiling of whole blood

Idiopathic pulmonary arterial hypertension (IPAH) is a rare but fatal disease diagnosed by right heart catheterisation and the exclusion of other forms of pulmonary arterial hypertension, producing a heterogeneous population with varied treatment response. Here we show unsupervised machine learning identification of three major patient subgroups that account for 92% of the cohort, each with unique whole blood transcriptomic and clinical feature signatures. These subgroups are associated with poor, moderate, and good prognosis. The poor prognosis subgroup is associated with upregulation of the ALAS2 and downregulation of several immunoglobulin genes, while the good prognosis subgroup is defined by upregulation of the bone morphogenetic protein signalling regulator NOG, and the C/C variant of HLA-DPA1/DPB1 (independently associated with survival). These findings independently validated provide evidence for the existence of 3 major subgroups (endophenotypes) within the IPAH classification, could improve risk stratification and provide molecular insights into the pathogenesis of IPAH.

Iron Deficiency in Pulmonary Arterial Hypertension: A Deep Dive into the Mechanisms

Pulmonary arterial hypertension (PAH) is a severe cardiovascular disease that is caused by the progressive occlusion of the distal pulmonary arteries, eventually leading to right heart failure and death. Almost 40% of patients with PAH are iron deficient. Although widely studied, the mechanisms linking between PAH and iron deficiency remain unclear. Here we review the mechanisms regulating iron homeostasis and the preclinical and clinical data available on iron deficiency in PAH. Then we discuss the potential implications of iron deficiency on the development and management of PAH.

Distinct patterns of soluble leukocyte activation markers are associated with etiology and outcomes in precapillary pulmonary hypertension

Activation of inflammatory processes has been identified as a major driver of pulmonary vascular remodeling that contributes to the development of precapillary pulmonary hypertension (PH). We hypothesized that circulating markers of leukocyte activation, reflecting monocytes/macrophages (sCD163, sCD14), T-cells (sCD25) and neutrophils (myeloperoxidase [MPO], neutrophil gelatinase-associated lipocalin [NGAL]) activity, could give prognostic information in precapillary PH. Circulating markers of leucocyte activation, sCD163, sCD14, sCD25, MPO and NGAL were measured by enzyme immunoassays in plasma from patients with idiopathic PAH (IPAH; n = 30); patients with PAH related to associated conditions (APAH; n = 44) and patients with chronic thromboembolic PH (CTEPH) (n = 32), and compared with 23 healthy controls. Markers of leucocyte activation were elevated in precapillary PH with particularly high levels in APAH. The elevated levels of monocyte/macrophage marker sCD163 was independently associated with poor long-term prognosis in the group as a whole, and elevated levels of sCD25 was associated with poor prognosis in APAH, while elevated levels of sCD163 and NGAL was associated with poor prognosis in IPAH and CTEPH. Our data show leucocyte activation in precapillary PH with different profiles and impact on prognosis according to etiology. The association of sCD163 with poor outcome in fully adjusted model may be of particular interest.

Higher plasma fibroblast growth factor 23 levels are associated with a higher risk profile in pulmonary arterial hypertension

