Relationship Between Hemoglobin Concentration and Cardiovascular Disease Mortality in a 25-Year Follow-up Study of a Japanese General Population - NIPPON DATA90

BACKGROUND

Deviations of hemoglobin from normal levels may be a factor in cardiovascular disease (CVD) risk; however, conclusive evidence is lacking. In addition, preclinical conditions may influence hemoglobin concentrations, but studies focusing on reverse causation are limited. Thus, we examined the relationship between hemoglobin concentrations and CVD mortality risk, considering reverse causation.Methods and Results: In a prospective cohort representative of the general Japanese population (1990-2015), we studied 7,217 individuals (mean age 52.3 years; 4,219 women) without clinical CVD at baseline. Participants were categorized into sex-specific hemoglobin quintiles (Q1-Q5) and data were analyzed using the Cox proportional hazards model adjusted for possible confounders. During a 25-year follow-up, 272 men and 334 women died from CVD. Adjusted hazard ratios for CVD mortality across sex-specific quintiles, using Q3 as the reference, were significantly higher for Q1 (1.40; 95% confidence interval [CI] 1.08-1.82) and Q5 (1.49; 95% CI 1.14-1.96), and remained significant after excluding deaths within the first 5 years of follow-up to consider reverse causation (1.35 [95% CI 1.02-1.79] and 1.45 [95% CI 1.09-1.94], respectively). A similar U-shaped association was seen between transferrin saturation levels and CVD mortality, but after excluding deaths within the first 5 years the association was significant only for Q1.

CONCLUSIONS

Low and high hemoglobin concentrations were associated with an increased risk of CVD mortality.

Elevation and blood traits in the mesquite lizard: Are patterns repeatable between mountains?

Ecogeographical patterns describe predictable variation in phenotypic traits between ecological communities. For example, high-altitude animals are expected to show elevated hematological values as an adaptation to the lower oxygen pressure. Mountains act like ecological islands and therefore are considered natural laboratories. However, the majority of ecophysiological studies on blood traits lack replication that would allow us to infer if the pattern reported is a local event or whether it is a widespread pattern resulting from larger-scale ecological processes. In lizards, in fact, the increase of hematological values at high altitudes has received mixed support. Here, for the first time, we compare blood traits in lizards along elevational gradients with replication. We tested the repeatability of blood traits in mesquite lizards between different elevations in three different mountains from the Trans-Mexican Volcanic Belt. We measured hematocrit, hemoglobin concentration, mean corpuscular hemoglobin concentration, and erythrocyte size in blood samples of low, medium, and high-elevation lizards. We obtained similar elevational patterns between mountains, but the blood traits differed among mountains. Middle-altitude populations had greater oxygen-carrying capacity than lizards from low and high altitudes. The differences found between mountain systems could be the result of phenotypic plasticity or genetic differentiation as a consequence of abiotic factors not considered.

Rapid determination of hemoglobin concentration by a novel ensemble extreme learning machine method combined with near-infrared spectroscopy

A novel ensemble extreme learning machine (ELM) approach that combines Monte Carlo (MC) sampling and least absolute shrinkage and selection operator (LASSO), named as MC-LASSO-ELM, is proposed to determine hemoglobin concentration of blood. It employs MC sampling to randomly select samples from the training set and LASSO further to choose variables from selected samples to establish plenty of ELM sub-models. The final prediction is obtained by combining the predictions of these sub-models. Combined with near-infrared spectroscopy, MC-LASSO-ELM is used to determine the hemoglobin concentration of blood. Compared with ELM, MC-ELM and LASSO-ELM, MC-LASSO-ELM can obtain the best stability and highest accuracy.

COVID-19 induces proatherogenic alterations in moderate to severe non-comorbid patients: A single-center observational study

Patients with COVID-19 can be asymptomatic or present mild to severe symptoms, leading to respiratory and cardiovascular complications and death. Type 2 diabetes mellitus (T2DM) and obesity are considered risk factors for COVID-19 poor prognosis. In parallel, COVID-19 severe patients exhibit dyslipidemia and alterations in neutrophil to lymphocyte ratio (NLR) associated with disease severity and mortality. To investigate whether such alterations are caused by the infection or results from preexisting comorbidities, this work analyzed dyslipidemia and the hemogram profile of COVID-19 patients according to the severity and compared with patients without T2DM or obesity comorbidities. Dyslipidemia, with a marked decrease in HDL levels, and increased NLR accompanied the disease severity, even in non-T2DM and non-obese patients, indicating that COVID-19 causes the observed alterations. Because decreased hemoglobin is involved in COVID-19 severity, and hemoglobin concentration is associated with metabolic diseases, the erythrogram of patients was also evaluated. We verified a drop in hemoglobin and erythrocyte number in severe patients, independently of T2DM and obesity, which may explain in part the need for artificial ventilation in severe cases. Thus, the control of such parameters (especially HDL levels, NLR, and hemoglobin concentration) could be a good strategy to prevent COVID-19 complications and death.

