Pulmonary hypertension in hemodialysis patients without arteriovenous fistula: the effect of dialyzer composition

Meta-analysis of the correlation between pulmonary hypertension and echocardiographic parameters in patients with chronic kidney disease

Objective

To investigate the correlation between pulmonary hypertension (PH) and echocardiographic parameters in patients with chronic kidney disease (CKD).

Methods

PubMed, Embase, Web of Science, Cochrane, VIP, CNKI, and Wanfang databases were systematically searched for articles published from inception to 19 May 2023. Study quality was estimated using the Quality Assessment of Case-Control Studies tool. Forest plots were drawn using R language software. The "metacor" function in the "meta" package was utilized for meta-analysis of the r-values and their standard errors. Heterogeneity and sensitivity analyses were carried out, with the main outcomes as r-value, p-value, and I2 value.

Results

Eleven studies were included, with 1,809 CKD patients. The correlations between 12 echocardiographic parameters and PH were analyzed. Except for FS and LVEF which were negatively correlated with CKD-PH, the other 10 parameters were positively correlated with CKD-PH. Among them, LA was highly correlated with CKD-PH (0.70 < r < 0.89); LVDD, RA, RV, LVMI, and LVDS were moderately correlated with CKD-PH (0.40 < r < 0.69); while PA, IVS, LVPW, SV, FS, and LVEF were lowly correlated with CKD-PH (0.20 < r < 0.39). The synthesized estimates were stable against heterogeneity.

Conclusion

CKD-PH patients may have large cardiac chambers, thickened septal tissue on both sides of the chambers, reduced pulmonary artery flow rates, and decreased left ventricular function.

The impact of vascular access location on pulmonary arterial pressure in chronic kidney disease patients undergoing hemodialysis

BACKGROUND AND AIM

It is feared that among chronic kidney disease patients undergoing hemodialysis, arteriovenous fistula (AVF) itself could contribute to pulmonary hypertension (PH). The impact of AVF location on PH is yet to be assessed. We hypothesize that patients with proximal AVF have higher access blood flow and hence higher pulmonary arterial systolic pressure (PASP) than those with distal AVF. We aimed to compare the PASP between patients with proximal and distal AVF.

METHODS

In this cross-sectional study, PASP was estimated using Doppler echocardiography and blood flow in the AVF was assessed by Doppler ultrasound. PASP was modeled by multivariate linear regression. AVF location was the primary exposure of interest.

RESULTS

Out of 89 patients undergoing hemodialysis, 72 (81%) had PH defined as PASP >35 mmHg. The mean blood flow in proximal and distal AVF was, respectively, 1240 and 783 mL/min (mean difference 457 mL/min, p < 0.001). Mean PASP in patients with proximal AVF was 16.6 mmHg higher than those with distal AVF (p < 0.001, 95% CI 8.3-24.9). There was a positive correlation between access blood flow and PASP (r = 0.28, p = 0.007). If access blood flow was included as a covariate in the multivariate model, the association between AVF location and PASP ceased to exist.

CONCLUSION

Patients with proximal AVF have a significantly higher PASP than those with distal AVF, and this could be attributed to the higher blood flow in proximal AVF compared to distal AVF.

Lung Dysfunction and Chronic Kidney Disease: A Complex Network of Multiple Interactions

Chronic kidney disease (CKD) is a progressive disease that affects > 10% of the total population worldwide or >800 million people. CKD poses a particularly heavy burden in low- and middle-income countries, which are least able to cope with its consequences. It has become one of the leading causes of death worldwide and is one of the few non-communicable diseases where the number of related deaths has increased over the last two decades. The high number of people affected, and the significant negative impact of CKD should be a reason to increase efforts to improve prevention and treatment. The interaction of lung and kidney leads to highly complex and difficult clinical scenarios. CKD significantly affects the physiology of the lung by altering fluid homeostasis, acid-base balance and vascular tone. In the lung, haemodynamic disturbances lead to the development of alterations in ventilatory control, pulmonary congestion, capillary stress failure and pulmonary vascular disease. In the kidney, haemodynamic disturbances lead to sodium and water retention and the deterioration of renal function. In this article, we would like to draw attention to the importance of harmonising the definitions of clinical events in pneumology and renal medicine. We would also like to highlight the need for pulmonary function tests in routine clinical practise for the management of patients with CKD, in order to find new concepts for pathophysiological based disease-specific management strategies.

