Calculated plasma volume status in hemodialysis patients

BACKGROUND

Plasma volume (PV) calculated from hematocrit and body weight has applications in cardiovascular disease. The current study investigated the validity of the calculated PV for predicting volume overload and its prognostic utility in patients undergoing hemodialysis (HD).

PATIENTS AND METHODS

Fifty-four HD patients were prospectively enrolled, and their actual PV (aPV) and relative PV status (PVS) were calculated. Bioelectrical impedance analysis (BIA) with assessment of and total body water (TBW), intracellular water (ICW), extracellular water (ECW), and overhydration (OH) and routine blood examinations were performed before dialysis. A second cohort of 164 HD patients was retrospectively enrolled to evaluate the relationship between the calculated PVS and the outcome, with an endpoint of all-cause mortality.

RESULTS

aPV was significantly associated with TBW, ICW, ECW, OH, and ECW/TBW (all p < 0.001), and most strongly with ECW (r = 0.83). aPV predicted the extent of volume overload with an AUC of 0.770 (p < 0.001), but PVS did not (AUC = 0.617, p = 0.091). Median follow-up time was 53 months, during the course of which 60 (36.58%) patients died. Values for PVS (12.94 ± 10.87% vs. 7.45 ± 5.90%, p = 0.024) and time-averaged PVS (12.83 ± 11.20 vs. 6.78 ± 6.22%, p < 0.001) were significantly increased in patients who died relative to those who survived. A value of time-averaged PVS >8.72% was significantly associated with an increased incidence of all-cause mortality (HR = 2.48, p = 0.0023).

CONCLUSIONS

aPV was most strongly associated with ECW measured using BIA. HD patients with higher time-averaged PVS had a higher rate of all-cause mortality.

Cardiopulmonary deconditioning and plasma volume loss are not sufficient to provoke orthostatic hypertension

Orthostatic hypertension, defined by an increase of systolic blood pressure (SBP) of ≥20 mmHg upon standing, harbors an increased cardiovascular risk. We pooled data from two rigorously conducted head-down tilt bedrest studies to test the hypothesis that cardiopulmonary deconditioning and hypovolemia predispose to orthostatic hypertension. With bedrest, peak VO2 decreased by 6 ± 4 mlO2/min/kg (p < 0.0001) and plasma volume by 367 ± 348 ml (p < 0.0001). Supine SBP increased from 127 ± 9 mmHg before to 133 ± 10 mmHg after bedrest (p < 0.0001). In participants with stable hemodynamics following head-up tilt, the incidence of orthostatic hypertension was 2 out of 67 participants before bedrest and 2 out of 57 after bedrest. We conclude that in most healthy persons, cardiovascular deconditioning and volume loss associated with long-term bedrest are not sufficient to cause orthostatic hypertension.

Effect of Sodium-Glucose Co-Transporter-2 Inhibitor on Estimated Plasma Volume in a Patient With Heart Failure With Reduced Ejection Fraction and a Patient With Heart Failure With Preserved Ejection Fraction

BACKGROUND

The increased diuresis after sodium-glucose cotransporter 2 inhibitor (SGLT2i) was associated with a reduction of the estimated plasma volume (ePV) in type 2 diabetic patients.

HYPOTHESIS

We hypothesized that the early effect of SGLT2i on ePV may be monitored by the change of biomarkers of hemoconcentration.

PATIENTS AND METHODS

We analyzed the early- and long-term effect of SGLT2i empagliflozin on the ePV as assessed by biomarkers of hemoconcentration in a nondiabetic patient with heart failure and reduced ejection fraction (HFrEF) and a nondiabetic patient with heart failure and preserved ejection fraction (HFpEF). The ePV was calculated from hemoglobin and hematocrit levels by Duarte formula and ePV change was calculated by Strauss formula.

RESULTS

The ePV change was -22.56% between baseline and 1 month, and -37.60% between baseline and 12 months follow-up in a patient with HFrEF, and -6.18% and -16.40% in a patient with HFpEF, respectively.

CONCLUSION

The early effect of SGLT2i on ePV in patients with heart failure may be monitored by biomarkers of hemoconcentration.

