Risk factors and prognostic impact of unwanted loneliness in heart failure.

Heart failure (HF) is associated with a high prevalence of unwanted loneliness. This study aimed to assess whether unwanted loneliness was associated with adverse clinical endpoints in HF patients. Additionally, we also aimed to examine the risk factors associated with unwanted loneliness in HF. We included 298 patients diagnosed with stable HF. Clinical, biochemical, echocardiographic parameters and loneliness using ESTE II scale were assessed. We analyzed the association between the exposure and adverse clinical endpoints by Cox (death or any hospitalization), and negative binomial regressions (recurrent hospitalizations or visits to the emergency room). Risk factors associated with loneliness were analyzed using logistic regression. The mean age was 75.8 ± 9.4 years, with 111 (37.2%) being women, 53 (17.8%) widowed, and 154 (51.7%) patients having preserved ejection fraction. The median (p25-p75%) ESTE II score was 9.0 (6.0-12.0), and 36.9% fulfilled the loneliness criteria (> 10). Both women (OR = 2.09; 95% CI 1.11-3.98, p = 0.023) and widowhood (OR = 3.25; 95% CI 1.51-7.01, p = 0.003) were associated with a higher risk of loneliness. During a median follow-up of follow-up of 362 days (323-384), 93 patients (31.3%) presented the combined episode of death or all-cause admissions. Loneliness was significantly related to the risk of time to the composite of death or any readmission during the composite (HR = 1.83; 95% CI 1.18-2.84, p = 0.007). Women and widowhood emerge as risk factors for unwanted loneliness in HF patients. Unwanted loneliness is associated with higher morbidity during follow-up.

High-sensitivity C-reactive protein and risk of clinical outcomes in patients with acute heart failure.

Inflammation is relevant in the pathogenesis and progression of heart failure (HF). Previous studies have shown that elevated high-sensitivity C-reactive protein (hsCRP) are associated with greater severity and may be associated with adverse outcomes. In this study, we sought to evaluate the prognostic role of hsCRP in a non-selected cohort of patients with acute HF. We prospectively included a multicenter cohort of 3,395 patients following an admission for acute HF. HsCRP levels were evaluated during the first 24 h following admission. Study endpoints were the risks of all-cause mortality, CV-mortality, and total HF readmissions. The mean age was 74.2 ± 11.2 years and 1,826 (53.8%) showed a left ventricular ejection fraction (LVEF) ≥ 50%. Median hsCRP was 12.9 mg/L (5.4-30 mg/L). Over a median follow-up of 1.8 (0.6-4.1) years, 1,574 (46.4%) patients died, and 1,341 (39.5%) patients were readmitted for worsening HF. After multivariable adjustment, hsCRP values were significantly and positively associated with a higher risk of all-cause and CV mortality (p = 0.003 and p = 0.001, respectively), as well as a higher risk of recurrent HF admissions (p < 0.001). These results remained consistent across important subgroups, such as LVEF, sex, age, or renal function. In patients with acute HF, hsCRP levels were independently associated with an increased risk of long-term death and total HF readmissions.

Lower heart rate in patients with acute heart failure: the role of left ventricular ejection fraction.

