Endothelial progenitor cells are suppressed in anemic patients with acute coronary syndrome

Impact of anemia on outcomes and resource utilization in patients with myocardial infarction: A national database analysis

BACKGROUND

Although anemia is common in patients with myocardial infarction (MI), management remains controversial. We quantified the association of anemia with in-hospital outcomes and resource utilization in patients admitted with MI using a large national database.

METHODS

All hospitalizations with a primary diagnosis code for acute MI in the National Inpatient Sample (NIS) between 2014 and 2018 were identified. Among these hospitalizations, patients with anemia were identified using a secondary diagnosis code. Data on demographic and clinical variables were collected. Outcomes of interest included in-hospital adverse events, length of stay (LOS), and total cost. Multivariable logistic regression and generalized linear models were used to evaluate the relationship between anemia and outcomes.

RESULTS

Among 1,113,181 MI hospitalizations, 254,816 (22.8%) included concomitant anemia. Anemic patients were older and more likely to be women. After adjustment for demographics and comorbidities, anemia was associated with higher mortality (7.1 vs. 4.3%; odds ratio 1.09; 95% confidence interval [CI] 1.07-1.12, p < 0.001). Anemia was also associated with a mean of 2.71 days longer LOS (average marginal effects [AME] 2.71; 95% CI 2.68-2.73, p < 0.05), and $ 9703 mean higher total costs (AME $9703, 95% CI $9577-$9829, p < 0.05). Anemic patients who received blood transfusions had higher mortality as compared with those who did not (8.2% vs. 7.0, p < 0.001).

CONCLUSION

In MI patients, anemia was associated with higher in-hospital mortality, adverse events, total cost, and length of stay. Transfusion was associated with increased mortality, and its role in MI requires further research.

Impact of anemia requiring transfusion or erythropoiesis-stimulating agents on new-onset cardiovascular events and mortality after continuous renal replacement therapy

Anemia is common in critically ill patients undergoing continuous renal replacement therapy (CRRT). We investigated the impact of anemia requiring red blood cell (RBC) transfusion or erythropoiesis-stimulating agents (ESAs) on patient outcomes after hospital discharge in critically ill patients with acute kidney injury (AKI) requiring CRRT. In this retrospective cohort study using the Health Insurance Review and Assessment database of South Korea, 10,923 adult patients who received CRRT for 3 days or more between 2010 and 2019 and discharged alive were included. Anemia was defined as the need for RBC transfusion or ESAs. Outcomes included cardiovascular events (CVEs) and all-cause mortality after discharge. The anemia group showed a tendency to be older with more females and had more comorbidities compared to the control group. Anemia was not associated with an increased risk of CVEs (adjusted hazard ratio [aHR]: 1.05; 95% confidence interval [CI]: 0.85-1.29), but was associated with an increased risk of all-cause mortality (aHR: 1.41; 95% CI 1.30-1.53). For critically ill patients with AKI requiring CRRT, anemia, defined as requirement for RBC transfusion or ESAs, may increase the long-term risk of all-cause mortality.

Impact of anaemia and iron deficiency on outcomes in cardiogenic shock complicating acute myocardial infarction

AIMS

Anaemia and iron deficiency (ID) are common comorbidities in cardiovascular patients and are associated with a poor clinical status, as well as a worse outcome in patients with heart failure and acute myocardial infarction (AMI). Nevertheless, data concerning the impact of anaemia and ID on clinical outcomes in patients with cardiogenic shock (CS) are scarce. This study aimed to assess the impact of anaemia and ID on clinical outcomes in patients with CS complicating AMI.