Association between estimated plasma volume status and acute kidney injury in patients who underwent coronary revascularization: A retrospective cohort study from the MIMIC-IV database

BACKGROUND

Acute kidney injury (AKI) remains a common complication of coronary revascularization and increases poor outcomes in critically ill surgical patients. Compared to the plasma volume status (PVS), estimated plasma volume status (ePVS) has the advantages of being noninvasive and simple and has been shown to be associated with worse prognosis in patients undergoing coronary revascularization. This study was to evaluate the association of ePVS with the risk of AKI in patients who underwent coronary revascularization.

METHODS

In this retrospective cohort study, data of patients who underwent coronary revascularization were extracted from the Medical Information Mart for Intensive Care (MIMIC)-IV database (2008-2019). The outcome was the occurrence of AKI after ICU admission. The covariates were screened via the LASSO regression method. Univariate and multivariate Logistic regression models were performed to assess the association of ePVS and PVS and the odds of AKI in patients who underwent coronary revascularization, with results shown as odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup analyses of age, surgery, and anticoagulation agents and sequential organ failure assessment (SOFA) score were performed to further explore the association of ePVS with AKI.

RESULTS

A total of 3,961 patients who underwent coronary revascularization were included in this study, of whom 2,863 (72.28%) had AKI. The high ePVS was associated with the higher odds of AKI in patients who received coronary revascularization (OR = 1.06, 95%CI: 1.02-1.10), after adjusting for the covariates such as age, race, SAPS-II score, SOFA score, CCI, weight, heart rate, WBC, RDW-CV, PT, BUN, glucose, calcium, PH, PaO2, mechanical ventilation, vasopressors, and diuretic. Similar results were found in patients who underwent the CABG (OR = 1.07, 95%CI: 1.02-1.11), without anticoagulation agents use (OR = 1.07, 95%CI: 1.03-1.12) and with high SOFA score (OR = 1.10, 95%CI: 1.04-1.17). No relationship was found between PVS and the odds of AKI in patients who underwent the coronary revascularization.

CONCLUSION

The ePVS may be a promising parameter to evaluate the risk of AKI in patients undergoing coronary revascularization, which provides a certain reference for the risk stratification management of ICU patients who underwent coronary revascularization.

Estimated plasma volume status is a simple and quick tool that could help define the severity of patients with infection on arrival at the emergency department

BACKGROUND

Infectious states are subtle and rapidly evolving conditions observed daily in the emergency department (ED), and their prognostic evaluation remains a complex clinical challenge. Recently, estimated plasma volume status (ePVS) has been suggested to have a prognostic role in conditions where volemic alteration is central to the pathophysiology. The aim of this study was to verify whether ePVS recorded at ED admission can provide prognostic indications of 30-day mortality in patients with infection.

METHODS

A prospective observational study was performed between 1 January 2021 and 31 December 2021 at the ED of the Merano Hospital. All patients with infection were enrolled. ePVS values were derived from haemoglobin and haematocrit measured on the immediate arrival of patients in the ED. The predictive power of ePVS for 30-day mortality was assessed using a multivariate model adjusted for severity, comorbidity and urgency. Kaplan-Meier analysis was also performed.

RESULTS

Of the 949 patients with infection enrolled in the study (47.9%, SOFA ≥2), 8.9% (84/949) died at 30 days. The median ePVS value was higher in patients who died at 30 days than in patients who survived (5.83 vs. 4.61, p < 0.001). Multivariate analysis revealed that ePVS in both continuous and categorical form around the median was an independent risk factor for 30-day mortality even after adjusting for severity, comorbidity and urgency. Kaplan-Meier analysis confirmed an increased risk of death in patients with high ePVS values.

CONCLUSIONS

ePVS recorded on ED admission of patients with infection was an independent predictor of risk for 30-day mortality.

Blood-based assessment of oxidative stress, inflammation, endocrine and metabolic adaptations in eventing horses accounting for plasma volume shift after exercise

BACKGROUND

After submaximal exercise, blood values of eventing horses show physiological reactions.

