Regional Blood Volume Research Articles

#1551 The presence of proteinuria is associated with impaired cerebral oxygenation during exercise in chronic kidney disease

Abstract Background and Aims Cognitive impairment and reduced exercise tolerance are common in patients with chronic kidney disease (CKD), in part due to reduced brain function. Cerebral perfusion and oxygenation are significant determinants of brain activation and have been shown to be significantly impaired in CKD. This analysis aims to examine the impact of proteinuria on cerebral oxygenation during a mild physical stress in patients with pre-dialysis CKD. Method 66 patients with CKD stage 2-4 were included in this post-hoc analysis; 24-h urine samples were used for evaluation of proteinuria. All participants underwent a 3-min intermittent handgrip exercise (HG) at 35% of their maximal voluntary contraction. Changes in cerebral oxygenation (oxyhemoglobin-O2Hb) and deoxyhemoglobin-HHb) and regional blood volume (total hemoglobin-tHb) were continuously recorded during HG-exercise by near-infrared spectroscopy (NIRS). Results No significant differences between the 2 groups were detected in age (proteinuric vs nonproteinuric: 68.4 ± 10.6 vs 67.2 ± 10.8; p = 0.676), eGFR (41.3 ± 18.9 vs 46.3 ± 14.8; p = 0.248) and BMI (28.4 ± 4.9 vs 28.1 ± 4.8; p = 0.803). The MMSE score (proteinuric vs nonproteinuric: 28.0 ± 1.6 vs 28.0 ± 1.7; p = 0.938) and MVC (22.3 ± 7.0 vs 23.9 ± 7.5; p = 0.416) were not significantly different between groups. The average response in cerebral oxygenation during exercise was lower in patients with proteinuric CKD (O2Hb: 1.02 ± 0.87 vs 1.61 ± 0.95; p = 0.018 and diffO2Hb 1.53 ± .97 vs 2.07 ± 1.25; p = 0.065). The average tHb response (index of regional-blood-volume) was also lower in patients with proteinuria (0.51 ± 1.08 vs 1.16 ± 0.92 p = 0.013); however, no differences in HHb (-0.50 ± 0.55 vs -0.45 ± 0.54; p = 0.717) –an index of oxygen extraction capacity- among groups were detected. In univariate linear analysis the level of proteinuria did not show significant correlations with NIRS parameters. Conclusion The presence and not the level of proteinuria is associated with impaired brain activation during a mild physical task in patients with predialysis CKD. Future studies evaluating the role of proteinuria in the decline of cerebral function and cognitive impairment are needed.

THE PRESENCE OF PROTEINURIA IS ASSOCIATED WITH IMPAIRED CEREBRAL OXYGENATION DURING EXERCISE IN CHRONIC KIDNEY DISEASE

Objective: Cognitive impairment and reduced exercise tolerance are common in patients with chronic kidney disease (CKD), in part due to reduced brain function. Cerebral perfusion and oxygenation are significant determinants of brain activation and have been shown to be significantly impaired in CKD. This analysis aims to examine the impact of proteinuria on cerebral oxygenation during a mild physical stress in patients with pre-dialysis CKD. Design and method: 66 patients with CKD stage 2-4 were included in this post-hoc analysis; 24-h urine samples were used for evaluation of proteinuria. All participants underwent a 3-min intermittent handgrip exercise (HG) at 35% of their maximal voluntary contraction. Changes in cerebral oxygenation (oxyhemoglobin-O2Hb) and deoxyhemoglobin-HHb) and regional blood volume (total hemoglobin-tHb) were continuously recorded during HG-exercise by near-infrared spectroscopy (NIRS). Results: No significant differences between the 2 groups were detected in age (proteinuric vs nonproteinuric: 68.4±10.6 vs 67.2±10.8; p=0.676), eGFR (41.3±18.9 vs 46.3±14.8; p=0.248) and BMI (28.4±4.9 vs 28.1±4.8; p=0.803). The MMSE score (proteinuric vs nonproteinuric: 28.0±1.6 vs 28.0±1.7; p=0.938) and MVC (22.3±7.0 vs 23.9±7.5; p=0.416) were not significantly different between groups. The average response in cerebral oxygenation during exercise was lower in patients with proteinuric CKD (O2Hb: 1.02±0.87 vs 1.61±0.95; p=0.018 and diffO2Hb 1.53±.97 vs 2.07±1.25; p=0.065). The average tHb response (index of regional-blood-volume) was also lower in patients with proteinuria (0.51±1.08 vs 1.16±0.92 p=0.013); however, no differences in HHb (-0.50±0.55 vs -0.45±0.54; p=0.717) –an index of oxygen extraction capacity- among groups were detected. In univariate linear analysis the level of proteinuria did not show significant correlations with NIRS parameters. Conclusions: The presence and not the level of proteinuria is associated with impaired brain activation during a mild physical task in patients with predialysis CKD. Future studies evaluating the role of proteinuria in the decline of cerebral function and cognitive impairment are needed.