Left Ventricular Mass and Functions in Egyptian Children with Chronic Kidney Disease in Comparison to Normal Subjects

Left ventricular hypertrophy (LVH) and cardiac fibrosis are common accompaniments of chronic kidney disease (CKD). They can be rather easily assessed by conventional cardiac imaging modalities, most practically by M-mode or two-dimensional (2D) echocardiography, with adequate recognition of pitfalls. This study uncovers the impact of impaired renal function on left ventricular mass (LVM) and LVM index (LVMI) in children with CKD on regular hemodialysis (HD) attending the Zagazig University Hospital for Children. A total of 80 Egyptian children, out of which 40 subjects having a mean age of 11.2 ± 3.12 years were cases with CKD in stage 5 on regular HD and the other 40 healthy subjects as controls, with a mean age of 12.2 ± 2.54 years, were included in the study and assessed for LVH and LVMI by 2D echocardiography. HD children had a significantly higher mean LVMI (102.3 ± 19.1 vs. 49.6 ± 4.11 g/m², P <0.001) than controls. Relative wall thickness was significantly higher in the patients with CKD patients on HD compared with controls (P <0.001) with a mean value of 0.46 indicating concentric LVH in renal patients. Comparing mitral inflow velocities between both the groups revealed that the patient group had a significant decrease in mitral E-wave velocity (0.88 ± 0.2 vs. 1.1 ± 0.1 m/sec, P <0.001) and E/A velocity ratio (1.3 ± 0.3 vs. 1.7 ± 0.3, P <0.001) in comparison with the control group, but there was no statistically significant difference in A-wave velocity. This indicates early diastolic dysfunction in CKD patients. LV mass changes in CKD children were strongly related to hypocalcemia and Vitamin D deficiency. Children with CKD are prone to the development of cardiac diastolic dysfunction and LVH, so early and regular echocardiographic studies of all children with CKD are recommended to detect early cardiac changes and institute interventions.

A porcine model of hemodialyzer reactions: roles of complement activation and rinsing back of extracorporeal blood

Hemodialysis reactions (HDRs) resemble complement-activation-related pseudoallergy (CARPA) to certain i.v. drugs, for which pigs provide a sensitive model. On this basis, to better understand the mechanism of human HDRs, we subjected pigs to hemodialysis using polysulfone (FX CorDiax 40, Fresenius) or cellulose triacetate (SureFlux-15UX, Nipro) dialyzers, or Dialysis exchange-set without membranes, as control. Experimental endpoints included typical biomarkers of porcine CARPA; pulmonary arterial pressure (PAP), blood cell counts, plasma sC5b-9 and thromboxane-B2 levels. Hemodialysis (60 min) was followed by reinfusion of extracorporeal blood into the circulation, and finally, an intravenous bolus injection of the complement activator zymosan. The data indicated low-extent steady rise of sC5b-9 along with transient leukopenia, secondary leukocytosis and thrombocytopenia in the two dialyzer groups, consistent with moderate complement activation. Surprisingly, small changes in baseline PAP and plasma thromboxane-B2 levels during hemodialysis switched into 30%-70% sharp rises in all three groups resulting in synchronous spikes within minutes after blood reinfusion. These observations suggest limited complement activation by dialyzer membranes, on which a membrane-independent second immune stimulus was superimposed, and caused pathophysiological changes also characteristic of HDRs. Thus, the porcine CARPA model raises the hypothesis that a second "hit" on anaphylatoxin-sensitized immune cells may be a key contributor to HDRs.

