Predictors, prevalence and prognostic role of pulmonary hypertension in patients with chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

To estimate the predictors, prevalence and prognostic role of pulmonary hypertension (PH) in patients with chronic kidney disease (CKD) using meta-analysis.

METHODS

The PubMed, EmBase, and the Cochrane library were systematically searched for eligible studies from inception till May 2024. All of pooled analyses were performed using the random-effects model.

RESULTS

Fifty observational studies involving 17,558 CKD patients were selected. The prevalence of PH in CKD patients was 38% (95% confidence interval [CI]: 33%-43%), and the prevalence according to CKD status were 31% (95% CI: 20%-42%) for CKD (I-V), 39% (95% CI: 25%-54%) for end stage kidney disease (ESKD) (predialysis), 42% (95% CI: 35%-50%) for ESKD (hemodialysis), and 26% (95% CI: 19%-34%) for renal transplant. We noted the risk factors for PH in CKD included Black individuals (relative risk [RR]: 1.39; 95% CI: 1.18-1.63; p < 0.001), chronic obstructive pulmonary disease (RR: 1.48; 95% CI: 1.21-1.82; p < 0.001), cardiovascular disease history (RR: 1.62; 95% CI: 1.05-2.51; p = 0.030), longer dialysis (RR: 1.70; 95% CI: 1.18-2.46; p = 0.005), diastolic dysfunction (RR: 1.88; 95% CI: 1.38-2.55; p < 0.001), systolic dysfunction (RR: 3.75; 95% CI: 2.88-4.87; p < 0.001), and grade 5 CKD (RR: 5.64; 95% CI: 3.18-9.98; p < 0.001). Moreover, PH in CKD patients is also associated with poor prognosis, including all-cause mortality, major cardiovascular events, and cardiac death.

CONCLUSION

This study systematically identified risk factors for PH in CKD patients, and PH were associated with poor prognosis. Therefore, patients with high prevalence of PH should be identified for treatment.

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.

Impact of pulmonary hypertension on arteriovenous fistula failure of hemodialysis patients: A 10 years follow-up cohort study

BACKGROUND

Pulmonary hypertension (PH) is common in patients with end-stage renal disease (ESRD). Arteriovenous fistulas (AVF) creation may involve in the pathogenesis of PH. The aim of this study was to explore the impact of PH after AVF creation on the AVF failure rate in maintenance hemodialysis (MHD) patients.

METHODS

From January 1, 2009, to January 1, 2019, we retrospectively collected data of 578 MHD patients in Guangdong Provincial People's Hospital Blood Purification Center, China. Patients were followed-up until AVF failure or death or May 25, 2020. According to the systolic pulmonary artery pressure (SPAP) within 1 year after the establishment of AVF, the MHD patients were divided into three groups: SPAP ⩽ 35 mmHg, 35 < SPAP < 45 mmHg, SPAP ⩾ 45 mmHg. The primary outcome was AVF failure defined as AVF cannot complete hemodialysis. The secondary outcomes were all-cause mortality.

RESULTS

A total of 578 patients were analyzed. The average age was 60.66 ± 15.34 years (58.1% men). Of these, 26.1% of patients were reported PH. The SPAP exhibited a left-skewed nonparametric distribution and the overall SPAP after the creation of AVF was 39.00 (29.00-52.00) mmHg. The median follow-up was 5.8 (5.5-6.3) years. Overall, 12.8% (74/578) patients were reported AVF failure events. There was no significant difference in AVF failure rate among three groups (p = 0.070). A total of 111 (19.2%) died during the follow-up period. Compared with the SPAP ⩽35 mmHg group, only the all-cause death rate significantly increased in MHD patients with PH (p < 0.001).

CONCLUSIONS

The secondary pulmonary hypertension after AVF creation did not increase the risk of AVF failure in MHD patients, but significantly increased the risk of mortality for this portion of the patients. Future larger sample sizes, multi-center, and prospective trials are needed to make sure which type of access will benefit on their survival for MHD patients with SPAP ⩾35 mmHg.

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.