A Case Report of Changes in Regional Cortical Blood Volume and Oxygenation During Induction of General Anaesthesia with Sevoflurane Versus Propofol in a Paediatric Moyamoya Disease, Evaluated by Near-Infrared Spectroscopy.

A safe induction method of general anaesthesia for paediatric moyamoya disease patients has not been fully established. We had the opportunity to administer general anaesthesia twice to a two-year-old girl diagnosed with moyamoya disease. We used different induction methods for general anaesthesia at each session, i.e. slow induction with sevoflurane and rapid induction with propofol, and were able to evaluate changes in her left regional cortical blood volume (rCBV) and oxygenation (rCBO) during both anaesthesia inductions using near-infrared spectroscopy (NIRS). The mean change value of total-Hb (rCBV) (mean±SD; μmol/L) in the rapid induction was lower than that in the slow induction (-0.54±1.43 vs. 1.82±1.74). However, the TOI (rCBO) levels during both anaesthesia inductions were constantly higher than these respective baseline values (64% in the slow induction, 71% in the rapid induction), and these mean change values in each of the anaesthesia induction were about the same. The present results suggested that both the slow induction method with sevoflurane and the rapid induction method with propofol might be safe and effective for anaesthesia induction in paediatric patients with moyamoya disease.

Physiological Responses to Supramaximal Running Exercise with End-Expiratory Breath Holding up to the Breaking Point.

This study aimed to assess the physiological responses to repeated running exercise performed at supramaximal intensity and with end-expiratory breath holding (EEBH) up to the breaking point. Eight male runners participated in two running testing sessions on a motorized treadmill. In the first session, participants performed two sets of 8 repetitions at 125% of maximal aerobic velocity and with maximum EEBH. Each repetition started at the onset of EEBH and ended at its release. In the second session, participants replicated the same procedure, but with unrestricted breathing (URB). The change in cerebral and muscle oxygenation (Δ[Hbdiff]), total haemoglobin concentration (Δ[THb]) and muscle reoxygenation were continuously assessed. End-tidal oxygen (PETO2) and carbon dioxide pressure (PETCO2), arterial oxygen saturation (SpO2) and heart rate (HR) were also measured throughout exercise.On average, EEBH was maintained for 10.1 ± 1 s. At the breaking point of EEBH, PETO2 decreased to 54.1 ± 8 mmHg, whereas PETCO2 increased to 74.8 ± 3.1 mmHg. At the end of repetitions, SpO2 (nadir values 74.9 ± 5.0 vs. 95.7 ± 0.8%) and HR were lower with EEBH than with URB. Cerebral and muscle Δ[Hbdiff] were also lower with EEBH, whereas this condition induced higher cerebral and muscle Δ[THb] and greater muscle reoxygenation. This study showed that performing repeated bouts of supramaximal running exercises with EEBH up to the breaking point induced a fall in arterial, cerebral and muscle oxygenation compared with the URB condition. These phenomena were accompanied by increases in regional blood volume likely resulting from compensatory vasodilation to preserve oxygen delivery to the brain and muscles.

Simulating of human physiological supersystems: interactions of cardiovascular, thermoregulatory and respiratory systems

Special quantitative model of the human thermoregulatory system (MTS) functioning with cardiovascular and lung systems is created. These systems form a human physiological supersystem (HPSS). MTS describes thermoregulatory responses to alterations of both external environmental physical characteristics and internal biological characteristics. Algorithms provide designing of scenarios including simulation of either short-time or long-time (hours or days) observations. Input data include different combinations of environmental variables (air or water temperature, air humidity, wind or water flow speed, light intensity, infrared radiation) for a naked or wear human, as well as for given dynamics of biological characteristics (rate of heat production including its components associated with metabolism and ATP molecules leasing during mental and physical activities). Human body is presented by a core, blood, and a skin compartments. Skin and lung evaporation are under hypothalamic control based on afferent impulse patterns from internal, and skin heat and cold receptors. Dynamic output data include blood, hypothalamic, and skin temperatures, hemodynamic parameters like heart rate, cardiac output, regional blood flows, vascular resistances, blood pressures, and regional blood volumes. Serotonin and melatonin concentrations modulating biological heat production rate are associated with a day/night light intensity. Currently, the PCbased simulator is autonomous software to be used both for educational purposes and for providing of special computer research. In a near future, this simulator has to be widened by models of kidneys, and a mechanism of liverpancreas interaction.