BACKGROUND: The clinical impact of heart rate (HR) in heart failure with preserved ejection fraction (HFpEF) is a matter of debate. Among those with HFpEF, chronotropic incompetence (CI) has emerged as a pathophysiological mechanism linked to the severity of the disease. In this study, we sought to evaluate whether admission heart rate in acute heart failure differs along left ventricular ejection fraction (LVEF). METHODS: We included retrospectively 3,712 consecutive patients admitted for acute heart failure (AHF) in the Cardiology department of a third level center. HR values were assessed at presentation. LVEF was assessed by transthoracic echocardiogram during the index admission and stratified into four categories: reduced ejection fraction (≤40%), mildly reduced ejection fraction (41-49%), preserved ejection fraction (50-64%) and supranormal ejection fraction (≥65%). The association between HR and LVEF was assessed by multivariate linear and multinomial regression analyses. RESULTS: The mean age of the sample was 73,9 ± 11.3 years, 1,734 (47,4%) were women, and 1,214 (33,2%), 570 (15,6%), 1,229 (33,6%) and 648 (17,7%) patients showed LVEF ≤40%, 41-49%, 50-64%, and ≥65% respectively. The median HR at admission was 95 (IQR 78-120) beats per minute and 1,653 were on atrial fibrillation (45.2%). There was an inverse relationship between HR at admission and LVEF. Lower HR was significantly associated with a higher LVEF in the whole sample (p < 0,001). This inverse relationship was found in sinus rhythm but not in patients with atrial fibrillation. CONCLUSION: HR at admission for AHF is a predictor of LVEF but only in patients with sinus rhythm.

CA125 outperforms NT-proBNP in the prediction of maximum aerobic capacity in heart failure with preserved ejection fraction and kidney dysfunction.

Background: Heart failure with preserved ejection fraction (HFpEF) often coexists with chronic kidney disease (CKD). Exercise intolerance is a major determinant of quality of life and morbidity in both scenarios. We aimed to evaluate the associations between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and carbohydrate antigen 125 (CA125) with maximal aerobic capacity (peak VO2) in ambulatory HFpEF and whether these associations were influenced by kidney function. Methods: This single-centre study prospectively enrolled 133 patients with HFpEF who performed maximal cardiopulmonary exercise testing. Patients were stratified across estimated glomerular filtration rate (eGFR) categories (<60 ml/min/1.73 m2 versus ≥60 ml/min/1.73 m2). Results: The mean age of the sample was 73.2 ± 10.5 years and 56.4% were female. The median of peak VO2 was 11.0 ml/kg/min (interquartile range 9.0-13.0). A total of 67 (50.4%) patients had an eGFR <60 ml/min/1.73 m2. Those patients had higher levels of NT-proBNP and lower peak VO2, without differences in CA125. In the whole sample, NT-proBNP and CA125 were inversely correlated with peak VO2 (r = -0.43, P < .001 and r = -0.22, P = .010, respectively). After multivariate analysis, we found a differential association between NT-proBNP and peak VO2 across eGFR strata (P for interaction = .045). In patients with an eGFR ≥60 ml/min/1.73 m2, higher NT-proBNP identified patients with poorer maximal functional capacity. In individuals with eGFR <60 ml/min/1.73 m2, NT-proBNP was not significantly associated with peak VO2 [ß = 0.02 (95% confidence interval -0.19-0.23), P = .834]. Higher CA125 was linear and significantly associated with worse functional capacity without evidence of heterogeneity across eGFR strata (P for interaction = .620). Conclusions: In patients with stable HFpEF, NT-proBNP was not associated with maximal functional capacity when CKD was present. CA125 emerged as a useful biomarker for estimating effort intolerance in HFpEF irrespective of the presence of CKD.

Role of spot urinary sodium in outpatients with heart failure.

