Intravenous superoxide dismutase as a protective agent to prevent impairment of lung function induced by high tidal volume ventilation

Background

Positive-pressure mechanical ventilation is essential in assisting patients with respiratory failure in the intensive care unit and facilitating oxygenation in the operating room. However, it was also recognized as a primary factor leading to hospital-acquired pulmonary dysfunction, in which pulmonary oxidative stress and lung inflammation had been known to play important roles. Cu/Zn superoxide dismutase (SOD) is an important antioxidant, and possesses anti-inflammatory capacity. In this study, we aimed to study the efficacy of Cu/Zn SOD, administered intravenously during high tidal volume (HTV) ventilation, to prevent impairment of lung function.

Methods

Thirty-eight male Sprague-Dawley rats were divided into 3 groups: 5 h ventilation with (A) low tidal volume (LTV; 8 mL/kg; n = 10), (B) high tidal volume (HTV; 18 mL/kg; n = 14), or (C) HTV and intravenous treatment of Cu/Zn SOD at a dose of 1000 U/kg/h (HTV + SOD; n = 14). Lung function was evaluated both at baseline and after 5-h ventilation. Lung injury was assessed by histological examination, lung water and protein contents in the bronchoalveolar lavage fluid (BALF). Pulmonary oxidative stress was examined by concentrations of methylguanidine (MG) and malondialdehyde (MDA) in BALF, and antioxidative activity by protein expression of glutathione peroxidase-1 (GPx-1) in the lung. Severity of lung inflammation was evaluated by white blood cell and differential count in BALF, and protein expression of inducible nitric oxide synthase (iNOS), intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9), and mRNA expression of nuclear factor-κB (NF-κB) in the lung. We also examined protein expression of surfactant protein (SP)-A and D and we measured hourly changes in serum nitric oxide (NO) level.

Results

Five hours of LTV ventilation did not induce a major change in lung function, whereas 5 h of HTV ventilation induced apparent combined restrictive and obstructive lung disorder, together with increased pulmonary oxidative stress, decreased anti-oxidative activity and increased lung inflammation (P < 0.05). HTV ventilation also decreased SP-A and SP-D expression and suppressed serum NO level during the time course of ventilation. Cu/Zn SOD administered intravenously during HTV ventilation effectively reversed associated pulmonary oxidative stress and lung inflammation (P < 0.05); moreover, it preserved SP-A and SP-D expressions in the lung and increased serum nitric oxide (NO) level, enhancing vascular NO bioavailability.

Conclusions

HTV ventilation can induce combined restrictive and obstructive lung disorders. Intravenous administration of Cu/Zn SOD during HTV ventilation can prevent lung function impairment and lung injury via reducing pulmonary oxidative stress and lung inflammation, preserving pulmonary surfactant expression, and enhancing vascular NO bioavailability.

Prognostic Nutritional Index and the Risk of Mortality in Patients With Acute Heart Failure

Background

Nutritional status has been related to clinical outcomes in patients with heart failure. We assessed the association between nutritional status, indexed by prognostic nutritional index (PNI), and survival in patients hospitalized for acute heart failure.

Methods and Results

A total of 1673 patients (age 76±13 years, 68% men) hospitalized for acute heart failure in a tertiary medical center were analyzed. PNI was calculated as 10×serum albumin (g/dL)+0.005×total lymphocyte count (per mm³). National Death Registry was linked to identify the clinical outcomes of all‐cause and cardiovascular death. With increasing tertiles of PNI, age and N‐terminal probrain natriuretic peptide decreased, and body mass index, estimated glomerular filtration rate, and hemoglobin increased. During a mean follow‐up duration of 31.5 months, a higher PNI tertile was related to better survival free from all‐cause and cardiovascular mortality in the total study population and in participants with either reduced or preserved left ventricular ejection fraction. After accounting for age, sex, estimated glomerular filtration rate, left ventricular ejection fraction, serum sodium level, and on‐admission systolic blood pressure, PNI was independently associated with cardiovascular death and total mortality (hazard ratio per 1 SD of the natural logarithm of the PNI: 0.76 [95% CI, 0.66–0.87] and 0.79 [95% CI, 0.73–0.87], respectively). In subgroup analyses stratified by age, sex, left ventricular ejection fraction, body mass index, or estimated glomerular filtration rate, PNI was consistently related to mortality.