METHODS AND RESULTS

The presence of anaemia (haemoglobin <13 g/dl in men and <12 g/dl in women) or ID (ferritin <100 ng/ml or transferrin saturation <20%) was determined in patients with CS due to AMI from the CULPRIT-SHOCK trial. Blood samples were collected in the catheterization laboratory during initial percutaneous coronary intervention. Clinical outcomes were compared in four groups of patients having neither anaemia nor ID, against patients with anaemia with or without ID and patients with ID only. A total of 427 CS patients were included in this analysis. Anaemia without ID was diagnosed in 93 (21.7%), anaemia with ID in 54 study participants (12.6%), ID without anaemia in 72 patients (16.8%), whereas in 208 patients neither anaemia nor ID was present (48.9%). CS patients with anaemia without ID were older (73 ± 10 years, p = 0.001), had more frequently a history of arterial hypertension (72.8%, p = 0.01), diabetes mellitus (47.8%, p = 0.001), as well as chronic kidney disease (14.1%, p = 0.004) compared to CS patients in other groups. Anaemic CS patients without ID presence were at higher risk to develop a composite from all-cause death or renal replacement therapy at 30-day follow-up (odds ratio [OR] 3.83, 95% confidence interval [CI] 2.23-6.62, p < 0.001) than CS patients without anaemia/ID. The presence of ID in CS patients, with and without concomitant anaemia, did not increase the risk for the primary outcome (OR 1.17, 95% CI 0.64-2.13, p = 0.64; and OR 1.01, 95% CI 0.59-1.73, p = 0.54; respectively) within 30 days of follow-up. In time-to-event Kaplan-Meier analysis, anaemic CS patients without ID had a significantly higher hazard ratio (HR) for the primary outcome (HR 2.11, 95% CI 1.52-2.89, p < 0.001), as well as for death from any cause (HR 1.90, 95% CI 1.36-2.65, p < 0.001) and renal replacement therapy during 30-day follow-up (HR 2.99, 95% CI 1.69-5.31, p < 0.001).

CONCLUSION

Concomitant anaemia without ID presence in patients with CS at hospital presentation is associated with higher risk for death from any cause or renal replacement therapy and the individual components of this composite endpoint within 30 days after hospitalization. ID has no relevant impact on clinical outcomes in patients with CS.

The predictive value of machine learning for mortality risk in patients with acute coronary syndromes: a systematic review and meta-analysis

BACKGROUND

Acute coronary syndromes (ACS) are the leading cause of global death. Optimizing mortality risk prediction and early identification of high-risk patients is essential for developing targeted prevention strategies. Many researchers have built machine learning (ML) models to predict the mortality risk in ACS patients. Our meta-analysis aimed to evaluate the predictive value of various ML models in predicting death in ACS patients at different times.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library were searched systematically from database establishment to March 12, 2022 for studies developing or validating at least one ML predictive model for death in ACS patients. We used PROBAST to assess the risk of bias in the reported predictive models and a random-effects model to assess the pooled C-index and accuracy of these models.

RESULTS

Fifty papers were included, involving 216 ML prediction models, 119 of which were externally validated. The combined C-index of the ML models in the validation cohort predicting the in-hospital mortality, 30-day mortality, 3- or 6-month mortality, and 1 year or above mortality in ACS patients were 0.8633 (95% CI 0.8467-0.8802), 0.8296 (95% CI 0.8134-0.8462), 0.8205 (95% CI 0.7881-0.8541), and 0.8197 (95% CI 0.8042-0.8354), respectively, with the corresponding combined accuracy of 0.8569 (95% CI 0.8411-0.8715), 0.8282 (95% CI 0.7922-0.8591), 0.7303 (95% CI 0.7184-0.7418), and 0.7837 (95% CI 0.7455-0.8175), indicating that the ML models were relatively excellent in predicting ACS mortality at different times. Furthermore, common predictors of death in ML models included age, sex, systolic blood pressure, serum creatinine, Killip class, heart rate, diastolic blood pressure, blood glucose, and hemoglobin.

CONCLUSIONS

The ML models had excellent predictive power for mortality in ACS, and the methodologies may need to be addressed before they can be used in clinical practice.

Association between serum hemoglobin and major cardiovascular adverse event in Chinese patients with ST-segment elevation myocardial infarction after percutaneous coronary intervention

Background

ST‐segment elevation myocardial infarction (STEMI) is a common clinical acute and severe disease, and it is of great significance to evaluate the prognosis of these patients. Hemoglobin levels are associated with a variety of diseases, but studies on Chinese patients with STEMI after percutaneous coronary intervention (PCI) have not been sufficient.