Cerebral oxygenation during exercise deteriorates with advancing chronic kidney disease.

Cognitive impairment and exercise intolerance are common in chronic kidney disease (CKD). Cerebral perfusion and oxygenation play a major role in both cognitive function and exercise execution. This study aimed to examine cerebral oxygenation during a mild physical stress in patients at different CKD stages and controls without CKD. Ninety participants (18 per CKD stage 2, 3a, 3b and 4 and 18 controls) underwent a 3-min intermittent handgrip exercise at 35% of their maximal voluntary contraction. During exercise, cerebral oxygenation [oxyhaemoglobin (O2Hb), deoxyhaemoglobin (HHb) and total haemoglobin (tHb)] was assessed by near-infrared spectroscopy. Indices of microvascular (muscle hyperaemic response) and macrovascular function (carotid intima-media thickness and pulse wave velocity (PWV)) and cognitive and physical activity status were also evaluated. No differences in age, sex and body mass index were detected among groups. The mini-mental state examination score was significantly reduced with advancing CKD stages (controls: 29.2±1.2, stage 2: 28.7±1.0, stage 3a: 27.8±1.9, stage 3b: 28.0±1.8, stage 4: 27.6±1.5; P=.019). Similar trends were observed for physical activity levels and handgrip strength. The average response in cerebral oxygenation (O2Hb) during exercise was lower with advancing CKD stages (controls: 2.50±1.54, stage 2: 1.30±1.05, stage 3a: 1.24±0.93, stage 3b: 1.11±0.89, stage 4: 0.97±0.80μmol/l; P<.001). The average tHb response (index of regional blood volume) showed a similar decreasing trend (P=.003); no differences in HHb among groups were detected. In univariate linear analysis, older age, lower estimated glomerular filtration rate (eGFR), Hb, microvascular hyperaemic response and increased PWV were associated with poor O2Hb response during exercise. In the multiple model, eGFR was the only parameter independently associated with the O2Hb response. Brain activation during a mild physical task appears to decrease with advancing CKD as suggested by the smaller increase in cerebral oxygenation. This may contribute to impaired cognitive function and reduced exercise tolerance with advancing CKD.

Contrast-enhanced ultrasonography for early prediction of response of neoadjuvant chemotherapy in breast cancer.

Neoadjuvant chemotherapy (NAC) is widely accepted as a primary treatment for inoperable or locally advanced breast cancer before definitive surgery. However, not all advanced breast cancers are sensitive to NAC. Contrast-enhanced ultrasonography (CEUS) has been considered to assess tumor response to NAC as it can effectively reflect the condition of blood perfusion and lesion size. Therefore, this study aimed to evaluate the diagnostic performance of CEUS to predict early response in different regions of interest in breast tumors under NAC treatment. This prospective study included 82 patients with advanced breast cancer. Parameters of TIC (time-intensive curve) between baseline and after the first cycle of NAC were calculated for the rate of relative change (Δ), including Δpeak, ΔTTP (time to peak), ΔRBV (regional blood volume), ΔRBF (regional blood flow) and ΔMTT (mean transit time). The responders and non-responders were distinguished by the Miller-Payne Grading (MPG) system and parameters from different regions of tumors were compared in these two groups. For ROI 1(the greatest enhancement area in the central region of the tumor), there were significant differences in Δpeak1, ΔRBV1 and ΔRBF1 between responders and non-responders. For ROI 2 (the greatest enhancement area on edge of the tumor), there were significant differences in Δpeak2 and ΔRBF2 between the groups. The Δpeak1 and ΔRBF2 showed good prediction (AUC 0.798-0.820, p ≤ 0.02) after the first cycle of NAC. When the cut-off value was 0.115, the ΔRBF2 had the highest diagnostic accuracy and the maximum NPV. Quantitative TIC parameters could be effectively used to evaluate early response to NAC in advanced breast cancer.

B-Mode and Contrast-Enhanced Ultrasonography Aspects of Benign and Malignant Superficial Neoplasms in Dogs: A Preliminary Study.