Conclusions

PNI is independently associated with long‐term survival in patients hospitalized for acute heart failure with either reduced or preserved left ventricular ejection fraction.

Performance of AHEAD Score in an Asian Cohort of Acute Heart Failure With Either Preserved or Reduced Left Ventricular Systolic Function

Background

AHEAD (A: atrial fibrillation; H: hemoglobin; E: elderly; A: abnormal renal parameters; D: diabetes mellitus) score has been related to clinical outcomes of acute heart failure. However, the prognostic value of the AHEAD score in acute heart failure patients with either reduced or preserved left ventricular ejection fraction (HFrEF and HFpEF) remain to be elucidated.

Methods and Results

The study population consisted of 2143 patients (age 77±12 years, 68% men, 38% HFrEF) hospitalized primarily for acute heart failure with a median follow‐up of 23.75 months. The performance of the AHEAD score (atrial fibrillation, hemoglobin <13 mg/dL for men and 12 mg/dL for women, age >70 years, creatinine >130 μmol/L, and diabetes mellitus) was evaluated by Cox's regression analysis for predicting cardiovascular and all‐cause mortality. The mean AHEAD scores were 2.7±1.2 in the total study population, 2.6±1.3 in the HFrEF group, and 2.7±1.1 in the HFpEF group. After accounting for sex, sodium, uric acid, and medications, the AHEAD score remained significantly associated with all‐cause and cardiovascular mortality (hazard ratio and 95% CI: 1.49, 1.38–1.60 and 1.48, 1.33–1.64), respectively. The associations of AHEAD score with mortality remained significant in the subgroups of HFrEF (1.63, 1.47–1.82) and HFpEF (1.34, 1.22–1.48). Moreover, when we calculated a new AHEAD‐U score by considering uric acid (>8.6 mg/dL) in addition to the AHEAD score, the net reclassification was improved by 19.7% and 20.1% for predicting all‐cause and cardiovascular mortality, respectively.

Conclusions

The AHEAD score was useful in predicting long‐term mortality in the Asian acute heart failure cohort with either HFrEF or HFpEF. The new AHEAD‐U score may further improve risk stratification.

Excess Pressure Integral Predicts Long-Term All-Cause Mortality in Stable Heart Failure Patients

BACKGROUND

Excess pressure integral (XSPI) derived from reservoir-excess pressure analysis is proposed as a novel indicator of cardiovascular dysfunction in hypertensives. Our study investigated the prognostic value of XSPI for stable heart failure (HF) patients.

METHODS

In total, 238 subjects (mean age 63 ± 18 years, 111 male), comprising 168 stable HF patients with either reduced (SHF; n = 64) left ventricular (LV) ejection fraction (EF) or isolated diastolic dysfunction (DHF, n = 104), and 70 healthy controls, were enrolled. Tonometry-derived carotid pressure waveforms were analyzed with the reservoir pressure theory. XSPI was calculated by subtracting the reservoir pressure from carotid pressure waveform.

RESULTS

XSPI in SHF and DHF (14.01 ± 5.16 and 13.90 ± 5.05 mm Hg•s) were significantly higher than that in controls (11.01 ± 3.67 mm Hg•s, both P < 0.001). During a median follow-up of 9.9 years, 56 deaths occurred. XSPI was a significant independent predictor of total mortality after adjusting for age, sex, left ventricular ejection fraction (LVEF), glomerular filtration rate (GFR), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) (hazard ratio = 4.37 per 1 SD, 95% confidence interval, 1.31-14.58). In subgroup analysis by different baseline characteristics including age, gender, NT-proBNP, LVEF, and GFR, higher XSPI was consistently associated with greater risk of total mortality.

CONCLUSION

In patients with stable HF, XSPI, a novel maker of cardiovascular dysfunction, was associated with long-term risk of total mortality.

