The relationship between arteriovenous fistula blood flow rate and pulmonary artery pressure in hemodialysis patients

Therapeutic approaches for pulmonary hypertension in patients with chronic kidney disease

PURPOSE OF REVIEW

Pulmonary hypertension is a common comorbidity in patients with chronic kidney disease (CKD), but therapeutic options are limited. We discuss the epidemiology of pulmonary hypertension in patients with CKD and review therapies for pulmonary hypertension with a focus on emerging treatments for pulmonary arterial hypertension (PAH).

RECENT FINDINGS

The definition of pulmonary hypertension has been updated to a lower threshold of mean pulmonary artery pressures of more than 20 mmHg, potentially leading to more patients with CKD to qualify for the diagnosis of pulmonary hypertension. Endothelin receptor antagonists, a class of medications, which demonstrated efficacy in patients with PAH, have been shown to slow progression of CKD, but their efficacy in lowering pulmonary artery pressures and their effects on reducing cardiovascular mortality in this population remains unproven. Sotatercept, a novel activin signaling inhibitor, which was previously studied in dialysis patients has been shown to increase exercise capacity in patients with PAH. These studies may lead to new specific therapies for pulmonary hypertension in patients with CKD.

SUMMARY

Pulmonary hypertension is common in patients with CKD. Although our understanding of factors leading to pulmonary hypertension in this population have evolved, evidence supporting disease-specific therapy in CKD is limited arguing for larger, long-term studies.

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.

Comparative analysis of RADAR vs. conventional techniques for AVF maturation in patients with blood viscosity and vessel elasticity-related diseases through fluid-structure interaction modeling: Anemia, hypertension, and diabetes

PURPOSE

This study aims to compare two surgical techniques, the standard Vein-to-Artery and the newer Artery-to-Vein (Radial Artery Deviation And Reimplantation; RADAR), for enhancing the success of Arterio-Venous Fistula maturation in end-stage renal disease patients. The impact of diseases like anemia, diabetes, hypertension, and chronic kidney disease were considered. The goals are to advance Arterio-Venous Fistula (AVF) surgery, improve patient outcomes, and contribute to evidence-based surgical guidelines.

METHODS

Fluid-structure interaction modeling was employed to investigate how hemodynamic and mechanical stresses impact arteriovenous fistula maturation, with a particular focus on the role of wall shear stress in determining maturation outcomes. The critical threshold for vessel injury was identified as wall shear stress values exceeding 35 N/m2, while stenosis formation was projected to occur at levels below 1 N/m2. This work introduced a novel approach by considering disease-related factors, including blood viscosity (anemia), and vessel elasticity (diabetes, hypertension, and chronic kidney diseases), which directly influence hemodynamics and the generation of wall shear stress. Furthermore, the model was designed to incorporate varying thicknesses and elasticities for both the vein and artery, accurately representing authentic vascular anatomy.

RESULTS

The RADAR technique has demonstrated superior performance compared to the standard technique by providing appropriate wall shear stress in critical regions and minimizing the risk of wall damage. Its use of a thicker vessel also reduces the risk of vessel injury, making it particularly effective for patients with Chronic Kidney Disease (CKD), hypertension, anemia, and diabetes, ensuring optimal blood flow and fewer complications. However, there are minor concerns about stenosis formation in hypertension and anemia cases, which could be mitigated by adjusting the anastomosis angle to be lower than 30°.

CONCLUSION

Diabetes and hypertension have significant physiological effects that increase the risks associated with arteriovenous fistula maturation. The anemic condition resulting from CKD may help reduce vessel injury but raises concerns about potential stenosis formation. Despite these co-morbidities, the RADAR technique has demonstrated its ability to induce more favorable hemodynamic changes, promoting arteriovenous fistula maturation.

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.

The problem of pulmonary arterial hypertension in end-stage renal disease: can peritoneal dialysis be the solution

BACKGROUND

Pulmonary arterial hypertension (PAH) in the setting of end-stage renal disease (ESRD) has important prognostic and therapeutic consequences. We estimated the prevalence of PAH among patients with ESRD treated with automated peritoneal dialysis (APD), investigated the effect of different variables and compared pulmonary artery pressure and cardiac function at the beginning and end of the study.

