Pulmonary hypertension in patients with end-stage renal disease

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.

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.

Burden of Pulmonary Hypertension in End-Stage Renal Disease Patients Receiving Maintenance Hemodialysis: Evaluation Factors and Treatment Strategies

Background Chronic kidney disease (CKD) is an emerging public health problem in India. Pulmonary hypertension (PH) is an overlooked cardiovascular complication of CKD. This study aimed to estimate the burden of PH among CKD patients undergoing hemodialysis in a selected tertiary care hospital. In addition, it aimed to determine the various factors associated with PH and response to various treatment modalities. Methodology This hospital-based, analytical, cross-sectional study was conducted in the nephrology department of a medical college hospital in Tamil Nadu from March 2023 to March 2024. The study included 150 adults diagnosed with stage 5 CKD and registered for hemodialysis. Results Of the 150 participants, 96 (64%) had PH. Of these, 81 (84%) were males and 15 (16%) were females. In the PH group, 58 (60.4%) had type 2 diabetes mellitus, 52 (54%) had been on dialysis for 6-12 months, 67 (69.8%) had chronic glomerulonephritis, 25 (26.04%) had chronic tubular interstitial nephritis, and 72 (75%) had microcytic anemia. PH patients had significantly higher rates of protein-energy malnutrition (26 (48.2%) vs. 67 (80.7%), p < 0.009) and more frequent hospitalizations (19 (35%) vs. 69 (71.9%)) compared to those without PH. Additionally, PH patients exhibited higher incidences of left ventricular hypertrophy (72% vs. 92%), pericardial effusion (0% vs. 65%), and tricuspid regurgitation (16% vs. 100%). Patients treated with a combination of isosorbide dinitrate (ISDN) and hydralazine; extended hemodialysis; and ISDN, hydralazine, and sildenafil showed significant improvement compared to other treatment modalities. Conclusions The high prevalence of PH among CKD patients undergoing hemodialysis underscores the importance of vigilant monitoring and targeted interventions.

Determinants of pulmonary hypertension in patients with end-stage kidney disease and arteriovenous access

BACKGROUND

Pulmonary Hypertension (PH) is a sequela of arteriovenous (AV) fistulas (AVF) or AV grafts (AVG) in patients with end-stage kidney disease (ESKD) due to the creation of shunt physiology and increased pulmonary blood flow. PH has been consistently associated with increased mortality but there is a paucity of data regarding management.

RESEARCH QUESTION

The objective of this study was to identify risk factors and outcomes in patients who develop PH after AVF or AVG creation for hemodialysis access.

METHODS

Using the United States Renal Data System, we identified all patients over age 18 initiated on dialysis from 2012-2019 who did not receive renal transplant. We identified a) the predictors of PH in patients with ESKD on hemodialysis; b) the independent mortality risk associated with development of PH.

RESULTS

We identified 478,896 patients initiated on dialysis from 2012-2019 of whom 27,787 (5.8 %) had a diagnosis of PH. The median age was 65 (IQR: 55-74) years and 59.1 % were male. Reduced ejection fraction, any congestive heart failure, obstructive sleep apnea, and female sex were the strongest predictors of PH diagnosis. Both AVG and AVF were also associated with an increased rate of PH diagnosis compared to catheter-based dialysis (p < 0.001). PH portended a poor prognosis and was associated with significantly increased mortality (p < 0.001).

CONCLUSIONS

Patients with AVF or AVG should be screened using echocardiography prior to creation and monitored with serial echocardiography for the development of PH, and if present, considered for revision of the AVA. This is also the first study to identify that AVG are a risk factor for PH in dialysis patients.

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.

Haemodialysis patient with chronic kidney disease and pulmonary hypertension treated effectively with pulmonary vasodilators

A male patient in his 70s on periodic haemodialysis complained of dysdialysis several months prior and was diagnosed subsequently with pulmonary hypertension (PH). To confirm this diagnosis, a catheter examination was performed after haemodialysis in the dry state. Pulmonary artery wedge pressure (PAWP), mean pulmonary artery (PA) pressure, cardiac index (CI) and pulmonary vascular resistance (PVR) were 9 mm Hg, 42 mm Hg, 2.63 L/min/m2 and 5.9 WU, respectively. The pathophysiological diagnosis was precapillary PH, which mimicked idiopathic PH. The pulmonary vasodilators were administered in a careful sequential manner. After initiation of therapy, dysdialysis disappeared within a few months, while mean PA pressure, CI and PVR improved to 24 mm Hg, 3.47 L/min/m2 and 2.3 WU, respectively. Although the cause of PH in haemodialysis patients is multifactorial, catheter examination in the dry state is useful for clarifying a patient's haemodynamic state. In a haemodialysis PH patient with precapillary PH, pulmonary vasodilators are an effective treatment option.

Survival Outcomes of Lung Transplant Recipients From Donors With Abnormal Kidney Function

BACKGROUND

Recovering lungs with pulmonary edema due to abnormal kidney function is considered one of the expanded selection criteria for lung transplant. The aim of this study is to assess lung transplant recipients' survival from donors with abnormal kidney function and to determine differences in lung recovery rates from donors with and donors without abnormal kidney function.

METHODS

We reviewed the United Network for Organ Sharing registry for first-time adult lung transplant donors and recipients from June 2005 to March 2017. Donor kidney function was categorized into three groups based on estimated glomerular filtration rate: group I, greater than 60 mL/min; group II, 15 to 59 mL/min; and group III, less than 15 mL/min. Recipient survival was stratified based on estimated glomerular filtration rate using Kaplan-Meier. A multivariate Cox Regression model with known risk factors that affect survival was used to compare survival among groups. Comparison of lung recovery among the three groups was also performed.