Hemodynamic Determinants of the Short-Term Blood Pressure Variability: Differential Roles of Arterial Stiffness and Wave Reflection

BACKGROUND

A high 24-hour ambulatory diastolic (DBP) but not systolic (SBP) blood pressure variability (BPV) is significantly predictive of long-term cardiovascular mortality in untreated hypertensive subjects, independent of office or 24-hour SBP. The present study was aimed to investigate hemodynamic factors that are independently associated with systolic and diastolic BPV from the 24-hour ambulatory blood pressure monitoring (ABPM).

METHODS

A cohort of 624 normotensive and 633 untreated hypertensive participants with baseline ABPM was drawn from a community-based survey. BPV was assessed by the read-to-read average real variability of the 24-hour SBP and DBP (ARVs and ARVd, respectively). Hemodynamic variables including total peripheral resistance (TPR), carotid-femoral pulse wave velocity (cf-PWV), and amplitudes of the decomposed forward (Pf) and backward (Pb) carotid pressure waves were analyzed.

RESULTS

In multivariable analyses, hemodynamic variables independently associated with 24-hour SBP were 24-hour heart rate (HR), TPR, cf-PWV, Pf, and Pb (model r2 = 0.535). Hemodynamic factors independently associated with ARV were 24-hour HR, Pf, and Pb for ARVs, and 24-hour HR, cf-PWV, Pf, and Pb for ARVd (model R2 = 0.345 and 0.220, respectively). Addition of 24-hour SBP to the ARV models only slightly improved variance explained by the models (R2 = 0.383 and 0.224, respectively). Pb accounted for >50% of total variance of ARVs and ARVd, whereas cf-PWV was a minor determinant of ARVd (<5% of total variance).

CONCLUSIONS

ARVd was associated with fewer hemodynamic variables than to 24-hour SBP. Among those hemodynamic variables wave reflection but not arterial stiffness had the dominant independent association with ARV.

Investigation of Viscoelasticity in the Relationship Between Carotid Artery Blood Pressure and Distal Pulse Volume Waveforms

We investigated the relationship between carotid artery blood pressure (BP) and distal pulse volume waveforms (PVRs) via subject-specific mathematical modeling. We conceived three physical models to define the relationship: a tube-load model augmented with a gain (TLG), Voigt (TLV), and standard linear solid (TLS) models. We compared these models using PVRs measured via BP cuffs at an upper arm and an ankle as well as carotid artery tonometry waveform collected from 133 subjects. At both upper arm and ankle, PVR was related to carotid artery tonometry by TLV and TLS models better than by TLG model; when root-mean-squared over all the subjects, the systolic and diastolic BP errors between measured carotid artery tonometry waveform and the one estimated from distal PVR reduced from 4.3 mmHg and 4.6 mmHg (TLG) to 1.1 mmHg and 1.0 mmHg (TLS) for the upper arm (p < 0.0167), and from 2.1 mmHg and 1.7 mmHg (TLG) to 2.1 mmHg and 1.5 mmHg (TLV) for the ankle. Further, TLV and TLS models exhibited superior Akaike's Information Criterion (AIC) in both locations than TLG model. However, the difference between TLG versus TLV and TLS models associated with the ankle was not large. Therefore, the relationship of central arterial BP to arm PVR arises from both wave reflection and viscoelasticity while the relationship to ankle PVR mainly arises from wave reflection. These findings may imply that an effective subject-specific transfer function for estimating accurate central arterial BP from an arm PVR should account for the impact of viscoelasticity.

C-Reactive Protein Predicts Incidence of Dementia in an Elderly Asian Community Cohort

BACKGROUND

Many studies have investigated the association between markers for peripheral inflammation and risk of dementia, but the results have been conflicting. We aimed to evaluate the association between a specific inflammation marker, C-reactive protein (CRP), and dementia in an elderly Asian community cohort.

METHODS

The cohort included 1436 individuals (ages 65 and older) from a national representative sample in Taiwan. Dementia incidence was identified using International Classification of Diseases, Ninth Revision codes for vascular dementia, Alzheimer disease, and nonvascular dementia. Baseline characteristics and CRP levels were determined. A Cox proportional hazard model and Fine and Grays model were adjusted for stroke and competing risk of death to estimate the association between inflammation and development of dementia.