Methods

This was a secondary analysis based on a prospective cohort study of patients undergoing PCI in Taizhou, Zhejiang, China. We performed multivariable logistic regression to explore the association between the serum hemoglobin and the incidence of major cardiovascular adverse event (MACE) in patients after PCI. We also used a generalized additive model and smooth curve fitting to explain the nonlinear relationship after adjusting the potential confounders. Finally, the heterogeneity among specific groups was examined by subgroup analysis.

Results

Of all 462 patients enrolled in this study, 118 (25.54%) developed MACE. There was a negative correlation between serum hemoglobin and MACE in all three models (hazard ratio [HR] 0.82, 95% confidence interval [CI 0.72, 0.93], HR 0.86, 95% CI [0.76,0.98], and HR 0.87, 95% CI [0.74,0.98], respectively). In the subgroup analysis, the negative correlation existed between the patients who had myocardial infarction (MI) history (p for interaction = 0.0059) after adjusting covariates. However, no significant differences were found between age and sex groups (p for interaction = 0.1381, 0.4103, respectively).

Conclusion

Our results indicated that patients who received PCI with low preoperative hemoglobin were more likely to develop MACE, especially if they have already had a history of MI.

Acute Anemia and Myocardial Infarction

Various studies have established the prognosis of anemia in myocardial infarction (MI). Both chronic and acute anemia lead to poor outcomes in MI. Regardless, the association of anemia with MI and its management varies. In this study, the literature was analyzed to determine the association between acute anemia and MI based on the pathophysiology, outcomes, and management options. Acute anemia results in decreased blood supply and sudden hypoxia to the heart. Additionally, it exacerbates the preexisting compromised coronary blood supply in patients with MI. Thus, there is a disproportionate oxygen supply and demand ratio to the heart. It was found that anemia increases all-cause mortality in acute MI. However, it is unclear whether anemia is the direct contributor to mortality in these patients. For the management of MI, percutaneous coronary intervention (PCI) is commonly used. Increased incidence of hospital-acquired anemia (HAA) is reported in patients after PCI. However, the cause of HAA in these patients is not well established. Antiplatelet therapy in these patients is also considered to be the culprit for HAA. Nonetheless, no clear evidence is available. There is no consensus or criteria for the treatment of acute anemia in MI patients. Researchers have explored management options such as blood transfusion, erythropoietin-stimulating agent, and iron therapy. Further studies are warranted for a better understanding and management of MI in patients with anemia and vice versa.

The impact of patient sex on the response to intramyocardial mesenchymal stem cell administration in patients with non-ischaemic dilated cardiomyopathy

AIMS

Sex differences impact the occurrence, presentation, prognosis, and response to therapy in heart disease. Particularly, the phenotypic presentation of patients with non-ischaemic dilated cardiomyopathy (NIDCM) differs between men and women. However, whether the response to mesenchymal stem cell (MSC) therapy is influenced by sex remains unknown. We hypothesize that males and females with NIDCM respond similarly to MSC therapy.

METHODS AND RESULTS

Male (n = 24) and female (n = 10) patients from the POSEIDON-DCM trial who received MSCs via transendocardial injections were evaluated over 12 months. Endothelial function was measured at baseline and 3 months post-transendocardial stem cell injection (TESI). At baseline, ejection fraction (EF) was lower (P = 0.004) and end-diastolic volume (EDV; P = 0.0002) and end-systolic volume (ESV; P = 0.0002) were higher in males vs. females. In contrast, baseline demographic characteristics, Minnesota Living with Heart Failure Questionnaire (MLHFQ), and 6-min walk test (6MWT) were similar between groups. EF improved in males by 6.2 units (P = 0.04) and in females by 8.6 units (P = 0.04; males vs. females, P = 0.57). EDV and ESV were unchanged over time. The MLHFQ score, New York Heart Association (NYHA) class, endothelial progenitor cell-colony forming units, and serum tumour necrosis factor alpha improved similarly in both groups.

CONCLUSION

Despite major differences in phenotypic presentation of NIDCM in males and females, this study is the first of its kind to demonstrate that MSC therapy improves a variety of parameters in NIDCM irrespective of patient sex. These findings have important clinical and pathophysiologic implications regarding the impact of sex on responses to cell-based therapy for NIDCM.

