Superior Mesenteric Artery Blood Flow Research Articles

Mesenteric blood flow and muscle sympathetic nerve activity during vasovagal syncope.

Vasovagal syncope is thought to be mediated by a progressive fall in cardiac output secondary to venous pooling of blood in the splanchnic circulation. How and when this occurs before syncope has not been determined. A total of 20 patients who became hypotensive during head-up tilt (age 40.9 ± 3.4 years; 10 females) were divided into two groups-the glyceryl trinitrate (GTN) group (n = 12) and the vasovagal syncope (VVS) group (n = 8) - on the basis of whether or not nitroglycerine provocation was required. They were compared with a control group (age 38.6 ± 3.3; 8 females; n = 13). Hemodynamics, including superior mesenteric artery blood flow (SMABF) and muscle sympathetic nerve activity (MSNA) were recorded continuously during early tilt, presyncope and recovery. We used pixel-weighting to calculate average velocity from the pulsed Doppler velocity envelope. During baseline and early tilt, resistance to mesenteric blood flow was lower in the VVS group: 0.30 ± 0.02 to 0.30 ± 0.02mmHg/ml/min versus controls 0.30 ± 0.03 to 0.38 ± 0.04mmHg/ml/min (p = 0.05). During presyncope, as blood pressure and stroke volume gradually fell, SMABF was higher in the VVS group, falling from 370 ± 46 to 248 ± 35ml/min, versus controls, falling from 342 ± 51 to 233 ± 19 (p = 0.03). At this time, MSNA was lower in the VVS group than controls: 39 ± 4 to 34 ± 3 bursts/min versus 45 ± 2 to 48 ± 3 (p = 0.001). During presyncope, increased splanchnic blood flow may pool more blood in capacitance vessels resulting in decreased venous return and cardiac output. This may be secondary to decreased vasoconstrictor sympathetic activity.

No difference in postprandial mesenteric blood flow between healthy younger and elderly individuals

We recently used phase-contrast magnetic resonance imaging (PC-MRI) to demonstrate an attenuated postprandial blood flow response in the superior mesenteric artery (SMA) in patients with Parkinson's disease compared to age- and sex-matched healthy controls. Since both groups showed substantial inter-individual variations, we extended the cohort of controls with a group of young individuals to investigate possible age-related effects. Seventeen healthy young subjects aged < 30 years and 17 elderly subjects aged > 50 years underwent serial PC-MRI to measure the postprandial blood flow response in the SMA after ingestion of a standardized liquid test meal (∼400 kcal). Postprandial blood flow dynamics in SMA did not differ between young and elderly subjects. A noticeable inter-individual variation in postprandial intestinal blood flow increase was found, and approximately 30% of the variation could be explained by the preprandial blood flow. Regardless of age, some subjects showed a remarkable transient SMA blood flow increase immediately after meal intake. This study provides tentative evidence that postprandial blood flow dynamics in SMA in healthy young and elderly subjects do not substantially differ, indicating that age is without impact on vascular response in SMA as an indicator for regulation of mesenteric perfusion in response to food intake.

The effect of Daikenchuto on blood flow of the superior mesenteric artery and portal vein in ELBW: A prospective study.

Focal intestinal perforation (FIP) is a devastating complication of premature birth, and extremely low birth weight (ELBW) infants are at highest risk. This study aimed to evaluate the relationship of the superior mesenteric artery (SMA) and portal vein (PV) blood flow velocities to investigate the association between intestinal blood flow and FIP. In addition, the herbal formula Daikenchuto (TJ-100) is expected to improve intestinal blood flow disorders; therefore, we evaluated its effect. We conducted a prospective cohort study of 15 ELBW infants from January 2020 to August 2021. Measured variables included birth weight, 5-minute Apgar score, time of oral feeding initiation, ductus arteriosus (PDA) closure (percent), diastolic and systolic blood pressure, SMA and PV blood flow velocity, and FIP onset data. Fifteen infants were divided into three groups: a non-surgery group (Group I; 6), a surgery group with FIP (Group II; 4), and a TJ-100 administration group (Group III; 5). The main outcome parameters included SMA and PV blood flow velocities with TJ-100. SMA and PV blood flow differed significantly for the SMA of Group I and the SMA and PV of Group III (P < 0.01, P = 0.01, and P = 0.04, respectively). There was a correlation between SMA and PV in Group III (P = 0.03). TJ-100 may increase SMA and PV blood flow and improve intestinal blood flow in ELBW infants at risk of FIP. Therefore, the effects of TJ-100 should undergo further study.

Effect of beta-blockers on multiple haemodynamics in cirrhosis: A cross-over study by MR-imaging and hepatic vein catheterization.