Long-term impacts of different dialysis modalities on right ventricular function in patients with end-stage renal disease

BACKGROUND

Right ventricular dysfunction is a major cause of heart failure and mortality in end-stage renal disease patients. Scarce data is available regarding the comparison of echocardiographic right ventricular function in end-stage renal disease patients on hemodialysis (HD) and peritoneal dialysis (PD). The aim of the study was to evaluate the long-term impacts of different dialysis modalities on right ventricular function assessed by conventional echocardiography, in end-stage renal disease patients with preserved left ventricular function.

METHODS

The study included 120 patients grouped as follows: PD (n = 40), HD with arterio-venous fistula (n = 40), and healthy control subjects (n = 40). Conventional echocardiography was performed on all patients. A classification of right ventricular function was defined in HD patients by using tricuspid annular plane systolic excursion (TAPSE), right ventricular myocardial performance index (RV-MPI), fractional area change (FAC), and tricuspid lateral annulus systolic velocity (Sa) values. Correlation analysis was performed by using the right ventricular dysfunction score, clinical, and echocardiographic parameters.

RESULTS

The mean age of the study population was 51.9 ± 13.1 years and 47.5% were females. TAPSE and Sa velocity were found to be significantly lower and RV-MPI was significantly higher in patients undergoing HD, compared with control and PD patients. Logistic regression analysis showed that HD treatment was an independent risk factor for developing right ventricular dysfunction.

CONCLUSION

RV function was impaired in patients undergoing HD compared with patients on PD.

Cardiorenal Nexus: A Review With Focus on Combined Chronic Heart and Kidney Failure, and Insights From Recent Clinical Trials

The cardiorenal nexus encompasses a bidirectional relationship between the heart and the kidneys. Chronic abnormalities in cardiac function can lead to progressive kidney disease, and chronic kidney disease can lead to progressively decreasing cardiac function and increasing risk of cardiovascular disease, including heart failure. About 15% of US adults have chronic kidney disease, 2% have heart failure, and 9% have cardiovascular disease. Prevalence rates of chronic kidney disease, cardiovascular disease, and associated morbidities such as type 2 diabetes are expected to increase with an aging population. Observational studies provide evidence for the cardiorenal nexus. Follow-up data from placebo arms of clinical trials in chronic kidney disease or cardiovascular disease show higher rates of renal and cardiovascular outcome events in patient subgroups with type 2 diabetes than in those without type 2 diabetes. The cardiorenal syndromes develop along an interlinked pathophysiological trajectory that requires a holistic, collaborative approach involving a multidisciplinary team. There is now a compendium of treatment options. Greater understanding of the underlying pathophysiology of the cardiorenal nexus will support optimization of the management of these interlinked disease states.

Beneficial Effects of Pulmonary Vasodilators on Pre-Capillary Pulmonary Hypertension in Patients with Chronic Kidney Disease on Hemodialysis

Background: In patients with chronic kidney disease (CKD) on hemodialysis, comorbid pulmonary hypertension (PH) aggravates exercise tolerance and eventually worsens the prognosis. The treatment strategy for pre-capillary PH, including combined pre- and post-capillary PH (Cpc-PH), has not been established. Objectives: This study aimed to evaluate the impact of pulmonary vasodilators on exercise tolerance and pulmonary hemodynamics in patients with CKD on hemodialysis. Methods and Results: The medical records of 393 patients with suspected PH who underwent right heart catheterization were reviewed. Of these, seven patients had isolated pre-capillary PH and end-stage CKD on hemodialysis. Pulmonary vasodilators decreased pulmonary vascular resistance from 5.9 Wood units (interquartile range (IQR), 5.5–7.6) at baseline to 3.1 Wood units (IQR, 2.6–3.3) post-treatment (p = 0.02) as well as increased pulmonary capillary wedge pressure from 10 mmHg (IQR, 7–11) to 11 mmHg (IQR, 8–16) (p = 0.04). Pulmonary vasodilators increased the World Health Organization functional class I or II from 0% to 100% (p = 0.0002) and the 6 min walk distance from 273 m (IQR, 185–365) to 490 m (IQR, 470–550) (p = 0.03). Conclusions: Pulmonary vasodilators for PH in patients with CKD on hemodialysis decrease pulmonary vascular resistance and eventually improve exercise tolerance. Pulmonary vasodilators may help hemodialysis patients with pre-capillary PH, although careful management considering the risk of pulmonary edema is required.

