Superior Mesenteric Artery Blood Flow Velocity Research Articles

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


 Abstract
 
 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.
 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.
 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 < 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 < 0.05 considered significant.
 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.

The effect of early-onset preeclampsia on the intestinal blood flow of preterm infants

Background Preeclampsia is associated with important vascular maternal changes. However, its repercussions on newborns’ circulation have hardly been reported. Objective To investigate whether early-onset preeclampsia is associated with altered blood flow of the superior mesenteric artery (SMA) in preterm infants. Materials and methods Prospective study with 60 preterm infants of mothers with early-onset preeclampsia (PE) and 60 of normotensive mothers, paired according to the gestational age, from 2013 to 2016. Maternal, gestational, and neonatal clinical data were evaluated. The outcome of interest was the blood flow velocity in SMA, evaluated by the peak systolic velocity and end-diastolic velocity and by the resistance index and pulsatility index, through the Doppler ultrasound in the first 72 h of life. Covariance analysis was used to determine the PE effect on the SMA blood flow, controlling for possible confounding variables. Results The mean gestational age was 30 weeks. Infants of mothers with PE had significantly lower values of peak systolic and end-diastolic velocity (57.75 ± 17.49 and 12.29 ± 5.74) compared with the control group (67.17 ± 29.57 and 15.03 ± 7.52), even after control of covariates. Conclusion Early-onset preeclampsia is associated with decreased blood flow of SMA in preterm infants on the first days of life.

Early prediction of feed intolerance in very low birth weight preterm infants using superior mesenteric artery blood flow velocity

Objective: To evaluate the utility of superior mesenteric artery (SMA) flow velocity post feeding for predicting time to achieve full enteral feeds in very low birth weight (VLBW) neonates.Subjects: In this prospective cohort study preterm VLBW infants were followed until they achieved full enteral feeding.Results: There was no significant difference between prefeed and post feed SMA flow measurements in study subjects. At baseline, it was observed that Small for gestational age (SGA) babies had a significantly lower peak systolic velocity. Time-averaged mean velocity (TAMV) was significantly lower in SGA babies at baseline, 15, 30, 45, and 60 min post feed, but there were no within-group differences noted over time.Conclusion: SMA blood flow velocity measured pre-feed and post-feed times do not correlate with the time to achieve full enteral feeding in very low birth weight neonates. The clinical significance of lower Peak systolic velocity (PSV) and TAMV in SGA infants is unclear.

Splanchnic hemodynamics as a predictor of feeding tolerance in preterm neonates

Background: The superior mesenteric artery (SMA) supplies the greatest volume of blood to the small intestine. The use of Doppler ultrasound to measure SMA blood flow velocity (BFV) is increasingly used to investigate intestinal hemodynamics in neonates. Aim: The aim of this study was designed to correlate Doppler indices of splanchnic perfusion and vascular resistance to early tolerance of feeding and development of necrotizing enterocolitis in preterm (PT) infants. Setting and Design: This study was conducted at the Neonatal Intensive Care Unit, Ain Shams University Hospital, Cairo Governorate, Egypt. Subjects and Methods: Complete Prenatal, natal, and postnatal history were taken; blood culture and complete blood count, C-reactive protein with titer, and assessment of BFA in SMA at day (D) 1 and D7 of life, including peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI), and pulsatility index (PI), were done upon enrollment of 65 neonates who subdivided into either PT groups, hypoxic-ischemic encephalopathy group, or full-term group. Results: There was a significant difference between the three groups regarding PSV, EDV, and RI before and after feeding. As for the qualitative data of the Doppler indices of SMA, there was a statistically significant difference between the three groups as regards the PI in D1 (P = 0.022), PSV in D7 (P = 0.018), and EDV in D7 (P = 0.040); however, there was no significant difference between the three groups as regard PSV in D1, EDV in D1, RI in D1 and D7, and PI in D7. Conclusion: Doppler hemodynamic studies of SMA in PT infants showed that change in RI parameter in response to small enteral feeds proved to have a highly significant difference with the dependent variable (feeding tolerance) which might be a good tool for the clinician in predicting early tolerance to enteral feeding.

Intestinal blood flow by Doppler ultrasound: the impact of clarithromycin treatment for feeding intolerance in preterm neonates

Objective: To compare the blood flow velocities of superior mesenteric artery (SMA) before versus after clarithromycin treatment for feeding intolerance in very low-birth weight infants.Methods: A prospective study was conducted in a group of infant <1500 g with feeding intolerance who received clarithromycin 7.5 mg/kg/dose bid. Before and at the third day of the clarithromycin therapy, SMA blood flow velocity was measured with Doppler ultrasound.Results: SMA peak systolic velocity (PSV) and mean systolic velocity (MV) on the third day of the treatment was found significantly higher than the initial measurement (p = 0.013 and p = 0.027, respectively). End diastolic velocity of the SMA did not change with clarithromycin therapy (p = 0.113). There were no significant changes about pulsatility and resistive index of SMA with regard to clarithromycin therapy.Conclusion: Clarithromycin effects the splanchnic circulation. The rise in PSV and MV in SMA is remarkable. These results suggest that the splanchnic blood flow increases significantly after clarithromycin usage.