Prognostic value of novel neutrophil-to-hemoglobin and lymphocyte score in patients with acute myocardial infarction

We developed and assessed whether a novel neutrophil-to-hemoglobin and lymphocyte (NHL) score would improve the ability to predict clinical outcome compared with neutrophil-to-lymphocyte ratio (NLR) and systemic immune-inflammation index (SII) in acute myocardial infarction (AMI). We examined 13,072 AMI patients from the Korean AMI Registry–National Institute of Health database. NHL score was calculated as follows: NHL score (U) = N/(Hb × L), where N, Hb, and L are baseline blood neutrophil, hemoglobin, and lymphocyte count. The primary outcome was the occurrence of major adverse cerebrocardiovascular events (MACCEs) at 2 years. The NLR, SII, and NHL score were independent predictors of 2-year MACCEs. The area under the curve of the NHL score (0.637) for predicting 2-year MACCEs was significantly higher compared with those of SII (0.589) and NLR (0.607). The NHL score significantly improved the reclassification and integrated discrimination compared with NLR ( p < 0.0001) and SII ( p < 0.0001). A high NHL score (≥ 0.35 U) was an independent predictor of 2-year MACCEs (adjusted hazard ratio, 1.41; 95% confidence interval, 1.29–1.55; p < 0.001). The NHL score could be a novel model for predicting long-term MACCEs in patients with AMI.

Pleiotropic effect of erythropoiesis-stimulating agents on circulating endothelial progenitor cells in dialysis patients

BACKGROUND

Recent studies have suggested that erythropoiesis-stimulating agents (ESAs) may accelerate not only angiogenesis but also vasculogenesis, beyond erythropoiesis.

METHODS

We conducted a 12-week prospective study in 51 dialysis patients; 13 were treated with recombinant human erythropoietin (EPO, 5290.4 ± 586.9 IU/week), 16 with darbepoetin (DA, 42.9 ± 4.3 µg/week), 12 with epoetin β pegol (CERA, 40.5 ± 4.1 µg/week) and 10 with no ESAs. Vascular mediators comprising endothelial progenitor cells (EPCs), vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2), and high-sensitivity C-reactive protein (hs-CRP) were measured at 0 and 12 weeks. EPCs were measured by flow cytometry as CD45^lowCD34⁺CD133⁺ cells.

RESULTS

The EPC count increased significantly to a greater extent in the EPO group than in the other three group, and increased significantly from 0 to 12 weeks in a EPO dose-dependent manner. In both the DA and CERA groups, the EPC count did not change at 12 weeks. Serum levels of VEGF, MMP-2 and hs-CRP were not affected by ESA treatment in all groups. In the CERA group, serum ferritin decreased significantly compared to the no-ESA group and correlated with CERA dose, although use of iron was permitted if required during the prospective study period of 12 weeks.

CONCLUSIONS

When patients on dialysis were treated with clinical doses of various ESAs, only EPO induced a significant increase of circulating EPCs from bone marrow, whereas, DA and CERA had no effect.

Incremental Prognostic Value of Anemia in Acute Coronary Syndrome from A Rural Hospital in India

Background:

Anemia is highly prevalent in low- and middle-income countries, where prevalence of acute coronary syndrome (ACS) is also rising. Evidence indicates that baseline anemia status can prognosticate ACS. However, the Global Registry of Acute Coronary Events (GRACE) score that is popularly used all over the world does not include information on anemia.

Objectives:

Our objective was to investigate if anemia at admission, along with the GRACE score, improves the prediction of adverse outcomes within 6 months in rural Indian patients of ACS.

Methods:

We enrolled 200 ACS patients at the Acharya Vinoba Bhave Rural Hospital—a rural, tertiary care hospital in central India. Patients were followed for 6 months for death and major adverse cardiac event (MACE). Improvement in the prediction of adverse events by including anemia in addition to the GRACE score was quantified using area under the receiver operating characteristic curve (AUC), integrated discrimination improvement (IDI) and the net reclassification index (NRI).

Results:

There were 31 deaths due to MACE and an additional 28 non-fatal MACE events during follow-up. Baseline hemoglobin was strongly and independently associated with both outcomes even after adjusting for a multivariable propensity score. For the outcome of death and death/MACE there was a moderate improvement in the AUC of 1% and 6%, respectively. However, for these outcomes the IDI for baseline hemoglobin was 6% (p = 0.03) and 12% (p << 0.0001), respectively, while the NRI was 0.50 (p = 0.01) and 0.78 (p << 0.0001), respectively.