Metabolic abnormalities are proposed to contribute to pulmonary arterial as well as right ventricular remodelling in pulmonary arterial hypertension. Among the proposed abnormalities are altered glucose and lipid processing, mitochondrial malfunction, oxidative stress as well as vitamin D and iron abnormalities. In the present study, we investigated 11 metabolic plasma biomarkers, with the hypothesis that metabolic proteins may mirror disease severity in pulmonary arterial hypertension. Using proximity extension assays, plasma metabolic biomarkers were measured in 48 pulmonary arterial hypertension patients at diagnosis and, in 33 of them, at an early treatment follow-up, as well as in 16 healthy controls. Among the studied metabolic biomarkers, plasma fibroblast growth factor-23 (p < 0.001), fibroblast growth factor-21 (p < 0.001), fatty acid binding protein 4 (p < 0.001) and lectin-like oxidised low-density lipoprotein receptor 1 (p < 0.001) were increased and paraoxonase-3 was decreased (p < 0.001) in pulmonary arterial hypertension at diagnosis versus controls. Fibroblast growth factor-23 showed the strongest correlations to studied clinical parameters and was therefore selected for further analyses. Fibroblast growth factor-23 correlated specifically to mean right atrial pressure (r = 0.67, p < 0.001), six-min walking distance (r = −0.66, p < 0.001), NT-proBNP (r = 0.64, p < 0.001), venous oxygen saturation (r = −0.61, p < 0.001), cardiac index (r = −0.39, p < 0.007) and pulmonary vascular resistance (r = 0.37, p < 0.01). Fibroblast growth factor-23 correlated moreover to ESC/ERS (r = 0.72, p < 0.001) and the REVEAL risk score (r = 0.61, p < 0.001). Comparing early treatment follow-up with baseline, fibroblast growth factor-23 decreased (p < 0.02), with changes in fibroblast growth factor-23 correlating to changes in six-min walking distance (r = −0.56, p < 0.003), venous oxygen saturation (r = −0.46, p < 0.01), pulmonary vascular resistance (r = 0.43, p < 0.02), mean right atrial pressure (r = 0.38, p < 0.04) and cardiac index (r = −0.39, p < 0.04). Elevated plasma fibroblast growth factor-23 levels at pulmonary arterial hypertension diagnosis were associated with worse haemodynamics and a higher risk profile, and were decreased after the administration of pulmonary arterial hypertension-specific treatment.

Pulmonary Hypertension Subtypes and Mortality in CKD

RATIONALE & OBJECTIVE

Pulmonary hypertension (PH) contributes to cardiovascular disease and mortality in patients with chronic kidney disease (CKD), but the pathophysiology is mostly unknown. This study sought to estimate the prevalence and consequences of PH subtypes in the setting of CKD.

STUDY DESIGN

Observational retrospective cohort study.

SETTING & PARTICIPANTS

We examined 12,618 patients with a right heart catheterization in the Duke Databank for Cardiovascular Disease from January 1, 2000, to December 31, 2014.

EXPOSURES

Baseline kidney function stratified by CKD glomerular filtration rate category and PH subtype.

OUTCOMES

All-cause mortality.

ANALYTICAL APPROACH

Multivariable Cox proportional hazards analysis.

RESULTS

In this cohort, 73.4% of patients with CKD had PH, compared with 56.9% of patients without CKD. Isolated postcapillary PH (39.0%) and combined pre- and postcapillary PH (38.3%) were the most common PH subtypes in CKD. Conversely, precapillary PH was the most common subtype in the non-CKD cohort (35.9%). The relationships between mean pulmonary artery pressure, pulmonary capillary wedge pressure, and right atrial pressure with mortality were similar in both the CKD and non-CKD cohorts. Compared with those without PH, precapillary PH conferred the highest mortality risk among patients without CKD (HR, 2.27; 95% CI, 2.00-2.57). By contrast, in those with CKD, combined pre- and postcapillary PH was associated with the highest risk for mortality in CKD in adjusted analyses (compared with no PH, HRs of 1.89 [95% CI, 1.57-2.28], 1.87 [95% CI, 1.52-2.31], 2.13 [95% CI, 1.52-2.97], and 1.63 [95% CI, 1.12-2.36] for glomerular filtration rate categories G3a, G3b, G4, and G5/G5D).

LIMITATIONS

The cohort referred for right heart catheterization may not be generalizable to the general population. Serum creatinine data in the 6 months preceding catheterization may not reflect true baseline CKD. Observational design precludes assumptions of causality.

CONCLUSIONS

In patients with CKD referred for right heart catheterization, PH is common and associated with poor survival. Combined pre- and postcapillary PH was common and portended the worst survival for patients with CKD.