RESULTS

During 11.04 years (median) of follow-up, 607 individuals (50.77%) died and 260 individuals (18.11%) were diagnosed with dementia. Those with high CRP had a 55% higher risk of dementia (hazard ratio 1.55; 95% confidence interval 1.21-2.00) compared with those with normal CRP. After adjusting for possible confounding cardiovascular risk factors, high CRP was independently associated with vascular dementia but not Alzheimer disease.

CONCLUSIONS

In this prospective study of an elderly Asian community cohort with more than 10 years of follow-up, the baseline serum CRP level was associated with future development of vascular dementia, but not Alzheimer disease after adjusting for common cardiovascular risk factors, stroke, and competing risk of death.

Efficient organic photovoltaic cells on a single layer graphene transparent conductive electrode using MoOx as an interfacial layer

The large surface roughness, low work function and high cost of transparent electrodes using multilayer graphene films can limit their application in organic photovoltaic (OPV) cells. Here, we develop single layer graphene (SLG) films as transparent anodes for OPV cells that contain light-absorbing layers comprised of the evaporable molecular organic semiconductor materials, zinc phthalocyanine (ZnPc)/fullerene (C60), as well as a molybdenum oxide (MoO_x) interfacial layer. In addition to an increase in the optical transmittance, the SLG anodes had a significant decrease in surface roughness compared to two and four layer graphene (TLG and FLG) anodes fabricated by multiple transfer and stacking of SLGs. Importantly, the introduction of a MoO_x interfacial layer not only reduced the energy barrier between the graphene anode and the active layer, but also decreased the resistance of the SLG by nearly ten times. The OPV cells with the structure of polyethylene terephthalate/SLG/MoO_x/CuI/ZnPc/C60/bathocuproine/Al were flexible, and had a power conversion efficiency of up to 0.84%, which was only 17.6% lower than the devices with an equivalent structure but prepared on commercial indium tin oxide anodes. Furthermore, the devices with the SLG anode were 50% and 86.7% higher in efficiency than the cells with the TLG and FLG anodes. These results show the potential of SLG electrodes for flexible and wearable OPV cells as well as other organic optoelectronic devices.

Comparison of Clinical Outcomes in Patients Undergoing Coronary Intervention with Drug-Eluting Stents or Bare-Metal Stents: A Nationwide Population Study

BACKGROUND

The aim of this propensity score-matched cohort study was to investigate the prognostic impacts of drug-eluting stents (DES) and bare-metal stents (BMS) in patients undergoing percutaneous coronary intervention (PCI).

METHODS

We conducted a retrospective cohort study based on the National Health Insurance program. Patients who had undergone coronary stenting between Jan. 2007 and Dec. 2008 were recruited and monitored until the end of 2010. Subjects with either BMS or DES were matched 2:1 by propensity score, which adjusted for age, sex, stent number and Charlson comorbidity index (CCI). The Kaplan-Meier method and Cox regression models were used for prognostic analyses.

RESULTS

Among a total of 966 patients with a mean age of 66 years, 644 subjects had BMS and 322 subjects had DES. The incidence of myocardial infarction (MI) and death were significantly lower in the DES group as compared with the BMS group for the three-year follow-up duration. With adjustments for age, sex, premium-based monthly salary, levels of hospital care, stent number, CCI, medications, and acute coronary syndrome presentation in the index hospitalization, use of DES rather than BMS was associated with reduced adverse coronary events (hazard ratio and 95% confidence interval: 0.55, 0.38-0.81 in the whole population, and 0.44, 0.26-0.73 in the subgroup patients with stable coronary artery disease).

CONCLUSIONS

Implantation of DES was related to better outcomes than for BMS, in terms of reducing MI and mortality after PCI. The survival benefit for patients with DES was even greater in patients with stable coronary artery disease.

Novel columnar metallomesogens based on cationic platinum(ii) complexes without long peripheral chains

Phosphorescent cationic platinum(ii) complexes without any peripheral flexible chains around the platinum(ii) center show thermotropic columnar liquid crystal properties.