Conclusions:

Inclusion of baseline anemia in addition to the GRACE score improves prognostication of ACS patients.

Anemia and acute coronary syndrome: current perspectives

Reference hemoglobin (Hb) values for the definition of anemia are still largely based on the 1968 WHO Scientific Group report, which established a cutoff value of <13 g/dL for adult men and <12 g/dL for adult nonpregnant women. Subsequent studies identified different normal values according to race and age. Estimated prevalence of anemia on admission in the setting of an acute coronary syndrome (ACS) is between 10% and 43% of the patients depending upon the specific population under investigation. Furthermore, up to 57% of ACS patients may develop hospital-acquired anemia (HAA). Both anemia on admission and HAA are associated with worse short- and long-term mortality, even if different mechanisms contribute to their prognostic impact. Baseline anemia can usually be traced back to preexisting disease that should be specifically investigated and corrected whenever possible. HAA is associated with clinical characteristics, medical therapy and interventional procedures, all eliciting cardiovascular adaptive response that can potentially worsen myocardial ischemia. The intrinsic fragility of anemic patients may limit aggressive medical and interventional therapy due to an increased risk of bleeding, and could independently contribute to worse outcome. However, primary angioplasty for ST elevation ACS should not be delayed because of preexisting (and often not diagnosed) anemia; delaying revascularization to allow fast-track anemia diagnosis is usually feasible and justified in non-ST-elevation ACS. Besides identification and treatment of the underlying causes of anemia, the only readily available means to reverse anemia is red blood cell transfusion. The adequate transfusion threshold is still being debated, although solid evidence suggests reserving red blood cell transfusions for patients with Hb level <8 g/dL and considering it in selected cases with Hb levels of between 8 and 10 g/dL. No evidence supports the use of iron supplements and erythropoiesis-stimulating agents in the setting of ACS.

Comparison of Transradial and Transfemoral Approaches for Percutaneous Coronary Intervention in Patients With Acute Coronary Syndrome and Anemia

Anemia is an independent predictor of bleeding complications and poor clinical outcomes after percutaneous coronary intervention. Percutaneous coronary transradial intervention (TRI) is better than percutaneous coronary transfemoral intervention (TFI) in terms of reducing bleeding complications that can affect the prognosis. This study aims to investigate the clinical outcomes between TRI and TFI for patients with anemia. We analyzed periprocedure complications, in-hospital mortality, and major adverse cardiac events for one year in the Korean TRI registry from January 2013 to April 2014. Patients with chronic kidney disease for whom TFI is preferred were excluded. Anemia was defined as hemoglobin <13 g/dl for men and <12 g/dl for women. A total of 1,279 patients were finally enrolled. Of these, 348 patients had anemia. Among them, 253 patients (72.7%) underwent TRI and 95 patients (27.3%) underwent TFI. There were no significant differences of baseline demographic characteristics between the TRI and TFI groups, except for the incidence of dyslipidemia (TRI 23.7% vs TFI 12.6%, p = 0.023). Multivariate logistic regression analysis revealed lower incidence of composite severe bleeding complications (hazard ratio 0.34, 95% CI 0.12 to 0.99, p = 0.049) and lower incidence of in-hospital mortality than TFI group (hazard ratio 0.74, 95% CI 0.62 to 0.88, p = 0.042). In conclusion, this study suggests that the TRI for patients with anemia may be translated into better prognosis in terms of lower rates of bleeding complications and in-hospital mortality.

Allogeneic Mesenchymal Stem Cells Restore Endothelial Function in Heart Failure by Stimulating Endothelial Progenitor Cells

BACKGROUND

Endothelial dysfunction, characterized by diminished endothelial progenitor cell (EPC) function and flow-mediated vasodilation (FMD), is a clinically significant feature of heart failure (HF). Mesenchymal stem cells (MSCs), which have pro-angiogenic properties, have the potential to restore endothelial function. Accordingly, we tested the hypothesis that MSCs increase EPC function and restore flow-mediated vasodilation (FMD).