Incidence, Clinical Correlates, and Outcomes of Pulmonary Hypertension After Kidney Transplantation: Analysis of Linked US Registry and Medicare Billing Claims

BACKGROUND

The incidence, risks, and outcomes associated with pulmonary hypertension (P-HTN) in the kidney transplant (KTx) population are not well described.

METHODS

We linked US transplant registry data with Medicare claims (2006-2016) to investigate P-HTN diagnoses among Medicare-insured KTx recipients (N = 35 512) using billing claims. Cox regression was applied to identify independent correlates and outcomes of P-HTN (adjusted hazard ratio [aHR] 95%LCLaHR95%UCL) and to examine P-HTN diagnoses as time-dependent mortality predictors.

RESULTS

Overall, 8.2% of recipients had a diagnostic code for P-HTN within 2 y preceding transplant. By 3 y posttransplant, P-HTN was diagnosed in 10.310.6%11.0 of the study cohort. After adjustment, posttransplant P-HTN was more likely in KTx recipients who were older (age ≥60 versus 18-30 y a HR, 1.912.403.01) or female (aHR, 1.151.241.34), who had pretransplant P-HTN (aHR, 4.384.795.24), coronary artery disease (aHR, 1.051.151.27), valvular heart disease (aHR, 1.221.321.43), peripheral vascular disease (aHR, 1.051.181.33), chronic pulmonary disease (aHR, 1.201.311.43), obstructive sleep apnea (aHR, 1.151.281.43), longer dialysis duration, pretransplant hemodialysis (aHR, 1.171.371.59), or who underwent transplant in the more recent era (2012-2016 versus 2006-2011: aHR, 1.291.391.51). Posttransplant P-HTN was associated with >2.5-fold increased risk of mortality (aHR, 2.572.843.14) and all-cause graft failure (aHR, 2.422.642.88) within 3 y posttransplant. Outcome associations of newly diagnosed posttransplant P-HTN were similar.

CONCLUSIONS

Posttransplant P-HTN is diagnosed in 1 in 10 KTx recipients and is associated with an increased risk of death and graft failure. Future research is needed to refine diagnostic, classification, and management strategies to improve outcomes in KTx recipients who develop P-HTN.

Pathological right ventricular changes in synthesized electrocardiogram in end-stage renal disease patients and their association with mortality and cardiac hospitalization: a cohort study

Background

Right ventricular (RV) function is an important prognostic predictor for end-stage renal disease (ESRD) patients. Non-invasive evaluation of RV function by simple electrocardiogram (ECG) is not yet evident. The purpose of this article was to investigate the presence and association of pathological right ventricular changes in synthesized ECG with cardiac hospitalization and mortality.

Methods

A prospective cohort study of 137 ESRD patients (mean age: 56 years) were recruited from the hemodialysis unit in An-Najah National University Hospital, Nablus, Palestine. Synthesized ECG was done right before the hemodialysis (HD) session. The pathological right ventricular changes were recorded for each patient. The relationship between pathological RV changes and mortality, cardiac and non-cardiac hospitalization was assessed through a 6-months follow-up period.

Results

Right ventricular Q wave was found in 2.2% of patients, while right ventricular ST elevation was found in 0.7% of patients, and right ventricular negative T wave was found in 0.7% of patients. During the 6-month period of follow-up, 36 (26.3%) patients were hospitalized, nine patients (6.6%) due to cardiac causes. A total of 8 (5.83%) patients died, out of those 4 patients (2.91%) due to cardiac causes. Using Fisher’s exact test, there was a significant association between pathological abnormalities in synthesized ECG and hospitalization among hemodialysis patients, (p = 0.047). Pathological changes in synthesized ECG were less prevalent in non-cardiac hospitalizations than in cardiac hospitalizations.

Conclusions

The presence of pathological RV synthesized ECG changes can predict cardiac hospitalization in ESRD patients. Synthesized ECG is a good available tool that can be easily performed in ESRD patients. To determine whether Synthesized ECG can be used as a screening tool for pathological RV changes in a dialysis patients, more research with a larger number of patients and a longer follow-up period is required.

Risk Factors of Pulmonary Hypertension in Patients on Hemodialysis: A Single Center Study

Introduction

Pulmonary hypertension (PH) is an underestimated cardiovascular consequence and a mortality predictor in patients on hemodialysis (HD). Thus, we studied its prevalence, risk factors, association with inflammation/oxidative stress, and cardiac changes in HD patients.