RESULTS

Lung recovery rates were 29.7% (15,670 of 52,747), 19.4% (3879 of 20,040), and 18.1% (704 of 3898) for groups I, II, and III, respectively. The 1-, 3-, and 5-year recipient survival rates were 86.2%, 69.2%, and 55.7% for group I; 84.9%, 66.9%, and 53.8% for group II; and 85.5%, 65.3%, and 50.3% for group III, respectively (adjusted P = .25; multivariate Cox regression method). When group I was used as reference, the adjusted hazard ratio for group II was 1.04 (95% CI, 0.98-1.10) and for group III, it was 1.08 (95% CI, 0.96-1.23), after adjusting with the multivariate Cox regression model.

CONCLUSIONS

There was no significant difference in lung recipient survival. The lung recovery rate from donors with abnormal kidney function was lower compared with that of donors with normal kidney function.

Pulmonary Manifestations at Different Stages in the Chronic Kidney Disease: An Observational Study

INTRODUCTION

By a variety of pathogenic pathways, kidney diseases can have a direct negative impact on the lungs and worsen the prognosis for those with chronic renal disease. Chronic kidney disease (CKD) is a public health concern throughout the world. The relationship between the kidneys and lungs is crucial for maintaining acid-base balance, fluid homeostasis, and blood pressure control. These patients have a higher prevalence of lung dysfunction regardless of the disease's stage, including sleep apnea syndrome, pulmonary hypertension, and chronic obstructive pulmonary disease (COPD). The chance of getting a pulmonary consequence increases with the severity of kidney disease. In individuals with chronic renal disease, this study looked at the prevalence of several respiratory disorders.

MATERIALS AND METHODS

From February 2021 to October 2021, 70 CKD patients who were receiving care at the Saveetha Medical College and Hospital were taken into consideration for the study. Clinical assessment and pertinent tests, such as a pulmonary function test, chest radiography, CT chest, sputum analysis, and pleural fluid analysis were performed. To evaluate left ventricular function, echocardiography was performed. Selected patients underwent polysomnography.

RESULTS

The study's population had a mean age of 50 years. There was a 20:50 sex ratio (M:F). Seventy percent of them had respiratory conditions, the most frequent of which was pleural effusion (70%), followed by pulmonary edema (52%). The pleural effusion was primarily transudative and right sided. Both tuberculous pleural effusion and pulmonary tuberculosis were detected in 2% of the population. Seven percent of them developed pneumonia. 10% of patients had thickening of the pleura. Using chest CT and x-ray, 3% of patients had pulmonary calcification visible. In 12 (60%) out of the 20 patients who were studied, sleep apnea was observed. Two patients with tuberculosis and pneumonia lacked the typical signs.

CONCLUSIONS

In our research study, CKD patients have a much higher preponderance of respiratory illnesses, which has negative effects on patient care.

Estimation of pulmonary artery systolic pressure in hemodialysis patients and its association with cardiorespiratory fitness and pulmonary function

PURPOSE

To evaluate the estimated pulmonary arterial systolic pressure (PASP) through transthoracic echocardiography in hemodialysis (HD) patients and associate it with cardiorespiratory fitness and pulmonary function.

METHODS

This study was a cross-sectional analysis of HD patients that performed evaluations of cardiac function, cardiorespiratory fitness, and pulmonary function, through transthoracic echocardiography, cardiopulmonary exercise test, spirometry, and manovacuometry, respectively. All patients underwent the evaluations on a non-dialysis day.

RESULTS

Thirty-five HD patients were evaluated and separated according to the presence of probable pulmonary hypertension (PH) (estimated PASP ≥ 35 mmHg) or not (estimated PASP < 35 mmHg). Those HD patients with probable PH had the worst cardiorespiratory fitness, evaluated by the peak oxygen consumption (VO_2peak) (17.11 ± 4.40 versus 12.90 ± 2.73 mL/kg/min; p = 0.011), and pulmonary function, evaluated by absolute and predicted of forced vital capacity (FVC) (85.52 ± 12.29 versus 71.38 ± 11.63%; p = 0.005) and absolute and predicted of forced expiratory volume in the first second (FEV₁) (83.37 ± 14.98 versus 69.21 ± 13.48%; p = 0.017). The secondary analysis showed that estimated PASP was correlated with VO_2peak (r = - 0.508; p = 0.002), FVC (r = - 0.450; p = 0.007), and FEV₁ (r = - 0.361; p = 0.033). Moreover, the adjusted odds ratio by HD vintage, dry weight and gender showed that increments in VO_2peak (OR 1.62; CI 95% 1.04-2.54; p = 0.034), FVC (OR 39.67; CI 95% 1.74-902.80; p = 0.021), and FEV₁ (OR 39.54; CI 95% 1.89-826.99; p = 0.018) were associated with 1-fold and 39-fold higher chance, respectively, for not having PH. However, all these associations were lost when age was included in the analysis.

CONCLUSIONS

The HD patients with probable PH had the worst cardiorespiratory fitness and pulmonary function. Exploratory analyses showed that greater cardiopulmonary fitness was associated with better cardiac function. Moreover, increments in cardiorespiratory fitness and pulmonary function may increase the chance of not having PH.

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.