METHODS

This is a 5-year study in which 31 ESRD patients on APD were recruited after fulfilling inclusion criteria. Blood samples were collected from all patients for the biochemical and hematological data at the beginning of the study and every month and at the study termination. Total body water (TBW) and extracellular water (ECW) were calculated using Watson's and Bird's calculation methods. All patients were followed-up at 3-month interval for cardiac evaluation. Logistic regression analysis was used to assess the relation between different variables and PAH.

RESULTS

The mean age of the study population (n = 31) was 51.23 ± 15.24 years. PAH was found in 24.2% of the patients. Mean systolic pulmonary artery pressure (sPAP) and mean pulmonary artery pressure (mPAP) were significantly higher in the APD patients at study initiation than at the end of the study (40.75 + 10.61 vs 23.55 + 9.20 and 29.66 + 11.35 vs 18.24 + 6.75 mmHg respectively, p = 0.001). The median ejection fraction was significantly lower in patients with PAH at zero point than at study termination [31% (27-34) vs 50% (46-52), p = 0.002]. Hypervolemia decreased significantly at the end of study (p <  0.001) and correlated positively with the PAP (r = 0.371 and r = 0.369), p = 0.002). sPAP correlated with left ventricular mass index, hemoglobin level, and duration on APD.

CONCLUSIONS

Long term APD (> 1 years) seemed to decrease pulmonary arterial pressure, right atrial pressure and improve left ventricular ejection fraction (LVEF). Risk factors for PAH in ESRD were hypervolemia, abnormal ECHO findings and low hemoglobin levels. Clinical and echocardiographic abnormalities and complications are not uncommon among ESRD patients with PAH. Identification of those patients on transthoracic echocardiography may warrant further attention to treatment with APD.

New Approaches to Cardiovascular Disease and Its Management in Kidney Transplant Recipients

Cardiovascular events, including ischemic heart disease, heart failure, and arrhythmia, are common complications after kidney transplantation and continue to be leading causes of graft loss. Kidney transplant recipients have both traditional and transplant-specific risk factors for cardiovascular disease. In the general population, modification of cardiovascular risk factors is the best strategy to reduce cardiovascular events; however, studies evaluating the impact of risk modification strategies on cardiovascular outcomes among kidney transplant recipients are limited. Furthermore, there is only minimal guidance on appropriate cardiovascular screening and monitoring in this unique patient population. This review focuses on the limited scientific evidence that addresses cardiovascular events in kidney transplant recipients. Additionally, we focus on clinical management of specific cardiovascular entities that are more prevalent among kidney transplant recipients (ie, pulmonary hypertension, valvular diseases, diastolic dysfunction) and the use of newer evolving drug classes for treatment of heart failure within this cohort of patients. We note that there are no consensus documents describing optimal diagnostic, monitoring, or management strategies to reduce cardiovascular events after kidney transplantation; however, we outline quality initiatives and research recommendations for the assessment and management of cardiovascular-specific risk factors that could improve outcomes.

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.

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.

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.

Kidney transplantation in valvular heart disease and pulmonary hypertension: Consensus in waiting

Kidney transplantation induces a lesser anesthetic, surgical, and physiological alterations than other solid organ transplantation. Concomitant valvular pathologies expose these patients to poor postoperative outcome. There is a critical gap in knowledge and lack of coherence in the guidelines related to the management in patients with end-stage renal disease with valvular heart disease. The individualized diagnostic and management plan should be based on the assessment of perioperative outcomes. Similarly, pulmonary hypertension in end-stage renal disease poses a unique challenge, it can manifest in isolation or may be associated with other cardiac lesions, namely left-sided valvular heart disease and left ventricular systolic and diastolic dysfunction. Quantification and stratification according to etiology are needed in pulmonary hypertension to ensure an adequate management plan to minimize the adverse perioperative outcomes. Lack of randomized controlled trials has imposed hindrance in proposing a unified approach to clinical decision-making in these scenarios. In this review, we have described the magnitude of the problems, pathophysiologic interactions, impact on clinical outcomes and have also proposed a management algorithm for both the scenarios.