Non-selective beta-blockers (NSBB) are widely used in the treatment of patients with cirrhosis. Only about 50% respond with a sufficient reduction in their hepatic venous pressure gradient (HVPG) and NSBB may induce detrimental cardiac and renal effects in the presence of severe decompensation. We aimed to assess the effects of NSBB on haemodynamics using magnetic resonance imaging (MRI) and to assess if these haemodynamic changes were related to the disease severity and HVPG response. A prospective cross-over study of 39 patients with cirrhosis. Patients underwent hepatic vein catheterization and MRI with assessments of HVPG, cardiac function, systemic and splanchnic haemodynamics before and after propranolol infusion. Propranolol induced significant decreases in cardiac output (-12%) and blood flow of all vascular compartments, with the largest reductions seen in the azygos venous (-28%), portal venous (-21%), splenic (-19%) and superior mesenteric artery (-16%) blood flow. Renal artery blood flow fell by -5% in the total cohort, with a more pronounced reduction in patients without ascites than in those with ascites (-8% vs. -3%, p = .01). Twenty-four patients were NSBB responders. Their changes in HVPG after NSBB were not significantly associated with other haemodynamic changes. The changes in cardiac, systemic and splanchnic haemodynamics did not differ between NSBB responders and non-responders. The effects of acute NSBB blockade on renal flow seem to depend on the severity of the hyperdynamic state, with the largest reduction in renal blood flow in compensated patients compared to decompensated patients with cirrhosis. However, future studies are needed to assess the effects of NSBB on haemodynamics and renal blood flow in patients with diuretic-resistant ascites.

Elevation of the head of bed reduces splanchnic blood flow in patients with intra-abdominal hypertension

BackgroundElevation of the head of bed (HOB) increases intra-abdominal pressure (IAP), but the effect of body position on abdominal splanchnic perfusion is not clear. The current study aimed to evaluate the effect of body position on the superior mesenteric artery (SMA) and the celiac artery (CA) blood flow by Doppler ultrasound in mechanically ventilated patients with intra-abdominal hypertension (IAH).MethodsThis prospective cohort study included 53 mechanically ventilated patients with IAH. IAP, hemodynamic variables, and Doppler parameters of the SMA and CA were measured in the supine position. The measurements were repeated after the HOB angle was raised to 15° for 5 min and similarly at HOB angles of 30° and 45°. Finally, the patient was returned to the supine and these variables were re-measured.ResultsThe median (interquartile range, IQR) superior mesenteric artery blood flow (SMABF) decreased from 269 (244–322) to 204 (183–234) mL/min and the median (IQR) celiac artery blood flow (CABF) from 424 (368–483) to 376 (332–472) mL/min (both p<0.0001) while median (IQR) IAP increased from 14(13–16) to 16(14–18) mmHg (p<0.0001) when the HOB angle was changed from 0° to 15°. However, SMABF and CABF were maintained at similar levels from 15° to 30°, despite median (IQR) IAP increased to 17(15–18) mmHg (p = 0.0002). Elevation from 30° to 45° further reduced median (IQR) SMABF from 200(169–244) to 164(139–212) mL/min and CABF from 389(310–438) to 291(241–383) mL/min (both p<0.0001), Meanwhile, median (IQR) IAP increased to 19(18–21) mmHg (p<0.0001).ConclusionsIn mechanically ventilated patients with IAH, progressive elevation of the HOB from a supine to semi-recumbent position was associated with a gradual reduction in splanchnic blood flow. However, the results indicate that splanchnic blood flow is not further reduced when the HOB is elevated from 15° to 30°.This study confirms the influence of head-up angle on blood flow of the splanchnic organs and may contribute to the selection of the optimal position in patients with abdominal hypertension.

Superior mesenteric artery blood flow in infants of very preterm and very low birthweight and its related factors