Methods

This was a single-center cross-sectional observational study conducted at a tertiary care hospital. Patients aged >18 years on hemodialysis for at least three months were included and divided into those with and without PH; patients with secondary causes for PH were excluded. Clinical characteristics, HD-related factors, lab parameters (C-reactive protein and malondialdehyde with thiol assay were used as markers of inflammation and oxidative stress, respectively), and echocardiography details were compared. PH was defined as a mean pulmonary artery pressure of >25 mmHg at rest, and it was further divided as mild (25–40 mmHg), moderate (40–60 mmHg), and severe (>60 mmHg).

Results

Of 52 patients, 28 patients had PH (mild 24, moderate 4, and none had severe PH) with prevalence of 54%. No difference was found in clinical characteristics, dialysis-related factors, biochemical parameters including inflammation (C-reactive protein; p=0.76), or oxidative stress (thiol; p=0.36 and MDA; p=0.46) between the groups. When compared to individuals without PH, HD patients with PH exhibited significantly more mitral regurgitation (p=0.002).

Conclusion

Hemodialysis patients have a high prevalence of PH. PH was significantly associated with the presence of mitral regurgitation on echocardiography. Our study did not find differences in traditional risk factors, HD-related factors, and inflammation/oxidative markers between the groups with and without PH.

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.

Five-year Outcomes of Pulmonary Hypertension With and Without Elevated Left Atrial Pressure in Patients Evaluated for Kidney Transplantation

BACKGROUND

Pulmonary hypertension (PH) is frequently reported in patients with advanced chronic kidney disease and is associated with early allograft failure and death. However, the causes of PH are heterogeneous, and patient prognosis may vary by etiologic subtype.

METHODS

Data from the University of North Carolina Cardiorenal Registry were examined to determine associations between PH, with or without elevated left atrial pressure (eLAP), and mortality in candidates for kidney transplantation. PH and eLAP were determined by Doppler echocardiography and by tissue Doppler imaging, respectively.

RESULTS

From 2006 to 2013, 778 registry patients were screened preoperatively by echocardiography. Most patients were black (64%) and men (56%); the mean age was 56 years. PH was identified in 97 (12%) patients; of these, eLAP was prevalent in half. During a median follow-up of 4.4 years, 179 (23%) received a kidney transplant, and 195 (25%) died. After adjustments for demographics, comorbidities, dialysis vintage, and kidney transplantation, PH was associated with twice the 5-year mortality (hazard ratio [HR] = 2.11; 95% confidence interval [CI]: 1.48-3.03), with stronger associations in the absence of eLAP (HR = 2.87; 95% CI: 1.83-4.49) than with eLAP (HR = 1.11; 95% CI: 0.57-2.17), P for interaction = 0.01.

CONCLUSIONS

The mortality risk associated with PH among patients with advanced chronic kidney disease appears to differ by etiology. Patients with PH in the absence of eLAP are at high risk of death and in need of focused attention. Future research efforts should investigate potential strategies to improve outcomes for these patients.

The potential effect of cardiac function on pulmonary hypertension, other risk factors, and its impact on survival in dialysis patients

INTRODUCTION

Pulmonary hypertension (PH) is a recently recognized as a complication of chronic kidney disease and end-stage renal disease. The pathogenesis of pulmonary hypertension in this group of patients is not fully understood, probably due to the interaction of multiple aspects of the altered cardiovascular physiology and also hormonal and metabolic disorders. The present study aimed to determine the prevalence of PH, correlation with cardiac function and other risk factors and its impact of survival in chronic hemodialysis and peritoneal dialysis patients.

METHODS

We studied 125 stable hemodialysis and peritoneal patients (females 40%, mean age 52.42 ± 11.88 years) on renal replacement therapy (RRT) for more than 3 months with a follow up 2 years. Demographic information, clinical characteristics, blood test, and thoroughly echocardiographic evaluation at the optimal dry weight were collected. After conventional echocardiographic examination, tissue Doppler echocardiographic (TDE) examination was performed to evaluate global and regional myocardial systolic as well as diastolic function, and pulmonary hypertension. PH was defined as systolic pulmonary artery pressure (sPAP) ≥ 35 mmHg. To rule out secondary PH, patients with pulmonary disease, collagen vascular disease, and volume overload at the time of echocardiography were excluded. Variables were compared between two groups-subjects with PH and non-PH. Logistic regression analysis was used to evaluate the risk factor for PH and its impact on survival.