Vascular aging and hypertension: Implications for the clinical application of central blood pressure

Vascular aging may be responsible for the high residual lifetime risk for hypertension in the middle-aged and elderly individuals. Increased arterial stiffness and wave reflection has been recognized as the dominant hemodynamic manifestations of vascular aging, and both are major determinants of central blood pressure (BP) and independent predictors for incident hypertension. Because central BP is strongly linearly associated with age, it can be regarded as an integrated marker for vascular aging. Central BP can be measured noninvasively using various techniques, including the convenient cuff-based oscillometric central BP monitors. Noninvasive central BP is likely better than the conventional brachial BP in association with target organ damages and long term cardiovascular outcomes. Based on the analysis of the long-term events of derivation and validation cohorts, the central BP threshold of 130/90mmHg for defining hypertension has been proposed. Recent studies suggest that the central BP strategy for confirming a diagnosis of hypertension may be more cost-effective than the conventional brachial BP strategy, and guidance of hypertension management with central BP may result in less use of medications to achieve BP control. Vascular aging-related hypertension is expected to become the dominant phenotype in many countries, especially in the Asian regions. Although noninvasive measurement of brachial BP is inaccurate and central BP has been shown to carry superior prognostic value beyond brachial BP, the use of central BP should be justified by studies comparing central blood pressure-guided therapeutic strategies with classic guidelines-guided strategies for preventing cardiovascular events. Future randomized control trials are required to support that the diagnosis and monitoring of vascular aging-related hypertension is best managed with the central BP strategy.

Patient-Specific Oscillometric Blood Pressure Measurement: Validation for Accuracy and Repeatability

Oscillometric devices are widely used for automatic cuff blood pressure (BP) measurement. These devices estimate BP from the oscillometric cuff pressure waveform using population average methods. Hence, the devices may only be accurate over a limited BP range. The objective was to evaluate a new patient-specific method, which estimates BP by fitting a physiologic model to the same waveform. One-hundred and forty-five cardiac catheterization patients and normal adults were included for study. The oscillometric cuff pressure waveform was obtained with an office device, while reference BP was measured via brachial artery catheterization or auscultation, during baseline and/or nitroglycerin administration. Fifty-seven of the subject records were utilized for refining the patient-specific method, while the remaining 88 subject records were employed for evaluation. The precision errors for all BP levels of the patient-specific method ranged from 6.3 to 7.6 mmHg. These errors were significantly lower than those of the office device (by 29% on average) in subjects with high pulse pressure (>50 mmHg) while being comparable to those of the device in subjects with normal pulse pressure (<50 mmHg). The bias and precision of the differences in repeated estimates for all BP levels of the patient-specific method ranged from 0.1 to 1.1 and 2.1 to 5.9 mmHg, respectively. These precision differences were significantly lower than those of the office device (by 64% on average). The patient-specific method may afford more accurate automatic cuff BP measurement in patients with large artery stiffening while limiting the number of required cuff inflations/deflations per measurement.

The relationship between the metabolic syndrome and arterial wall thickness: A mosaic still to be interpreted

BACKGROUND AND AIMS

We aimed to identify clusters of metabolic syndrome (MetS) components, risky for extremely high intima-media thickness.

METHODS

We studied 41,513 volunteers (men and women) from eleven cohorts worldwide, participating in the MARE (Metabolic syndrome and Artery REsearch) Consortium.

RESULTS

Specific clusters of MetS components - high triglycerides-high blood pressure-abdominal obesity (TBW), low HDL cholesterol-high blood pressure-abdominal obesity (HBW), high glucose-high blood pressure-abdominal obesity (GBW) - were accompanied by a 50-90% significantly greater likelihood of presenting extremely high intima-media thickness (via ultrasound of carotid artery, CCA IMT), after controlling for age, sex, smoking, non-HDL cholesterol, and presence of diabetes mellitus. This likelihood is comparable to the effect of being 7-8 years older or of being a cigarette smoker or of having non-HDL cholesterol 50 mg/dl higher.

CONCLUSIONS

The consistent association of specific clusters of MetS components with extremely thick (older) large artery cross-culturally suggests that identification of those clusters in clinical practice will facilitate a personalized health care and a better - i.e. more healthy and cost-effective - prevention of major cardiovascular (CV) events.

Is Noninvasive Brachial Systolic Blood Pressure an Accurate Estimate of Central Aortic Systolic Blood Pressure?