&#x0D; Abstract&#x0D; &#x0D; Background Significant hemodynamic changes in preterm infants during early life could have consequences, especially on the intestinal blood flow. Alteration of superior mesenteric artery (SMA) blood flow may lead to impairment in gut function and feeding intolerance.&#x0D; Objectives To assess SMA blood flow velocity in very preterm and/or very low birth weight (VLBW) infants in early life and to elucidate the factors influencing them.&#x0D; Methods This is a cross-sectional study conducted in NICU at Cipto Mangunkusumo Hospital, Jakarta. Superior mesenteric artery (SMA) blood flow was evaluated by peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive index (RI) measurement using Color Doppler US at &lt; 48 hours after birth. Maternal and neonatal data that could be potentially associated with SMA blood flow were obtained. Bivariate analyses were conducted with a P value of &lt; 0.05 considered significant.&#x0D; Results We examined 156 infants eligible for the study. PSV, EDV, and RI of SMA blood flow were not related to both gestational age and birth weight. Infant with small for gestational age (SGA) showed significantly lower EDV median [15.5 (range 0.0-32.8) vs 19.4 (range 0.0-113.0)] and higher RI [0.80 (range 0.58-1.00) vs 0.78 (range 0.50-1.00)] compared to appropriate for gestational age (AGA). Infants born from mother with preeclampsia showed lower PSV median [(78.2 (range 32.0-163.0) vs 89.7 (range 29.2-357.0)]) and EDV [16.2 (range 0.0-48.5) vs 19.4 (range 0.0-113.0)] compared to without PE, while absent/reverse end-diastolic velocity (AREDV) revealed a lower EDV median [16.9 (range 0.0 – 32.4) vs 19.4 (range 0.0 – 113.0)] compared to no AREDV. Furthermore, infants with hs-PDA showed lower EDV median [16.2 (range 0.0-113.0) vs 19.4 (range 0.0-71.1)] but higher RI median [0.80 (range 0.50-1.00) vs 0.78 (range 0.55-1.00)] compared to non hs-PDA. No difference in SMA blood flow across other factors was observed.

Detection of exhaled methane levels for monitoring trauma-related haemorrhage following blunt trauma: study protocol for a prospective observational study

IntroductionEarly recognition and effective treatment of internal bleeding impose a cardinal challenge for trauma teams. The reduction of the superior mesenteric artery (SMA) blood flow is among the first compensatory...

The relationship of foetal superior mesenteric artery blood flow and the time to first meconium passage in newborns with late-onset foetal growth restriction

This study aimed to assess the relationship between the foetal superior mesenteric artery (SMA) Doppler and the time to first meconium passage (FMP) in foetuses with late-onset foetal growth restriction. This single-centre, prospective, observational, cohort study included 57 patients with late-onset FGR. The newborn infants were divided into two groups: preterm (36.8%) and term (63.2%). The time to FMP of the infants was compared to the foetal SMA parameters obtained within a week before delivery. The median time to FMP was similar between two groups (p = .31). The SMA pulsatility index (PI) was higher in the preterm group (p < .01). There was no correlation between foetal SMA PI or resistance index and time to FMP. In late-onset FGR infants, our study found no association between SMA Doppler measurements and time to FMP. However, a significant difference was detected in SMA PI between preterm and term infants. Impact Statement What is already known in this subject? Foetal growth restriction (FGR) can affect splanchnic circulation of the foetus and this alteration can be associated with some disorders including necrotising enterocolitis. What do the results of this study add? Superior mesenteric artery (SMA) Doppler indices are not associated with first meconium passage in neonates with late-onset foetal growth restriction. The pulsatility index of SMA is significantly higher in foetuses delivered before term. What are the implications of these findings for clinical practice and/or further research? Further research should be conducted to investigate the relationship between foetal SMA Doppler indices and neonatal gastrointestinal morbidities in foetuses with early onset FGR with Doppler anomalies. These studies can shed light from the prenatal to the postnatal period, allowing clinicians to predict potential problems and take precautions.

Velocity-Encoded Phase-Contrast MRI for Measuring Mesenteric Blood Flow in Patients With Newly Diagnosed Small-Bowel Crohn Disease.