OBJECTIVES

This prospective longitudinal study investigated blood parameters in 20 elite eventing horses before and after two-four-star cross-country rides.

METHODS

Using a mixed model adjusting for plasma volume shift, we assessed exercise-dependent parameters and compared blood values with reference ranges for healthy horses at rest.

RESULTS

Following exercise, cortisol, triiodothyronine (T3) and thyroxine (T4) showed short-term increases, and superoxide-dismutase showed a small short-term increase. Hepatic values showed short-term (haemoglobin [HGB], globulins) or sustained increases (bilirubin, glutamate dehydrogenase, alanine aminotransferase). Digestion-related parameters showed small short-term increases (α-amylase, triglycerides) or decreases (cholesterol, DGGR-lipase), apparent through plasma shift adjustment. Zinc decreased in the short term, and iron showed a delayed decrease. White blood cell count increased persistently after training, whereas serum amyloid A remained unchanged.

CONCLUSIONS

Exercised eventing horses had consistently elevated HGB and cortisol levels 10 and 30 min after submaximal exercise, exceeding the reference ranges for healthy horses at rest. Exercise activates the hypothalamic-pituitary-adrenocortical and hypothalamic-pituitary-thyroid axes. Antioxidant activity was observed. Increased energy requirements led to the mobilization of energy reserves, and a sustained increase in liver enzymes indicated hepatocellular injury. Mild haemolysis suggested increased muscle metabolism, whereas signs of inflammation were subtle. Further research is needed to identify which horses deviate from mean values.

Effects of ingesting beverages containing glycerol and sodium with isomaltulose or sucrose on fluid retention in young adults: a single-blind, randomized crossover trial

We evaluated changes in hyperhydration and beverage hydration index (BHI, a composite measure of fluid balance after consuming a test beverage relative to water) during resting, induced by the consumption of beverages containing glycerol and sodium supplemented with fast-absorbing sucrose or slow-absorbing isomaltulose. In a randomized crossover, single-blinded protocol (clinical trials registry: UMIN000042644), 14 young physically active adults (three women) consumed 1 L of beverage containing either 7% glycerol + 0.5% sodium (Gly + Na), Gly + Na plus 7% sucrose (Gly + Na + Suc), Gly + Na plus 7% isomaltulose (Gly + Na + Iso), or water (CON) over a 40 min period. We assessed the change in plasma volume (ΔPV), BHI (calculated from cumulative urine output following consumption of water relative to that of the beverage), and blood glucose and sodium for 180 min after initiating ingestion. Total urine volume was reduced in all beverages containing glycerol and sodium compared to CON (all P ≤ 0.002). The addition of isomaltulose increased BHI by ∼45% (3.43 ± 1.0 vs. 2.50 ± 0.7 for Gly + Na, P = 0.011) whereas sucrose did not (2.6 ± 0.6, P = 0.826). The PV expansion was earliest for Gly + Na (30 min), slower for Gly + Na + Suc (90 min), and slowest for Gly + Na + Iso (120 min) with a concomitant lag in the increase of blood glucose and sodium concentrations. Supplementation of beverages containing glycerol and sodium with isomaltulose but not sucrose enhances BHI from those of glycerol and sodium only under a resting state, likely due to the slow absorption of isomaltulose-derived monosaccharides (i.e., glucose and fructose).

Predictive value of estimated plasma volume for postoperative hypotension in percutaneous intramyocardial septal radiofrequency ablation treating for hypertrophic obstructive cardiomyopathy

BACKGROUND

Estimated plasma volume status (ePVS) estimated by the Duarte formula is associated with clinical outcomes in patients with heart failure. It remains unclear the predictive value of the ePVS to the postoperative hypotension (POH) in percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) treating hypertrophic obstructive cardiomyopathy (HOCM).

METHODS

Data of HOCM patients who underwent PIMSRA were retrospectively collected. Preoperative ePVS was calculated using the Duarte formulas which derived from hemoglobin and hematocrit ratios. Clinical variables including physical assessment, biological and echocardiographic parameters were recorded. Patients were labeled with or without POH according to the medical record in the hospital. Univariable and multivariable logistic regression were performed to evaluate the association between ePVS and POH. Using different thresholds derived from quartiles and the best cutoff value of the receiver operating characteristic curve, the diagnostic performance of ePVS was quantified.