Simple SummaryIn dogs, superficial neoplasms are common, and it is crucial to determine their malignancy, as this will have an impact on treatment and prognosis. So far, the diagnostic value of ultrasound modalities, such as B-mode and contrast enhanced ultrasound, for superficial neoplasms in dogs is still unclear, despite promising studies in humans. B-mode ultrasound enables assessment of the size, shape and arrangement of the neoplastic tissue, whereas contrast enhanced ultrasound enables the assessment of blood flow intensity and pattern. The aim of this study was to identify B-mode and contrast enhanced ultrasound characteristics that may be used to distinguish benign and malignant superficial neoplasms in dogs. Ultrasonographic characteristics, for which a significant difference was observed between benign and malignant neoplasms, were border definition, echogenicity, echotexture, blood flow pattern at wash-in and blood flow intensity during wash-out at the center of the neoplasm. Despite these significant differences, there was a considerable overlap in ultrasonographic characteristics between benign and malignant neoplasms. In conclusion, B-mode and contrast enhanced ultrasound might contribute to malignancy prediction; however, based on individual ultrasonographic characteristics, they seem unable to replace cytology or histopathology.Contrast-enhanced ultrasonography (CEUS) is considered a promising technique for differentiation of benign and malignant tumors in humans. However, few studies have assessed superficial neoplasms in dogs by means of CEUS. The aim of this study was to identify ultrasonographic criteria evaluated by B-mode ultrasound (US) and CEUS that may be used to distinguish benign and malignant superficial neoplasms in dogs. A total of 63 superficial neoplasms from 59 dogs were evaluated using B-mode US and CEUS prior to histopathologic examination. Qualitative and quantitative parameters were compared between benign and malignant neoplasms by Fischer’s exact test or fixed effects model. With B-mode US, a significant difference was found for border definition, echogenicity and echotexture. With CEUS, a significant difference was found for the enhancement pattern at wash-in and the wash-out area under the curve at the center of the neoplasm. Malignant neoplasms had on average a lower regional blood volume during the wash-out phase compared to benign neoplasms. Despite these significant differences, there was a considerable overlap in B-mode and CEUS parameters between benign and malignant neoplasms. In conclusion, B-mode US and CEUS might contribute to malignancy prediction; however, based on individual ultrasonographic parameters, they seem unable to replace cytology or histopathology.

Angiosome-directed endovascular intervention and infrapopliteal disease: Intraoperative evaluation of distal hemodynamic changes and foot blood volume of lower extremity.

ObjectivesTo evaluate foot blood volume and hemodynamics and explore whether quantitative techniques can guide revascularization.Materials and methodsA prospective single-center cohort study included thirty-three patients with infrapopliteal artery occlusion who underwent percutaneous transluminal angioplasty (PTA) between November 2016 and May 2020. The time-to-peak (TTP) from color-coded quantitative digital subtraction angiography (CCQ-DSA) and parenchymal blood volume (PBV) were used to evaluate the blood volume and hemodynamic changes in different regions of the foot before and after the operation.ResultsAfter the intervention procedure, the overall blood volume significantly increased from 25.15 ± 21.1 ml/1,000 ml to 72.33 ± 29.3 ml/1,000 ml (p < 0.001, with an average increase of 47.18 ml/1,000 ml. The overall TTP decrease rate, postoperative blood flow time significantly faster than those preoperatively, from 22.93 ± 7.83 to 14.85 ± 5.9 s (p < 0.001, with an average decrease of 8.08 s). Direct revascularization (DR) resulted in significant blood volume improvement than compared with indirect revascularization (IR) [188% (28, 320) vs.51% (10, 110), p = 0.029]. Patients with DR had a significantly faster blood flow time than those with IR [80% (12, 180) vs. 26% (5, 80), p = 0.032]. The ankle-brachial index (ABI) of the affected extremity also showed an significant change from 0.49 ± 0.3 to 0.63 ± 0.24 (p < 0.001) after the intervention. The relative values of ΔTTP and ΔABI showed a weak correlation (r = −0.330).ConclusionsThe quantitative measurement results based on PBV and CCQ-DSA techniques showed that the overall blood volume increased significantly and that the foot distal hemodynamics were significantly improved after endovascular treatment. DR in the ischemic area could r improve foot perfusion.

Measurement of Near infrared Spectroscopy based Biomarkers under in-vitro Ischemic stroke condition.