Development of renal function during staged balloon pulmonary angioplasty for inoperable chronic thromboembolic pulmonary hypertension

Balloon pulmonary angioplasty (BPA), for chronic thromboembolic pulmonary hypertension, improves pulmonary and systemic hemodynamics. The kidney might benefit from this effect. However, staged BPA therapy comes along with repetitive administration of contrast agent. This study examined the overall effect of BPA therapy on renal function. This study included consecutive patients who underwent BPA treatment and completed a 6-month follow-up between March 2014 and March 2017. Biomarker-based evaluation of renal function was performed at baseline, consecutively prior to and after each BPA and at 6-month follow-up. The 51 patients underwent an average of 5 (±2) BPA sessions. In this course, patients received 133 (±48; 21-300) mL of contrast agent per session and 691 (±24; 240-1410) mL during the whole sequence. Acute kidney injury occurred after 6 (2.3%) procedures. The creatinine [80.1 (IQR 67.8-96.8) µmol/L vs. 77.4 (IQR 66.9-91.5) µmol/L, p = .02] and urea level [13.7 (IQR10.7-16.6) mmol/L vs. 12.5 (IQR 10.0-15.5) mmol/L, p = .02] decreased from baseline to the 6-month follow-up. The estimated glomerular filtration rate (eGFR) [79 (IQR 59-94) mL/min/m² vs. 79.6 (IQR 67.1-95.0) mL/min/m², p = .11] did not change. The Chronic kidney disease (CKD) stages at baseline were: G1:15; G2:23; G3a:10; G3b:2; G4:1; G5:0. Among patients with a CKD-stage ≥2, analysis revealed an increase of eGFR, decrease of creatinine and urea from baseline to 6-month follow-up. Among those patients, the baseline-CKD-stage improved in 14 (41.2%) patients. BPA therapy improves pulmonary and systemic hemodynamics, with positive effects on renal function. Repetitive administration of contrast agent seems not to be harmful regarding renal function.

The level of ROCK1 and ROCK2 in patients with pulmonary hypertension in plateau area

Pulmonary hypertension (PH) is defined as the mean pulmonary artery pressure (mPAP) ≥25 mmHg under the sea level in resting state. ROCK1 and ROCK2 can be combined to cause the damage of vascular endothelial function. To explore the differences of ROCK1 and ROCK2 in subjects with pulmonary hypertension or normal pulmonary artery pressure in plateau area, and to further understand the mechanism of Rho/rho-kinase pathway activation for promoting pulmonary hypertension, we collected 64 patients with pulmonary hypertension and 87 normal pulmonary artery healthy controls. All subjects were hospitalized in Cardiology or Respiration Department of Qinghai Provincial Peoples’ Hospital from December 2016 to June 2017. The pulmonary artery systolic pressure was measured by Doppler ultrasound, and serum ROCK1 and ROCK2 levels were tested by enzyme linked immunosorbent assay (ELISA). We found that the serum ROCK2 concentration in the pulmonary hypertension group was significantly higher than that in the control group, but serum ROCK1 level had no significant difference. ROCK2 plays a leading role in pulmonary hypertension in the plateau region, so selective ROCK2 inhibitors will be more effective in improving pulmonary hypertension.

Impact of age and comorbidity on risk stratification in idiopathic pulmonary arterial hypertension

Recent reports from worldwide pulmonary hypertension registries show a new demographic picture for patients with idiopathic pulmonary arterial hypertension (IPAH), with an increasing prevalence among the elderly.We aimed to investigate the effects of age and comorbidity on risk stratification and outcome of patients with incident IPAH.The study population (n=264) was categorised into four age groups: 18-45, 46-64, 65-74 and ≥75 years. Individual risk profiles were determined according to a risk assessment instrument, based on the European Society of Cardiology and the European Respiratory Society guidelines. The change in risk group from baseline to follow-up (median 5 months) and survival were compared across age groups. In the two youngest age groups, a significant number of patients improved (18-45 years, Z= -4.613, p<0.001; 46-64 years, Z= -2.125, p=0.034), but no significant improvement was found in the older patient groups. 5-year survival was highest in patients aged 18-45 years (88%), while the survival rates were 63%, 56% and 36% for patients in the groups 46-64, 65-74 and ≥75 years, respectively (p<0.001). Ischaemic heart disease and kidney dysfunction independently predicted survival.These findings highlight the importance of age and specific comorbidities as prognostic markers of outcome in addition to established risk assessment algorithms.