RESULTS

According to the echocardiographic findings, PH was found in 28% (35 patients) of all patients. Mean PH was 33.46 ± 5.38 mmHg. The higher level of higher parathormone (PTH), C-reactive protein (CRP) and E/E' average, lower left ventricular ejection fraction (EF), peak systolic velocity at the lateral mitral annulus (MASa) and the peak systolic velocity at the lateral tricuspid annulus (TASa) were found predictor of PH. The cardiovascular mortality rate was 15.5%. Patients evaluated with PH have a significantly lower cardiovascular survival rate [Long Rank (Mantel-Cox) p = 0.0001]. In ROC analysis for CV mortality, the area under the curve (AUC) for PH and CRP was found 0.8; for LVM-I, E/E' and PP, AUC = 0.76; 0.75; 0.72 respectively while the inverse relationship was found with MASa and TASa with AUC = 0.66 and 0.95 respectively.

CONCLUSION

Our study shows that PH is frequent in dialysis patients. It is influenced by inflammation, CKD-MBD biomarkers associated with diastolic and also systolic left and right ventricle dysfunction. Pulmonary hypertension, inflammation, vascular stiffness, and left ventricular hypertrophy are interrelated and all contribute to cardiovascular morbidity and mortality among dialysis patients. Easy to implement, cardiac imaging at the bedside and in outpatient clinics offers a positive perspective in early diagnosis of cardiac abnormalities and immediate approach to this condition, so is highly recommended in the dialysis population.

Diagnosis and Management of Pulmonary Hypertension in Patients With CKD

Pulmonary hypertension (PH) is a highly prevalent and important condition in adults with chronic kidney disease (CKD). In this review, we summarize the definition of PH, discuss its pathophysiology and classifications, and describe diagnostic and management strategies in patients with CKD, including those with kidney failure treated by kidney replacement therapy. In the general population, PH is classified into 5 groups based on clinical presentation, pathology, hemodynamics, and management strategies. In this classification system, PH in CKD is placed in a diverse group with unclear or multifactorial mechanisms, although underlying cardiovascular disease may account for most cases. CKD may itself directly incite pulmonary circulatory dysfunction and remodeling through uremic toxins, inflammation, endothelial dysfunction, and altered vasoregulation. Despite several studies describing the higher prevalence of PH in CKD and kidney failure, along with an association with poor outcomes, high-quality evidence is not available for its diagnostic and management strategies in those with CKD. In CKD not requiring kidney replacement therapy, volume management along with treatment of underlying risk factors for PH are critical. In those receiving hemodialysis, options are limited and transition to peritoneal dialysis may be considered if recurrent hypotension precludes optimal volume control.

Pulmonary hypertension in end-stage renal disease

Pulmonary hypertension associated with end-stage renal disease (ESRD) is an important yet under-recognized condition and can lead to life-threatening complications. The pathogenesis of pulmonary hypertension is peculiar in ESRD, and understanding it is important to recognize such patients at the earliest and commence appropriate treatment. Many studies have discovered the prevalence of pulmonary hypertension to be up to 80% in ESRD and have been associated with increased mortality. WHO has classified pulmonary hypertension in renal failure to be in group 5, a group defined by unclear multifactorial etiologies. Moreover, there is an improvement with renal transplant and closure of AV fistula, thus confirming the contribution from these. The pharmacological management of pulmonary hypertension in this unique population is not very different from other etiologies. However, one should understand that pulmonary hypertension as such, could be multifactorial, and other secondary causes of pulmonary hypertension should also be recognized and treated accordingly. In this article, we will discuss the concept of pulmonary hypertension in ESRD in detail and the options of treatment.