Near infrared spectroscopy (NIRS) is an optical method which has been used widely to measure the change in the blood chromophores. Abrupt change in blood chromophore viz, oxyhemoglobin [hbo2] and deoxyhemoglobin [hb] happens in ischemia stroke condition, which occurs due to impairment of the oxygenated compounds viz, oxygen and glucose. The current study presents measurement and analysis of near infrared spectroscopy (NIRS) based regional oxygenation level biomarkers Viz., change in regional blood volume index [Formula: see text] and change in regional oxygen saturation [Formula: see text]. To measure these NIRS biomarkers dynamic phantom has been designed in such a way that, it mimics the ischemic stroke condition in-vitro by continuously changing (decrease, increase) the oxygenation level of human blood sample in the closed loop arterial system of dynamic phantom. Continuous decline of the [Formula: see text] % and [Formula: see text] 5% has been observed of the average reading of the samples in an ischemic stroke condition, while 15% and 2% increment has been recorded in reversal of ischemic stroke condition, by increasing the oxygenation level of the arterial system. Correlation between biomarkers in ischemic stroke condition has been found strongly positive (r=56%) and regular residual percentage error in measurement has been measured which has found under 10%. Clinical Relevance- This help in understanding and characterizing the ischemic stroke. Biomarker's trend can be use for classification of stroke types.

ASSOCIATION OF CEREBRAL OXYGENATION DURING EXERCISE WITH TARGET ORGAN DAMAGE IN HYPERTENSIVE AND NORMOTENSIVE INDIVIDUALS

Objective: To investigate whether indices of cerebral oxygenation during exercise correlate with subclinical markers of target organ damage (TOD), namely carotid intima-media thickness (cIMT), arterial stiffness, and retinal vessel diameter in newly diagnosed hypertensives and healthy individuals. Design and method: Hypertension was diagnosed using 24-hour ambulatory blood pressure (BP) monitoring. Patients with white coat or masked hypertension were excluded. Cerebral oxygenation was measured continuously during a three-minute isometric hand grip exercise at 30% of maximal voluntary contraction using near infrared spectroscopy. The average response during exercise in oxygenated-hemoglobin (O2Hb), deoxygenated-hemoglobin (HHb), and total-hemoglobin (tHb, reflecting changes in regional blood volume) were examined. CIMT was measured using ultrasound, arterial stiffness was estimated with augmentation index and pulse wave velocity, and retinal vessel diameters were estimated by the central retinal arteriolar (CRAE) and vein (CRVE) equivalent and retinal arteriovenous ratio (AVR). Univariate analyses were performed and partial correlation was used to account for traditional cardiovascular risk factors to identify independent associations between cerebral oxygenation indices and TOD. Results: Fifty-two newly-diagnosed, never treated hypertensives and 41 healthy normotensive individuals with no known medical history of any other disease were included in our study. There were no differences in anthropometric and laboratory variables between groups except for their BP levels, as expected by study design. Mean cIMT was negatively correlated with the average exercise response in cerebral oxygenation (rhoO2Hb = -0.348, pO2Hb = 0.001; rhotHb = -0.253, ptHb = 0.02). Augmentation index was negatively correlated with cerebral-oxygenation during exercise (rhoO2Hb = -0.374, p &lt; 0.001; rhotHb = -0.332, p = 0.02), whereas no significant correlation was observed between pulse wave velocity and cerebral oxygenation indices. In the adjusted analysis, cerebral oxygenation was correlated with central retinal arteriolar diameter (CRAE rO2Hb = 0.233, pO2Hb = 0.043). Conclusions: Our novel findings suggest that indices of cerebral oxygenation during a submaximal physical task are associated with markers of early, subclinical target organ damage, namely increased carotid intima-media thickness, arterial stiffness and retinal arteriolar narrowing in a population of newly diagnosed hypertensive individuals.

Use of Contrast-Enhanced Ultrasound of the Testes after Non-Surgical Sterilization of Male Dogs with CaCl2 in Alcohol.