Presence of Kidney Disease as an Outcome Predictor in Patients with Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) may lead to right heart failure and subsequently alter glomerular filtration rates (GFR). Chronic kidney disease (CKD, GFR <60 mL/min/1.73 m2) may also adversely affect PAH prognosis. This study aimed to assess how right heart hemodynamics was associated with reduced estimated GFR (eGFR) and the association of CKD with survival in PAH patients.

METHODS

In a prospective PAH cohort (2003-2012), invasive hemodynamics and eGFR were collected at diagnosis (179 patients) and during follow-up (159 patients). The prevalence of CKD was assessed at PAH diagnosis. Variables, including hemodynamics, associated with reduced eGFR at diagnosis and during follow-up were tested in multivariate analysis. The association of CKD with survival was evaluated using a multivariate Cox regression model.

RESULTS

At diagnosis, mean age was 60.4 ± 16.5 years, mean pulmonary arterial pressure was 43 ± 12 mm Hg, and eGFR was 74.4 ± 26.4 mL/min/1.73 m2. CKD was observed in 52 incident patients (29%). Independent determinants of reduced eGFR at diagnosis were age, systemic hypertension, and decreased cardiac index. Independent determinants of reduced eGFR during follow-up were age, female gender, PAH etiology, systemic hypertension, decreased cardiac index, and increased right atrial pressure. Age ≥60 years, female gender, NYHA 4, and CKD at diagnosis were independently associated with decreased survival. The adjusted hazards ratio for death associated with CKD was 1.81 (95% confidence interval [1.01-3.25]).

CONCLUSION

CKD is frequent at PAH diagnosis and is independently associated with increased mortality. Right heart failure may induce renal hypoperfusion and congestion, and is associated with eGFR decrease.

Measurement of Serum Klotho in Systemic Sclerosis

Background

The aim of our study was to evaluate the serum concentration of klotho in a cohort of systemic sclerosis (SSc) patients compared to that of healthy controls and to correlate its levels with the degree and the kind of organ involvement.

Methods

Blood samples obtained from both patients and controls were collected and analysed by an ELISA test for the determination of human soluble klotho. Scleroderma patients were evaluated for disease activity through clinical, laboratory, and instrumental assessment.

Results

Our cohort consisted of 81 SSc patients (74 females, mean age 63.9 ± 13.1 years) and 136 healthy controls (78 females, mean age 50.5 ± 10.7 years). When matched for age, serum klotho concentration significantly differed between controls and patients (p < 0.001). However, in SSc patients, we did not find any significant association between serum klotho and clinical, laboratory, and instrumental findings. Lower serum levels of klotho were detected in 4 patients who were anticitrullinated peptide antibody (ACPA) positive (p = 0.005).

Conclusions

Our data show a lower concentration of klotho in the serum of SSc patients compared to that of healthy controls, without any significant association with clinical manifestations and laboratory and instrumental findings. The association between serum klotho and ACPA positivity requires further investigation.

Hepatoma-derived Growth Factor Predicts Disease Severity and Survival in Pulmonary Arterial Hypertension

RATIONALE

Pulmonary arterial hypertension (PAH) is a fatal disease, and pulmonary microvascular remodeling is an important contributor to PAH development. Therefore, we hypothesized that a circulating angiogenic factor could predict disease severity and survival.

OBJECTIVES

We sought to assess the relationship of serum hepatoma-derived growth factor (HDGF) with PAH disease severity and survival.

METHODS

Using a newly developed enzyme-linked immunosorbent assay, we evaluated circulating HDGF levels in two independent PAH cohorts and two different characterized control cohorts. Clinical and laboratory data were also used to assess the value of HDGF as a PAH prognostic biomarker.

MEASUREMENTS AND MAIN RESULTS

Serum HDGF levels were significantly elevated in two independent PAH cohorts. Importantly, serum HDGF levels were not elevated in a noncardiac chronic disease cohort. Further, patients with elevated HDGF had significantly lower exercise tolerance, worse New York Heart Association functional class, and higher levels of N-terminal pro-brain natriuretic peptide. HDGF was a strong predictor of mortality, with an unadjusted hazard ratio of 4.5 (95% confidence interval, 1.9-10.3; P = 0.003 by log-rank test). In multivariable Cox proportional hazards models, elevated HDGF levels predicted decreased survival after being adjusted for age, PAH subtype, invasive hemodynamics, and N-terminal pro-brain natriuretic peptide.