Feeding interval and postprandial intestinal blood flow in premature infants

The feeding interval is an important factor in enteral feeding of premature infants. We investigated postprandial intestinal blood flow in stable very-low-birthweight infants fed at 2-h and 3-h intervals. We used pulsed wave Doppler ultrasound to measure blood flow velocity of the superior mesenteric artery (SMA) before feeding and at 15, 30, 45, and 60 min after feeding. Measurements were made on the day of starting enteral nutrition (1 or 2 days of age), and at 3 and 5 days of age. A total of 21 studies were performed in seven infants fed every 2 h, and 54 studies were performed in 18 infants fed every 3 h. In infants fed every 2 h, SMA blood flow velocity increased from before feeding to 30 min after feeding and then decreased at 60 min after feeding. In infants fed every 3 h, SMA blood flow velocity increased after feeding, reaching a peak at 30 min. The correlation coefficients between the volume of milk per feed and the postprandial increase in time-averaged mean blood flow velocity were 0.398 (P = 0.074, n = 21) and 0.597 (P = 0.000, n = 54) in infants fed at 2-h and 3-h intervals, respectively. SMA blood flow velocity significantly increased after feeding in infants fed at 2-h and 3-h intervals. The volume of milk per feed might affect the postprandial increase in SMA blood flow velocity.

Umbilical artery catheters do not affect intestinal blood flow responses to minimal enteral feedings

To investigate the effects of umbilical artery catheters (UACs) on superior mesenteric artery (SMA) blood flow velocity (BFV) following enteral feedings in very low birth weight preterm infants. Very low birth weight preterm infants who had UACs inserted as part of standard clinical care were enrolled in this prospective study. On the day the UAC was scheduled to be removed, pre- and postprandial SMA BFV (mean, peak systolic and end diastolic velocities) were measured in conjunction with a minimal enteral feeding given while the UAC was in place. The same measurements were made with the next feeding given after the UAC was removed. Preprandial measurements were made at least 3 h after the last enteral feeding, and postprandial measurements were made 30, 45 and 60 min after the feeding began. The same volume and type of feeding were used for both studies. The birth weight and gestational age of the 19 infants who completed the study were 1014+/-221 g and 27.4+/-1.9 weeks, respectively. Infants were 4.6+/-1.7-days-old when the first SMA BFV measurement was made, the volume of enteral feedings was 1.3+/-0.6 ml, and the time between the two enteral feedings was 4.7+/-3.2 h. Preprandial SMA BFV did not differ with the UAC in place compared with the UAC removed. Peak postprandial velocities were at 45 min after feedings began. The percent increase from baseline was not significantly different with the UAC in place compared with the UAC removed. Preprandial SMA BFV and postprandial SMA BFV responses to minimal enteral feedings were not affected by the presence of a UAC.

Dietary Nucleotides and Intestinal Blood Flow Velocity in Term Infants

ABSTRACTObjectives:Two previous studies have shown that the addition of nucleotides to single feedings of formula is associated with increased 90‐minute postprandial superior mesenteric artery (SMA) blood flow velocity (BFV). To assess the effect of chronic feeding of nucleotide‐supplemented formula, we measured pre‐ and postprandial SMA BFV in term infants fed formula with or without added nucleotides for 4 weeks.Methods:At 1 week of age, healthy, term infants were randomized to receive formula with added nucleotides (NT+), or formula without added nucleotides (NT−) from age 1 to 5 weeks. When the infants were 5 weeks of age, SMA BFV was measured by Doppler ultrasound 15 minutes before the assigned feeding (baseline) and 30, 60, and 90 minutes after the start of feeding. A reference group of human milk‐fed infants was studied before and after breast feeding.Results:Thirty formula‐fed (NT+ = 17; NT− = 13) and 10 human milk‐fed infants were studied. Baseline BFV was similar among the three groups. BFV increased in each group from baseline to 30 minutes after initiation of feeding and progressively declined from 30 to 90 minutes in infants fed NT− formula or human milk. In infants fed NT+ formula, BFV decreased between 30 and 60 minutes. However, from 60 to 90 minutes, velocity was unchanged or increased. At 90 minutes, mean and peak systolic velocities were significantly greater in the NT+ group than the NT− group (P &lt; 0.001).Conclusions:These data agree with those of previous studies showing increased 90‐minute postprandial SMA BFV after a feeding with nucleotide‐supplemented formula. The clinical significance of these findings is unknown.

Prediction of early tolerance to enteral feeding in preterm infants by measurement of superior mesenteric artery blood flow velocity

AIMSTo evaluate whether serial Doppler measurements of superior mesenteric artery (SMA) blood flow velocity after the first enteral feed could predict early tolerance to enteral feeding in preterm infants.METHODSWhen clinicians...

Duplex ultrasound for assessment of superior mesenteric artery blood flow.

Duplex ultrasound (DU) is recognised as a valuable tool for the assessment of blood flow in many vascular territories. The application of this technique to the superior mesenteric artery (SMA) has increased rapidly throughout the last decade. The purpose of this review is to collate currently available information on the utility of SMA DU, both in terms of research and clinical practice. Research investigations have revealed low intra- and interobserver variability in the estimation of Doppler variables, while reliable evaluation of B-mode dimensions requires repeated measurements. SMA blood flow velocity has been found to be dependent upon changes in central haemodynamics and in peripheral resistance, which was documented in studies with hypotension, medication and post-prandially. Food intake induces mesenteric vasorelaxation reflected by a 10-fold increase in the diastolic velocity. This feature has been utilised in studies on mesenteric physiology, which confirmed parasympathetic activity during hypovolaemia, and showed that exercise increases splanchnic resistance and reduces its blood flow following a 50% reduction in the hepato-splenic and a 25% reduction in the mesenteric blood flow. Clinical studies have documented high sensitivity and specificity of DU in detection of disease in splanchnic arteries. Diastolic velocity was found to be the most accurate indicator of SMA stenosis, while an absent Doppler signal from a well visualised vessel has been found to be a reliable predictor of occlusion. The high predictive value of DU in the detection of mesenteric artery disease, together with its simplicity and non-invasiveness, suggests that DU should take precedence over arteriography in both clinical practice and laboratory investigations.