The potential effect of cardiac function on pulmonary hypertension, other risk factors, and its impact on survival in dialysis patients. Int Urol Nephrol. 2021;53:343-351. [PMID: 33389501 DOI: 10.1007/s11255-020-02655-z]

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.

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.

Emerging role of exosomes in vascular diseases

Exosomes are biological small spherical lipid bilayer vesicles secreted by most cells in the body. Their contents include nucleic acids, proteins, and lipids. Exosomes can transfer material molecules between cells and consequently have a variety of biological functions, participating in disease development while exhibiting potential value as biomarkers and therapeutics. Growing evidence suggests that exosomes are vital mediators of vascular remodeling. Endothelial cells (ECs), vascular smooth muscle cells (VSMCs), inflammatory cells, and adventitial fibroblasts (AFs) can communicate through exosomes; such communication is associated with inflammatory responses, cell migration and proliferation, and cell metabolism, leading to changes in vascular function and structure. Essential hypertension (EH), atherosclerosis (AS), and pulmonary arterial hypertension (PAH) are the most common vascular diseases and are associated with significant vascular remodeling. This paper reviews the latest research progress on the involvement of exosomes in vascular remodeling through intercellular information exchange and provides new ideas for understanding related diseases.

Association between subclinical left ventricular ejection fraction and platelet-to-lymphocyte ratio in patients with peritoneal dialysis

Background

Reduced left ventricular ejection function (LVEF) was associated with increased mortality in patients with peritoneal dialysis (PD) in Asia and the United States of America. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were correlated with LVEF in PD. However, little information is available regarding the relationship between monocyte-to-lymphocyte ratio (MLR), left ventricular ejection fraction (LVEF), and the use of NLR, PLR, and MLR in predicting left ventricular systolic dysfunction (LVSD) in patients with PD.

Methods

All 181 patients with PD were enrolled between 2014 and 2021 from the Nephrology Department of the First Affiliated Hospital of the University of South China. Demographic features, clinical characteristics, laboratory values, and echocardiographic parameters were collected.

Results

The mean age of patients with PD was 47.4 ± 12.6, and 90 (49.7%) of the patients were men. LVEF showed a negative correlation with PLR (r = −0.200, p = 0.007) and MLR (r = −0.146, p = 0.049). The levels of NLR, PLR, and MLR were elevated in patients with PD with LVSD compared with those without (all p &lt; 0.05). PLR (OR 4.331, 95% CI: 1.223, 15.342) and albumin (OR 13.346, 95% CI: 3.928, 45.346) were significantly associated with LVSD patients with PD in the multivariate logistic analysis. For differentiating patients with PD with LVSD, optimal cutoffs of NLR, PLR, MLR, and albumin were 4.5 (sensitivity: 76.7%, specificity: 55.0%, and overall accuracy: 58%), 202.6 (sensitivity: 66.7%, specificity: 69.5%, and overall accuracy: 69%), 0.483 (sensitivity: 53.3%, specificity: 72.8%, and overall accuracy: 30%), and 34.6 (sensitivity: 72.2%), respectively.

Conclusions

Our results revealed that PLR was better than NLR, MLR, and albumin in predicting LVSD in PD.

Prognostic effect of pulmonary hypertension in patients with chronic kidney disease: Univariate and multivariate analyses of factors associated with survival

Background

Prognostic effect of pulmonary hypertension (PH) in patients with chronic kidney disease (CKD) is not fully clear yet, this study was designed to elucidate baseline characteristics of CKD patients with different severities of PH, the association between kidney indicators and PH severity, and survival factors in CKD patients with PH.

Methods

We extracted clinical data from electronic medical records of all patients diagnosed with PH in CKD from Jan 2016 to Dec 2020, and those with comorbid conditions causing PH were excluded. CKD stages were defined by estimated glomerular filtration rate thresholds. PH was defined as a systolic pulmonary artery pressure (sPAP) >35 mmHg estimated using echocardiograms. Demographics, clinical data, and test results were analyzed, and all-cause mortality data were obtained.

Results

A total of 137 patients were included in the study. The mean age of the participants was 60 (42.5, 67) years, the mean sPAP was 58 (51, 69.5) mmHg, and 40.9% of the patients were women. Moderate PH group had more patients undergoing dialysis and higher frequency of coronary heart disease. Moderate-severe PH group had higher parathyroid hormone levels and lower low-density lipoprotein levels. Severe PH group had better kidney function parameters and lower serum phosphorus levels. PH severity had no direct relationship with CKD stages. In the univariate analysis, age and PH severity influenced survival. Multivariate analysis also showed independent prognostic effects for age and sPAP. Kaplan-Meyer curve intuitively displayed the survival differences among CKD patients with different PH severity. Predictor values of nomogram identified from survival analyses enabled calculation of death probabilities for CKD with PH patients. Nomogram was validated by ROC analysis.