RESULTS

Among the 405 patients included in this study, 53 (13.1%) patients were observed with symptomatic POH. Median (IQR) of ePVS in overall patients was 3.77 (3.27~4.40) mL/g and in patients with POH were higher than those without POH. The ePVS was associated with POH, with the odds ratio of 1.669 (95% CI 1.299 ~ 2.144) per mL/g. After adjusted by potential confounders, ePVS remained independently associated with POH, with the approximate odds ratio in different models.

CONCLUSION

The preoperative ePVS derived from the Duarte formulas was independently associated with postoperative hypotension in HOCM patients who underwent PIMSRA and showed prognostic value to the risk stratification of postoperative management.

TRIAL REGISTRATION

NCT06003478 (22/08/2023).

Exercise induced plasma volume expansion lowers cardiovascular strain during 15-km cycling time-trial in acute normobaric hypoxia

The purpose of our study was to assess the influence of a single high-intensity interval exercise (HIIE) bout in normoxia on plasma volume (PV) and consequent cycling performance in normobaric hypoxia (0.15 FiO2, simulating ~2,500 m). Eight males (VO2peak: 48.8 ± 3.4 mL/kg/min, 24.0 ± 1.6 years) completed a hypoxic 15 km cycling time trial (TT), followed by a crossover intervention of either HIIE (8x4 min cycling bouts at 85% of VO2peak) or CON (matched kJ production from HIIE at 50% of VO2peak). 48 hours post intervention, an identical TT was performed. Cardiovascular parameters were measured via impedance cardiography during each TT. Changes in PV was measured 24 and 48 hours post HIIE and CON. HIIE increased PV at 24 (4.1 ± 3.9%, P = 0.031) and 48 (6.7 ± 1.7, P = 0.006) hours post, while no difference was observed following the CON (1.3 ± 1.1% and 0.3 ± 2.8%). The higher PV led to an increased stroke volume (P = 0.03) and cardiac output (P = 0.02) during the hypoxic TT, while heart rate was not changed (P = 0.49). We observed no changes in time to completion (-0.63 ± 0.57 min, P = 0.054) and power output (7.37 ± 7.98 W, P = 0.078) between TTs. In the absence of environmental stress, a single bout of HIIE was an effective strategy to increase PV and reduce the cardiovascular strain during a cycling TT at moderate simulated altitude but did not impact hypoxic exercise performance. Trial registration: Clinical Trials ID: NCT05800808.

Evidence of serial connection between the plasma volume and two interstitial fluid compartments

BACKGROUND

Kinetic analysis of fluid volume shifts can identify two interstitial fluid compartments with different turnover rates, but how they are connected to the bloodstream is unknown.

METHODS

Retrospective data were retrieved from 217 experiments where 1.5 L of Ringer's solution (mean) had been administered by intravenous infusion over 30 min to awake and anesthetized humans (mean age 40 years). Urinary excretion and hemoglobin-derived plasma dilution served as input variables in a volume kinetic analysis using mixed models software. Possible modes of connection between the two interstitial fluid compartments and the bloodstream were judged by covariance analysis between kinetic rate constants, physiological variables, and time factors.

RESULTS

The return flow of already distributed fluid to the plasma via a fast-exchange interstitial compartment was inhibited ongoing infusion of fluid (-38 %), which was probably due to increase of the venous pressure during volume loading. Ongoing infusion also greatly retarded the entrance of fluid to the slow-exchange compartment (-85 %), which suggests that infused Ringer's first had to enter the fast-exchange compartment. A high mean arterial pressure markedly increased the urine output and, to a lesser degree, also the rate of entrance of fluid to the fast-exchange compartment. Moreover, a high blood hemoglobin concentration retarded the rate of entrance of fluid to the fast-exchange compartment.

CONCLUSIONS

The fast-exchange but not the slow-exchange interstitial fluid compartment was affected by intravascular events, which suggests that only the fast-exchange compartment is directly connected to the circulating blood.