Vasodilator use in precapillary pulmonary hypertension with end stage kidney disease: A single center experience

BACKGROUND AND OBJECTIVES

Pulmonary hypertension is commonly seen in end stage kidney disease and is most commonly due to elevated left heart pressures. There is limited data about vasodilator use during the management of Group 1 pulmonary arterial hypertension in the context of those who also have or later developed end stage kidney disease. The objective of this study was to determine safety and efficacy of vasodilator therapy in precapillary pulmonary hypertension requiring renal replacement therapy.

DESIGN

This was a single-center retrospective case series. Patients were identified from our Pulmonary Hypertension Clinic using a historical roster from 2012 to 2020. Patients were included if they >18 years of age, had Group 1 or Group 4 (precapillary) pulmonary hypertension on right heart catheterization, and also had end stage kidney disease requiring either intermittent hemodialysis or peritoneal dialysis.

RESULTS

18 patients were identified with invasively confirmed Group 1 or Group 4 pulmonary hypertension and end stage kidney disease on renal replacement therapy. Scleroderma was the most common etiology for renal failure. 17 patients were treated with vasodilator therapy. Fifteen patients had paired right heart catheterizations that showed a significant decrease in mean pulmonary artery pressure and pulmonary vascular resistance. Therapy was relatively well tolerated but hypotension was common and midodrine was often helpful. Two patients had successful renal transplantation after starting vasodilator therapy.

CONCLUSION

We found vasodilator therapy was reasonably well tolerated and associated with a drop in mean pressure and pulmonary vascular resistance in patients with end stage kidney disease on dialysis.

Epidemiology, Pathogenesis, and Clinical Approach in Group 5 Pulmonary Hypertension

Pulmonary hypertension (PH) is recognized to be associated with a number of comorbid conditions. Based on these associations, PH is classified into 5 groups, considering common pathophysiologic drivers of disease, histopathologic features, clinical manifestations and course, and response to PH therapy. However, in some of these associated conditions, these characteristics are less well-understood. These include, among others, conditions commonly encountered in clinical practice such as sarcoidosis, sickle cell disease, myeloproliferative disorders, and chronic kidney disease/end stage renal disease. PH in these contexts presents a significant challenge to clinicians with respect to disease management. The most recent updated clinical classification schemata from the 6th World Symposium on PH classifies such entities in Group 5, highlighting the often unclear and/or multifactorial nature of PH. An in-depth review of the state of the science of Group 5 PH with respect to epidemiology, pathogenesis, and management is provided. Where applicable, future directions with respect to research needed to enhance understanding of the clinical course of these entities is also discussed.

Pulmonary Hypertension in Various Stages of Chronic Kidney Disease in Indian Patients

The prevalence of pulmonary hypertension (PH) in chronic kidney disease (CKD) in Indian patients has been evaluated in this study. In addition, association of PH with CKD etiology, its prevalence in various CKD stages, correlation between the severity of PH with CKD duration, various related biochemical parameters, and their relation to PH in CKD patients were analyzed. This cross-sectional and prospective study included 200 CKD patients. Detailed history and clinical examination were recorded. Hemoglobin, blood urea nitrogen (BUN), serum creatinine, albumin, and calcium-phosphorus product were recorded. Pulmonary function test was evaluated and two-dimensional echo was done 4 hours post dialysis. The prevalence of PH in CKD patients was 60.5%, with mean pulmonary artery systolic pressure (PASP) of 38.52 ± 7.32 mmHg. The mean age of those with PH was 47.85 ± 13.09 years. PH was more common in males (p = 0.03). The prevalence of PH increased as CKD stage advanced (p < 0.001). Diabetes and hypertension had a strong association with PH (p < 0.001). The prevalence (p = 0.003) and severity (p = 0.011) of PH increased with increase in CKD duration. In patients on hemodialysis (HD), the prevalence (p < 0.001) and severity (p = 0.022) of PH was significant compared to those on conservative treatment. The prevalence (p < 0.001) and severity (p < 0.001) of PH significantly increased as duration of HD increased. The prevalence of PH was significantly higher in patients with arteriovenous fistula (p = 0.002). Serum creatinine (p = 0.02) and serum calcium-phosphorus product (p < 0.001) were significantly higher in patients with PH. The prevalence of PH in CKD patients was 60.5%. There was a positive correlation between PH and duration of CKD, duration of HD, BUN, serum creatinine, and serum calcium-phosphorus product.