Conclusions

PH begins with early-stage CKD, and PH severity is not related to CKD progression. A higher pulmonary artery pressure and an older age are associated with an increased risk of death.

Complement-containing small extracellular vesicles from adventitial fibroblasts induce proinflammatory and metabolic reprogramming in macrophages

Pulmonary hypertension (PH) is a severe cardiopulmonary disease characterized by complement-dependent, fibroblast-induced perivascular accumulation and proinflammatory activation of macrophages. We hypothesized that, in PH, nanoscale-sized small extracellular vesicles (sEVs), released by perivascular/adventitial fibroblasts, are critical mediators of complement-dependent proinflammatory activation of macrophages. Pulmonary adventitial fibroblasts were isolated from calves with severe PH (PH-Fibs) and age-matched controls (CO-Fibs). PH-Fibs exhibited increased secretion of sEVs, compared with CO-Fibs, and sEV biological activity was tested on mouse and bovine bone marrow-derived macrophages (BMDMs) and showed similar responses. Compared with sEVs derived from CO-Fibs, sEVs derived from PH-Fibs (PH-Fib-sEVs) induced augmented expression of proinflammatory cytokines/chemokines and metabolic genes in BMDMs. Pharmacological blockade of exosome release from PH-Fibs resulted in significant attenuation of proinflammatory activation of BMDMs. "Bottom-up" proteomic analyses revealed significant enrichment of complement and coagulation cascades in PH-Fib-sEVs, including augmented expression of the complement component C3. We therefore examined whether the PH-Fib-sEV-mediated proinflammatory activation of BMDMs was complement C3 dependent. Treatment of PH-Fibs with siC3-RNA significantly attenuated the capacity of PH-Fib-sEVs for proinflammatory activation of BMDMs. PH-Fib-sEVs mediated proglycolytic alterations and complement-dependent activation of macrophages toward a proinflammatory phenotype, as confirmed by metabolomic studies. Thus, fibroblast-released sEVs served as critical mediators of complement-induced perivascular/microenvironmental inflammation in PH.

Prediction of mortality among patients with chronic kidney disease: A systematic review

BACKGROUND

Chronic kidney disease (CKD) is a common medical condition that is increasing in prevalence. Existing published evidence has revealed through regression analyses that several clinical characteristics are associated with mortality in CKD patients. However, the predictive accuracies of these risk factors for mortality have not been clearly demonstrated.

AIM

To demonstrate the accuracy of mortality predictive factors in CKD patients by utilizing the area under the receiver operating characteristic (ROC) curve (AUC) analysis.

METHODS

We searched Ovid MEDLINE, EMBASE, and the Cochrane Library for eligible articles through January 2021. Studies were included based on the following criteria: (1) Study nature was observational or conference abstract; (2) Study populations involved patients with non-transplant CKD at any CKD stage severity; and (3) Predictive factors for mortality were presented with AUC analysis and its associated 95% confidence interval (CI). AUC of 0.70-0.79 is considered acceptable, 0.80-0.89 is considered excellent, and more than 0.90 is considered outstanding.

RESULTS

Of 1759 citations, a total of 18 studies (n = 14579) were included in this systematic review. Eight hundred thirty two patients had non-dialysis CKD, and 13747 patients had dialysis-dependent CKD (2160 patients on hemodialysis, 370 patients on peritoneal dialysis, and 11217 patients on non-differentiated dialysis modality). Of 24 mortality predictive factors, none were deemed outstanding for mortality prediction. A total of seven predictive factors [N-terminal pro-brain natriuretic peptide (NT-proBNP), BNP, soluble urokinase plasminogen activator receptor (suPAR), augmentation index, left atrial reservoir strain, C-reactive protein, and systolic pulmonary artery pressure] were identified as excellent. Seventeen predictive factors were in the acceptable range, which we classified into the following subgroups: predictors for the non-dialysis population, echocardiographic factors, comorbidities, and miscellaneous.

CONCLUSION

Several factors were found to predict mortality in CKD patients. Echocardiography is an important tool for mortality prognostication in CKD patients by evaluating left atrial reservoir strain, systolic pulmonary artery pressure, diastolic function, and left ventricular mass index.