BACKGROUND. Intestinal inflammation is associated with radiologic and histologic hyperemia. A paucity of studies have used MRI to measure mesenteric blood flow in patients with Crohn disease. OBJECTIVE. The purpose of this study was to evaluate the application of velocity-encoded phase-contrast MRI for measuring mesenteric blood flow in patients with newly diagnosed small-bowel Crohn disease. METHODS. This prospective study included 20 patients with ileal Crohn disease newly diagnosed between December 2018 and October 2021 (eight female participants, 12 male participants; median age, 14.0 years), and 15 healthy control participants (eight female participants, seven male participants; median age, 17.0 years). Patients with Crohn disease underwent investigational MRI and laboratory assessments at diagnosis and at 6 weeks and 6 months after initiating anti-tumor necrosis factor-α medical therapy; control participants underwent a single investigational MRI examination. All MRI examinations included a velocity-encoded phase-contrast acquisition, which was used to measure blood flow in the abdominal aorta, superior mesenteric artery (SMA), and superior mesenteric vein (SMV). Mann-Whitney U test was used to compare blood flow measurements (ratios of SMA and SMV blood flow to aorta blood flow [hereafter, SMA-to-aorta and SMV-to-aorta blood flow, respectively]) between groups; Friedman test was used to evaluate temporal changes in blood flow. Spearman correlation was used to assess relationships between blood flow measurements and laboratory markers of intestinal inflammation. Diagnostic performance was assessed by ROC analysis. RESULTS. At baseline, SMA-to-aorta blood flow in patients versus control participants was 0.44 versus 0.30 (p = .003), and SMV-to-aorta blood flow was 0.36 versus 0.21 (p = .002). At 6 weeks and 6 months, SMA-to-aorta blood flow in patients decreased to 0.30 and 0.27 (p < .001), and SMV-to-aorta blood flow decreased to 0.27 and 0.21 (p = .02), respectively. SMA-to-aorta and SMV-to-aorta blood flow were positively correlated with C-reactive protein (rho, 0.34 [p = .01] and 0.35 [p = .008], respectively) and fecal calprotectin (rho, 0.34 [p = .01] vs 0.47 [p < .001]). AUCs for differentiating patients from controls were 0.79 for SMA-to-aorta (sensitivity, 60%; specificity, 100%) and 0.82 for SMV-to-aorta (sensitivity, 75%; specificity, 87%) blood flow. CONCLUSION. Mesenteric blood flow is quantifiable using velocity-encoded phase-contrast MRI. The measurements differ between patients with ileal Crohn disease and healthy control participants and change in response to medical therapy. CLINICAL IMPACT. MRI-based mesenteric blood flow measurements provide a potential novel marker of intestinal inflammation.

Gastric Emptying Is Not Delayed and Does Not Correlate With Attenuated Postprandial Blood Flow Increase in Medicated Patients With Early Parkinson's Disease.

BackgroundWe have recently used phase-contrast magnetic resonance imaging (PC-MRI) to demonstrate an attenuated postprandial blood flow response in the superior mesenteric artery (SMA) in 23 medicated patients with Parkinson's disease (PD) compared to 23 age- and sex-matched healthy controls.ObjectiveTo investigate in a sub-sample of the original cohort whether the observed blood flow response in SMA after oral food intake is related to a delay in gastric emptying.MethodsWe studied 15 patients with PD in an “ON-medication” state with a mean disease duration of 3.9 ± 2.2 years and 15 healthy age- and sex-matched individuals. Participants underwent dynamic gastric scintigraphy 0, 30, 60, 120, 180 and 240 minutes after the intake of a standardized radiolabeled test meal. Gastric emptying was compared between groups. 14 of the 15 PD patients and 12 of the 15 healthy control subjects had previously undergone serial postprandial PC-MRI measurements. In these individuals, we tested for a relationship between gastric emptying and postprandial blood flow response in the SMA.ResultsThe dynamics of gastric emptying did not differ between groups (p = 0.68). There was substantial inter-subject variability of gastric emptying in PD patients and healthy participants. Only a single PD patient had delayed gastric emptying. In those participants who had undergone PC-MRI, postprandial increase in SMA blood flow was attenuated in PD compared to healthy controls as reported previously (p = 0.006). Gastric emptying did not correlate with the timing and amplitude of postprandial blood flow increase in SMA.ConclusionOur preliminary results, obtained in a small group of early-stage PD patients who continued their usual dopamine replacement therapy, suggest that variations in gastric emptying after solid meal intake is within the normal range in the majority of cases. There is also no evidence for a tight relationship between the attenuated postprandial blood flow response in the SMA and normal variations in gastric emptying.

Assessment of Small Bowel Motility and SMA Blood Flow Studied with Transabdominal Ultrasound.

Purpose Gastrointestinal ultrasound (GIUS) is a noninvasive imaging technique that may be used to study physiological changes in the small bowel. The aim of the study was to investigate the feasibility of measuring blood flow (BF) in the superior mesenteric artery (SMA) and regional motility in the small bowel with GIUS before and after a test meal and to compare ultrasound parameters to demographic factors such as age, sex, height, weight, and smoking habits. Materials and Methods 122 healthy volunteers aged 20 to 80 were examined after an overnight fast. Small bowel motility was registered in the upper left and lower right quadrants (ULQ and LRQ) with TUS and BF in the SMA with pulsed wave Doppler. The first 23 volunteers also received a 300 Kcal test meal and were re-examined 30 min postprandial. Results The feasibility of measuring BF was 97% in fasting patients while motility could be detected in 52% and 62% in the ULQ and LRQ, respectively. Females had a lower resistive index (RI) and a higher mean velocity than males, while the overall BF correlated with height. The RI had a negative correlation with age. Healthy volunteers with motility in the ileum were on average younger than those without motility. After the test meal, motility could be detected in the ULQ and LRQ in 95% and 90%, respectively, and the mean number of contractions in the ULQ increased significantly. As expected, there was a clear increase in all BF-parameters postprandially. Conclusion Regional motility in the small bowel was easier to detect after a test meal. There were some associations between demographic parameters and ultrasound parameters but overall the effects were relatively small.