Ultrasound-guided Microwave Ablation in the Management of Symptomatic Uterine Myomas: A Systematic Review and Meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the clinical effects and safety of ultrasound-guided microwave ablation (MWA) for the treatment of symptomatic uterine myomas.

DATA SOURCES

We searched PubMed, Web of Science Core Collection, Cochrane Library, Embase, Scopus, and Google Scholar for studies from January 2000 to January 2021.

METHODS OF STUDY SELECTION

We included all studies that reported the clinical outcomes of ultrasound-guided MWA in women with symptomatic uterine myomas. Two researchers conducted the study selection according to the screening criteria.

TABULATION, INTEGRATION, AND RESULTS

We evaluated the risk of bias and evidence quality using the Newcastle-Ottawa scale. Two researchers independently extracted information from the included studies. We extracted the standardized mean difference (SMD) and pooled proportion with a 95% confidence interval (CI) for the outcome measures of interest. A total of 10 studies representing 671 patients were included. The Uterine Fibroid Symptom and Quality of Life (UFS-QoL) questionnaire was used to assess the clinical effects. Compared with baseline, the UFS scores decreased significantly (SMD 3.37; 95% CI, 2.27-4.47; p <.001; reduction rate 65.9%), QoL scores increased significantly (SMD -3.12; 95% CI, -3.93 to -2.30; p <.001; rate of increase 72.0%), and hemoglobin concentration increased significantly (SMD -2.13; 95% CI, -3.44 to -0.81; p = .002; rate of increase 30.3%) at follow-up. The mean operation time was 34.48 minutes (95% CI, 22.82-46.13; p <.001). The rate of reduction in myoma volume after MWA was 85.3% (95% CI, 82.7%-88.0%, p <.001). No major adverse event was reported, and the incidence of minor adverse events was 21.1% (95% CI, 15.1%-27.0%, p <.001).

CONCLUSION

Ultrasound-guided MWA is an effective and safe minimally invasive therapy for symptomatic uterine myomas.

What is the best wavelength for the measurement of hemolysis index?

BACKGROUND

Hemolysis is a common problem in the handling of serum specimens. The hemolysis index (HI) provides a warning of hemolysis in auto-analyzers. However, HI has not been standardized, and each laboratory's original method is applied. Especially, the wavelength used for HI measurement is different in each laboratory. Thus, we investigated the warning ability of HI at various wavelengths.

METHODS

We selected 4 wavelength types, and each HI was measured and calculated (410 nm/HI-1, 451 nm/HI-2, 545 nm/HI-3, and 571 nm/HI-4). To compare the 4 HI types, we investigated the influence of 3 interference components using artificially hemolyzed specimens (AHSs). We also investigated both the relationship between HI and hemoglobin concentration (Hb) and that between HI and 31 biochemical test values in AHSs.

RESULTS

In the interference assessment, only HI-4 showed no influence on the 3 interference components. The correlation between Hb and HI-4 was very strong (r_S = 0.9987). A 1-unit increase in HI-4 corresponded to a 14.8-mg/dL increase in Hb.

CONCLUSION

We found the best wavelength for HI to be at or near 571 nm.

Hemoglobin levels and anemia evaluation among pregnant women in the remote and rural high lands of mid-western Nepal: a hospital based study

Background

Anemia though is a major risk factor for unfavorable pregnancy outcomes; no previous studies have yet described the hemoglobin (Hb) concentrations and anemia prevalence among pregnant women of remote mid western highlands of Nepal where the aggravating factors that increase the risk of anemia are very common. In addition, the physiological adaptive Hb rise to altitude was considered in the study while evaluating anemia. Thus, our primary objectives were to study the hemoglobin levels and prevalence of anemia among pregnant women of Jumla and its adjoining districts, and to assess the potential associations of hemoglobin and anemia with women’s characteristics.