INTRODUCTION AND OBJECTIVES: Spot determination of urinary sodium (UNa+) has emerged as a useful tool for monitoring diuretic response in patients with acute heart failure (AHF). However, the evidence in outpatients is scarce. We aimed to examine the relationship between spot UNa+ levels and the risk of mortality and worsening heart failure (WHF) events in individuals with chronic HF. METHODS: This observational and ambispective study included 1145 outpatients with chronic HF followed in a single center specialized HF clinic. UNa+ assessment was carried out 1-5 days before each visit. The endpoints of the study were the association between UNa+ and risk of a) long-term death and b) AHF-hospitalization and total WHF events (including AHF-hospitalization, emergency department visits or parenteral loop-diuretic administration in HF clinic), assessed by multivariate Cox and negative binomial regressions. RESULTS: The mean±standard deviation of age was 73±11 years, 670 (58.5%) were men, 902 (78.8%) were on stable NYHA class II, and 595 (52%) had LFEF ≥50%. The median (interquartile range) UNa+ was 72 (51-94) mmol/L. Over a median follow-up of 2.63 (1.70-3.36) years, there were 293 (25.6%) deaths and 382 WHF events (244 AHF-admissions) in 233 (20.3%) patients. After multivariate adjustment, baseline UNa+ was inverse and linearly associated with the risk of total WHF (IRR, 1.07; 95%CI, 1.02-1.12; P=.007) and AHF-admissions (IRR, 1.08; 95%CI, 1.02-1.14; P=.012) and borderline associated with all-cause mortality (HR, 1.04; 95%CI, 0.99-1.09; P=.068). CONCLUSIONS: In outpatients with chronic HF, lower UNa+ was associated with a higher risk of recurrent WHF events.

Association between N-terminal pro-brain natriuretic peptide and maximal functional capacity in heart failure with preserved ejection fraction: The modifying role of obesity.

This study investigates the association between maximal functional capacity (peakVO2) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in 133 ambulatory patients with heart failure with preserved ejection fraction (HFpEF), focusing on patients with obesity. Across all participants, NT-proBNP inversely correlated with peakVO2. However, this association varied based on obesity status. In patients without obesity, there was an inverse relationship between NT-proBNP and peakVO2, while no significant correlation was observed in patients with obesity. These findings suggest that in stable ambulatory HFpEF, NT-proBNP did not predict peakVO2 in patients with obesity.

Combining loop with thiazide diuretics in patients discharged home after a heart failure decompensation: Association with 30-day outcomes.

OBJECTIVE: To investigate the association of the addition of thiazide diuretic on top of loop diuretic and standard of care with short-term outcomes of patients discharged after surviving an acute heart failure (AHF) episode. METHODS: This is a secondary analysis of 14,403 patients from three independent cohorts representing the main departments involved in AHF treatment for whom treatment at discharge was recorded and included loop diuretics. Patients were divided according to whether treatment included or not thiazide diuretics. Short-term outcomes consisted of 30-day all-cause mortality, hospitalization (with a separate analysis for hospitalization due to AHF or to other causes) and the combination of death and hospitalization. The association between thiazide diuretics on short-term outcomes was explored by Cox regression and expressed as hazard ratios (HR) with 95 % confidence intervals, which were adjusted for 18 patient-related variables and 9 additional drugs (aside from loop and thiazide diuretics) prescribed at discharge. RESULTS: The median age was 81 (interquartile range=73-86) years, 53 % were women, and patients were mainly discharged from the cardiology (42 %), internal medicine or geriatric department (29 %) and emergency department (19 %). There were 1,367 patients (9.5 %) discharged with thiazide and loop diuretics, while the rest (13,036; 90.5 %) were discharged with only loop diuretics on top of the remaining standard of care treatments. The combination of thiazide and loop diuretics showed a neutral effect on all outcomes: death (adjusted HR 1.149, 0.850-1.552), hospitalization (0.898, 0.770-1.048; hospitalization due to AHF 0.799, 0.599-1.065; hospitalization due to other causes 1.136, 0.756-1.708) and combined event (0.934, 0.811-1.076). CONCLUSION: The combination of thiazide and loop diuretics was not associated with changes in risk of death, hospitalization or a combination of both.

Intrarenal Venous Flow Pattern Changes Do Relate With Renal Function Alterations in Acute Heart Failure.