Effects of Pulmonary Hypertension and Right Ventricular Function in Short and Long-Term Kidney Function

BACKGROUND

Pulmonary hypertension is not uncommon in patients with renal disease and vice versa; therefore, it influences treatments and outcomes. There is a large body of literature on pulmonary hypertension in patients with kidney disease, its prognostic implications, economic burden, and management strategies. However, the converse, namely the hemodynamic effects of pulmonary hypertension on kidney function (acute and chronic kidney injury) is less studied and described. There is also increasing interest in the effects of pulmonary hypertension on kidney transplant outcomes. The relationship is a complex phenomenon and multiple body systems and mechanisms are involved in its pathophysiology. Although the definition of pulmonary hypertension has evolved over time with the understanding of multiple interplays between the heart, lungs, kidneys, etc; there is limited evidence to provide a specific treatment strategy when kidneys and lungs are affected at the same time. Nevertheless, available evidence appears to support new therapeutics and highlights the importance of individualized approach. There is sufficient research showing that the morbidity and mortality from PH are driven by the influence of the pulmonary hemodynamic dysfunction on the kidneys.

CONCLUSION

This concise review focuses on the effects of pulmonary hypertension on the kidneys, including, the patho-physiological effects of pulmonary hypertension on acute kidney injury, progression of CKD, effects on kidney transplant outcomes, progression of kidney disease in situations such as post LVAD implantation and novel diagnostic indices. We believe a review of this nature will fill in an important gap in understanding the prognostic implication of pulmonary hypertension on renal disease, and help highlight this important component of the cardio-reno-pulmonary axis.

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.

Long-term impacts of hemodialysis on the right ventricle: Assessment via 3-dimensional speckle-tracking echocardiography

BACKGROUND

Right ventricular (RV) dysfunction is a major cause of death in patients undergoing maintenance hemodialysis (MHD). We used 3-dimensional speckle-tracking echocardiography (3DSTE) to evaluate long-term impacts of MHD on RV function.

HYPOTHESIS

In this study, RV dysfunction in MHD patients will be revealed and studied in depth by 3DSTE.

METHODS

Echocardiography was performed on 110 consecutively enrolled individuals: 30 controls and 80 patients with MHD. Conventional echocardiographic parameters and 3DSTE parameters were obtained and compared between groups. Univariate and multivariate logistic regression analysis identified independent predictors of intradialytic hypotension (IDH).

RESULTS

Compared with the control group, RV end-diastolic volume (RVEDV) was markedly enlarged (46.1 ± 11.8 mL/m² vs 42.3 ± 8.6 mL/m² ; P = 0.047), whereas RV ejection fraction (RVEF) was significantly lower in the MHD group (50.6% ± 5.8% vs 55.2% ± 3.7%; P < 0.001). RV global, septal, and lateral wall longitudinal strains were also decreased in the MHD group (-18.2 ± 3.6 vs -22.6 ± 4.3%; -13.1 ± 3.8 vs -17.5 ± 5.5%; and -23.4 ± 4.7 vs -27.7 ± 4.0%, respectively; all P < 0.001). RVEF (odds ratio [OR]: 0.72, 95% confidence interval [CI]: 0.51 to 1.01, P = 0.038) and history of diabetes (OR: 11.14, 95% CI: 1.16 to 106.71, P = 0.036) were 2 independent predictors of IDH. Ultrafiltration rate was an independent factor associated with RVEF (β = -0.01, 95% CI: -0.019 to 0.001, P = 0.039).

CONCLUSIONS

RVEF by 3DSTE could be an important predictor of IDH in MHD patients, and lower ultrafiltration rate was protective for RVEF. 3DSTE may have potential in RV evaluation and risk stratification in MHD patients.

Hemodialysis access thrombosis

For the over 400,000 patients in the United States dependent on hemodialysis, arteriovenous (AV) access thrombosis may lead to missed dialysis sessions, inpatient admissions and the need for placement of temporary dialysis catheters. It is also the leading cause of permanent access loss. Percutaneous declotting is generally preferred over surgical thrombectomy. Various percutaneous approaches can be employed including the lyse-and-wait technique, thromboaspiration, pulse spray aided pharmacomechanical thrombolysis, and use of mechanical thrombectomy device.

The Pros and Cons of Preserving a Functioning Arteriovenous Fistula after Kidney Transplantation

The autologous arteriovenous fistula (AVF) for hemodialysis burdens the cardiovascular system with increased cardiac output and pulmonary artery pressure, increasing cardiovascular risk. This article reviews literature on the benefits and drawbacks of a functioning AVF after kidney transplantation and discusses the cardiovascular effects of AVF closure. Several cohort studies demonstrate a significant cardiac burden of an AVF and improvement of cardiac dimensions after AVF ligation. However, no randomized trials have been conducted on routine AVF closure after successful kidney transplantation. Therefore, clinical trials are warranted to evaluate whether the cardiovascular benefits of routine AVF closure outweigh the potential harm for patients after successful kidney transplantation.