Simple SummaryThe uncontrolled stray dog population presents a serious threat to public health due to the increased risk of transmitting zoonotic diseases and inflicting human injury. There is a growing interest in non-surgical chemical sterilization via intratesticular injection of chemical neutering agents such as calcium chloride, which causes sterility due to azoospermia. In this study, we monitored immediate vascular alterations in dogs from chemical sterilization, using contrast-enhanced ultrasound (CEUS) before and after intratesticular inoculation with calcium chloride. The CEUS is an imaging technique used to obtain a quali-quantitative assessment of tissue perfusion by intravenously injecting gas-filled microbubble contrast agent. The CEUS evaluation was performed in canine testes before and after intratesticular inoculation with calcium chloride. Our results showed that the hardening agent caused a drastic reduction of the intratesticular blood flow, which was reflected by sonographic findings. CEUS can help clinicians define immediate testicular vascular alterations achieved by chemical castration. Nevertheless, more studies are required to apply this methodology to more subjects in a broader weight range among stray dogs.Sterilization by intratesticular injection of chemical agents is a non-surgical alternative to neutering male companion animals. We used contrast-enhanced ultrasound (CEUS) to monitor vascular alterations to testes immediately after the intratesticular injection of CaCL2 in alcohol. We evaluated the CEUS features of normal and damaged testes in 20 dogs after the intratesticular injection of CaCl2. The CEUS evaluation was performed at the site of the chemical agent inoculation. In treated testes, qualitative CEUS showed a lower intensity enhancement of the parenchyma than pre-treatment normal testes with a predominantly anechoic pattern and only a few hyperechoic vascular focal spots. Quantitative CEUS showed significantly lower values of time-intensity curve (TIC) parameters, including signal intensity (Peak: 4.72 ± 2.1), regional blood volume (RBV: 134.3 ± 63.7), and regional blood flow (RBF: 4.36 ± 2.18) than normal testes (p < 0.001). Sonographic findings from CEUS showed hypovascularization of the canine testicular parenchyma caused by the hardening agent. This diagnostic technique helps clinicians define testicular vascular alterations achieved by chemical castration more efficiently. Nevertheless, more studies are required to apply this methodology to more subjects with a broader weight range and stray dogs.

Dynamic changes of the hemoglobin index during resuscitation in patients with out-of-hospital cardiopulmonary arrest due to freshwater drowning: A retrospective observational study

BackgroundThe hemoglobin index (HbI) represents the amount of hemoglobin, which reflects the regional tissue blood volume. The HbI is calculated by a regional oxygen saturation monitor. In freshwater drowning, inhaled water is immediately absorbed into the blood causing hemodilution. We hypothesized that this blood dilution could be observed in real time using HbI values in patients with out-of-hospital cardiac arrest (OHCA) due to freshwater drowning. MethodsIn this single-center retrospective, observational study, we examined the HbI in patients with OHCA due to freshwater drowning from April 2015 to May 2020. Patients with OHCA due to hanging were selected as a control group. ResultsThirty-two patients in the freshwater drowning group and 21 in the control group were eligible for inclusion. In the freshwater drowning group, the HbI values in the return of spontaneous circulation (ROSC) group were significantly decreased in comparison to the non-ROSC group (−0.28 [IQR −0.55, −0.12] vs. −0.04 [IQR −0.16, 0.025]; p = 0.024). In the control group, the change of HbI during resuscitation in the ROSC and non-ROSC groups was not significantly different (0.11 [IQR −0.3525, 0.4225] vs. −0.02 [IQR −0.14, 0.605]; p = 0.8228). In each patient with ROSC in the freshwater drowning group, the HbI value after ROSC was significantly decreased in comparison to before ROSC (1.2±0.5 vs. 0.9±0.5]; p = 0.0156). In contrast, this difference was not observed in patients with an ROSC in the control group (3.7±1.3 vs. 3.8±1.4]; p = 0.7940). ConclusionBlood dilution induced by freshwater drowning might be detected in real time using the HbI. To prove the validity of this research’s result, further prospective large study is needed.

Effect of nitroglycerin on splanchnic and pulmonary blood volume

BackgroundSublingual nitroglycerin (SL NTG) is useful for treating acute decompensated heart failure, possibly by increasing splanchnic capacitance and reducing left ventricular (LV) preload. We evaluated a radionuclide method to study these effects, initially in subjects without heart failure. Methods and ResultsRed blood cells were labelled by an in vitro method. Abdominal and chest images were obtained at rest, showing relative regional blood volumes. The abdomen was then re-imaged during progressive escalation of intrathoracic pressure using continuous positive airway pressure to assess baseline splanchnic capacitance (pressure-volume relationship, PVR) and compliance (slope of PVR). The procedure was repeated after 0.6 mg SL NTG, followed by chest images. Relative splanchnic blood volume increased at rest after SL NTG (P < .002), signifying an increase in splanchnic capacitance. The slope of the splanchnic PVR decreased in proportion to the baseline PVR (P = .0014), signifying increased compliance. The relative pulmonary blood volume decreased in proportion to the increase in splanchnic blood volume (P = .01). ConclusionsA semi-quantitative radionuclide method demonstrated the effect of SL NTG for increasing splanchnic capacitance and compliance, with a proportional decrease in pulmonary blood volume. These data may be applied to quantitatively evaluate the importance of splanchnic vasodilation as a mechanism of LV preload reduction in the treatment of heart failure.Clinical Trials Registration: NCT02425566.