Pulmonary vascular resistance determines mortality in end-stage renal disease patients with pulmonary hypertension

The multifactorial etiology of pulmonary hypertension (PH) in end-stage renal disease (ESRD) includes patients with and without elevated pulmonary vascular resistance (PVR). We explored the prognostic implication of this distinction by evaluating pretransplant ESRD patients who underwent right heart catheterization and echocardiography. Demographics, clinical data, and test results were analyzed. All-cause mortality data were obtained. Median follow-up was 4 years. Of the 150 patients evaluated, echocardiography identified 99 patients (66%) with estimated pulmonary artery (PA) systolic pressure > 36 mm Hg, which correlated poorly with mortality (HR = 1.28, 95% CI 0.72-2.27, P = .387). Right heart catheterization identified 88 (59%) patients with mean PA pressure ≥ 25 mm Hg. Of these, 70 had PVR ≤ 3 Wood units and 18 had PVR > 3 Wood units. Survival analysis demonstrated a significant prognostic effect of an elevated PVR in patients with high mean PA pressures (HR = 2.26, 95% CI 1.07-4.77, P = .03), while patients with high mean PA pressure and normal PVR had equivalent survival to those with normal PA pressure. Despite the high prevalence of PH in ESRD patients, elevated PVR is uncommon and is a determinant of prognosis in patients with PH. Patients with normal PVR had survival equivalent to those with normal PA pressures.

Prevalence of pulmonary hypertension in patients with chronic kidney disease without dialysis: a meta-analysis

PURPOSE

Recent epidemiological evidence attempts to demonstrate the risk of pulmonary hypertension (PH) among patients with chronic kidney disease (CKD) without dialysis, but prevalence estimates of PH in CKD without dialysis vary widely in the existing studies. This meta-analysis was to summarize the point prevalence of PH in adults with CKD without dialysis.

METHODS

PubMed, EMBASE, the Cochrane Collaboration, and the reference lists of relevant articles were searched to identify eligible studies. We used a random-effect meta-analysis model to estimate the prevalence of PH. Associations were tested in subgroups and meta-regression analyses. We also performed sensitivity analyses and assessments of publishing bias.

RESULTS

Twenty-one observational studies (n = 8012 participants) were included in this meta-analysis. The result of analysis in random-effect model showed that the pooled prevalence was 32% (95% CI 23-42%), with significant heterogeneity between these studies (I² = 98%, P < 0.01). Stratified analyses found that the study design, region, sample size, year of publication, and definition of PH based on PASP ≥ 35 mmHg may explain the variation between studies. Sensitivity analysis further demonstrated the results to be robust. There was no evidence of publication bias.

CONCLUSIONS

PH is highly prevalent in patients with CKD without dialysis. Owing to the high heterogeneity, future well-designed and large prospective studies are encouraged to confirm the findings and definitively clarify the potential biological mechanisms.

Pulmonary Hypertension, Mortality, and Cardiovascular Disease in CKD and ESRD Patients: A Systematic Review and Meta-analysis

BACKGROUND

Pulmonary hypertension is common in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) and may be associated with poor outcomes. The magnitude of the association between pulmonary hypertension and mortality is uncertain due to the small size and variable findings of observational studies.