Resistance Index of the Superior Mesenteric Artery: Correlation With Lactate Concentration and Kinetics Prediction After Cardiac Surgery.

Objective: This study aimed to measure blood flow changes in the superior mesenteric artery (SMA), using Doppler ultrasound, in post-cardiac surgery patients, to evaluate the correlation between the SMA resistance index (SMA-RI) and lactate concentrations.Methods: The patients' basic hemodynamics, blood gas parameters and lactate concentration were collected at admission. Simultaneously, the SMA blood flow parameters were collected using Doppler ultrasound with the patients in the supine position. The lactate concentrations were measured again at 2, 6, and 12-h time points after the first test. The length of intensive care unit stays and prognoses continued to be monitored.Results: A total of 67 patients were included. The SMA-RI correlated with the admission (r = 0.3117, P = 0.0102), 2-h (r = 0.5091, P < 0.0001), 6-h (r = 0.5061, P < 0.0001), and 12-h (r = 0.2483, P = 0.0428) lactate concentrations. The SMA-RI could predict the 2-h 10% [area under the curve (AUC) = 0.8294, P < 0.0001] and 6-h 40% lactate kinetics (AUC = 0.7708, P = 0.0012). The cut-off value was 0.83. When the SMA-RI was <0.83, the specificity and sensitivity were 86.38 and 75.56%, respectively for the prediction of the 2-h >10% lactate kinetics, and 64.71 and 75.00%, respectively, for the prediction of the 6-h >40% lactate kinetics. The lactate concentrations at admission, 2 and 6-h points were higher in the high-RI group (RI ≥ 0.83) and the intensive care unit stays were significantly longer than in the low-RI group (P = 0.0005).Conclusions: The increase in SMA-RI was associated with higher lactate concentrations and worse lactate kinetics in post-cardiac surgery patients. This may be related to intestinal hypoperfusion. The SMA-RI may be one of the indicators that should be monitored to guide resuscitation in these patients.

Abdominal hemodynamics in patients with visceroptosis

Abstract Background Abdominal circulation plays the important physiological role for structure and function of the digestive system, maintenance of nutrient homeostasis. Purpose To study the features of abdominal hemodynamics in patients with visceroptosis. Methods We studied 69 patients (mean age 22.28±3.7 years) with splanchnoptosis (visceroptosis) and 52 age- and sex- matched patients without splanchnoptosis (controls). Exclusion criteria: a history of digestive system surgery of taking blood circulation activating drugs. Doppler ultrasonography of the common hepatic artery, splenic artery, superior mesenteric artery, portal vein was performed on an empty stomach and 30 minutes after a food sample (standardized for proteins (14 g), fats (10 g) and carbohydrates (45 g)) using the Sonoace-8000 ultrasound scanner (Medison, South Korea). The data were analyzed using the Statistica-6 packages. Results There were no differences in hemodynamic parameters of fasting abdominal blood flow (ABF). After a food testing, in the postprandial period the ABF in all vessels in patients with splanchnoptosis was lower than in controls: the portal vein blood flow (BF) 1124,0 [1030,0–1419,0] ml/min vs 1373,0 [1136,0–1567,5] ml/min respectively (U=433,5; Z=−2,1; p=0,0342); the common hepatic artery BF 341,0 [295,0–394,0] ml/min vs 412,0 [331,0–521,0] ml/min respectively (U=335,0; Z=−2,3; p=0,0218); the splenic artery BF 396,0 [292,0–538,0] ml/min vs 502,0 [394,0–594,0] ml/min respectively (U=328,0; Z=−2,1; p=0,0399); the superior mesenteric artery BF 988,0 [837,0–1272,0] ml/min vs 1136,5 [992,0–1465,0] ml/min respectively (U=1625,5; Z=−2,2; p=0,0314). Changes in ABF were correlated with splanchnoptosis: the portal vein BF with any ptosis (rs=−0,21; p&amp;lt;0.05), the common hepatic artery BF with gastroptosis (rs=−0,38; p&amp;lt;0.05), the superior mesenteric artery BF with colonoptosis (rs=−0,86; p&amp;lt;0.05). The peripheral vascular resistance was correlated with the common hepatic artery BF (rs=−0,46; p&amp;lt;0.05), with the splenic artery BF (rs=−0,33; p&amp;lt;0.05) and with the superior mesenteric artery BF (rs=−0.79; p&amp;lt;0.05). Conclusions Patients with splanchnoptosis in the postprandial period have low volumetric BF in abdominal aorta vessels. This can be associated with the length of the mesenteric vessels, which undergoes the greatest changes in splanchnoptosis. Food testing reveals latent BF deficit in patients with splanchnoptosis. Funding Acknowledgement Type of funding sources: None.