BACKGROUND: There is scarce evidence supporting the clinical utility of congestive intrarenal venous flow (IRVF) patterns in patients with acute heart failure. OBJECTIVES: This study aims to: 1) investigate the association between IRVF patterns and the odds of worsening renal function (WRF); 2) track the longitudinal changes of serum creatinine (sCr) across IRVF at predetermined points and its association with decongestion; and 3) explore the relationship between IRVF/WRF categories and patient outcomes. METHODS: IRVF was assessed at baseline (pre-decongestive therapy), 72 hours, and 30 and 90 days postdischarge. Changes in sCr trajectories across dynamic IRVF variations and parameters of decongestion were assessed using linear mixed effect models. The association between IRVF/WRF categories and outcomes was evaluated using univariable/multivariable models. RESULTS: In this prospective, multicenter study with 188 participants, discontinuous IRVF patterns indicated higher odds of WRF (OR: 3.90 [95% CI: 1.24-12.20]; P = 0.020 at 72 hours; and OR: 5.76 [95% CI: 1.67-19.86]; P = 0.006 at 30 days) and an increase in sCr (Δ-72 hours 0.14 mg/dL [95% CI: 0.06-0.22]; P = 0.001; Δ-discharge 0.13 mg/dL [95% CI: 0.03-0.23]; P = 0.007). However, the diuretic response and decongestion significantly influenced the magnitude of these changes. Patients exhibiting both WRF and discontinuous IRVF at 30 days experienced an increased hazard of adverse events (HR: 5.96 [95% CI: 2.63-13.52]; P < 0.001). CONCLUSIONS: Discontinuous IRVF identifies patients with higher odds of WRF during admission and postdischarge periods. Nonetheless, adequate diuretic response and decongestion could modify this association. Patients showing both WRF and discontinuous IRVF at 30 days had increased rates of adverse events.

Noncardiovascular morbidity and mortality across left ventricular ejection fraction categories following hospitalization for heart failure.

INTRODUCTION AND OBJECTIVES: Noncardiovascular events represent a significant proportion of the morbidity and mortality burden in patients with heart failure (HF). However, the risk of these events appears to differ by left ventricular ejection fraction (LVEF) status. In this study, we sought to evaluate the risk of noncardiovascular death and recurrent noncardiovascular readmission by LVEF status following an admission for acute HF. METHODS: We retrospectively assessed a cohort of 4595 patients discharged after acute HF in a multicenter registry. We evaluated LVEF as a continuum, stratified in 4 categories (LVEF ≤ 40%, 41%-49%, 50%-59%, and ≥ 60%). Study endpoints were the risks of noncardiovascular mortality and recurrent noncardiovascular admissions during follow-up. RESULTS: At a median follow-up of 2.2 [interquartile range, 0.76-4.8] years, we registered 646 noncardiovascular deaths and 4014 noncardiovascular readmissions. After multivariable adjustment including cardiovascular events as a competing event, LVEF status was associated with the risk of noncardiovascular mortality and recurrent noncardiovascular admissions. When compared with patients with LVEF ≤ 40%, those with LVEF 51%-59%, and especially those with LVEF ≥ 60%, were at higher risk of noncardiovascular mortality (HR, 1.31; 95%CI, 1.02-1,68; P=.032; and HR, 1.47; 95%CI, 1.15-1.86; P=.002; respectively), and at higher risk of recurrent noncardiovascular admissions (IRR, 1.17; 95%CI, 1.02-1.35; P=.024; and IRR, 1.26; 95%CI, 1.11-1.45; P=.001; respectively). CONCLUSIONS: Following an admission for HF, LVEF status was directly associated with the risk of noncardiovascular morbidity and mortality. Patients with HFpEF were at higher risk of noncardiovascular death and total noncardiovascular readmissions, especially those with LVEF ≥ 60%.

Kidney function changes in acute heart failure: a practical approach to interpretation and management.

Worsening kidney function (WKF) is common in patients with acute heart failure (AHF) syndromes. Although WKF has traditionally been associated with worse outcomes on a population level, serum creatinine concentrations vary greatly during episodes of worsening heart failure, with substantial individual heterogeneity in terms of their clinical meaning. Consequently, interpreting such changes within the appropriate clinical context is essential to unravel the pathophysiology of kidney function changes and appropriately interpret their clinical meaning. This article aims to provide a critical overview of WKF in AHF, aiming to provide physicians with some tips and tricks to appropriately interpret kidney function changes in the context of AHF.