Intensive ultrafiltration strategy restores kidney transplant candidacy for patients with echocardiographic evidence of pulmonary hypertension

INTRODUCTION

Pulmonary hypertension (PH) is prevalent in those with end-stage kidney disease (ESKD) and poses a barrier to kidney transplant due to its association with poor outcomes. Studies examining these adverse outcomes are limited and often utilize echocardiographic measurements of pulmonary artery systolic pressure (PASP) instead of the gold standard right heart catheterization (RHC). We hypothesized that in ESKD patients deemed ineligible for kidney transplant because of an echocardiographic diagnosis of PH the predominant cause of PH is hypervolemia and is potentially reversible.

METHODS

We conducted a prospective study of 16 patients with ESKD who were denied transplant candidacy. Prior echocardiograms and RHCs were reviewed for confirmation of PH. Patients were admitted for daily sessions of ultrafiltration for volume removal and repeat RHCs were performed following intervention. RHC parameters and body weight were compared before and after intervention. Statistical analysis was performed using PRISM GraphPad software. A p-value <.05 was considered statistically significant.

RESULTS

Following intervention, the mean pulmonary artery pressure (mPAP) and pulmonary arterial wedge pressure decreased from 45.0 ± 3.06 to 29.1 ± 7.77 mmHg (p < .0001) and 22.2 ± 5.06 to 13.1 ± 7.25 mmHg (p = .003), respectively. The pulmonary vascular resistance decreased from 4.73 ± 1.99 to 4.28 ± 2.07 WU (p = .30). Eleven patients from the initial cohort underwent successful kidney transplantation post-intervention with 100% survival at 1-year.

CONCLUSIONS

In ESKD patients, diagnoses of PH made by echocardiography may be largely due to hypervolemia and may be optimized using an intensive ultrafiltration strategy to restore transplant candidacy.

Microemboli induced by air bubbles may be deposited in organs as a consequence of contamination during medical care

Background

Larger volumes of accidental air infused during medical care may end up as emboli while microbubbles of air are supposed to be absorbed and cause no harm. The aim of this autopsy study was to investigate if microbubbles of air accidently entering the bloodline may be detected as microemboli (ME) in tissue such as lungs, brain and heart. If so, do differences in prevalence exist between haemodialysis (HD) and amyotrophic lateral sclerosis (ALS) patients.

Methods

Included were data from 44 patients treated by medical healthcare before death. Twenty-five cases had been treated with chronic HD and 19 cases died from ALS. Since air in the bloodline activates coagulation, ME could appear. To discriminate between microbubbles caused by artificial contamination during autopsy versus microbubbles deposited in vivo, tissues were stained with a polyclonal fluorescent antibody against fibrinogen, fibrin and fragments E and D. Fluorescence staining was used to visualize ME counted within 25 microscopic fields (600×) of a tissue preparation. One tissue preparation was used if available from the lung, heart and frontal lobe of the brain and in five cases also the cerebellum.

Results

Microbubbles can be verified at autopsy as ME in the lung, heart and brain in tissue from patients exposed to more extensive medical care. There were significantly more ME in the lungs versus the heart or brain. Women had fewer ME than men. The HD group had a higher median of ME per section than the ALS group (lung: 6 versus 3, P = .007; heart: 2.5 versus 1, P = .013; brain: 7.5 versus 2, P = .001) and had more sections with ME findings than the ALS group (P = .002). A correlation existed between the time on HD (months) and ME in the lungs.

Conclusions

More ME were present in HD patients compared with those who suffered from ALS. Minimizing air contamination from syringes, infusions and bloodlines will decrease ME and subsequent tissue injury.

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.

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.

The echocardiographic course of pretransplant pulmonary hypertension following kidney transplantation and associated outcomes

The post 3 kidney transplant course of pretransplant echocardiographically‐defined pulmonary hypertension (PH) was reviewed in 115 patients. Of these 61 patients (the largest cohort reported to date), underwent 160 “for indication” echocardiograms posttransplant (mean echocardiograms per patient: 2.6 ± 2.3). Patients undergoing posttransplant echocardiograms demonstrated greater risks for worse outcomes than those without posttransplant echocardiograms; however, there was no difference in mortality, death‐censored graft failure or the composite of death or graft failure between these two groups. Of patients tested, 36 (59%) showed resolution of PH at a median of 37.5 months. Six patients (16.7%) in whom PH resolved (at a median of 29 months), experienced recurrence of PH after an interval of 48 months. No pretransplant demographic or echocardiographic characteristics distinguished those in whom PH persisted versus resolved. Though there was no difference in the risk for mortality or death‐censored graft loss between the two groups at 3 and 5 years, there was a higher risk for the composite of mortality or graft loss at three but not at five years in the group with persistent PH. In conclusion, echocardiographically defined PH resolved in 59% of patients following kidney transplantation; but irrespective of resolution there was no clear association with worse outcome.

The Results of The Interposition Graft-Technique in Treatment of High Flow Vascular Access

OBJECTIVE

High-flow (HF) vascular access (VA) is a fearsome condition potentially responsible for cardiac or pulmonary complications, steal syndrome and hand ischemia. The present study was conducted to report the results achieved in a group of patients undergoing interposition-graft technique to treat HF.

MATERIALS AND METHODS

An analysis of clinical, ultrasound and echocardiography data collected from the review of medical charts was performed. Flow reduction, complications and need for secondary interventions were investigated.