METHODS

Idiopathic dilated and ischemic cardiomyopathy patients were randomly assigned to receive autologous (n = 7) or allogeneic (n = 15) MSCs. We assessed EPC-colony forming units (EPC-CFUs), FMD, and circulating levels of vascular endothelial growth factor (VEGF) in patients before and three months after MSC transendocardial injection (n = 22) and in healthy controls (n = 10).

FINDINGS

EPC-colony forming units (CFUs) were markedly reduced in HF compared to healthy controls (4 ± 3 vs. 25 ± 16 CFUs, P < 0.0001). Similarly, FMD% was impaired in HF (5.6 ± 3.2% vs. 9.0 ± 3.3%, P = 0.01). Allogeneic, but not autologous, MSCs improved endothelial function three months after treatment (Δ10 ± 5 vs. Δ1 ± 3 CFUs, P = 0.0067; Δ3.7 ± 3% vs. Δ-0.46 ± 3% FMD, P = 0.005). Patients who received allogeneic MSCs had a reduction in serum VEGF levels three months after treatment, while patients who received autologous MSCs had an increase (P = 0.0012), and these changes correlated with the change in EPC-CFUs (P < 0.0001). Lastly, human umbilical vein endothelial cells (HUVECs) with impaired vasculogenesis due to pharmacologic nitric oxide synthase inhibition, were rescued by allogeneic MSC conditioned medium (P = 0.006).

INTERPRETATION

These findings reveal a novel mechanism whereby allogeneic, but not autologous, MSC administration results in the proliferation of functional EPCs and improvement in vascular reactivity, which in turn restores endothelial function towards normal in patients with HF. These findings have significant clinical and biological implications for the use of MSCs in HF and other disorders associated with endothelial dysfunction.

Is anemia a new cardiovascular risk factor?

Anemia is frequent in patients with cardiovascular disease and is often characterized as the fifth cardiovascular risk factor. It is considered to develop due to a complex interaction of iron deficiency, cytokine production and impaired renal function, although other factors, such as blood loss, may also contribute. Unfortunately, treatment of anemia in cardiovascular disease lacks clear targets and specific therapy is not defined. Treatment with erythropoietin-stimulating agents in combination with iron is the basic strategy but clear guidelines are not currently available. This review aims to clarify poorly investigated and defined issues concerning the relation of anemia and cardiovascular risk--in particular in patients with acute coronary syndromes and chronic heart failure--as well as the current therapeutic strategies in these clinical conditions.

Pathways mediating the interaction between endothelial progenitor cells (EPCs) and platelets

Introduction

Endothelial progenitor cells (EPCs) have an important role in the process of vascular injury repair. Platelets have been shown to mediate EPC recruitment, maturation and differentiation. Yet, the mechanism underlying this interaction is unclear. We, therefore, aimed to examine whether direct contact between platelets and EPCs is essential for the positive platelets-EPC effect, and to investigate the main mediators responsible for the improvement in EPCs function.

Methods

Human EPCs were isolated from donated buffy coats and cultured in either: 1. EPCs co-incubated with platelets placed in a 1 µm-Boyden chamber. 2. EPCs incubated with or without platelets in the presence or absence of bFGF/PDGF Receptor inhibitor (PDGFRI). After 7 days culture, EPCs ability to form colonies, proliferate and differentiate was examined. Culture supernatants were collected and growth factors levels were evaluated using ELISA. Growth factors mRNA levels in EPCs were evaluated using RT-PCR.

Results and Conclusions

After 7 days culture, EPCs functional properties were higher following co-incubation with platelets (directly or indirectly), implying that direct contact is not essential for the platelet’s positive effect on EPCs. This effect was reduced by PDGFRI inhibition. Additionally, higher levels of PDGFB in EPCs-platelets supernatant and higher levels of PDGFC mRNA in EPCs co-incubated with platelets were found. In contrast, FGF and other potential mediators that were examined and inhibited did not significantly affect the interaction between platelets and EPCs. Thus, we conclude that PDGF has a central role in the interaction between platelets and EPCs. Further study is required to examine additional aspects of EPC-platelets interaction.