Estimated plasma volume status in COVID-19 patients and its relation to comorbidities and clinical outcomes

Blood plasma is a large reservoir of circulating mediators of inflammation and its expansion has been associated with unfavorable outcomes in patients with inflammatory and cardiovascular diseases. The aim of this study was to determine clinical and prognostic value of estimated plasma volume status (ePVS) in hospitalized patients with COVID-19. We retrospectively investigated 5871 consecutive COVID-19 patient hospitalized in our tertiary-level institution in period 3/2020-6/2021. ePVS was determined using the Strauss-derived Duarte formula and was correlated with clinical characteristics and unwanted outcomes. Median ePVS was 4.77 dl/g with interquartile range 4.11-5.74. Higher ePVS was significantly associated with older age, female sex, higher comorbidity burden, worse functional status, less severe COVID-19 clinical presentation with lower severity and longer duration of symptoms, but more pronounced inflammatory profile with higher C-reactive protein, interleukin-6 and D-dimer levels (P < 0.05 for all analyses). In the multivariate regression analysis U shaped relationship of ePVS with mortality was revealed, present independently of age, sex, COVID-19 severity and comorbidity burden. In addition, higher ePVS was independently associated with higher tendency for mechanical ventilation, intensive care unit treatment, venous thromboembolism, major bleeding and bacteriemia and lower ePVS was independently associated with tendency for arterial thrombotic events. Higher ePVS, indicative of plasma volume expansion and inflammatory cytokine accumulation, may predispose respiratory deterioration and venous thromboembolism, despite less severe initial clinical presentation. Lower ePVS, indicative of hemoconcentration, may predispose arterial thrombotic events. Both may be associated with higher mortality in hospitalized COVID-19 patients.

Intravascular volumes and the influence on anemia assessed by a carbon monoxide rebreathing method in patients undergoing maintenance hemodialysis

INTRODUCTION

Fluid overload is a major challenge in hemodialysis patients and might cause hypervolemia. We speculated that hemodialysis patients reaching dry weight could have undetected hypervolemia and low hemoglobin (Hb) concentration (g/dL) due to hemodilution.

METHODS

The study included hemodialysis patients (n = 22) and matched healthy controls (n = 22). Blood volume, plasma volume, red blood cell volume, and total Hb mass were determined using a carbon monoxide (CO)-rebreathing method in hemodialysis patients reaching dry weight and controls. Blood volume measurements were also obtained by a dual-isotope labeling technique in a subgroup for validation purposes.

FINDINGS

In the hemodialysis group, the median specific blood volume was 89.3 mL/kg (interquartile range [IQR]: 76.7-95.4 mL/kg) and was higher than in the control group (79.9 mL/kg [IQR: 70.4-88.0 mL/kg]; p < 0.037). The median specific plasma volume was 54.7 mL/kg (IQR: 47.1-61.0 mL/kg) and 44.0 mL/kg (IQR: 38.7-49.5 mL/kg) in the hemodialysis and control groups, respectively (p < 0.001). Hb concentration was lower in hemodialysis patients (p < 0.001), whereas no difference in total Hb mass was observed between groups (p = 0.11). A correlation was found between blood volume measured by the CO-rebreathing test and the dual-isotope labeling technique in the control group (r = 0.83, p = 0.015), but not the hemodialysis group (r = 0.25, p = 0.60).

DISCUSSION

The hemodialysis group had increased specific blood volume at dry weight due to high plasma volume, suggesting a hypervolemic state. However, correlation was not established against the dual-isotope labeling technique underlining that the precision of the CO-rebreathing test should be further validated. The total Hb mass was similar between hemodialysis patients and controls, unlike Hb concentration, which emphasizes that Hb concentration is an inaccurate marker of anemia among hemodialysis patients.

Plasma Volume Oscillations during Fluid Therapy in Humans

INTRODUCTION

Oscillations are frequently observed on plasma dilution curves during intravenous fluid therapy. This study aimed to examine how common these oscillations are and what they represent.

METHODS

Fourier transforms were used to analyze the residuals obtained during fitting of a volume kinetic model to 269 plasma dilution curves. Oscillating patterns were identified in two-thirds of the fluid infusion experiments.