STUDY DESIGN

Systematic review and meta-analysis of observational studies using subgroup analyses and metaregression.

SETTING & POPULATION

Patients with ESRD or earlier stages of CKD.

SELECTION CRITERIA FOR STUDIES

Observational studies reporting clinical outcomes in patients with co-existing pulmonary hypertension and CKD or ESRD identified using a systematic search of PubMed and Embase.

PREDICTOR

Pulmonary hypertension diagnosed by Doppler echocardiography.

OUTCOMES

All-cause mortality, cardiovascular mortality, and cardiovascular events.

RESULTS

16 studies, with 7,112 patients with an overall pulmonary hypertension prevalence of 23%, were included. Pulmonary hypertension was associated with increased risk for all-cause mortality among patients with CKD (relative risk [RR], 1.44; 95% CI, 1.17-1.76), with ESRD receiving maintenance dialysis (RR, 2.32; 95% CI, 1.91-2.83), and with a functioning kidney transplant (RR, 2.08; 95% CI, 1.35-3.20). Pulmonary hypertension was associated with increased risk for cardiovascular events in patients with CKD (RR, 1.67; 95% CI, 1.07-2.60) and ESRD receiving dialysis (RR, 2.33; 95% CI, 1.76-3.08). There was an association between pulmonary hypertension and increased risk for cardiovascular mortality in patients with CKD or ESRD (RR, 2.20; 95% CI, 1.53-3.15).

LIMITATIONS

Heterogeneity of included studies, possibility of residual confounding, unavailability of individual patient-level data, and possibility of outcome reporting bias.

CONCLUSIONS

Pulmonary hypertension is associated with a substantially increased risk for death and cardiovascular events in patients with CKD and ESRD. Risk is higher in patients with ESRD receiving dialysis compared with patients with CKD stages 1 to 5. Understanding the effect of interventions to lower pulmonary artery pressure on the survival of these patents awaits their evaluation in randomized controlled trials.

[The concurrence of kidney and liver dysfunctions in decompensated heart failure]

AIM

To study the incidence, pattern, and predictive factors of concurrent kidney and liver dysfunctions in patients with decompensated heart failure (HF).

SUBJECTS AND METHODS

The kidney and liver function indicators were estimated in 322 patients aged 69.5±10.6 years with decompensated HF (hypertension in 87%, myocardial infarction in 57%, atrial fibrillation in 65%, chronic kidney disease in 39%, type 2 diabetes in 42%, a left ventricular ejection fraction (EF) of 38±13%, EF <35% 39%, NYHA Functional Class IV in 56%). Cardiohepatic syndrome (CHS) was diagnosed if at least one indicator of liver function was increased; acute kidney injury (AKI) was diagnosed using the KDIGO criteria.

RESULTS

AKI and CHS had been previously diagnosed in 60 (18.6%) and 274 (85.1%) patients, respectively. Among the patients with signs of kidney and/or liver dysfunction, the incidence of isolated CHS, concurrent AKI and CHS, and isolated AKI was 78.4, 20.1, and 1.5%, respectively. The patients with concurrent kidney and liver dysfunctions were observed to have more profound systemic hemodynamic changes (hypoperfusion and congestion). The risk of concurrent AKI and CHS increased glomerular filtration rate (GFR) <45 ml/min/1.73 m2, admission systolic blood pressure <110 mm Hg, needs for vasopressors, hydropericardium, and EF <35%. The concurrence of AKI and CHS was associated with longer hospital stay (15.7±6.5 and 13.5±4.8 days, respectively; p<0.05).

CONCLUSION

The incidence of concurrent AKI and CHS in patients with decompensated HF is 20.1%. Concurrent kidney and liver dysfunctions is associated with more obvious signs of hypoperfusion and congestion and characterized by worse prognosis.

[Risk factors for pulmonary hypertension at the predialysis stage of chronic kidney disease]

AIM

To investigate the incidence and risk factors of pulmonary hypertension (PH) in patients with chronic kidney disease (CKD).