RESULTS

Among a total 498 hemodialysis access interventions performed during a 6-years period, 30 patients (n 15, 50% male, median age 63.5, range 42-91 years) presented with high-flow (median flow 1.9 L/min, range 1.5-4 L/min). 18 patients were asymptomatic (60%); 6 (20%) suffered from a severe distal hand ischemia; 5 (16.6%) developed signs of congestive heart failure and 1 patient (3.3%) presented with pulmonary hypertension. In twenty patients (66.7%) the access was preserved by the interposition of a 6 mm polytetrafluroethylene (PTFE) prosthesis. This approach was used as a primary flow reduction technique in 16 patients (80%) or the failure of a previously attempted procedure in 4 cases. No intraoperative complications were observed. Post-operative median VA flow was 1.1 L/min (range 0.900-2 L/min), with a median flow reduction of 0.770 L/min (range 0.100-2.8 L/min). At a median follow-up of 9 months (range 1-42), 95% (n 19) of patients were free from recurrences.

CONCLUSION

In treatment of HF-VA graft interposition demonstrated satisfactory results at the mid-term follow-up. More data are needed to affirm this technique as the preferential one.

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.

Pulmonary Hypertension in Chronic Kidney Disease

There is a high prevalence of pulmonary hypertension in chronic kidney disease (CKD), with rates increasing as glomerular filtration rate declines. Pulmonary hypertension is associated with a higher risk of cardiovascular events and mortality in non-dialysis-dependent CKD stages 3 to 5, dialysis-dependent CKD, as well as kidney transplant recipients. The pathophysiology of pulmonary hypertension in CKD is multifactorial and includes higher pulmonary capillary wedge pressure caused by ischemic heart disease and cardiomyopathy, higher cardiac output caused by anemia and arteriovenous access used for hemodialysis, as well as potentially higher pulmonary vascular resistance. Treatment should focus on the underlying cause.

Kidney Transplantation Confers Survival Benefit for Candidates With Pulmonary Hypertension

Kidney transplantation (KT) is controversial in patients with pretransplant pulmonary hypertension (PtPH). We aimed to quantify post-KT graft and patient survival as well as survival benefit in recipients with PtPH.

Methods

Using UR Renal Data System (2000-2018), we studied 90 819 adult KT recipients. Delayed graft function, death-censored graft failure, and mortality were compared between recipients with and without PtPH using inverse probability weighted logistic and Cox regression. Survival benefit of KT was determined using stochastic matching and stabilized inverse probability treatment Cox regression.

Results

Among 90 819 KT recipients, 2641 (2.9%) had PtPH. PtPH was associated with higher risk of delayed graft function (odds ratio, 1.23; 95% CI, 1.10-1.36; P < 0.01), death-censored graft failure (hazard ratio [HR], 1.23; 95% CI, 1.11-1.38; P < 0.01), and mortality (HR, 1.56; 95% CI, 1.44-1.69; P < 0.01). However, patients with PtPH who received a KT had a 46% reduction in mortality (HR, 0.54; 95% CI, 0.48-0.61; P < 0.01) compared with those who remained on the waitlist.

Conclusions

Although PtPH is associated with inferior post-KT outcomes, KT is associated with better survival compared with remaining on the waitlist. Therefore, KT is a viable treatment modality for appropriately selected patients with PtPH.

Reduction of arteriovenous access blood flow leads to biventricular unloading in haemodialysis patients

AIMS

Patients on chronic haemodialysis have a wide range of changes in cardiac function and structure, including left ventricular hypertrophy, dilation and diastolic dysfunction or pulmonary hypertension. All these changes were linked to increased mortality in previous studies. High-flow arteriovenous fistulas (AVF) are supposed to be a factor contributing to their development. This study investigated the early effect of surgical AVF blood flow (Qa) reduction on these changes in patients with or without heart failure changes.

METHODS AND RESULTS

Forty-two patients in chronic haemodialysis programme with high-flow AVF (Qa over 1500 mL/min), indicated for surgery for ≥1 of the following indications: 1.manifest heart failure; 2.hand ischemia; 3.advanced structural heart changes detected by echocardiography. The patients underwent echocardiography on selection visit, before blood flow reducing surgery and six weeks thereafter. The Qa reduction led to decrease of left ventricular mass (p = 0.02), end-diastolic volume (p = 0.008), end-diastolic diameter (p = 0.003) and left atrial volume (p = 0.0006). Diastolic function improved. Similarly, right ventricular diameter and right atrial volume decreased (p = 0.000001 and 0.00009, respectively) together with the decrease of estimated pulmonary artery systolic pressure. 81% of patients suffered from pulmonary hypertension prior to surgery, only 36% thereafter.

CONCLUSION

The surgical restriction of the hyperkinetic circulation leads to several improvements of heart structure and function, which was linked to higher mortality in other studies. The beneficial effect of Qa reduction is present even in patients without symptoms of heart failure. The contribution of AVF must be considered with structural or functional heart changes.

Right Ventricular Dysfunction and Adverse Outcomes after Renal Transplantation

INTRODUCTION

Pulmonary hypertension is common among patients with end-stage renal disease, although data regarding the impact of right ventricular (RV) failure on postoperative outcomes remain limited. We hypothesized that echocardiographic findings of RV dilation and dysfunction are associated with adverse clinical outcomes after renal transplant.

METHODS

A retrospective review of adult renal transplant recipients at a single institution from January 2008 to June 2010 was conducted. Patients with transthoracic echocardiograms (TTEs) within 1 year leading up to transplant were included. The primary end point was a composite of delayed graft function, graft failure, and all-cause mortality.

RESULTS

Eighty patients were included. Mean follow-up time was 9.4 ± 0.8 years. Eight patients (100%) with qualitative RV dysfunction met the primary end point, while 39/65 patients (60.0%) without RV dysfunction met the end point (p = 0.026). Qualitative RV dilation was associated with a significantly shorter time to all-cause graft failure (p = 0.03) and death (p = 0.048). RV systolic pressure was not measurable in 45/80 patients (56%) and was not associated with outcomes in the remaining patients.