Pulmonary hypertension - prevalence, risk factors, and its association with vascular calcification in chronic kidney disease and hemodialysis patients

Pulmonary hypertension (PHTN) is a recently recognized complication in dialysis and it is associated with a poor outcome. We estimated the prevalence of PHTN and its association with vascular calcification in chronic kidney disease (CKD) and hemodialysis (HD) patients. One hundred and thirteen adult CKD patients were included in this study, of which 56 (49.6%) were on conservative treatment (nondialysis group) and 57 (50.4%) were on maintenance HD (dialysis group). Demographic, clinical, and biochemical parameters were collected and compared between the groups. Thirty-nine (69.6%) and 33 (57.8%) males were included in nondialysis and dialysis group, respectively. Mean age was 47.5 ± 13.7 in nondialysis group and 52.8 ± 13.9 in the dialysis group. PHTN was estimated using Doppler echocardiography and peripheral vascular calcification by lateral lumbar X-ray with aortic calcification scoring. Patients with and without PHTN and vascular calcification in dialysis and nondialysis group were compared. PHTN was found in 55 patients (48.7%) and it was high in patients on dialysis compared to nondialysis(59.6% vs. 37.5%, P <0.019). Abdominal aortic calcification was present in 35 patients (30.9%), dialysis versus nondialysis group was 22.8% and 39.3%. Increased left atrial diameter was significantly associated with PHTN (P <0.003), whereas peripheral artery calcification was not related to PHT (P = 0.248). The prevalence of PHTN in CKD was 48.7% which was higher in dialysis group than non dialysis group. Increased left atrial (LA) diameter was associated with PHTN but not peripheral arterial calcification.

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.

Right Ventricular Function After Creation of an Atriovenous Fistula in Patients With End Stage Renal Disease

BACKGROUND

Right ventricular (RV) dysfunction is associated with increased risk of heart failure and mortality in end stage renal disease (ESRD) patients. Accumulating evidence suggests an association between atriovenous fistula (AVF) and RV dysfunction; however, there is no adequate data on the relation between AVF characteristics and risk of RV dysfunction after AVF creation.

METHODS

The study included 30 ESRD patients (median age: 44years, 17 male) who had their first autogenous mature AVF. Before and 6months after AVF creation the following were measured: myocardial performance index of RV (MPI-RV) using tissue Doppler imaging echocardiography and flow rate (Qa), feeding artery and receiving vein diameters using colour-flow Doppler ultrasound. Change (Δ) in MPI-RV was calculated by subtracting follow-up value from baseline value. Worsening RV function was defined as Δ MPI-RV>0.015 and high AVF flow as Qa≥950ml/min.

RESULTS

Compared to patients with lower AVF flow, patients with higher flow showed increased Δ in MPI-RV (0.12 vs. -0.03, p=0.04), basal RV diameter (0.3 vs. -0.02cm, p=0.014), left ventricular end diastolic volume index (9.9 vs. 0ml/m², p=0.004) and left atrial volume index (3 vs. 1ml/m², p=0.016). Among all clinical, echocardiographic and AVF-related parameters, univariate predictors of worsening of RV function were: high Qa, upper arm AVF, and large feeding artery diameter at baseline. Δ MPI-RV showed significant correlations with feeding artery diameter at baseline (r=0.46, p=0.01), and Qa (0.37, p=0.04) and no significant correlation with pulmonary artery pressures. Qa≥950ml/min, feeding artery diameter at baseline≥4mm and upper arm AVF can predict worsening of RV function with 73%, 73%, 75% sensitivity and 67%, 67%, 70% specificity, respectively.

CONCLUSIONS

In patients with ESRD, higher AVF flow adversely affects RV remodelling, manifested as increased size and worsening function. Predictors of worsening of RV function are: higher AVF flow rate, AVF in the upper arm, and large feeding artery diameter.

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.