Short-Term Changes in Peak VO2 After Initiation of Dapagliflozin in Heart Failure Across Iron Status.

BACKGROUND: Some studies have indicated that sodium-glucose cotransporter-2 (SGLT2) inhibitors promote an increase in cell iron use. OBJECTIVES: The aim of this study was to examine, in patients with stable heart failure with reduced left ventricular ejection fraction (HFrEF), the effect of dapagliflozin on ferrokinetic parameters and whether short-term changes in peak oxygen consumption (Vo2) after dapagliflozin treatment are influenced by baseline and serial ferrokinetic status. METHODS: This was an exploratory analysis of a randomized, double-blind clinical trial that evaluated the effect of dapagliflozin vs placebo on peak Vo2 in patients with HFrEF (NCT04197635) and included 76 of the 90 patients initially enrolled in the trial. Changes in peak Vo2 at 1 and 3 months were explored according to baseline and longitudinal ferrokinetic parameters (natural logarithm [ln] ferritin, transferrin saturation index [TSAT], soluble transferrin receptor, and hepcidin). Linear mixed-effect regression was used for the analyses. RESULTS: Compared with placebo, dapagliflozin led to a significant decrease in 3-month ln ferritin (P = 0.040) and an increase in 1-month ln soluble transferrin receptor (P = 0.023). Between-treatment comparisons revealed a stepwise increase in peak Vo2 in the dapagliflozin group at 1 and 3 months, which was especially apparent at lower baseline values of TSAT and ferritin (P < 0.05). Lower time-varying values of TSAT (1 and 3 months) also identified patients with greater improvements in peak Vo2. CONCLUSIONS: In patients with stable HFrEF, treatment with dapagliflozin resulted in short-term increases in peak Vo2, which were most marked in patients with surrogates of greater iron deficiency at baseline and during treatment. (Short-Term Effects of Dapagliflozin on Peak Vo2 in HFrEF [DAPA-VO2]; NCT04197635).

Early glomerular filtration rates changes and risk of mortality in acute heart failure. The modifying role of admission renal function and decongestion.

BACKGROUND: The pathophysiology of changes in estimated glomerular filtration rate (eGFR) in acute heart failure (AHF) is complex and multifactorial. We evaluated the associated mortality risk of early changes in eGFR across baseline renal function on admission and early changes in natriuretic peptides in patients admitted with AHF. METHODS: We retrospectively evaluated 2,070 patients admitted with AHF. Renal dysfunction on admission was defined as eGFR<60 ml/min/1.73m2 and successful decongestion as NT-proBNP decreased >30% from baseline. We assessed the mortality risk associated with eGFR changes from baseline at 48-72 h after admission (ΔeGFR%) according to baseline renal function, and NT-proBNP changes at 48-72 h through Cox regression analyses. RESULTS: The mean age was 74.4 ± 11.2 years, and 930 (44.9%) were women. The proportion of admission eGFR<60 ml/min/1.73m2 and 48-72 h changes in NT-proBNP>30% were 50.5% and 32.8%, respectively. At a median follow-up of 1.75 years, 928 deaths were registered. In the whole sample, changes in renal function were not associated with mortality (p = 0.208). The adjusted analysis revealed that the risk of mortality related to ΔeGFR% was heterogeneous across baseline renal function and changes in NT-proBNP (p-value for interaction=0.003). ΔeGFR% was not associated with mortality in patients with baseline eGFR≥60 ml/min/1.73m2. In those with eGFR<60 ml/min/1.73m2, a decrease in eGFR was associated with higher mortality, particularly in those with a reduction in NT-proBNP<30%. CONCLUSION: In patients with AHF, early ΔeGFR% was associated with the risk of long-term mortality only in patients with renal dysfunction on admission and no early decline in NT-proBNP.