CONCLUSION

RV dilation and dysfunction are associated with adverse outcomes after renal transplant. TTE assessment of RV size and function should be a standard part of the pre-kidney transplant cardiovascular risk assessment.

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.

Development of hyperacute high-output heart failure at access creation

High-output heart failure can occur in patients undergoing hemodialysis via permanent access. We have described two cases of hyperacute high-output heart failure. Two patients with multiple previous failed access attempts presented for redo access. Each patient experienced high-output heart failure in the operating room during access placement. A delay in the diagnosis led to the first patient's death, although early recognition led to successful treatment of the second patient. Hyperacute heart failure during access creation is uncommon. Early recognition of this complication is important because timely intervention can be life-saving.

Clinical impact of pre-kidney transplant pulmonary hypertension on post-transplant outcomes

Outcomes of kidney transplant (KT) patients with pre-transplant pulmonary hypertension (PH) are poorly understood. PH patients are often considered high risk and excluded from KT. We investigated the association of pre-transplant PH with KT recipient's outcomes. A single-center, retrospective study that reviewed all patients transplanted from 2010 to 2016, who had a transthoracic echocardiogram (TTE) before KT and at least one TTE post-KT. The TTE closest to the KT was used for analyses. PH is defined as pulmonary artery systolic pressure (PASP) ≥ 40 mm Hg. Of 204 patients, 61 had PASP ≥ 40 mm Hg (with PH) and 143 had PASP < 40 mm Hg (without PH) prior to KT. No statistically significant differences existed between the two groups in baseline demographics, renal failure etiologies, dialysis access type, and cardiovascular risk factors. The mean difference in pre-KT PASP was 18.1 ± 7 mm Hg (P < 0.001). Patients with PH had a statistically significant decrease in PASP post-KT compared to the patients without PH with a mean change of -7.03 ± 12.28 mm Hg vs. + 3.96 ± 11.98 mm Hg (p < 0.001), respectively. Moderate mitral and moderate-severe tricuspid regurgitation were the only factors found to be independently associated with PH (p = 0.001) on multivariable analysis. No statistically significant difference was notable in patient survival, graft function, and creatinine post-KT in both groups. PH pre-KT particularly mild-moderate PH did not adversely affect intermediate (90-day) and long-term allograft and patient survival. Patients with mild-moderate PH should not be excluded from KT.

RNA interactions in right ventricular dysfunction induced type II cardiorenal syndrome

Right ventricular (RV) dysfunction induced type II cardiorenal syndrome (CRS) has a high mortality rate, but little attention has been paid to this disease, and its unique molecular characteristics remain unclear. This study aims to investigate the transcriptomic expression profile in this disease and identify key RNA pairs that regulate related molecular signaling networks. We established an RV dysfunction-induced type II CRS mouse model by pulmonary artery constriction (PAC). PAC mice developed severe RV hypertrophy and fibrosis; renal atrophy and dysfunction with elevated creatinine were subsequently observed. Expression profiles in RV and kidney tissues were obtained by whole transcriptome sequencing, revealing a total of 741 and 86 differentially expressed (DE) mRNAs, 159 and 29 DEmiRNAs and 233 and 104 DEcircRNAs between RV and kidney tissue, respectively. Competing endogenous RNA (ceRNA) networks were established. A significant alteration in proliferative, fibrotic and metabolic pathways was found based on GO and KEGG analyses, and the network revealed key ceRNA pairs, such as novel_circ_002631/miR-181a-5p/Creb1 and novel_circ_002631/miR-33-y/Kpan6. These findings indicate that significantly dysregulated pathways in RV dysfunction induced type II CRS include Ras, PI3K/Akt, cGMP-PKG pathways, and thyroid metabolic pathways. These ceRNA pairs can be considered potential targets for the treatment of type II CRS.

Interdialytic weight gain of less than 2.5% seems to limit cardiac damage during hemodialysis

Aims:

To investigate if a single low-flux HD induces a rise in cardiac biomarkers and if a change in clinical approach may limit such mechanism.

Material and methods:

A total of 20 chronic HD patients each underwent three different study-dialyses. Dialyzers (low-flux polysulfone, 1.8 sqm) had been stored either dry or wet (Wet) and the blood level in the venous chamber kept low or high. Laboratory results were measured at baseline, 30 and 180 min, adjusted for the effect of fluid shift. Ultrasound measured microemboli signals (MES) within the return line.

Results:

Hemodialysis raised cardiac biomarkers (p < 0.001): Pentraxin 3 (PTX) at 30 min (by 22%) and at 180 min PTX (53%), Pro-BNP (15%), and TnT (5%), similarly for all three HD modes. Baseline values of Pro-BNP correlated with TnT (rho = 0.38, p = 0.004) and PTX (rho = 0.52, p < 0.001). The changes from pre- to 180 min of HD (delta-) were related to baseline values (Pro-BNP: rho = 0.91, p < 0.001; TnT: rho = 0.41, p = 0.001; PTX: rho = 0.29, p = 0.027). Delta Pro-BNP (rho = 0.67, p < 0.001) and TnT (rho = 0.38, p = 0.004) correlated with inter-dialytic-weight-gain (IDWG). Biomarkers behaved similarly between the HD modes. The least negative impact was with an IDWG ⩽ 2.5%. Multiple regression analyses of the Wet-High mode does not exclude a relation between increased exposure of MES and factors such as release of Pro-BNP.