Postprandial superior mesenteric artery blood flow is related to changes in peripheral pulse wave harmonics and heart rate: implications for wearable technology?

Postprandial superior mesenteric artery (SMA) blood flow is associated with the caloric content of a meal. Whether spectral analysis of a peripheral pulse wave or heart rate can model postprandial SMA blood flow is unclear. We hypothesized that altering the caloric content of a meal would evoke dose-response increases in postprandial SMA hyperemia and distinct changes in the pulse wave harmonic spectrum and heart rate. Twenty healthy subjects (10 male, 26 ± 10 yr) completed a randomized cross-over trial, comparing three meals (280, 560, or 840 kcal) on SMA blood flow (Doppler ultrasound), heart rate, and the first to seventh harmonic amplitudes (derived from a finger pulse wave). Supine SMA diameter and blood velocity were collected at baseline and every 15 min throughout 2 h of postprandial recovery. SMA blood flow was smaller across all time points following meal 1 (280 kcal) compared with both meal 2 (560 kcal) and meal 3 (840 kcal) (all P < 0.001), while meal 2 had attenuated responses compared with meal 3 at 60, 90, 105, and 120 min postprandial (all P < 0.01). Distinct changes in heart rate and the amplitude of second to fifth harmonics were observed between meals (all P < 0.05). The changes in harmonic spectrum or heart rate explained 66-69% (adjusted r2) of the variance in postprandial SMA blood flow. These results provide proof-of-concept that easily obtained and noninvasive postprandial harmonic profiles or heart rate may be used to explain changes in SMA blood flow and exploited for the development of wearable technology to noninvasively track caloric intake.NEW & NOTEWORTHY We studied the superior mesenteric artery (SMA) blood flow responses to three meals of varying caloric value and examined whether these responses could be modeled using changes in heart rate or the peripheral pulse wave harmonic spectrum. We found that both inputs could explain 66-69% of the SMA blood flow variance over 2 h of postprandial recovery. Noninvasive methods may be able to predict SMA blood flow and thus used to measure caloric intake.

Effect of intraabdominal hypertension on splanchnic blood flow in children with appendicular peritonitis.

Background and Aims:Intraabdominal hypertension (IAH) is poorly diagnosed condition that cause splanchnic hypoperfusion and abdominal organs ischemia and can lead to multiple organ failure. There are no scientific data regarding effect of intraabdominal pressure (IAP) on splanchnic circulation in children.Material and Methods:Ninety-four children after surgery for appendicular peritonitis were enrolled in the study. After IAP measurement children were included in one of two groups according IAP levels: “without IAH” (n = 51) and “with IAH” (n = 43). Superior mesenteric artery (SMA) and portal vein (PV) blood flows (BFSMA, BFPV, mL/min) were measured, and SMA and PV blood flow indexes (BFISMA, BFIPV, ml/min*m2) and abdominal perfusion pressure (APP) were calculated in both groups.Results:Median BFISMA and BFIPV in group “with IAH” were lower by 54.38% (P < 0.01) and 63.11% (P < 0.01) respectively compared to group “without IAH”. There were strong significant negative correlation between IAP and BFISMA (rs = –0.66; P < 0.0001), weak significant negative correlation between IAP and BFIPV (rs = –0.36; P = 0.0001) in group “with IAH” and weak significant negative correlation between IAP and BFISMA (rs = –0.30; P = 0.0047) in group “without IAH”. There were no statistically significant correlations between IAP and BFIPV in group “without IAH”, between BFISMA and APP in both groups and between BFIPV and APP in both groups.Conclusion:Elevated IAP significantly reduces splanchnic blood flow in children with appendicular peritonitis. BFISMA and BFIPV negatively correlate with IAP in these patients. There is no correlation between BFISMA/BFIPV and APP in children with IAH due to appendicular peritonitis.

Superior Mesenteric Artery Blood Flow in Parenterally Fed Versus Enterally Fed Preterm Infants.