Why Is Your Patient Still Short of Breath? Understanding the Complex Pathophysiology of Dyspnea in Chronic Kidney Disease

Dyspnea is one of the most common symptoms associated with CKD. It has a profound influence on the quality of life of CKD patients, and its underlying causes are often associated with a negative prognosis. However, its pathophysiology is poorly understood. While hemodialysis may address fluid overload, it often does not significantly improve breathlessness, suggesting multiple and co-existing alternative issues exist. The aim of this article is to discuss the main pathophysiologic mechanisms and the most important putative etiologies underlying dyspnea in CKD patients. Congestive heart failure, unrecognized chronic lung disease, pulmonary hypertension, lung fibrosis, air microembolism, dialyzer bio-incompatibility, anemia, sodium, and fluid overload are potential frequent causes of breathing disorders in this population. However, the relative contributions in any one given patient are poorly understood. Systemic inflammation is a common theme and contributes to the development of endothelial dysfunction, lung fibrosis, anemia, malnutrition, and muscle wasting. The introduction of novel multimodal imaging techniques, including pulmonary functional magnetic resonance imaging with inhaled contrast agents, could provide new insights into the pathophysiology of dyspnea in CKD patients and ultimately contribute to improving our clinical management of this symptom.

Evaluation of pulmonary artery pressure and resistance by pulsed Doppler echocardiography in patients with end-stage renal disease on dialysis therapy

BACKGROUND

Pulmonary hypertension (PH) is one of the most important comorbidities in patients undergoing hemodialysis (HD). The goal of the present work is to determine the possible etiologic factors for its occurrence.

METHODS

The prevalence of PH was estimated by Doppler echocardiography in a cohort of 100 patients aged 49.3 ± 13.9 years on regular HD. Mean pulmonary artery pressure was estimated from pulmonary acceleration time by Mahan's regression equation. Pulmonary vascular resistance and pulmonary capillary wedge pressure were calculated. We focused on the effect of HD on left and right ventricle diastolic and systolic function. Right ventricle systolic function was assessed by tricuspid annular systolic excursion and pulsed Doppler myocardial performance index. Since impaired endothelial function was postulated as an underlying cause of PH, we studied the effects of HD on brachial artery endothelial function.

RESULTS

The current study found that pulmonary hypertension was prevalent in 70% of patients on dialysis. Left atrium diameter, left ventricle mass indexed to body surface area, and mitral E/E' were increased in the dialysis group (4.4 ± 0.2 cm, 126.5 ± 24.6 g/m(2), and 16.9 ± 4.4, respectively, p < 0.001 for all). Pulmonary artery systolic pressure was positively correlated to duration of dialysis and negatively correlated to glomerular filtration rate (p < 0.001 and r = -0.991). Pulmonary vascular resistance was significantly increased in dialysis patients (1.9 ± 0.2 Wood units vs. 1.2 Wood units in controls, p < 0.001). Endothelial dysfunction, defined as brachial artery flow mediated dilatation <6%, was found in 46% of dialysis group.

CONCLUSION

Increased pulmonary artery systolic pressure in the HD population could be attributed to left atrium dilatation and left ventricle diastolic dysfunction. Pulmonary vascular resistance was significantly increased in dialysis group. This might be explained by impaired endothelial nitric oxide synthesis that not only caused systemic vasoconstriction but also affected the pulmonary vasculature.

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.

Cardiac complications of arteriovenous fistulas in patients with end-stage renal disease

Cardiovascular disease is the leading cause of the death in dialysis patients. Arteriovenous fistulas (AVFs) are associated with lower mortality and are viewed as the desired access option in most patients with advanced kidney disease needing dialysis. However, AVFs have significant and potentially deleterious effects on cardiac functions particularly in the setting of preexisting heart disease. This article provides a comprehensive and contemporary review to what is known about the impact of AVFs on: congestive heart failure, left ventricular hypertrophy, pulmonary hypertension, right ventricular dysfunction, coronary artery disease and valvular heart disease.

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.

Pulmonary hypertension: epidemiology in different CKD stages and its association with cardiovascular morbidity

Background

Pulmonary hypertension (PH) was recently recognized as a common complication of end-stage renal disease (ESRD) that causes an increased risk of mortality. Epidemiological data for this disorder in earlier stages of chronic kidney disease (CKD) and its association with cardiovascular (CV) morbidity are scarce.