Characterization of cortical hemodynamic changes following sensory, visual, and speech activation by intraoperative optical imaging utilizing phase-based evaluation methods.

Alterations within cerebral hemodynamics are the intrinsic signal source for a wide variety of neuroimaging techniques. Stimulation of specific functions leads due to neurovascular coupling, to changes in regional cerebral blood flow, oxygenation and volume. In this study, we investigated the temporal characteristics of cortical hemodynamic responses following electrical, tactile, visual, and speech activation for different stimulation paradigms using Intraoperative Optical Imaging (IOI). Image datasets from a total of 22 patients that underwent surgical resection of brain tumors were evaluated. The measured reflectance changes at different light wavelength bands, representing alterations in regional cortical blood volume (CBV), and deoxyhemoglobin (HbR) concentration, were assessed by using Fourier‐based evaluation methods. We found a decrease of CBV connected to an increase of HbR within the contralateral primary sensory cortex (SI) in patients that were prolonged (30 s/15 s) electrically stimulated. Additionally, we found differences in amplitude as well as localization of activated areas for different stimulation patterns. Contrary to electrical stimulation, prolonged tactile as well as prolonged visual stimulation are provoking increases in CBV within the corresponding activated areas (SI, visual cortex). The processing of the acquired data from awake patients performing speech tasks reveals areas with increased, as well as areas with decreased CBV. The results lead us to the conclusion, that the CBV decreases in connection with HbR increases in SI are associated to processing of nociceptive stimuli and that stimulation type, as well as paradigm have a nonnegligible impact on the temporal characteristics of the following hemodynamic response.

Abstract P193: Effect Of Nitroglycerin And Sympathetic Withdrawal On Splanchnic Capacitance And Cardiac Blood Volumes

The splanchnic vasculature is the largest blood volume reservoir in the human body. Reduced capacitance of this vascular bed, in part due to sympathetic venoconstriction, is proposed to play a role in hypertension and heart failure. Thus, interventions that increase splanchnic capacitance or decrease sympathetic activity may be beneficial in these conditions. In a proof-of-concept study in healthy and hypertensive subjects, we evaluated whether venodilation with nitroglycerin (NTG; Study 1) or sympathetic withdrawal with trimethaphan (Study 2) increase splanchnic capacitance and reduce cardiac and stroke volumes. In Study 1 (n=10, 36±4 yrs, BMI 26.1±1.7, 4 men), abdominal and chest scintigrams, to measure regional blood volumes, were obtained before and after 0.6 mg sublingual NTG. Splanchnic capacitance (volume-pressure relationships, VPR) and compliance (VPR slope) were estimated by recording abdominal scintigrams during progressive escalation of intrathoracic pressure using continuous positive airway pressure (CPAP) at 0, 4, 8, 12, and 16 cm H 2 O, each for ≤2 min. We found that NTG increased splanchnic blood volume at rest (4%, IQR 1.81-9.95; P&lt;0.01) resulting in a rightward parallel shift in splanchnic VPR (P slope =0.46 and P intercept =0.01), indicating an increase in splanchnic capacitance. This was associated with a decrease in cardiac blood volume (-9%, IQR 2.2-10.3; P&lt;0.01). In Study 2, we measured blood pressure (BP) and stroke volume, used as a surrogate of venous return, during the same CPAP protocol before and during autonomic blockade with trimethaphan in 12 hypertensive subjects (49±2 yrs, BMI 29.9±1.7, 5 men). Sympathetic withdrawal decreased systolic BP (-27±14 mmHg) and produced a leftward parallel shift in VPR (i.e. reduced stroke volume; P slope =0.12 and P intercept &lt;0.01), indicating a reduction in venous return likely due to an increase in splanchnic capacitance. In conclusion, venodilation with NTG increased splanchnic capacitance and decreased cardiac volume. Sympathetic withdrawal had similar hemodynamic effects. These findings highlight the importance of splanchnic capacitance in cardiovascular regulation.