CONCLUSIONS

Elevated HDGF was associated with worse functional class, exertional intolerance, and increased mortality in PAH, suggesting HDGF as a potential biomarker for predicting mortality and as having possible diagnostic value for distinguishing PAH from non-PAH. HDGF may add additional value in PAH risk stratification in clinical trials and may represent a potential target for future PAH drug development.

Pulmonary hypertension in patients with chronic kidney disease: invasive hemodynamic etiology and outcomes

Pulmonary hypertension (PH) is common in patients with chronic kidney disease (CKD) and associated with increased mortality but the hemodynamic profiles, clinical risk factors, and outcomes have not been well characterized. Our objective was to define the hemodynamic profile and related risk factors for PH in CKD patients. We extracted clinical and hemodynamic data from Vanderbilt's de-identified electronic medical record on all patients undergoing right heart catheterization during 1998-2014. CKD (stages III-V) was defined by estimated glomerular filtration rate thresholds. PH was defined as mean pulmonary pressure ≥ 25 mmHg and categorized into pre-capillary and post-capillary according to consensus recommendations. In total, 4635 patients underwent catheterization: 1873 (40%) had CKD; 1518 (33%) stage 3, 230 (5%) stage 4, and 125 (3%) stage 5. PH was present in 1267 (68%) of these patients. Post-capillary (n = 965, 76%) was the predominant PH phenotype among CKD patients versus 302 (24%) for pre-capillary ( P < 0.001). CKD was independently associated with pulmonary hypertension (odds ratio = 1.4, 95% confidence interval = 1.18-1.65). Mortality among CKD patients rose with worsening stage and was significantly increased by PH status. PH is common and independently associated with mortality among CKD patients referred for right heart catheterization. Post-capillary was the most common etiology of PH. These data suggest that PH is an important prognostic co-morbidity among CKD patients and that CKD itself may have a role in the development of pulmonary vascular disease in some patients.

Kidney dysfunction in patients with pulmonary arterial hypertension

Pulmonary arterial hypertension (PH) and chronic kidney disease (CKD) both profoundly impact patient outcomes, whether as primary disease states or as co-morbid conditions. PH is a common co-morbidity in CKD and vice versa. A growing body of literature describes the epidemiology of PH secondary to chronic kidney disease and end-stage renal disease (ESRD) (WHO group 5 PH). But, there are only limited data on the epidemiology of kidney disease in group 1 PH (pulmonary arterial hypertension [PAH]). The purpose of this review is to summarize the current data on epidemiology and discuss potential disease mechanisms and management implications of kidney dysfunction in PAH. Kidney dysfunction, determined by serum creatinine or estimated glomerular filtration rate, is a frequent co-morbidity in PAH and impaired kidney function is a strong and independent predictor of mortality. Potential mechanisms of PAH affecting the kidneys are increased venous congestion, decreased cardiac output, and neurohormonal activation. On a molecular level, increased TGF-β signaling and increased levels of circulating cytokines could have the potential to worsen kidney function. Nephrotoxicity does not seem to be a common side effect of PAH-targeted therapy. Treatment implications for kidney disease in PAH include glycemic control, lifestyle modification, and potentially Renin-Angiotensin-Aldosterone System (RAAS) blockade.

Pulmonary Arterial Capacitance Predicts Cardiac Events in Pulmonary Hypertension Due to Left Heart Disease

Background

Although pulmonary hypertension due to left heart disease (LHD-PH) accounts for the largest proportion of pulmonary hypertension, few reports on the epidemiological analysis of LHD-PH exist. Recently, pulmonary arterial capacitance (PAC) has attracted attention as a possible factor of right ventricular afterload along with pulmonary vascular resistance. We therefore investigated the clinical significance of PAC in LHD-PH.