SUBJECTS AND METHODS

86 patients (53% men, 47% women; mean age, 45±13 years) with nondiabetic CKD were examined. According to the magnitude of glomerular filtration rate (GFR) decrease, all the patients were divided into 3 groups: 1) 33 patients with a GFR of 89--45 ml/min; 2) 33 with a GFR of 44--15 ml/min; 3) 20 with a GFR of <15 ml/min who were treated with hemodialysis. A control group consisted of 20 individuals with preserved kidney function (a GFR of >90 ml/min). Physical examination and transthoracic echocardiography were performed in all the patients. The serum concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNT) and cystatin C were determined.

RESULTS

PH was detected in 21 (24.4%) of the 86 patients with CKD. As CKD progressed, its prevalence in Groups 1, 2, and 3 increased, amounting to 18.2, 24.2, and 35%, respectively. The most predictably significant risk factors for PH were hypertension (ρ=0.35; р=0.001) and kidney dysfunction (creatinine (ρ=0.23; р=0.02). Elevated pulmonary artery systolic pressure (PASP) correlated with right ventricular (RV) dimension index (ρ=0.45; р<0.0001), right atrial volume index (ρ=0.3; р=0.02), left atrial volume index (ρ=0.3; р=0.009), and left ventricular mass index (ρ=0.35; р=0.03). In all the patients with CKD in the presence of PH, the NT-proBNP level was significantly higher than in its absence: 37.43 (5.83; 59.84) and 8.54 (5.1; 20.43) fmol/ml, respectively (р=0.01). Positive correlations were found between the level of cystatin C and the presence of PH (ρ=0.32; р=0.003). Analysis of the ROC curve (AUC=0.718; р=0.03) in the predialysis-stage CKD groups (n=66) revealed that the cystatin C level of > 1045 ng/ml with a sensitivity of 71% and a specificity of 60% suggested that PH was present. Multivariate analysis showed that the factors correlating with the presence of PH were NT-proBNP (β=0.34; р=0.008) and RV dimension index (β=0.3; р=0.002).

CONCLUSION

EchoCG reveals PH in almost 25% of the patients with CKD, which occurs at its predialysis stage. Elevated PASP is associated with myocardial structural changes. Traditional risk factors (hypertension) and diminished kidney function affect the development of PH.

Pulmonary hypertension: prevalence and risk factors

Introduction

Pulmonary arterial hypertension (PAH), defined as a systolic pulmonary artery pressure above 35 mm Hg, is another vascular disease entity recently described in patients receiving hemodialysis. It is a major problem due to its high prevalence and morbidity and mortality. Its pathophysiological mechanism is just known and the strategies for its supported not yet defined.

Aims

To determine the prevalence of PAH in our hemodialysis patients and its risk factors.

Methodology

Single center descriptive and analytical cross-sectional study, including 111 hemodialysis patients who had benefit from a trans-thoracic cardiac Doppler ultrasound during 2014. A value greater than or equal to 35 mm Hg is considered PAH and classified as follows: mild PAH (35 50 mm Hg), moderate PAH (50 70 mm Hg), and severe pulmonary hypertension (> 70 mm Hg). Patients with a high probability of secondary PAH, especially those with the following history: chronic obstructive pulmonary disease, pulmonary embolism, were not included.

Results

The mean age was 44.3 ± 14.2 years. Among the 111 patients, 18 had pulmonary arterial pressure above 35 mm Hg corresponding to 16.22% of PAH prevalence. The average pressure was 45 mm Hg. Of these 18 patients, 11.8% had mild PAH, 3.4% moderate PAH and 0.8% severe PAH. The average hemodialysis duration was significantly associated with PAH (p = 0.003); as well as valvular calcification (p = 0.000), mitral regurgitation (p = 0.001) and tricuspid regurgitation (p = 0.002).