RESULTS

The wave frequency usually had a dominating frequency of 1 h or multiples thereof. The wave amplitudes varied between 1% and 4% of the plasma volume. The "peak-to-peak" amplitudes were then twice as large, which corresponded to blood volume changes of 60-240 mL. A population kinetic analysis of the distribution of infused fluid between body fluid compartments was then applied to search for clues that could explain the oscillations. This analysis showed that amplitudes >1.5% were associated with doubled turnover of fluid in a fast-exchange interstitial fluid compartment and, together with data on plasma albumin, suggested that oscillations might represent bursts of efferent lymph.

CONCLUSIONS

Oscillations with very low frequency were often observed on plasma dilution-time curves obtained during fluid therapy. They were associated with fast turnover of interstitial fluid and can possibly have resulted from accelerated lymphatic flow.

Association of plasma volume status with outcomes in hospitalized Covid-19 ARDS patients: A retrospective multicenter observational study

PURPOSE

To evaluate the association of estimated plasma volume (ePV) and plasma volume status (PVS) on admission with the outcomes in COVID-19-related acute respiratory distress syndrome (ARDS) patients.

MATERIALS AND METHODS

We performed a retrospective multi-center study on COVID-19-related ARDS patients who were admitted to the Mayo Clinic Enterprise health system. Plasma volume was calculated using the formulae for ePV and PVS, and these variables were analyzed for correlation with patient outcomes.

RESULTS

Our analysis included 1298 patients with sequential organ failure assessment (SOFA) respiratory score ≥ 2 (PaO2/FIO2 ≤300 mmHg) and a mortality rate of 25.96%. A Cox proportional multivariate analysis showed PVS but not ePV as an independent correlation with 90-day mortality after adjusting for the covariates (HR: 1.015, 95% CI: 1.005-1.025, p = 0.002 and HR 1.054, 95% CI 0.958-1.159, p = 0.278 respectively).

CONCLUSION

A lower PVS on admission correlated with a greater chance of survival in COVID-19-related ARDS patients. The role of PVS in guiding fluid management should be investigated in future prospective studies.

Estimated plasma volume is not a robust indicator of the severity of congestion in patients with heart failure

BACKGROUND

Congestion is the main cause of morbidity and a prime determinant of survival in patients with heart failure (HF). However, the assessment of congestion is subjective and estimation of plasma volume (ePV) has been suggested as a more objective measure of congestion. This study aimed to explore the relationships and interactions between ePV, the severity of congestion and survival using a nationwide registry.

METHODS

Of the 1054 patients with HF enrolled in the registry, 769 had sufficient data to calculate ePV (using the Duarte, Kaplan, and Hakim equations) and relative plasma volume status (rPVS), and these patients were subsequently included in the present analysis. The severity of congestion was assessed using a 6-point congestion score (CS). Patients were divided into three groups according to the degree of congestion.

RESULTS

Out of four equations tested, only ePVDuarte and rPVS were statistically higher in patients with severe congestion as compared to patients with no congestion (p<0.001 for both). Both ePVDuarte (r = 0.197, p<0.001) and rPVS (r = 0.153, p<0.001) showed statistically significant correlations with CS and both had a modest accuracy (70.4% for ePVDuarte and 69.4% for rPVS) to predict a CS ≥3. After a median follow up of 496 days, both ePVDuarte (OR:1.14,95%CI:1.03-1.26, p = 0.01) and rPVS (OR:1.02, 95%CI:1.00-1.03, p = 0.03) were associated with all-cause mortality after adjusting for demographic and clinical variables. However, none of the indices were associated with mortality following the introduction of CS to the models (p>0.05 for both).

CONCLUSIONS

Elevated ePVDuarte and rPVS were indicators of congestion but with a limited robustness, and either parameter could be clinically useful when a comprehensive clinical evaluation of congestion is not feasible.