Methods

The study was conducted in 319 singleton term non-smoker pregnant women who visited to the teaching hospital for delivery. Their blood samples were tested for Hb and related sociodemographic information was collected. One-way analysis of variance (ANOVA) and independent t-test were used to compare the mean Hb levels. Multiple linear regression model and multiple logistic regression model were used to assess the association of Hb level and anemia with pregnant women’s characteristics. The prevalence of anemia was calculated based on the altitude and pregnancy-adjusted Hb cut off value for anemia [{11+ adjustment factor (1.3)} gm./dl].

Results

The overall mean hemoglobin concentration was (13.497 ± 1.64) gm/dl, ranging from 8 to 19.20 g/dl. The pregnant women Hb level showed significant association with their age (Coeff = 0.059; 95% CI: 0.011, 0.106; p = 0.015) and parity (Coeff = − 0.21; 95% CI: − 0.382, − 0.038; p = 0.017). The overall prevalence of anemia in the study population was 17.9% (57/319), which varied with age, parity and ethnicity. The disadvantaged Janajatis were more likely (OR = 4.615, 95% CI: 1.48, 14.35, p = 0.008) to have anemia compared to upper cast group.

Conclusion

The mean Hb concentration was high and prevalence rate of anemia was low among pregnant women in karnali zone compared to average Nepali pregnant women. Women’s age and parity were significant predictors of Hb level. Ethnicity, however, was associated with the occurrence of anemia.

A systematic review of near-infrared spectroscopy in flap monitoring: Current basic and clinical evidence and prospects

BACKGROUND

Near-infrared spectroscopy (NIRS) has been reported to be a reliable non-invasive modality for free flap monitoring; however, the history of its application in flap monitoring is short, and there is no definite consensus regarding its use at present.

OBJECTIVES

The aim of this review is to clarify the evidence related to post-operative flap monitoring using NIRS and examine its appropriateness and usability.

MATERIALS AND METHODS

The PubMed and Web of Science databases were searched using the strings "flap monitoring AND near-infrared spectroscopy" and "flap monitoring AND tissue oxygen saturation," with a study period from inception to December 31, 2016. Two authors independently extracted articles and assessed the quality of the studies. Articles related to NIRS for flap perfusion monitoring were classified and selected regardless of study type.

RESULTS

A total of 15 clinical studies and 8 animal studies were identified and reviewed. The evidence and information on various aspects of NIRS flap monitoring were summarized. The overall flap success rate was 99.5%, and the flap salvage rate was 91.1%, when measuring StO₂ at intervals of every 2 h or sooner. Single StO₂ monitoring was able to detect vascular compromise with 99.1% sensitivity and 99.9% specificity, and earlier than other monitoring methods, but additional Hb concentration monitoring was useful for avoiding false negatives and differentiating arterial and venous occlusion.

CONCLUSIONS

NIRS can be used for flap monitoring and displays high accuracy in various situations; however, further studies are needed to take full advantage of the potential of NIRS.

Low-dose carperitide (α-human A-type natriuretic peptide) alleviates hemoglobin concentration decrease during prolonged oral surgery: a randomized controlled study

PURPOSE

Surgical injury stimulates the renin-angiotensin-aldosterone system (RAAS) and causes antidiuresis, leading to postoperative oliguria. Carperitide (α-human A-type natriuretic peptide) is a cardiac peptide hormone secreted from the atrium. This peptide hormone enhances diuresis by suppressing the RAAS. In our experience, carperitide alleviates decreased hemoglobin (Hb) concentration during elective surgery. In the current study, we investigated the relationship between low-dose carperitide (0.01 µg/kg/min) and Hb concentration during oral surgery.

METHODS

Patients (ASA-PS: I-II, 40-80 years old) undergoing oral maxillofacial surgery (duration of operation >8 h) were enrolled in this study. Patients were divided into two groups: the carperitide group received carperitide at 0.01 µg/kg/min and the control group received normal saline. Body fluid water [including total body water (TBW), extracellular water (ECW), and intracellular water (ICW)], urine volume, and chemical parameters such as Hb concentration, PaO₂, and serum electrolytes were evaluated every 2 h.

RESULTS

In the carperitide group (n = 15), Hb decreased from 12.6 ± 1.1 to 10.8 ± 1.5 g/dl, while it decreased from 12.6 ± 1.4 to 9.5 ± 1.3 g/dl in the control group (n = 15) (p < 0.05). Urine volume (2557.3 ± 983.5 mL) in the carperitide group was significantly more than it was in the control group (1108.8 ± 586.4 mL; p < 0.001). There were no significant differences in clinical characteristics, body fluid water, PaO₂, and serum electrolytes between the two groups. In addition, there were no perioperative clinical respiratory and hemodynamic complications in the groups.