OBJECTIVES

Noninvasive brachial systolic blood pressure (nSBP-B) usually approaches invasive central systolic blood pressure (iSBP-C) with a high correlation. Whether nSBP-B is an accurate estimate of iSBP-C remained to be investigated. Thus, this study aimed to compare the errors of nSBP-B and noninvasive central systolic blood pressure (nSBP-C) with different techniques in estimating iSBP-C.

METHODS

Simultaneous invasive high-fidelity central aortic pressure waveforms and the noninvasive left brachial pulse volume recording (PVR) waveform were recorded in a Generation group ( N = 40) and a Validation group ( N = 100). The accuracy of the noninvasive estimates of iSBP-C obtained from analysis of the calibrated PVR waveform using the generalized transfer function (GTF), pulse waveform analysis (PWA), and N-point moving average (NPMA) methods was examined in the Validation group by calculating the mean absolute error (MAE).

RESULTS

In Generation group, the MAE was 4.6±4.1mm Hg between nSBP-B and invasive brachial SBP, and 6.8±5.5mm Hg between nSBP-B and iSBP-C. In comparison, the MAE of between iSBP-C and nSBP-C with PWA, NPMA, and GTF were 5.5±4.5, 5.8±4.9, and 5.9±5.0mm Hg, respectively. In Validation group, the MAE of nSBP-B (6.9±4.6mm Hg) for estimating iSBP-C was significantly greater than that of PWA (5.0±3.4mm Hg) and NPMA (6.1±4.4mm Hg), and GTF (6.1±4.9mm Hg). The percentage of absolute band error ≤5mm Hg was 62% for nSBP-B, 69% for GTF, 83% for PWA, and 69% for NPMA.

CONCLUSIONS

The accuracy of nSBP-B was inferior to the n SBP-C measures in estimating iSBP-C.

Accuracy of optical coherence tomography for the diagnosis of superficial basal cell carcinoma: a prospective, consecutive, cohort study of 168 cases

BACKGROUND

Superficial basal cell carcinoma (sBCC) can be safely treated topically. Potentially noninvasive imaging techniques, such as optical coherence tomography (OCT), may be useful to diagnose and manage patients with sBCC and obviate the need for biopsy.

OBJECTIVES

To evaluate in OCT (i) the sensitivity and specificity for sBCC diagnosis, (ii) the accuracy in determining BCC depth and (iii) the role in management of sBCC mimickers.

METHODS

A prospective, consecutive cohort of lesions for which sBCC was considered in the differential diagnosis. These lesions underwent clinical, dermoscopic and OCT assessment. Diagnosis and its confidence were recorded for each modality and were correlated with the histopathological diagnosis (punch biopsy). Interpretation of the OCT images and assessment of individual features were performed blinded to the biopsy results.

RESULTS

In total, 168 lesions were recruited: 52% were sBCC, 26% were other BCC variants and the remaining lesions were actinic keratosis, squamous cell carcinoma in situ, other benign inflammatory processes and two other malignant tumours. The sensitivity and specificity of OCT for diagnosis of sBCC were 0·87 and 0·80, respectively. There was excellent correlation between OCT and biopsy for tumour depth amongst tumours ≤ 0·4 mm (Pearson correlation r = 0·86, P < 0·001), but the correlation was less as depth increased (Pearson correlation r = 0·71, P < 0·001 for all tumours < 1·0 mm).

CONCLUSIONS

OCT has good diagnostic accuracy for diagnosing sBCC and measuring depth in tumours ≤ 0·4 mm. Potentially OCT can reduce the need for biopsy in clinically suspected sBCCs. However, careful follow-up is required in such cases as there is a small risk (5%) of misdiagnosis.

Estimation of Pulse Transit Time as a Function of Blood Pressure Using a Nonlinear Arterial Tube-Load Model

OBJECTIVE

pulse transit time (PTT) varies with blood pressure (BP) throughout the cardiac cycle, yet, because of wave reflection, only one PTT value at the diastolic BP level is conventionally estimated from proximal and distal BP waveforms. The objective was to establish a technique to estimate multiple PTT values at different BP levels in the cardiac cycle.