Conclusion:

Hemodialysis, independent of type of dialyzer storage, was associated with raised cardiac biomarkers, more profoundly in patients with higher pre-dialysis values and IDWG. A limitation in IDWG to <2.5% and prolonged ultrafiltration time may limit cardiac strain during HD, especially in patients with cardiovascular risk.

Echocardiography to Screen for Pulmonary Hypertension in CKD

Introduction

Pulmonary hypertension (PH) is a common yet incompletely understood complication of chronic kidney disease (CKD). Although transthoracic echocardiogram is commonly used to noninvasively estimate PH, it has not been validated in a CKD population. We investigated the utility of this diagnostic tool for CKD-associated PH in a large right heart catheterization (RHC) cohort.

Methods

We reviewed RHC and echocardiography data in 4036 patients (1714 with CKD) obtained between 2011 and 2014 at a single center. We used multivariate regression to determine the associations of echocardiography measurements with PH, and evaluated whether estimated glomerular filtration rate (eGFR) modified these associations. Using internal validation, we sequentially added measurements to predictive models and analyzed the incremental predictive performance using the change in the area under the receiver operating characteristic curve (ΔAUC) and net reclassification improvement.

Results

The echocardiography measurements most strongly associated with the diagnosis of PH included tricuspid regurgitant velocity (TRV), tricuspid annular plane systolic excursion (TAPSE), right atrial pressure, diastolic dysfunction, and right ventricular function. Among these measurements, eGFR significantly modified the associations of TAPSE and diastolic dysfunction with the diagnosis of PH. The model consisting of a combination of TRV, right atrial pressure, and TAPSE most accurately predicted the diagnosis of PH in a CKD population (AUC 0.82).

Conclusions

The optimal model to predict PH diagnosis included TRV, right atrial pressure, and TAPSE. Since TAPSE more strongly associated with PH in the CKD population, these findings support a CKD-specific approach to the development of noninvasive screening algorithms for PH.

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.

Prevalence and factors associated with pulmonary arterial hypertension on maintenance hemodialysis patients in Kinshasa, Democratic Republic of Congo: a cross-sectional study

Background

Although cardiovascular diseases in particular Pulmonary Arterial Hypertension (PAH) is associated with, high morbid-mortality in chronic hemodialysis, but its magnitude remains paradoxically unknown in sub-Saharan Africa. The aim of this study was to evaluate the prevalence of PAH and associated factors in chronic hemodialysis in Sub-Saharan African population.

Method

In a cross-sectional study, patients treated with HD for at least 6 months in 4 hemodialysis centers were examined. PAH was defined as estimated systolic pulmonary arterial pressure (sPAP) ≥ 35 mmHg using transthoracic Doppler echocardiography performed 24 h after the HD session.

Results

Eighty-five HD patients were included; their average age was 52.6 ± 15.9 years. Fifty-seven patients (67.1%) were male. Mean duration of HD was 13.3 ± 11 months. With reference to vascular access, 12 (14.1%), 29 (34.1%) and 44 (51.8%) patients had AVF, tunneled cuff and temporary catheter, respectively. The underlying cause of ESRD was diabetes in 30 patients (35.3%). The prevalence of PAH was 29.4%. Patients with PAH had more hyponatremia (11 (44%) vs 10 (16.7%), p = 0.010). In multivariate analysis, unsecured healthcare funding (aOR 4, 95% CI [1.18–6.018]), arrhythmia (aOR 3, 95% CI [1.29–7.34]), vascular access change (aOR 4, 95% CI [1.18–7.51]) and diastolic dysfunction (aOR 5, 95% CI [1.35–9.57] were independently associated with PAH.

Conclusion

One third of hemodialysis patients exhibit PAH, which is independently associated with low socioeconomic status (unsecured funding, vascular access change) and cardiovascular complications (arrhythmia, diastolic dysfunction).

Association of Pulmonary Hypertension With End-Stage Renal Disease Among the Obese Population

Introduction

Pulmonary hypertension (PH) is a known complication that occurs in patients of end-stage renal disease (ESRD) that have an arteriovenous fistula (AVF) for hemodialysis (HD). It is defined as pulmonary artery pressure (PAP) of greater than 30 mmHg on echocardiography. The presence of PH in ESRD is an independent risk factor and decreases the survival likelihood among HD patients. Unexplained PH is frequently seen in ESRD following AVF.

Obesity can lead to various complications, such as sleep apnea, cardiac complications, pulmonary hypertension, and mortality. Data on the prevalence of coexisting PH and obesity are scarce.

Obese patients often have increased albumin excretion rates (AER) that can lead to early renal impairment and an increase in intraglomerular pressure, which may increase the risk of cardiovascular (CV) morbidity and mortality.

Therefore, the study aimed to evaluate and compare the associated PH and obesity separately and collectively among ESRD patients.

Methods

This comparative cross-sectional study was conducted in a tertiary care public sector hospital with the approval of the medical ethics review board committee.

The study enrolled all consecutive patients with ESRD as defined by having an estimated glomerular filtration rate (GFR) of <15 mL/min/1.7 3 m² from April 2017 till March 2019, who presented to our facility. These patients underwent dialysis twice or thrice a week, each session lasting three to four hours approximately. On initial encounter, trans-thoracic echocardiography (TTE) was done by the cardiologist to diagnose pulmonary hypertension.

In addition, body mass index (BMI) was calculated for all patients, and the patients were categorized into underweight, normal, overweight, or obese. All patients underwent post-dialysis TTE at one hour or when patients were at the optimal dry weight. Systolic PAP and ejection fraction were measured, and pulmonary hypertension was defined as a PAP of 30 mmHg or greater on TTE.