CONCLUSION

The Hb concentration in the group administered low-dose carperitide at 0.01 µg/kg/min remained higher than that in the control group during surgery. Administration of low-dose carperitide may therefore reduce the risk of blood transfusion during surgery.

Transverse water relaxation in whole blood and erythrocytes at 3T, 7T, 9.4T, 11.7T and 16.4T; determination of intracellular hemoglobin and extracellular albumin relaxivities

Blood is a physiological substance with multiple water compartments, which contain water-binding proteins such as hemoglobin in erythrocytes and albumin in plasma. Knowing the water transverse (R₂) relaxation rates from these different blood compartments is a prerequisite for quantifying the blood oxygenation level-dependent (BOLD) effect. Here, we report the Carr-Purcell-Meiboom-Gill (CPMG) based transverse (R_2CPMG) relaxation rates of water in bovine blood samples circulated in a perfusion system at physiological temperature in order to mimic blood perfusion in humans. R_2CPMG values of blood plasma, lysed packed erythrocytes, lysed plasma/erythrocyte mixtures, and whole blood at 3 T, 7 T, 9.4 T, 11.7 T and 16.4 T were measured as a function of hematocrit or hemoglobin concentration, oxygenation, and CPMG inter-echo spacing (τ_cp). R_2CPMG in lysed cells showed a small τ_cp dependence, attributed to the water exchange rate between free and hemoglobin-bound water to be much faster than τ_cp. This was contrary to the tangential dependence in whole blood, where a much slower exchange between cells and blood plasma applies. Whole blood data were fitted as a function of τ_cp using a general tangential correlation time model applicable for exchange as well as diffusion contributions to R_2CPMG, and the intercept R_20blood at infinitely short τ_cp was determined. The R_20blood values at different hematocrit and the R_2CPMG values of lysed erythrocyte/plasma mixtures at different hemoglobin concentration were used to determine the relaxivity of hemoglobin inside the erythrocyte (r_2Hb) and albumin (r_2Alb) in plasma. The r_2Hb values obtained from lysed erythrocytes and whole blood were comparable at full oxygenation. However, while r_2Hb determined from lysed cells showed a linear dependence on oxygenation, this dependence became quadratic in whole blood. This possibly suggests an additional relaxation effect inside intact cells, perhaps due to hemoglobin proximity to the erythrocyte membrane. However, we cannot exclude that this is a consequence of the simple tangential model used to remove relaxation contributions from exchange and diffusion. The extensive data set presented should be useful for future theory development for the transverse relaxation of blood.

A case-control study of prevalence of anemia among patients with type 2 diabetes

BACKGROUND

Anemia is defined as a reduction in the hemoglobin concentration of blood, which consequently reduces the oxygen-carrying capacity of red blood cells such that they are unable to meet the body's physiological needs. Several reports have indicated that anemia mostly occurs in patients with diabetes with renal insufficiency while limited studies have reported the incidence of anemia in people with diabetes prior to evidence of renal impairment. Other studies have also identified anemia as a risk factor for the need for renal replacement therapy in diabetes. Understanding the pathogenesis of anemia associated with diabetes may lead to the development of interventions to optimize outcomes in these patients. The aim of this study was therefore to determine the prevalence of anemia among patients with type 2 diabetes.

METHODS

A total of 100 (50 with type 2 diabetes and 50 controls) participants were recruited for our study. Participants' blood samples were analyzed for fasting blood glucose, full blood count and renal function tests among others. The prevalence of anemia was then determined statistically.

RESULTS

A high incidence of anemia was observed in the cases. Of the patients with diabetes, 84.8% had a hemoglobin concentration that was significantly less (males 11.16±1.83 and females 10.41±1.49) than the controls (males 14.25±1.78 and females 12.53±1.14). Renal insufficiency determined by serum creatinine level of >1.5 mg/dL, estimated glomerular filtration rate <60 ml/minute/1.73 m2, and erythropoietin levels was also observed to be high in the cases (54.0%; with mean creatinine concentration of 3.43±1.73 and erythropoietin 6.35±1.28 mIU/mL). A significantly increased fasting blood glucose, urea, sodium, potassium, and calcium ions were observed in the cases (7.99±1.30, 5.19±1.99, 140.90±6.98, 4.86±0.53 and 1.47±0.31 respectively) as compared to the controls (4.66±0.54, 3.56±2.11, 135.51±6.84, 4.40±0.58 and 1.28±0.26 respectively). Finally, a significant association between hemoglobin concentration and fasting blood glucose was also observed in the cases.