An update on utilising brain natriuretic peptide for risk stratification, monitoring and guiding therapy in heart failure.

INTRODUCTION: Heart failure (HF) is a dominant health problem with an overall poor prognosis. Natriuretic peptides (NPs) are upregulated in HF as a compensatory mechanism. They have been extensively used for diagnosis and risk stratification. AREAS COVERED: This review addresses the history and physiology of NPs in order to understand their current role in clinical practice. It further provides a detailed and updated narrative review on the utility of those biomarkers for risk stratification, monitoring, and guiding therapy in HF. EXPERT OPINION: NPs show excellent predictive ability in heart failure patients, both in acute and chronic settings. Understanding their pathophysiology and their modifications in specific situations is key for an adequate interpretation in specific clinical scenarios in which their prognostic value may be weaker or less well evaluated. To better promote risk stratification in HF, NPs should be integrated with other predictive tools to develop multiparametric risk models. Both inequalities of access to NPs and evidence caveats and limitations will need to be addressed by future research in the coming years.

Short-term Changes in Hemoglobin and Changes in Functional Status, Quality of Life and Natriuretic Peptides After Initiation of Dapagliflozin in Heart Failure With Reduced Ejection Fraction.

BACKGROUND: We aimed to evaluate the effect of dapagliflozin on short-term changes in hemoglobin in patients with stable heart failure with reduced ejection fraction (HFrEF) and whether these changes mediated the effect of dapagliflozin on functional capacity, quality of life and NT-proBNP levels. METHODS: This is an exploratory analysis of a randomized, double-blinded clinical trial in which 90 stable patients with HFrEF were randomly allocated to dapagliflozin or placebo to evaluate short-term changes in peak oxygen consumption (peak VO2) (NCT04197635). This substudy evaluated 1- and 3-month changes in hemoglobin levels and whether these changes mediated the effects of dapagliflozin on peak VO2, Minnesota Living-With-Heart-Failure test (MLHFQ) and NT-proBNP levels. RESULTS: At baseline, mean hemoglobin levels were 14.3 ± 1.7 g/dL. Hemoglobin levels significantly increased in those taking dapagliflozin (1 month: + 0.45 g/dL (P = 0.037) and 3 months:+ 0.55 g/dL (P = 0.012)]. Changes in hemoglobin levels positively mediated the changes in peak VO2 at 3 months (59.5%; P < 0.001). Changes in hemoglobin levels significantly mediated the effect of dapagliflozin in the MLHFQ at 3 months (-53.2% and -48.7%; P = 0.017) and NT-proBNP levels at 1 and 3 months (-68.0%; P = 0.048 and -62.7%; P = 0.029, respectively). CONCLUSIONS: In patients with stable HFrEF, dapagliflozin caused a short-term increase in hemoglobin levels, identifying patients with greater improvements in maximal functional capacity, quality of life and reduction of NT-proBNP levels.

Risk of death associated with incident heart failure in patients with known or suspected chronic coronary syndrome.