Methods

We retrospectively analyzed 2,351 Chinese CKD patients with complete clinical records and echocardiography data between Jan 2008 and May 2012. The patients were divided into the following 6 groups: CKD Stages 1–4; Stage 5 for those not on or initiated on hemodialysis for <3 months; and Stage 5D for the patients undergoing hemodialysis for ≥3 months. The prevalence of PH and CV morbidity was investigated, and their association was evaluated with a logistic regression model.

Results

PH was detected in 426 patients (18.1%). Mild, moderate and severe PH was diagnosed in 12.1%, 4.9% and 1.1% of the patients, respectively. Severe PH was detected in CKD Stages 5 and 5D. CV morbidity was found in 645 patients (27.4%). Compared with the non-PH group, the PH group had a higher risk for cardiac disease but not for cerebrovascular disease risk. PH severity was associated with cardiac morbidity risk [odds ratio (95% CI) for mild PH: 1.79 (1.30–2.47); moderate PH: 2.75 (1.73–4.37); severe PH: 3.90 (1.46–10.42)].

Conclusions

Our study showed for the first time the epidemiology profile of PH across the spectrum of CKD. Mild-to-moderate PH occurs with more frequency in advanced CKD, and severe PH is scarce in non-ESRD CKD. PH in CKD is associated with cardiac but not cerebrovascular disease, with increasing cardiac morbidity seen with increasing PH severity. Evidence from prospective studies addressing PH in this population is needed to predict cardiac events.

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.

Pulmonary Hypertension in Peritoneal Dialysis Patients: Prevalence and Risk Factors

Aim

To investigate the prevalence of pulmonary arterial hypertension (PAH) and the possible contributing factors for PAH in patients receiving regular continuous ambulatory peritoneal dialysis (CAPD).

Patients and Methods

The study included 135 CAPD patients and 15 disease-free controls. Patients that had chronic obstructive pulmonary disease, severe mitral or aortic valve disease, connective tissue disease, history of pulmonary embolism, left ventricular ejection fraction <50%, or chest wall or parenchymal lung disease were excluded. All patients and controls were examined using echocardiography and bioelectrical impedance analysis. PAH was defined as systolic pulmonary artery pressure (PAP) >35 mmHg at rest.

Results

Mean systolic PAP was higher in the CAPD patients than in the controls (19.66 ± 11.66 vs 14.27 ± 4.55 mmHg, p = 0.001). PAH was detected in 17 (12.6%) of the 135 CAPD patients. Mean systolic PAP was significantly higher in patients with PAH than in those without PAH (42.00 ± 9.13 vs 16.44 ± 7.83 mmHg, p = 0.001). Serum albumin level and ejection fraction were lower in patients with PAH than in those without PAH ( p = 0.001 and 0.003 respectively). The ratio of extracellular water/total body water (ECW/TBW), which can reflect hydration status, was significantly higher in patients with PAH than in those without PAH ( p = 0.008). In the PD group, no patients were hypovolemic; 51 (37.8%) of the 135 PD patients were hypervolemic and 84 (62.2%) were normovolemic. Only 3 of the 17 patients with PAH were normovolemic; the rest were hypervolemic. Mean systolic PAP was significantly higher in hypervolemic PD patients (24.57 ± 14.19 mmHg) than in normovolemic PD patients (16.68 ± 7.61 mmHg) ( p = 0.001). PAP correlated with ECW/TBW ( r=0.317, p = 0.001) and left ventricular mass index (LVMI; r=0.286, p = 0.001). On the other hand, it inversely correlated with serum albumin level ( r = –0.281, p = 0.001), hemoglobin level ( r = –0.165, p = 0.044), and ejection fraction ( r = –0.263, p = 0.001). Serum albumin level, ECW/TBW, and LVMI were found in multivariate analysis to be independent risk factors for PAP.

Conclusion

PAH is a frequent cardiovascular complication in CAPD patients. Serum albumin level, hypervolemia, and LVMI are major risk factors for PAH. Therefore, strategies for treatment of hypervolemia, left ventricular hypertrophy, and hypoalbuminemia should be enhanced to prevent the development of PAH in CAPD patients.