Estimated plasma volume status adds prognostic value to hemodynamic parameters in advanced heart failure

BACKGROUND

Estimated plasma volume status (ePVS) is a marker of intravascular congestion and has prognostic value in patients with heart failure (HF). The elevation of intracardiac filling pressures is defined as hemodynamic congestion and is also associated with poor prognosis. However, the relationship between intravascular congestion and hemodynamic congestion remains unclear. This study sought to explore the correlation between ePVS and hemodynamic parameters and determine the association between ePVS and clinical outcomes in patients with advanced HF.

METHODS

Patients with advanced HF underwent right heart catheterization (RHC) for hemodynamic profiles. The sum of right atrial pressure (RAP) and pulmonary arterial wedge pressure (PAWP) > 30 mmHg was considered to present with hemodynamic congestion. Blood tests were conducted within 24 h of RHC. We calculated ePVS using the Strauss-derived Duarte formula. The primary outcome was all-cause mortality.

RESULTS

A total of 195 patients were divided into two groups based on the cut-off value of ePVS (4.08 dL/g) calculated from receiver operating characteristic analysis. Patients with ePVS > 4.08 dL/g were more likely to present with wet rales (21.2% vs. 9.9%, P = 0.032) and had a higher risk of death (HR 4.748, 95% CI 2.385-9.453), regardless of whether RAP + PAWP was normal or elevated (all P < 0.05). Hemodynamic parameters and ePVS were not correlated (all P > 0.05). High ePVS significantly improved the predictive value beyond the clinical plus hemodynamic prognostic model (area under the curve of 0.844, Delong test, P = 0.024).

CONCLUSION

ePVS could additionally add prognostic value to hemodynamic parameters in advanced heart failure, although not correlated with hemodynamic parameters.

The effects of empagliflozin on measured glomerular filtration rate and estimated extracellular and plasma volumes in patients with type 2 diabetes

AIMS

To investigate the effects of empagliflozin on measured glomerular filtration rate (mGFR), estimated plasma volume (PV) and estimated extracellular volume (ECV) in a cohort of patients with type 2 diabetes (T2D) and high risk of cardiovascular events.

MATERIALS AND METHODS

In this prespecified substudy of the randomized, placebo-controlled SIMPLE trial, patients with T2D at high risk of cardiovascular events were allocated to either empagliflozin 25 mg or placebo once daily for 13 weeks. The prespecified outcome was between-group change in mGFR, measured by the 51 Cr-EDTA method after 13 weeks; changes in estimated PV and estimated ECV were included.

RESULTS

From April 4, 2017 to May 11, 2020, 91 participants were randomized. Of these, 45 patients from the empagliflozin group and 45 patients from the placebo group were included in the intention-to-treat analysis. Treatment with empagliflozin reduced mGFR by -7.9 mL/min (95% confidence interval [CI] -11.1 to -4.7; P < 0.001), estimated ECV by -192.5 mL (95% CI -318.0 to -66.9; P = 0.003) and estimated PV by -128.9 mL (95% CI -218.0 to 39.8; P = 0.005) at Week 13.

CONCLUSIONS

Treatment with empagliflozin for 13 weeks reduced mGFR, estimated ECV and estimated PV in patients with T2D and high risk of cardiovascular events.

Prediction of plasma volume and total hemoglobin mass with machine learning

Hemoglobin concentration ([Hb]) is used for the clinical diagnosis of anemia, and in sports as a marker of blood doping. [Hb] is however subject to significant variations mainly due to shifts in plasma volume (PV). This study proposes a newly developed model able to accurately predict total hemoglobin mass (Hbmass) and PV from a single complete blood count (CBC) and anthropometric variables in healthy subject. Seven hundred and sixty-nine CBC coupled to measures of Hbmass and PV using a CO-rebreathing method were used with a machine learning tool to calculate an estimation model. The predictive model resulted in a root mean square error of 33.2 g and 35.6 g for Hbmass, and 179 mL and 244 mL for PV, in women and men, respectively. Measured and predicted data were significantly correlated (p < 0.001) with a coefficient of determination (R2 ) ranging from 0.76 to 0.90 for Hbmass and PV, in both women and men. The Bland-Altman bias was on average 0.23 for Hbmass and 4.15 for PV. We herewith present a model with a robust prediction potential for Hbmass and PV. Such model would be relevant in providing complementary data in contexts such as the epidemiology of anemia or the individual monitoring of [Hb] in anti-doping.