Permanent Arteriovenous Fistula or Catheter Dialysis for Heart Failure Patients

Heart failure (HF) is the most frequent cardiovascular disease associated with chronic kidney disease and represents a high risk for cardiovascular mortality in incident hemodialysis (HD) patients. This risk is especially high during the arteriovenous fistula (AVF) maturation period due to the marked hemodynamic changes related to the large increase in the blood flow and also within the first 120 days after HD inception because in this period the highest mortality rate occurs. When planning the vascular access for each incident HF patient, the risk of aggravating HF after AVF creation must be evaluated carefully alongside the risk of catheter-related complications, but avoiding a non-selective ‘catheter first’ approach for all these patients. HF patients classified within the New York Heart Association (NYHA) Class I-II and the American College of Cardiology/American Heart Association (ACC/AHA) Stage A-B could initiate HD through a distal arm AVF. High-flow brachial artery-based AVF creation must be avoided because it displays the highest risk of worsening the cardiac function. The decision for AVF creation or tunneled central catheter placement in HF patients classified within the NYHA Class III and the ACC/AHA Stage C must have been individualized according the degree of systolic and/or diastolic dysfunction. HF patients with significant reduction in systolic function (ejection fraction lower than 30%) or classified within the NYHA Class IV and the ACC/AHA Stage D, are candidates for tunneled catheter placement to start HD treatment.

Pulmonary hypertension complicating multiple myeloma

Pulmonary hypertension (PH) is an infrequently reported complication of multiple myeloma (MM). PH has been more commonly associated with amyloidosis, myeloproliferative diseases, and the POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) syndrome. PH in MM is typically mild to moderate and may be secondary to a variety of conditions, which include left ventricular dysfunction, high-output cardiac failure, chronic kidney disease, treatment-related toxicities, and precapillary involvement. We describe 3 patients with MM and severe PH. Each patient underwent right heart catheterization. All patients demonstrated elevated pulmonary pressures, transpulmonary gradients, and pulmonary vascular resistance. Each patient was ultimately treated with pulmonary vasodilator therapy with improvement in cardiopulmonary symptoms. Additional studies are needed to define the prevalence, prognosis, and pathogenesis of PH in this complex population and to help clarify who may benefit from targeted PH therapy.

Case series of 5 patients with end-stage renal disease with reversible dyspnea, heart failure, and pulmonary hypertension related to arteriovenous dialysis access

Patients with end-stage renal disease (ESRD) with arteriovenous dialysis access (AVDA) can develop symptoms of heart failure and pulmonary hypertension (PH). We report on 5 patients with ESRD and AVDA who presented with shortness of breath, heart failure, and PH. All patients had partial or complete closure of AVDA and were reevaluated after AVDA revision. All 5 subjects had clinical and echocardiographic evidence of heart failure, hypertensive heart disease, left ventricular diastolic dysfunction, and PH at baseline. After complete closure ([Formula: see text]) or partial banding ([Formula: see text]) of AVDA, mean New York Heart Association class improved from [Formula: see text] to [Formula: see text] ([Formula: see text]). Mean 6-minute walk distance improved from [Formula: see text] to [Formula: see text] m ([Formula: see text]). Serial echocardiography revealed a decrease in the right ventricle∶left ventricle ratio from [Formula: see text] to [Formula: see text] ([Formula: see text]) and improved diastolic dysfunction parameters. On right heart catheterization before definitive AVDA revision, acute manual fistula or graft occlusion led to an average decrease in cardiac output of 1.1 L/min with no other changes in hemodynamics: [Formula: see text] to [Formula: see text] L/min ([Formula: see text]). However, the average decrease in cardiac output after definitive revision of the AVDA (mean, 90 days) was 4.0 L/min with marked improvements in biventricular filling pressures and pulmonary artery pressure. In patients with ESRD and AVDA presenting with heart failure and PH, revision or closure of AVDA can markedly improve dyspnea as well as the clinical, echocardiographic, and hemodynamic manifestations of heart failure and PH.