Methods

The subject consisted of 252 LHD-PH patients (145 men, mean age 63.4 ± 14.7 years) diagnosed by right heart catheterization. PAC was estimated by the ratio between stroke volume and pulmonary arterial pulse pressure. Patients were classified into four groups according to the PAC (1^st quartile was 0.74 to 1.76 ml/mmHg, the 2^nd quartile 1.77 to 2.53 ml/mmHg, the 3^rd quartile 2.54 to 3.59 ml/mmHg, and the 4^th quartile 3.61 to 12.14 ml/mmHg). The end-points were defined as rehospitalization due to worsening heart failure and/or cardiac death. The Cox proportional hazard regression model was used to determine what variables were associated with cardiac events.

Results

The patients in the 1^st quartile had the lowest cardiac index and stroke volume index, and the highest mean pulmonary arterial pressure, mean pulmonary capillary wedge pressure, and pulmonary vascular resistance compared with the 2^nd, 3^rd, and 4^th quartiles. Fifty-four patients experienced cardiac events during the follow-up period (median 943 days). The event-free rate of the 1^st quartile was significantly lower than that of the 3^rd and 4^th quartiles (66.7% vs 82.5% [3^rd quartile], P = 0.008; and 92.1% [4^th quartile], P < 0.001). The Cox hazard analysis revealed that PAC was significantly associated with cardiac events (HR 0.556, 95% CI 0.424–0.730, P < 0.001).

Conclusion

PAC is useful in the prediction of cardiac event risk in LHD-PH patients.

Cardio-Pulmonary-Renal Interactions: A Multidisciplinary Approach

Over the past decade, science has greatly advanced our understanding of interdependent feedback mechanisms involving the heart, lung, and kidney. Organ injury is the consequence of maladaptive neurohormonal activation, oxidative stress, abnormal immune cell signaling, and a host of other mechanisms that precipitate adverse functional and structural changes. The presentation of interorgan crosstalk may include an acute, chronic, or acute on chronic timeframe. We review the current, state-of-the-art understanding of cardio-pulmonary-renal interactions and their related pathophysiology, perpetuating nature, and cycles of increased susceptibility and reciprocal progression. To this end, we present a multidisciplinary approach to frame the diverse spectrum of published observations on the topic. Assessment of organ functional reserve and use of biomarkers are valuable clinical strategies to screen and detect disease, assist in diagnosis, assess prognosis, and predict recovery or progression to chronic disease.

Serum endostatin is a genetically determined predictor of survival in pulmonary arterial hypertension

RATIONALE

Pulmonary arterial hypertension (PAH) is a medically incurable disease resulting in death from right ventricular (RV) failure. Both pulmonary vascular and RV remodeling are linked to dynamic changes in the microvasculature. Therefore, we hypothesized that circulating angiostatic factors could be linked to outcomes and represent novel biomarkers of disease severity in PAH.

OBJECTIVES

We sought to determine the relationship of a potent angiostatic factor, endostatin (ES), with disease severity and mortality in PAH. Furthermore, we assessed genetic predictors of ES expression and/or function and their association with outcomes in PAH.

METHODS

We measured levels of serum ES in two independent cohorts of patients with PAH. Contemporaneous clinical data included New York Heart Association functional class, 6-minute-walk distance, invasive hemodynamics, and laboratory chemistries.

MEASUREMENTS AND MAIN RESULTS

Serum ES correlated with poor functional status, decreased exercise tolerance, and invasive hemodynamics variables. Furthermore, serum ES was a strong predictor of mortality. A loss-of-function, missense variant in the gene encoding ES, Col18a1, was linked to lower circulating protein and was independently associated with reduced mortality.

CONCLUSIONS

Our data link increased expression of ES to disease severity in PAH and demonstrate a significant relationship with adverse outcomes. Circulating ES levels can be genetically influenced, implicating ES as a genetically determined modifier of disease severity impacting on survival. These observations support serum ES as a potential biomarker in PAH with the capacity to predict poor outcomes. More importantly, this study implicates Col18a1/ES as a potential new therapeutic target in PAH.