The aim of the study was to compare superior mesenteric artery (SMA) flow in premature infants with parenteral and enteral nutrition. A prospective study was conducted on 2 groups of preterm infants with gestational age of 280/7 to 366/7 weeks: group 1 did not qualify for early enteral feeds and received parenteral nutrition (PN), and group 2 received early enteral feeding. SMA peak systolic velocity (PSV), end diastolic velocity (EDV), and pulsatility index (PI) were measured using Doppler ultrasound before starting feeds at day 1 and at day 5. The study recruited 40 infants; 20 in each group. At baseline, PSV, EDV, and PI did not differ between groups. At day 5, enteral nutrition was associated with significant increases in PSV (91.53 ± 29.15 vs 65.49 ± 19.18, P = 0.003) and EDV (15.91 ± 7.01 vs 11.65 ± 5.58, P = 0.026) and a decrease in PI (1.28 ± 0.40 vs 2.48 ± 0.83, P < 0.001). Regression analysis to control for confounders showed enterally fed infants to have increased PSV (adjusted odds ratio [aOR] = 25.45; 95% confidence interval [CI]: 8.53-42.38, P = 0.004) and EDV (aOR 8.630; 95% CI: 2.987-14.273, P = 004) and decreased PI (aOR = -1.133; 95% CI: -1.603 to -0.664, P < 0.001). Infants in the PN group later developed more frequent feeding intolerance when compared with the enterally fed group (65% vs 15%, respectively, P < 0.001). In preterm neonates, early EF is associated with increased SMA blood flow, decreased vascular intestinal resistance, and less frequent incidence of feeding intolerance.

Non-invasive assessment of mesenteric hemodynamics in patients with suspected chronic mesenteric ischemia using 4D flow MRI.

Chronic mesenteric ischemia (CMI) is a rare disease with a particularly difficult diagnosis. In this study, 4D flow MRI is used to quantitatively evaluate mesenteric hemodynamics before and after a meal in patients suspected of having CMI and healthy individuals. Nineteen patients suspected of CMI and twenty control subjects were analyzed. Subjects were scanned using a radially undersampled 4D flow MR sequence (PC-VIPR). Flow rates were assessed in the supraceliac (SCAo) and infrarenal aorta, celiac artery, superior mesenteric artery (SMA), left and right renal arteries, superior mesenteric vein (SMV), splenic vein, and portal vein (PV) in a fasting state (preprandial) and 20min after a 700-kcal meal (postprandial). Patients were subcategorized into positive diagnosis (CMI+, N = 6) and negative diagnosis (CMI-, N = 13) groups based on imaging and clinical findings. Preprandial, postprandial, and percent change in flow rates were compared between subgroups using a Welch t test. In controls and CMI- patients, SCAo, SMA, SMV, and PV flow increased significantly after meal ingestion. No significant flow increases were observed in CMI+ patients. Percent changes in SMA, SMV, and PV flow were significantly greater in controls compared to CMI+ patients. Additionally, percent changes in flow in the SMV and PV were significantly greater in CMI- patients compared to CMI+ patients. 4D flow MRI with large volumetric coverage demonstrated significant differences in the redistribution of blood flow in SMA, SMV, and PV in CMI+ patients after a meal challenge. This approach may assist in the challenging diagnosis of CMI.

Effects of delayed cord clamping in intrauterine growth-restricted neonates: a randomized controlled trial.

The time of cord clamping in intrauterine growth-restricted (IUGR) neonates remains an area of uncertainty. This assessor-blinded randomized controlled trial compared the effects of delayed cord clamping (DCC) with early cord clamping (ECC) on the systemic blood flow (SBF) and cerebral hemodynamics in IUGR neonates of gestational age ≥28 weeks, not requiring resuscitation. Eligible newborns were randomized to DCC (cord clamping after 60 s; n=55) or ECC (cord clamping within 30 s; n=55) group immediately after delivery. The primary outcome variable was superior vena cava (SVC) blood flow at 24±2 h. The secondary outcome variables were right ventricular output (RVO), anterior cerebral artery (ACA) blood flow velocity (BFV), superior mesenteric artery (SMA)-BFV and venous hematocrit at 24±2 h, peak total serum bilirubin (TSB), incidences of polycythemia, intraventricular hemorrhage, respiratory distress, feeding intolerance, and necrotizing enterocolitis, outcome, duration of hospital stay, screening audiometry, and serum ferritin levels at the postnatal age of 3 months. Compared to ECC, DCC was associated with significantly higher SVC flow (101.22±21.02 and 81.27±19.12 mL/kg/min, in DCC and ECC groups, respectively; p<0.0001), and significantly increased RVO, SMA-BFV, venous hematocrit, and serum ferritin levels. Though peak TSB was significantly higher with DCC, duration of phototherapy was comparable. ACA-BFV, incidence of polycythemia, and other outcomes were comparable between the groups.Conclusions: DCC was a safe and beneficial intervention in IUGR infants with an improved SBF and SMA-BFV and an increased hematocrit and serum ferritin levels without higher incidences of polycythemia and requirement of phototherapy for significant hyperbilirubinemia.Trial registration: Clinical Trials Registry of India (CTRI/2019/05/018904) What is Known: • Delayed cord clamping (DCC) increases superior vena cava (SVC) blood flow in preterm neonates. • DCC increases hematocrit and serum ferritin in intrauterine growth-restricted (IUGR) neonates, but there may be an associated risk of polycythemia and neonatal hyperbilirubinemia. What is New: • DCC increases SVC blood flow, right ventricular output, superior mesenteric artery blood flow velocity, venous hematocrit, and serum ferritin in IUGR neonates. • Incidences of polycythemia and duration of phototherapy for significant neonatal hyperbilirubinemia do not increase with DCC.