AIMS: Traditional adverse events in chronic coronary syndrome (CCS) include atherothrombotic events but usually exclude heart failure (HF). Data are scarce about how new-onset HF modifies mortality risk. We aimed to determine the incidence of HF and compare its long-term mortality risk with myocardial infarction (MI) and stroke in patients with known or suspected CCS. METHODS: We prospectively evaluated 5811 consecutive HF-free patients submitted to vasodilator stress cardiac magnetic resonance (CMR) for known or suspected CCS. Ischaemic burden and left ventricular ejection fraction were assessed by CMR. HF included outpatient diagnosis or acute HF hospitalization. The mortality risk for the incident events and their cross-comparisons were evaluated using a Markov illness-death model with transition-specific survival models. RESULTS: The mean age was 55 ± 11 years, and 38.9% were female. At a median follow-up of 5.44 (IQR = 2.53-8.55) years, 591 deaths were registered (1.79 per 100 P-Y). The rates of new-onset HF were higher compared with MI and stroke [1.02, 0.62, and 0.51, respectively (P < 0.05)]. The adjusted association between new-onset HF, MI, and stroke, and subsequent mortality was time dependent. The risk increased almost linearly for HF and became significant by the third year. By Year 10, the mortality risk attributable to new-onset HF was more than 2.5-fold (HR: 2.68, 95% CI = 1.74-4.12). For MI, there was a significant increase in mortality risk up to the second year, followed by a monotonic decrease. For stroke, the mortality risk increased for the entire follow-up but became significant by the third year. A cross-comparison among incident endpoints HF outnumbers risk for those with MI by the sixth year (HRyear6.3 : 1.88, 95% CI = 1.03-3.43). There was no difference in mortality risk between incident HF and stroke. CONCLUSIONS: In patients with CCS, long-term rates of incident HF were higher than MI and stroke. Patients with new-onset HF showed a higher risk of long-term mortality.

Innovative Design of Residual Stress and Strain Distributions for Analyzing the Hydrogen Embrittlement Phenomenon in Metallic Materials.

Round-notched samples are commonly used for testing the susceptibility to hydrogen embrittlement (HE) of metallic materials. Hydrogen diffusion is influenced by the stress and strain states generated during testing. This state causes hydrogen-assisted micro-damage leading to failure that is due to HE. In this study, it is assumed that hydrogen diffusion can be controlled by modifying such residual stress and strain fields. Thus, the selection of the notch geometry to be used in the experiments becomes a key task. In this paper, different HE behaviors are analyzed in terms of the stress and strain fields obtained under diverse loading conditions (un-preloaded and preloaded causing residual stress and strains) in different notch geometries (shallow notches and deep notches). To achieve this goal, two uncoupled finite element (FE) simulations were carried out: (i) a simulation by FE of the loading sequences applied in the notched geometries for revealing the stress and strain states and (ii) a simulation of hydrogen diffusion assisted by stress and strain, for estimating the hydrogen distributions. According to results, hydrogen accumulation in shallow notches is heavily localized close to the wire surface, whereas for deep notches, hydrogen is more uniformly distributed. The residual stress and plastic strains generated by the applied preload localize maximum hydrogen concentration at deeper points than un-preloaded cases. As results, four different scenarios are established for estimating "a la carte" the HE susceptibility of pearlitic steels just combining two notch depths and the residual stress and strain caused by a preload.

On the Use of Multi-Step Dies for Improving the Performance against Hydrogen Embrittlement of Cold Drawn Prestressing Steel Wires.

The main cause of in-service failure of cold drawn wires in aggressive environments is hydrogen embrittlement (HE). The non-uniform plastic strains and residual stresses generated after cold drawing play a significant role in the matter of HE susceptibility of prestressing steels. In this paper, a new and innovative design of the drawing scheme is developed, geared towards the reduction in both manufacturing-induced residual stresses and plastic strains. To achieve this goal, three innovative cold drawing chains (consisting in diverse multi-step dies where multiple diameter reductions are progressively carried out in a single die) are numerically simulated by the finite element (FE) method. From the residual stress and plastic strain fields revealed from FE numerical simulations, hydrogen accumulation for diverse times of exposure is obtained by means of FE simulations of the hydrogen diffusion assisted by stress and strains. Thus, an estimation of the HE susceptibility of the cold drawn wires after each process was obtained. Results reveal that cold drawn wire using multi-step dies exhibits lower stress and strain states nearby the wire surface. This reduction causes a decrease in the hydrogen concentration at the prospective damage zones, thereby improving the performance of the prestressing steel wires in hydrogenating environments promoting HE. Thus, the optimal wire drawing process design is carried out using special dies with several reductions per die.