Assessment of sorafenib induced changes in tumor perfusion of uveal melanoma metastases with dynamic contrast-enhanced ultrasound (DCE-US)

PurposeDynamic contrast-enhanced ultrasound (DCE-US) was used to monitor early response to sorafenib therapy in patients with liver metastases from uveal melanoma.MethodsIn total, 21 patients with liver metastases were recruited within a prospective trial and underwent daily sorafenib therapy. DCE-US of a target lesion was performed before initiation of treatment, on day 15 and 56. Two independent blinded investigators performed software analysis for DCE-US parameters and inter-observer-correlation was calculated. Response to treatment was evaluated on day 56. DCE-US parameters were correlated with clinical response and RECIST1.1 criteria.ResultsInter-observer-correlation (r) of DCE-US parameters [time-to-peak (TTP), mean-transit-time (MTT), peak intensity (PI), regional blood volume (RBV), regional blood flow (RBF)] at baseline, day 15, and day 56 was highly significant (r-range 0.73–0.97, all p < 0.001). Out of 17 evaluable patients, 12 patients survived day 56 (clinical responders, cRE), whereas, five patients died before day 56 and were classified as non-responders (cNR). TTP values significantly increased in the cRE group 15 days after initiation of treatment for investigator 1 (p = 0.034) and at day 56 for both investigators (p = 0.028/0.028). MTT had increased significantly in the cRE group on day 56 (p = 0.037/0.022). In the cNR group changes for TTP and MTT remained insignificant. Thus, increase of the DCE-US parameters TTP and MTT are associated with response to treatment and prognosis.ConclusionAn increase of TTP and MTT at frequent intervals could serve as a surrogate marker for early response evaluation to anti-angiogenic treatment of metastatic uveal melanoma.

Differential diagnosis between acinic cell carcinoma and pleomorphic adenoma using the quantitative parameters of contrast-enhanced ultrasound.

To investigate the value of differential diagnosis between acinic cell carcinoma (ACC) and pleomorphic adenoma (PA) using the quantitative parameters of contrast-enhanced ultrasound (CEUS). Twenty-two ACC and 98 PA were retrospectively analyzed. These patients had been examined via routine pre-surgical two-dimensional ultrasound and CEUS. The examination results were confirmed by biopsy pathology. Qontrast 4.0 imaging analysis software was applied to obtain the maximum intensity (PEAK), time to peak (TTP), regional blood volume (RBV), regional blood flow (RBF), maximum signal intensity (SImax) and mean signal intensity (SImean) through quantitative analysis. The differences between ACC and PA were compared regarding the conventional ultrasound images and the quantitative parameters of CEUS. ROC curves were drawn to evaluate the diagnostic value of these parameters. There were no statistically significant differences between salivary gland ACC and PA in the manifestations of conventional two-dimensional ultrasound examination regarding morphology, internal echo and the boundary (p > 0.05). However, there were significant differences in PEAK, RBV, RBF, SImax and SImean between ACC and PA (p < 0.05). Additionally, the five quantitative parameters of CEUS were all highly accurate diagnostic indicators. The maximum area under the curve of each parameter was 0.888, sensitivity 72.6%, specificity 90.9% and accuracy 81.8%. The quantitative parameters of CEUS are helpful for differentially diagnosing salivary ACC and PA.

Monitoring of lower limb regional saturation and blood volume index during minimally invasive cardiac surgery

Monitoring of lower limb regional saturation and blood volume index during minimally invasive cardiac surgery

The pathological role of Pb in AD through impairing functions of blood‐brain barrier system

AbstractBackgroundLead (Pb) is an environmental factor has been suspected of contributing to Alzheimer’s disease (AD) and other dementia. Our previous study has shown that chronic Pb exposure increased brain levels of beta‐amyloid (Aβ) and amyloid plaques, a pathological hallmark for AD, in APP transgenic mice possibly by inhibiting Aβ clearance. However, it remains unclear how different levels of Pb affect Aβ clearance and the blood‐brain system (BBBS) in the blood‐brain barrier system.MethodTg‐APP mice were administrated with Pb‐acetate at three different doses by oral gavage for 4 weeks. Dynamic contrast‐enhanced CT (DCE‐CT) imaging method was used to quantify the real‐time brain regional blood flow, blood volume, and BBBS permeability.ResultChronic Pb exposures significantly increased permeability surface area product (PS) and brain perfusion, indicating that Pb disrupted the mouse blood‐brain barrier system was possibly mediated by inflammation.ConclusionChronic Pb exposure at toxic and even subtoxic levels would damage the BBBS and induce dementia by allowing blood contents to escape into the brain parenchyma.