CONCLUSIONS

The findings suggest that a high incidence of anemia is likely to occur in patients with poorly controlled diabetes and in patients with diabetes and renal insufficiency.

Capillary-scale direct measurement of hemoglobin concentration of erythrocytes using photothermal angular light scattering

We present a direct, rapid and chemical-free detection method for hemoglobin concentration ([Hb]), based on photothermal angular light scattering. The iron oxides contained in hemoglobin molecules exhibit high absorption of 532-nm light and generate heat under the illumination of 532-nm light, which subsequently alters the refractive index of blood. We measured this photothermal change in refractive index by employing angular light scattering spectroscopy with the goal of quantifying [Hb] in blood samples. Highly sensitive [Hb] measurement of blood samples was performed by monitoring the shifts in angularly dispersed scattering patterns from the blood-loaded microcapillary tubes. Our system measured [Hb] over the range of 0.35-17.9 g/dL with a detection limit of ~0.12 g/dL. Our sensor was characterized by excellent correlation with a reference hematology analyzer (r>0.96), and yielded a precision of 0.63 g/dL for a blood sample of 9.0 g/dL.

Photothermal spectral-domain optical coherence reflectometry for direct measurement of hemoglobin concentration of erythrocytes

A novel optical detection method for hemoglobin concentration is described. The hemoglobin molecules consisting mainly of iron generate heat upon their absorption of light energy at 532 nm, which subsequently changes the refractive index of the blood. We exploit this photothermal effect to determine the hemoglobin concentration of erythrocytes without any preprocessing of blood. Highly sensitive measurement of refractive index alteration of blood samples is enabled by a spectral-domain low coherence reflectometric sensor with subnanometer-level optical path-length sensitivity. The performance and validity of the sensor are presented by comparing the measured results against the reference data acquired from an automatic hematology analyzer.

Physiology of natriuretic peptides: The volume overload hypothesis revisited

The discovery of the natriuretic peptide system in the early 1980s aroused great interest among clinical cardiologists. The heart was not a mechanical pump alone, but also an endocrine organ that had powerful effects on blood circulation. Natriuretic peptides caused both natriuresis and diuresis, and they responded to a volume overload which caused either stretch or pressure on the heart. As a result, the findings led to the conclusion that the human body had a hormone with effects similar to those of a drug which treats high blood pressure. Later, it became evident that the volume contraction was fortified by extrarenal plasma shift. Here, a hypothesis is presented in which the role of natriuretic peptides is to regulate oxygen transport as the volume contraction leads to hemoconcentration with an increased oxygen-carrying capacity. Wall stress, either chemical or mechanical, changes the oxygen gradient of the myocardium and affects the diffusion of oxygen within a myocyte. In support of this hypothesis, hypoxia-response elements have been found in both the atrial natriuretic peptide and the brain natriuretic peptide genes.

Dynamic model for the tissue concentration and oxygen saturation of hemoglobin in relation to blood volume, flow velocity, and oxygen consumption: Implications for functional neuroimaging and coherent hemodynamics spectroscopy (CHS)

This article presents a dynamic model that quantifies the temporal evolution of the concentration and oxygen saturation of hemoglobin in tissue, as determined by time-varying hemodynamic and metabolic parameters: blood volume, flow velocity, and oxygen consumption. This multi-compartment model determines separate contributions from arterioles, capillaries, and venules that comprise the tissue microvasculature, and treats them as a complete network, without making assumptions on the details of the architecture and morphology of the microvascular bed. A key parameter in the model is the effective blood transit time through the capillaries and its associated probability of oxygen release from hemoglobin to tissue, as described by a rate constant for oxygen diffusion. The solution of the model in the time domain predicts the signals measured by hemodynamic-based neuroimaging techniques such as functional near-infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI) in response to brain activation. In the frequency domain, the model yields an analytical solution based on a phasor representation that provides a framework for quantitative spectroscopy of coherent hemodynamic oscillations. I term this novel technique coherent hemodynamics spectroscopy (CHS), and this article describes how it can be used for the assessment of cerebral autoregulation and the study of hemodynamic oscillations resulting from a variety of periodic physiological challenges, brain activation protocols, or physical maneuvers.