METHODS

a technique was developed for estimating PTT as a function of BP (to indicate the PTT value for every BP level) from proximal and distal BP waveforms. First, a mathematical transformation from one waveform to the other is defined in terms of the parameters of a nonlinear arterial tube-load model accounting for BP-dependent arterial compliance and wave reflection. Then, the parameters are estimated by optimally fitting the waveforms to each other via the model-based transformation. Finally, PTT as a function of BP is specified by the parameters. The technique was assessed in animals and patients in several ways including the ability of its estimated PTT-BP function to serve as a subject-specific curve for calibrating PTT to BP.

RESULTS

the calibration curve derived by the technique during a baseline period yielded bias and precision errors in mean BP of 5.1 ± 0.9 and 6.6 ± 1.0 mmHg, respectively, during hemodynamic interventions that varied mean BP widely.

CONCLUSION

the new technique may permit, for the first time, estimation of PTT values throughout the cardiac cycle from proximal and distal waveforms.

SIGNIFICANCE

the technique could potentially be applied to improve arterial stiffness monitoring and help realize cuff-less BP monitoring.

Blood Pressure, Carotid Flow Pulsatility, and the Risk of Stroke: A Community-Based Study

BACKGROUND AND PURPOSE

High blood pressure is a major cause of cardiovascular events, and carotid flow pulsatility may be associated with cardiovascular events. However, the combined effect of blood pressure and flow pulsatility on the development of stroke remains unclear. Therefore, we investigated the combined influence of central blood pressure and pulsatility index (PI) on the incidence of stroke.

METHODS

Baseline data from 2033 adults (≥30 years) without stroke history in the Cardiovascular Disease Risk Factor Two-Township Study were linked to incident stroke. Common carotid flow PI was calculated by peak systolic velocity, end-diastolic velocity, and mean vessel velocity, which were measured in the common carotid artery. Hazard ratios for the risk of total stroke resulting from high central systolic blood pressure (CSBP) and high PI were calculated with Cox proportional hazard models.

RESULTS

Over a median follow-up of 9.81 years, 132 people incurred stroke events. The incidence rates of stroke were 1.3, 6.4, and 13.2 per 1000 person-years for tertile groups of CSBP (P for trend<0.05) and 4.3, 7.0, and 9.4 per 1000 person-years for tertile groups of PI (P for trend<0.05). Compared with the first tertile of CSBP, hazard ratios were 4.88 (95% confidence interval, 2.29-10.43) for the second tertile and 10.42 (5.05-21.53) for the third tertile. Hazard ratios of PI were 2.18 (1.39-3.42; third tertile) and 1.64 (1.02-2.63; second tertile) compared with the first tertile. The individuals with a high CSBP and high PI had a 13-fold higher stroke risk compared with those with low CSBP and low PI (13.2; 1.75-99.71) after adjusting for age, sex, and traditional cardiovascular risk.

CONCLUSIONS

CSBP and common carotid PI jointly and independently predicted future stroke. Carotid flow pulsatility may play an important role in the development of stroke.

Prognostic significance of mechanical biomarkers derived from pulse wave analysis for predicting long-term cardiovascular mortality in two population-based cohorts

BACKGROUND

Numerous mechanical biomarkers derived from pulse wave analysis (PWA) have been proposed to predict cardiovascular outcomes. However, whether these biomarkers carry independent prognostic value and clinical utility beyond traditional cardiovascular risk factors hasn't been systematically evaluated. We aimed to investigate the additive utility of PWA-derived biomarkers in two independent population-based cohorts.

METHODS

PWA on central arterial pressure waveforms obtained from subjects without a prior history of cardiovascular diseases of two studies was conducted based on the wave transmission and reservoir-wave theory: firstly in the Kinmen study (1272 individuals, a median follow-up of 19.8years); and then in the Cardiovascular Disease Risk Factors Two-Township Study (2221 individuals, median follow-up of 10years). The incremental value of the biomarkers was evaluated by net reclassification index (NRI).