A Randomized Porcine Study in Low Cardiac Output of Vasoactive and Inotropic Drug Effects on the Gastrointestinal Tract.

ABSTRACTBackground:Splanchnic vasodilation by inodilators is an argument for their use in critical cardiac dysfunction. To isolate peripheral vasoactivity from inotropy, such drugs were investigated, and contrasted to vasopressors, in a fixed low cardiac output (CO) model resembling acute cardiac dysfunction effects on the gastrointestinal tract. We hypothesized that inodilators would vasodilate and preserve the aerobic metabolism in the splanchnic circulation in low CO.Methods:In anesthetized pigs, CO was lowered to 60% of baseline by partial inferior caval vein balloon inflation. The animals were randomized to placebo (n = 8), levosimendan (24 μg kg−1 bolus, 0.2 μg kg−1 min−1, n = 7), milrinone (50 μg kg−1 bolus, 0.5 μg kg−1 min−1, n = 7), vasopressin (0.001, 0.002 and 0.006 U kg−1 min−1, 1 h each, n = 7) or norepinephrine (0.04, 0.12, and 0.36 μg kg−1 min−1, 1 h each, n = 7). Hemodynamic variables including mesenteric blood flow were collected. Systemic, mixed-venous, mesenteric-venous, and intraperitoneal metabolites were analyzed.Results:Cardiac output was stable at 60% in all groups, which resulted in systemic hypotension, low superior mesenteric artery blood flow, lactic acidosis, and increased intraperitoneal concentrations of lactate. Levosimendan and milrinone did not change any circulatory variables, but levosimendan increased blood lactate concentrations. Vasopressin and norepinephrine increased systemic and mesenteric vascular resistances at the highest dose. Vasopressin increased mesenteric resistance more than systemic, and the intraperitoneal lactate concentration and lactate/pyruvate ratio.Conclusion:Splanchnic vasodilation by levosimendan and milrinone may be negligible in low CO, thus rejecting the hypothesis. High-dose vasopressors may have side effects in the splanchnic circulation.

Postprandial Increase in Mesenteric Blood Flow is Attenuated in Parkinson's Disease: A Dynamic PC-MRI Study.

Background:Gastrointestinal dysfunction and related clinical symptoms are common in Parkinson’s disease (PD), but the underlying mechanisms are still poorly understood.Objective:In this study, we investigated how PD affects the postprandial vascular response in the splanchnic circulation.Methods:23 patients with PD in the “ON-medication” state and 23 age- and sex-matched healthy control participants underwent serial phase-contrast magnetic resonance imaging (PC-MRI) to measure the postprandial blood flow response in the superior mesenteric artery (SMA). Participants ingested a standardized liquid test meal (∼400 kcal) and underwent four PC-MRI runs within the following hour. Each PC-MRI run consisted of six consecutive measurements of SMA blood flow.Results:In both groups, standardized food intake triggered an increase of blood flow in the SMA, but absolute and relative increases in blood flow were attenuated in patients compared to the control group (p < 0.001). While baseline blood flow in the SMA was comparable in both groups, the postprandial maximum blood flow was attenuated in patients (p = 0.03). The temporal dynamics of the postprandial blood flow did not differ between groups. Postprandial SMA blood flow increase in patients correlated neither with subjective reports of non-motor symptoms or upper gastrointestinal complaints, nor with levodopa equivalent daily dose or disease duration. Blood glucose measurements in between the PC-MRI runs showed a smaller postprandial increase in blood glucose in the patient group (p = 0.006).Conclusion:This study provides first-time evidence that patients with PD have an attenuated postprandial blood flow response in the SMA, indicating an impaired functional regulation of gastrointestinal perfusion in response to food intake in PD.