Document Detail

Physiological aspects of the determination of comprehensive arterial inflows in the lower abdomen assessed by Doppler ultrasound.
Jump to Full Text
MedLine Citation:
PMID:  22443486     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Non-invasive measurement of splanchnic hemodynamics has been utilized in the clinical setting for diagnosis of gastro-intestinal disease, and for determining reserve blood flow (BF) distribution. However, previous studies that measured BF in a "single vessel with small size volume", such as the superior mesenteric and coeliac arteries, were concerned solely with the target organ in the gastrointestinal area, and therefore evaluation of alterations in these single arterial BFs under various states was sometimes limited to "small blood volumes", even though there was a relatively large change in flow. BF in the lower abdomen (BF(Ab)) is potentially a useful indicator of the influence of comprehensive BF redistribution in cardiovascular and hepato-gastrointestinal disease, in the postprandial period, and in relation to physical exercise. BF(Ab) can be determined theoretically using Doppler ultrasound by subtracting BF in the bilateral proximal femoral arteries (FAs) from BF in the upper abdominal aorta (Ao) above the coeliac trunk. Prior to acceptance of this method of determining a true BF(Ab) value, it is necessary to obtain validated normal physiological data that represent the hemodynamic relationship between the three arteries. In determining BF(Ab), relative reliability was acceptably high (range in intra-class correlation coefficient: 0.85-0.97) for three arterial hemodynamic parameters (blood velocity, vessel diameter, and BF) in three repeated measurements obtained over three different days. Bland-Altman analysis of the three repeated measurements revealed that day-to-day physiological variation (potentially including measurement error) was within the acceptable minimum range (95% of confidence interval), calculated as the difference in hemodynamics between two measurements. Mean BF (ml/min) was 2951 ± 767 in Ao, 316 ± 97 in left FA, 313 ± 83 in right FA, and 2323 ± 703 in BF(Ab), which is in agreement with a previous study that measured the sum of BF in the major part of the coeliac, mesenteric, and renal arteries. This review presents the methodological concept that underlies BF(Ab), and aspects of its day-to-day relative reliability in terms of the hemodynamics of the three target arteries, relationship with body surface area, respiratory effects, and potential clinical usefulness and application, in relation to data previously reported in original dedicated research.
Authors:
Takuya Osada
Related Documents :
20081756 - Splenic artery aneurysm performed vascular reconstruction: a case report.
11770586 - Angiographic embolization of a ruptured renal artery aneurysm during pregnancy.
9013536 - Helical ct evaluation of arterial invasion in pancreatic tumors: comparison with angiog...
15285546 - Aneurysm of the splenic vein.
8902976 - Cervical myelopathy caused by the anomalous vertebral artery. a case report.
21030806 - Carotid artery stenting in a patient with internal carotid artery stenosis and ipsilate...
Publication Detail:
Type:  Journal Article     Date:  2012-03-26
Journal Detail:
Title:  Cardiovascular ultrasound     Volume:  10     ISSN:  1476-7120     ISO Abbreviation:  Cardiovasc Ultrasound     Publication Date:  2012  
Date Detail:
Created Date:  2012-06-05     Completed Date:  2012-08-29     Revised Date:  2013-06-26    
Medline Journal Info:
Nlm Unique ID:  101159952     Medline TA:  Cardiovasc Ultrasound     Country:  England    
Other Details:
Languages:  eng     Pagination:  13     Citation Subset:  IM    
Affiliation:
Department of Sports Medicine for Health Promotion, Tokyo Medical University, Tokyo, Japan. DENTACMAC@aol.com
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Blood Flow Velocity / physiology
Celiac Artery / physiology*,  ultrasonography
Female
Femoral Artery / physiopathology*,  ultrasonography
Humans
Male
Reproducibility of Results
Sensitivity and Specificity
Splanchnic Circulation / physiology*
Splenic Artery / physiopathology*,  ultrasonography
Ultrasonography, Doppler / methods*
Young Adult
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Full Text
Journal Information
Journal ID (nlm-ta): Cardiovasc Ultrasound
Journal ID (iso-abbrev): Cardiovasc Ultrasound
ISSN: 1476-7120
Publisher: BioMed Central
Article Information
Download PDF
Copyright ©2012 Osada; licensee BioMed Central Ltd.
open-access:
Received Day: 12 Month: 12 Year: 2011
Accepted Day: 26 Month: 3 Year: 2012
collection publication date: Year: 2012
Electronic publication date: Day: 26 Month: 3 Year: 2012
Volume: 10First Page: 13 Last Page: 13
ID: 3366871
Publisher Id: 1476-7120-10-13
PubMed Id: 22443486
DOI: 10.1186/1476-7120-10-13

Physiological aspects of the determination of comprehensive arterial inflows in the lower abdomen assessed by Doppler ultrasound
Takuya Osada12 Email: DENTACMAC@aol.com
1Department of Sports Medicine for Health Promotion, Tokyo Medical University, Tokyo, Japan
2Cardiac Rehabilitation Centre, Tokyo Medical University Hospital, Tokyo, Japan

Background

The splanchnic circulation has been described as the "blood-giver of circulation" and is believed to play a major role in overall cardiovascular regulation [1]. The splanchnic system receives nearly 30% of the cardiac output through three large arteries: the coeliac and the superior and inferior mesenteric arteries. Hemodynamics in the splanchnic organs are altered under various stressful conditions, such as during physical activity and in the postprandial state [2], due to balancing of tone between sympathetic and vagus activity; consequently, clinical assessment of the splanchnic circulation could potentially provide valuable information regarding hepato-gastrointestinal disease [3-5] and cardiac dysfunction [6].