Conclusion

Primary pulmonary hypertension is a major problem among our hemodialysis because of its high prevalence and its risk factors.

The Relationship of Fluid Overload as Assessed by Bioelectrical Impedance Analysis with Pulmonary Arterial Hypertension in Hemodialysis Patients

Background

Pulmonary arterial hypertension (PAH) is common disease among hemodialysis (HD) patients and is associated with increased morbidity and mortality. However, its pathogenesis has not been completely elucidated. We aimed to evaluate the frequency of PAH in HD patients, as well as the relationship between fluid status and PAH.

Material/Methods

We enrolled 77 HD patients in this study. Multifrequency bioimpedance analysis (BIA) was used to assess fluid status. BIA was performed before and 30 min after the midweek of HD. Overhydration (OH)/extracellular water (ECW)% ratio was used as an indicator of fluid status. Fluid overload was defined as OH/ECW ≥7%. Echocardiographic examinations were performed before and after the HD. Pulmonary arterial hypertension was defined as systolic pulmonary artery pressure at rest (sPAP) higher than 35 mmHg.

Results

PAH was found in 33.7% of the HD patients. OH/ECW and the frequency of fluid overload were significantly higher in HD patients with PAH than those without PAH, whereas serum albumin and hemoglobin levels were significantly lower. sPAP level was significantly higher in HD patients with fluid overload than in those without fluid overload after hemodialysis session. Furthermore, sPAP, OH/ECW levels, and the frequency of PAH were significantly reduced after HD. We also found a significant positive correlation between sPAP and OH/ECW. Multivariate logistic regression analysis demonstrated fluid overload to be an independent predictor of PAH after HD.

Conclusions

PAH is prevalent among HD patients. This study demonstrated a strong relationship between fluid overload and PAH in HD patients.

World Health Organization group 5 pulmonary hypertension

World Health Organization (WHO) group 5 pulmonary hypertension (PH) entails a heterogeneous group of disorders that may cause PH by unclear and/or multiple mechanisms. In particular, group 5 includes PH caused by hematologic disorders, systemic diseases, metabolic disorders, chronic renal failure, and disorders leading to pulmonary vascular occlusion or compression. This article discusses common pathogenic mechanisms leading to group 5 PH, followed by a detailed overview of epidemiology, pathogenesis, and disease-specific management of the individual group 5 conditions. Off-label use of vasomodulatory therapies, typically indicated for pulmonary arterial hypertension (WHO group 1 PH), in group 5 conditions is also discussed.

Pulmonary hypertension in renal disease: epidemiology, potential mechanisms and implications

Pulmonary hypertension (PH) is highly prevalent in end-stage renal disease. Several observational studies, based on an echocardiographic diagnosis of PH, have suggested a prevalence of 30-60% and an association with increased mortality and poorer outcome following renal transplantation. The pathogenesis of PH in this population remains poorly understood. Reported associations include arteriovenous fistulae, cardiac dysfunction, fluid overload, bone mineral disorder and non-biocompatible dialysis membranes. However, due to the small numbers, the cross-sectional nature of the majority of studies in this field, and the reliance on echocardiography for the diagnosis of PH, no consistent association with any individual risk factor has been demonstrated. There is no difference in prevalence between patients receiving different dialysis modalities and emerging evidence suggests that the onset of the condition may precede dialysis treatment in many patients. Furthermore, little is known about the impact of the 'uraemic vasculopathy' on the pulmonary vasculature. Given the similarities between vascular changes in uraemia and those seen in pulmonary arterial hypertension, it is possible that a pulmonary vasculopathy may be present in a proportion of patients. There is a need for better understanding of the natural history and the pathogenesis of the condition which would help to individualise treatment of PH in end-stage renal disease. To enable such understanding, prospective adequately powered studies with an integrated investigational approach including right heart catheterisation are needed.