RESULTS

In multivariate Cox analyses accounting for age, gender, body mass index, systolic blood pressure, fasting glucose, high-density- and low-density-lipoprotein cholesterol, and smoking, only systolic (SC) and diastolic rate constant (DC) of reservoir pressure could independently and consistently predict cardiovascular mortality in both cohorts and the combined cohort (SC: hazard ratio 1.18 [95% confidence interval 1.08-1.28, p<0.001; DC: 1.18 [1.09-1.28], p<0.001]. Risk prediction estimates in traditional risk prediction models were significantly more accurate when incorporating peak of reservoir pressure (NRI=0.049, p=0.0361), SC (NRI=0.043, p=0.0236) and DC (NRI=0.054, p=0.047).

CONCLUSIONS

Of all PWA-derived biomarkers, SC and DC were consistently identified as valuable parameters for incremental cardiovascular risk prediction in two large prospective cohorts.

High Short-Term Blood Pressure Variability Predicts Long-Term Cardiovascular Mortality in Untreated Hypertensives But Not in Normotensives

BACKGROUND

The prognostic value of the short-term blood pressure variability (BPV) from the 24-hour ambulatory blood pressure monitoring (ABPM) remains controversial. The present study aimed to investigate the long-term prognostic value of a high BPV in normotensive and hypertensive subjects from a community-based population.

METHODS

A cohort of 624 normotensive and 633 untreated hypertensive Taiwanese participants (overall 669 men, aged 30-79 years) with baseline ABPM and 20-year all-cause and cardiovascular mortality data was drawn from a community-based survey. BPV was assessed by the read-to-read average real variability of the 24-hour diastolic and systolic blood pressure (SBP) (ARVd and ARVs, respectively).

RESULTS

In Cox proportional hazards analysis, ARVd predicted cardiovascular mortality independently of office SBP (hazard ratios (HRs) and 95% confidence intervals (CIs) per 1 SD: 1.31 (1.10-1.55), respectively, bivariate analysis), 24-hour SBP (HR: 1.19, 95% CI: 1.00-1.43), and conventional risk factors (age, sex, smoking, total cholesterol, high-density lipoprotein cholesterol, and fasting blood glucose, HR: 1.40, 95% CI: 1.18-1.67). In subjects with hypertension, a high vs. low ARVd (median: 8.8mm Hg) significantly predicted cardiovascular mortality (HR: 2.11, 95% CI: 1.23-3.62 and HR: 2.04, 95% CI: 1.19-3.51, respectively), when the conventional risk factors plus office SBP or 24-hour SBP were accounted for, respectively. Similar but less significant results were obtained with ARVs. A high ARVd or ARVs did not significantly predict cardiovascular mortality in the normotensive subjects.

CONCLUSIONS

A high short-term BPV is significantly predictive of long-term cardiovascular mortality in untreated hypertensive but not normotensive community-based subjects, independently of office or 24-hour SBP.

Hypoglycemia and risk of vascular events and mortality: a systematic review and meta-analysis

AIMS

Hypoglycemia has been associated with adverse outcomes in patients with diabetes and critical illness. However, such associations in these populations have not been systematically examined.

METHODS

We conducted a systematic review and meta-analysis of longitudinal follow-up cohort studies to investigate the associations between hypoglycemia and various adverse outcomes.

RESULTS

After removing duplicates and critically appraising all screened citations, a total of 19 eligible studies were included. As demonstrated by random-effects meta-analysis, hypoglycemia was strongly associated with a higher risk of adverse events (HR 1.90, 95 % CI 1.63-2.20; P < 0.001). Comparable risk ratios were shown in prespecified stratified analyses investigating above association for different study endpoints, in patients with or without critical illness, in patients with and without diabetes (from 1.47 to 3.31; p for interaction or heterogeneity >0.1). Additionally, a dose-dependent relationship between the severity of hypoglycemia and adverse vascular events and mortality (HR for mild hypoglycemia: 1.68, 95 % CI 1.25-2.26; P < 0.001 and HR for severe hypoglycemia: 2.33, 95 % CI 2.07-2.61; P < 0.001; p for trend 0.02) was observed. Suggested by a bias analysis, the above observations were unlikely to have resulted from unmeasured confounding parameters.

CONCLUSIONS

This is the first study demonstrating that hypoglycemia was associated with comparable risk ratios in different study populations and various study endpoints, and a trend of a dose-dependent relationship between hypoglycemia severity and adverse events. The findings of this systematic review support the speculation that hypoglycemia is a risk factor for adverse vascular events and mortality.