Longitudinal haematological responses to training load and heat acclimation preceding a male team pursuit cycling world record

This study evaluated relationships between changes in training load, haematological responses, and endurance exercise performance during temperate and heat acclimation (HA) training preceding a male team cycling pursuit world record (WR). Haemoglobin mass (Hbmass) and concentration ([Hb]), plasma volume (PV) and blood volume (BV) were assessed in nine male track endurance cyclists (∼3 occasions per month) training in temperate conditions (247-142 days prior to the WR) to establish responses to differing acute (ATL) and chronic (CTL) training loads. Testing was performed again pre- and post-HA (22-28 days prior to the WR). Endurance performance (V̇O₂max, 4MMP, lactate threshold 1 and 2) was assessed on three occasions (238-231, 189-182 and 133-126 days prior to the WR). In temperate conditions, CTL was associated with Hbmass (B = 0.62, P = 0.02), PV (B = 4.49, P = 0.01) and BV (B = 6.51, P = 0.04) but not [Hb] (B = -0.01, P = 0.17). ATL was associated with PV (B = 2.28, P < 0.01), BV (B = 2.63, P = 0.04) and [Hb] (B = -0.01, P = 0.04) but not Hbmass (B = 0.10, P = 0.41). During HA, PV increased 8.2% (P < 0.01), while Hbmass, CTL and ATL were unchanged. Hbmass and [Hb] were associated with all performance outcomes (P < 0.05), except V̇O2max. PV and BV were not associated with performance outcomes. During temperate training, changes in Hbmass were most strongly associated with changes in CTL. Both CTL and ATL were associated with changes in PV, but HA was associated with increased PV and maintenance of Hbmass without increasing ATL or CTL. In practical terms, maintaining high CTL and high Hbmass might be beneficial for improving endurance performance.HIGHLIGHTSChanges in haemoglobin mass were associated with endurance exercise performance and changes in chronic training load in temperate conditions.Heat acclimation increased plasma volume and maintained haemoglobin mass independently of chronic training load.Chronic training loads and haemoglobin mass should be increased to improve endurance exercise performance.Heat acclimation may optimise haematological adaptations when training load is reduced.

Impact of estimated plasma volume status on clinical outcomes in patients with lower extremity artery disease who underwent endovascular therapy

Lower extremity artery disease (LEAD) is an arterial occlusive disease associated with high morbidity and mortality. Estimated plasma volume status (ePVS), a marker of plasma volume expansion and contraction, is gaining attention in the field of cardiovascular diseases. However, the impact of ePVS on the clinical outcomes of patients with LEAD remains unclear. We calculated ePVS using two different formulas, Kaplan-Hakim (KH-ePVS) and Duarte (D-ePVS), in 288 patients (mean age, 73 years; 77% male) with LEAD who underwent the first endovascular therapy (EVT), and prospectively followed them up between 2014 and 2019. All patients were divided into two groups based on the median ePVS values. The primary endpoints were composite events, including all-cause death and major adverse limb events (death/MALE). The median follow-up duration was 672 days. There were 183, 40 and 65 patients in Fontaine classes II, III, and IV, respectively. The median KH-ePVS and D-ePVS was 5.96 and 5.09, respectively. The ePVS significantly increased with advancing Fontaine classes. Kaplan-Meier analysis demonstrated that the high ePVS group had higher rates of death/MALE than the low ePVS group. Multivariate Cox proportional hazard analysis revealed that each ePVS was an independent predictor for death/MALE after adjusting for confounding risk factors. The prognostic ability for death/MALE was significantly improved by adding ePVS to the basic predictors. ePVS was associated with LEAD severity and clinical outcomes, suggesting that ePVS could be an additional risk factor for death/MALE in patients with LEAD who underwent EVT. We demonstrated that the association between ePVS and the clinical outcomes of patients with LEAD. The prognostic ability for death/MALE was significantly improved by adding ePVS to the basic predictors. LEAD lower extremity artery disease, MALE major adverse limb events, PVS plasma volume status.