Pulmonary hypertension among patients on dialysis and kidney transplant recipients

Pulmonary arterial hypertension (PAH) is a serious cardiac complication among patients with end-stage renal disease (ESRD). We investigated pulmonary hypertension and its associated factors among patients who were on chronic dialysis and kidney transplant recipients. One hundred-eighty patients in three groups of hemodialysis (HD), peritoneal dialysis (PD), and kidney transplant were studied. Demographic and clinical characteristics and echocardiographic findings were evaluated. A multivariable linear regression model was used to find factors associated with pulmonary artery pressure. The mean age of participants was 50.3 ± 15.5 years and 63.9% were male. We found pulmonary hypertension (mean pulmonary artery pressure >25 mmHg) in 31.6%, 8.3%, and 5% of the patients on HD, PD, and transplant recipients, respectively (p < 0.001). In multivariate analyses, being on HD (B = 5.276, confidence interval [CI] 95%: 1.211-9.341), age (B = -0.319, CI 95%: -0.501 to -0.138), smoking (B = 11.631, CI 95%: 1.847-21.416), systolic cardiac dysfunction (B = 6.313, CI 95%: 3.073-9.554), and diastolic cardiac dysfunction (B = 5.227, CI 95%: 1.176-9.277) were associated with systolic pulmonary artery pressure. These results showed that pulmonary hypertension is a frequent cardiac complication among patients with ESRD, and the type of renal replacement therapy (HD), systolic and diastolic cardiac dysfunction, and smoking are associated with increased pulmonary artery pressure. Further studies with larger sample sizes and also prospective studies are recommended in this regard.

Pulmonary Hypertension and Right Heart Failure in Chronic Kidney Disease: New Challenge for 21st-Century Cardionephrologists

Pulmonary hypertension is defined as an increased systolic pulmonary pressure of >30 mm Hg, and it shows a 40% prevalence in hemodialysis patients due to vascular access (both central venous catheter and arteriovenous fistula). Secondary pulmonary hypertension in chronic kidney disease patients is strictly related to pulmonary circulation impairment together with chronic volume overload and increased levels of cytokines and growth factors, such as FGF, PDGF, and TGF-β, leading to fibrosis. Endothelial dysfunction, together with lower activation of NOS, increased levels of serum endothelin and fibrin storages, involves an extensive growth of endothelial cells leading to complete obliteration of pulmonary vessels. Pulmonary hypertension has no pathognomonic and distinctive symptoms and signs; standard transthoracic echocardiography allows easy assessment of compliance of the right heart chambers. The therapeutic approach is based on traditional drugs such as digitalis-derived drugs, vasodilatory agents (calcium channel blockers), and oral anticoagulants. New pharmacological agents are under investigation, such as prostaglandin analogues, endothelin receptor blockers, and phosphodiesterase-5 inhibitors.

Pulmonary hypertension in CKD

Pulmonary arterial hypertension is a rare disease often associated with positive antinuclear antibody and high mortality. Pulmonary hypertension, which rarely is severe, occurs frequently in patients with chronic kidney disease (CKD). The prevalence of pulmonary hypertension ranges from 9%-39% in individuals with stage 5 CKD, 18.8%-68.8% in hemodialysis patients, and 0%-42% in patients on peritoneal dialysis therapy. No epidemiologic data are available yet for earlier stages of CKD. Pulmonary hypertension in patients with CKD may be induced and/or aggravated by left ventricular disorders and risk factors typical of CKD, including volume overload, an arteriovenous fistula, sleep-disordered breathing, exposure to dialysis membranes, endothelial dysfunction, vascular calcification and stiffening, and severe anemia. No specific intervention trial aimed at reducing pulmonary hypertension in patients with CKD has been performed to date. Correcting volume overload and treating left ventricular disorders are factors of paramount importance for relieving pulmonary hypertension in patients with CKD. Preventing pulmonary hypertension in this population is crucial because even kidney transplantation may not reverse the high mortality associated with established pulmonary hypertension.