ESRD patients that were diagnosed with PH prior to hemodialysis or had primary PH were excluded from the study. Only ESRD patients developing secondary PH after hemodialysis were included in the study.

The chi-square test was used to see the correlation of gender, ambulation status, smoking status, obesity, pulmonary hypertension, body mass index (BMI), and pulmonary hypertension and obesity combined on the final outcome. A p-value of 0.05 was considered significant. Odds ratio (OR) and relative risk (RR) were calculated for pulmonary hypertension and obesity combined, obesity, and pulmonary hypertension in the final outcome.

Results

The study enrolled 204 patients with a mean age of 46.23 (±20.45 SD) having higher female participation of 108 (52.9%), whereas 96 (47.1%) were males. The average weight of the cohort was 66.78 kg (±22.98 SD) with a mean BMI of 29.91 kg/m² (±13.29SD), 52 (25.5%) patients were underweight, 40 (19.6%) had a normal BMI, 29 (14.2%) were overweight, and 83 (40.7%) patients were obese.

Pulmonary hypertension and obesity combined were observed in 48 (23.5%) of the cases and there was a 4.60 relative risk of death among these individuals, with an odds ratio of 13.35 and a p-value of 0.00.

Conclusion

The study shows a strong synergistic effect of pulmonary hypertension and obesity towards the final survival outcome in ESRD patients who are on hemodialysis.

The Association of Pretransplant Pulmonary Hypertension With Patient and Graft Survival After Kidney Transplantation: A Retrospective Cohort Study

BACKGROUND

Pulmonary hypertension (PH) has been well characterized in end-stage kidney disease and carries a grave prognosis. Its relationship to kidney transplantation outcomes is uncertain. The purpose of the present study was to characterize PH in kidney transplant candidates and to evaluate the relationship of PH to post-transplantation outcomes.

METHODS

A retrospective review of medical records and echocardiographic findings in all patients listed and transplanted at a large urban academic medical center from 2010 to 2015 was undertaken. PH (defined as echocardiographic evidence of pulmonary artery systolic pressure ≥ 35 mm Hg) was assessed along with demographics, and comorbidities for its relationship to patient, and graft survival by univariable and multivariable analysis.

RESULTS

Of 733 patients, 15.6% (115) had PH. PH in this population was primarily due to left ventricular (LV) diastolic dysfunction. Patient survival (78.3% vs 89.6%, P = .02) and the composite of patient and graft survival (70.7% vs 85.0%, P = .04) was reduced at 5 years in patients with PH as compared to patients with No PH, respectively. However, multivariable analysis suggested that age at presentation, race, and left ventricular systolic function but not PH were significantly associated with patient mortality or graft loss.

CONCLUSION

Reduced patient and graft survival seen in patients with pulmonary hypertension appears to be related to risk factors other than the pulmonary hypertension itself; therefore, pretransplant PH should not be considered as a barrier to kidney transplantation.

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.

Pulmonary Hypertension in Patients Starting Peritoneal Dialysis

BACKGROUND

Cardiovascular complications are the major cause of morbidity and mortality in patients with chronic kidney disease (CKD). One such complication is pulmonary hypertension (PH). Its prevalence in patients in peritoneal dialysis (PD) varies from 12.6-41.7% and its related factors are not well known. The main objective of this multicenter study was to determine the prevalence of PH and its risk factors in patients starting in PD.

METHODS

Patients incident in PD were studied. Clinical, biochemical, and PD parameters were evaluated. A transthoracic echocardiography was performed and the evaluated according to the American Society of Echocardiography. Systolic pulmonary artery pressure (sPAP) was calculated with tricuspid regurgitation gradient and PH considered if pulmonary artery pressure was ≥35 mmHg.

RESULTS

There were 105 men and 72 women included in the study (aged 53.7 ± 12.8 vs. 52.9 ± 15.5 years). PH was found in 69 patients (38.98%), they had sPAP of 49.05 ± 13.80 vs. 18.81 ± 11.15 mmg, in patients without PH (p <0.001). Patients with PH tend to be more frequently men than women (42 vs. 35%, p = 0.33), and were younger (51.0 ± 14.9 vs. 55,1 ± 12.8 years; p = 0.05). Risk factor for PH were diastolic dysfunction of the left ventricle (LV) (OR = 1.46, 95% CI 1.094-1.973), left ventricular hypertrophy (LVF) (OR = 2.56, 95% CI 1.29-5.09); and residual renal function (RRF) was a protector factor (OR = 0.78, 95% CI 0.068-0.915).

CONCLUSIONS

Prevalence of PH in patient's incident in PD was 38%. The factors associated with PH were diastolic dysfunction of the LV and LV hypertrophy. RRF was a protector factor.

Pulmonary Hypertension Subtypes and Mortality in CKD

RATIONALE & OBJECTIVE

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

STUDY DESIGN

Observational retrospective cohort study.

SETTING & PARTICIPANTS

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

EXPOSURES

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

OUTCOMES

All-cause mortality.

ANALYTICAL APPROACH

Multivariable Cox proportional hazards analysis.

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

Preoperative Noncoronary Cardiovascular Assessment and Management of Kidney Transplant Candidates

The pretransplant risk assessment for patients with ESKD who are undergoing evaluation for kidney transplant is complex and multifaceted. When considering cardiovascular disease in particular, many factors should be considered. Given the increasing incidence of kidney transplantation and the growing body of evidence addressing ESKD-specific cardiovascular risk profiles, there is an important need for a consolidated, evidence-based model that considers the unique cardiovascular challenges that these patients face. Cardiovascular physiology is altered in these patients by abrupt shifts in volume status, altered calcium-phosphate metabolism, high-output states (in the setting of arteriovenous fistulization), and adverse geometric and electrical remodeling, to name a few. Here, we present a contemporary review by addressing cardiomyopathy/heart failure, pulmonary hypertension, valvular dysfunction, and arrhythmia/sudden cardiac death within the ESKD population.