Frequency of pulmonary hypertension in hemodialysis patients

Objective: Pulmonary hypertension (PH) has been described in hemodialysis (HD) patients and has been associated with increased morbidity and mortality. Our objective was to determine the prevalence of pulmonary hypertension in patients on regular hemodialysis.

Methods: This cross sectional study was conducted in Department of Nephrology, Liaquat National Hospital Karachi from April 2013 to March 2014. Eighty patients of end stage renal disease (ESRD), on maintenance hemodialysis (HD); underwent Trans thoracic Echocardiography were selected. Systolic pulmonary arterial pressure (SPAP) was recorded. Pulmonary hypertension was defined as, pulmonary artery pressure (PAP) greater than 30 mm Hg at rest. Pulmonary hypertension was further divided into mild (PAP b/w 30-45mmHg), moderate (PAP b/w 45-65mmHg) and severe pulmonary hypertension (PAP > 65mmHg). The effect of different vascular accesses, age, gender, dialysis vintage on the development of pulmonary hypertension was observed.

Results: Out of 80 patients, 45 patients (56%) had pulmonary hypertension (PH); 25(55.5%) had moderate, 13(29%) had mild, and 7 (15.5%) patients had severe pulmonary hypertension (PH). Pulmonary hypertension was present in 41(60%) patients with AVF, 3(27%) patients with tunnel cuffed catheter and 1 patient had AV bridge graft. Pulmonary hypertension was more common in females; present in 28 females (67%) and 17 males (45%), that was statistically significant (p<0.05). Mean duration of hemodialysis in (months) of patients with PH was 20.93 ± 12 vs. 10.29 ±10 in patients without PH (p<0.05). Age had no relation to development of PH.

Conclusion: ESRD patients on HD have strong tendency to develop PH. Our study demonstrated that PH is more common among females. Duration of hemodialysis and AV access has strong relation to the development of PH.

Interaction between the Haptoglobin 2 Phenotype and Diabetes Mellitus on Systolic Pulmonary Arterial Pressure and Nitric Oxide Bioavailability in Hemodialysis Patients

Elevated systolic pulmonary artery pressure (s-PAP, ≥35 mmHg) serves as an independent predictor of mortality in hemodialysis (HD) and diabetic (DM) patients. A polymorphism in the antioxidant Haptoglobin (Hp) gene has been shown to regulate the bioavailability of nitric oxide (NO), a major mediator of pulmonary vascular tone. We therefore set out to test the hypothesis that the Hp polymorphism may be a determinant of developing elevated s-PAP specifically in the DM state due to a decreased bioavailability of NO. To test our hypothesis we Hp typed and performed transthoracic echocardiography on a series of HD patients and stratified them into elevated and normal s-PAP groups and then evaluated whether there was a significant association between the Hp type, elevated s-PAP, and decreased NO bioavailability as defined by low plasma nitrite. We found a statistically significant interaction between the Hp type and DM on the prevalence of elevated s-PAP and lower mean nitrite levels with the combination of elevated s-PAP and low nitrite levels being significantly more prevalent in Hp 2-2 DM individuals. We conclude that the Hp 2 type is associated with elevated s-PAP levels and low plasma nitrite levels in HD patients specifically in the DM state.

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 patients with chronic and end-stage kidney disease

Pulmonary hypertension is defined as a mean pulmonary artery pressure ≥25 mm Hg and is a recently recognized complication of chronic kidney disease and end-stage renal disease. There is significant epidemiological overlap with kidney disease and the underlying causes of World Health Organization group 1-4 pulmonary hypertension (pulmonary arteriopathy, left heart disease, chronic pulmonary disease, and chronic thromboembolic disease, respectively). In addition, an entity of 'unexplained pulmonary hypertension,' group 5, in patients with chronic kidney disease and end-stage renal disease has emerged, with prevalence estimates of 30-50%. The pathogenesis of pulmonary hypertension in this population is due to alterations in endothelial function, increased cardiac output, and myocardial dysfunction leading to elevated left heart filling pressure, with recent data suggesting that left heart dysfunction may account for the vast majority of pulmonary hypertension in patients with kidney disease. Pulmonary hypertension is an independent predictor of increased mortality in patients on dialysis and those undergoing kidney transplantation. This review summarizes what is known about the epidemiology, pathogenesis, transplantation outcomes, mortality, and treatment of pulmonary hypertension in patients with chronic kidney disease and end-stage renal disease.

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.