Relationship between volume status and possibility of pulmonary hypertension in dialysis naive CKD5 patients

Background

Chronic fluid overload is common in patients with chronic kidney disease (CKD) and can with time lead to poor prognosis regarding to the cardiovascular events. Serum NT-proBNP and OH/ECW might reflect fluid status of the patients, and the maximal tricuspid regurgitation velocity (TRVmax) could reflect systolic pulmonary artery pressure (SPAP). We investigated the relationship between markers of volume status and marker of pulmonary hypertension (PH) in non-dialysis CKD5 (CKD5-ND) patients.

Methods

Bioimpedance spectroscopy (BIS), echocardiography, and measurement of serum NT-proBNP were performed in 137 consecutive patients on the same day. TRVmax greater than or equal to 2.9 m/s, corresponding to SPAP of approximately 36 mmHg, was used as a definition of the possibility of PH in the absence of left heart disease and chronic respiratory disease (PH group).

Results

Patients with possibility of PH (TRVmax ≥ 2.9 m/s) was found in 27 (19.70%) patients. Among the values obtained from BIS, those reflecting the fluid balance (OH, OH/ECW, and E/I ratio) were significantly higher in the PH group. The OH/ECW in patients with PH were significantly higher than those patients without (26.76 ± 15.07 vs. 13.09 ± 15.05, P < 0.001). NT-proBNP was also significantly higher in PH group compared to the non-PH group (median = 10,112 pg/ml, IQR = 30,847 pg/ml vs. median = 1,973 pg/ml, IQR = 7,093 pg/ml, P < 0.001). OH/ECW was positively associated with TRVmax (r = 0.235, P = 0.006). Multivariate logistic regression revealed that increased OH/ECW and serum NT-proBNP were significantly associated with an increased risk of PH.

Conclusions

A significant number of patients showed increased TRVmax, which was closely related to volume status in CKD5-ND patients. Echocardiography and BIS could be important players in a high possibility of PH detection and treatment in asymptomatic CKD patients. Therefore, these measures could be helpful to improve the cardiac outcomes after initiating renal replacement therapy. Further research may be needed to validate the consistency of this association across other stages of CKD.

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.

Air contamination during medical treatment results in deposits of microemboli in the lungs: An autopsy study

INTRODUCTION

Microbubbles of air may enter into patients during conventional hemodialysis, infusions of fluids, or by injections. The aim of this study was to investigate whether the air that enters the patient during hemodialysis can be detected in the lungs after death, and if so, whether this may be related to tissue damage.

METHODS

The material consisted of lung tissue from five chronic hemodialysis patients who died either during (two) or after hemodialysis (range 10 min from start until 3333 min after the last hemodialysis session); as reference group tissue was taken from seven patients who died due to amyotrophic lateral sclerosis. The lung tissue was investigated by microscopy after autopsy using a fluorescein-marked polyclonal antibody against fibrinogen as a marker for clots preformed before death.

RESULTS

All five hemodialysis patients had microbubbles of air in the lung tissue, whereas two of seven amyotrophic lateral sclerosis patients had such findings (Fisher's test p = 0.0278, relative risk = 3.5, confidence interval: 1.08-11.3). There were more microbubbles of air/10 randomly investigated microscopic fields of tissue in the hemodialysis patients than the amyotrophic lateral sclerosis patients (Student's test, p < 0.05). All hemodialysis patients had a medium graded extent of pulmonary fibrosis that was not found in any of the ALS patients. The microbubbles of air were surrounded by fibrin as a sign of development of clots around the air bubbles while the patients were still alive.

CONCLUSION

Exposure to microbubbles of air during various treatments such as hemodialysis may result in microemboli. Future studies should clarify whether microbubbles of air contribute to tissue scarring. We suggest preventive measures against the exposure to microbubbles of air during especially repeated exposures such as hemodialysis.

Changes in pulmonary artery systolic pressure and right ventricular function in patients with end-stage renal disease on maintenance dialysis

AIM

Pulmonary hypertension is common in patients with end-stage renal disease, and portends a poor prognosis. There are little data in this population, and previous studies have not evaluated quantitative changes in haemodynamics over time while on maintenance dialysis. This study sought to estimate changes in pulmonary artery systolic pressure (PASP) and right ventricular function over time, and to predict PASP change using clinical variables routinely available at time of initial measurement, in patients on maintenance dialysis.

METHODS

We retrospectively studied patients with end-stage renal disease at a university-affiliated dialysis centre who had two separate echocardiograms 1-4 years apart.

RESULTS

Seventy-six patients (65 haemodialysis, 11 peritoneal dialysis) were included. PASP was estimated by echocardiography. Baseline PASP was predicted by left-sided valvular disease, anaemia, COPD, left-ventricular mass index, and haemodialysis modality (P = 0.07 for modality). Average increase in PASP was 2.41 mmHg per year. Higher rates of PASP change were predicted by E/e' ratio by tissue doppler on echocardiogram, diabetes mellitus, low LV mass, and left-sided valvular heart disease (P = 0.07 for valvular disease). Patients with higher PASP had higher incidence of new-onset right ventricular dysfunction.

CONCLUSION

In patients with end-stage renal disease, PASP increases over time. Changes are moderately predictable. Higher PASP predicted development of right ventricular dysfunction.

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.