Previous Doppler ultrasound studies that measured splanchnic blood flow in a "single vessel with small size volume", such as the superior mesenteric, coeliac artery, or portal vein, were concerned solely with the target organ in the gastrointestinal area [2,7-9]; therefore, evaluation of alterations in these single arterial blood flows under the various states were sometimes limited to small volumes, even though there was a relatively large change in flow. Evaluation of the comprehensive arterial blood flow in the lower abdomen (BFAb), including the liver, spleen, gastro-intestine, kidney, and pelvic organs as a multiple arterial function, may potentially be a feasible method of determining the distribution of abdominal blood-flow volume or disorder in cases of splanchnic or cardiovascular dysfunction, as well as the distribution following nutritious meal intake or physical exercise [10,11].

Our previous studies used ultrasonography to assess whole arterial BFAb hemodynamics: BFAb was obtained by subtracting blood flow in the bilateral proximal femoral arteries [left femoral artery (LFA) and right femoral artery (RFA)] from blood flow in the upper abdominal aorta (Ao) above the coeliac artery bifurcation [10-14].

This method of quantitative assessment is a challenging but unique and non-invasive procedure for determining the comprehensive inflows of all abdominal organs, and is a potentially useful indicator of blood flow redistribution in cardiovascular and hepato-gastrointestinal disease, in the postprandial period, and in relation to physical exercise.

Variability in the hemodynamics (blood velocity, vessel diameter and blood flow) of the three target arteries is valuable information for determining BFAb. Therefore, the purpose of the present review is to summarize the methodology for determining BFAb using validated data of three target arteries, to discuss methodological considerations and limitations in view of previously reported findings, and to consider the potential clinical usefulness and application of measurements for the comprehensive lower abdominal flows.


Methodology
Subjects

The subjects were the participants of three studies: 60 healthy males (mean age, 24.1 ± 5.5 years; mean height, 173.3 ± 7.1 cm; and mean body weight, 68.5 ± 9.3 kg), 50 healthy males (mean age, 23.5 ± 4.9 years; mean height, 172.8 ± 7.1 cm; and mean body weight, 67.6 ± 9.9 kg) and 10 healthy males (mean age, 25.2 ± 6.6 years; mean height, 175.6 ± 7.0 cm; and mean body weight, 70.1 ± 7.6 kg). All values are expressed as mean ± standard deviation (SD). Participants had no previous history of cardiovascular disease, gastrointestinal disease, hypertension, or anaemia, and no abnormality of the peripheral vasculature. The studies were conducted according to the principles of the Declaration of Helsinki (1976) and with the approval of the Institutional Ethics Committee of the author's institution. All participants gave their written consent and were informed of the nature and purpose of the study, as well as potential risks and discomfort. The participants also understood that they could withdraw from the study at any time without consequence. The study populations reviewed in the present study do not include the elderly.

Approach for Doppler ultrasound assessment of three target arteries for determining BFAb

The target vessels were the following three conduit arteries: 1) the Ao at ~3 cm above the coeliac artery bifurcation, 2) the proximal LFA, and 3) the proximal RFA (Figure 1). The Ao region was most commonly measured just below the diaphragm in longitudinal section view (from the sub-sternal area) to enable Ao sample volume to be maintained at the end of the expiratory phase during spontaneous breathing. Detection of the Ao was relatively constant and free from interference from intestinal gas. For both femoral arteries, measurement location was chosen to minimize turbulence and the influence of the inguinal region on blood flow above the bifurcation, thereby enabling easy and reliable measurement [10-18]. Blood velocity (pulsed wave) and vessel diameter (2-dimensional) measurements were obtained using a curvilinear array probe (3.5 MHz) for Ao and a linear array probe (7.5 MHz) for the LFA and RFA. The insonation angle was maintained below 60° for each participant and remained constant throughout the experiments [10-14,19]. The sample volume was placed in the precise centre of the vessel before being adjusted to cover the width of the vessel diameter and blood velocity distribution.

The data in the present review were obtained using an ultrasound unit (SONOS 1500, HP77035A; Hewlett-Packard, Tokyo, Japan) with a real-time two-dimensional ultrasonic imager and a pulsed-Doppler flowmeter for calculating maximum envelope in the blood velocity profile. The Doppler instrument used in this review, however, could not determine time- and spatial-averaged and amplitude (signal intensity)-weighted mean blood velocities; thus, the measured blood velocity determined by integration of the outer envelope (maximum velocities) would have reflected the higher (maximum) velocity component at the centre of the vessel through the cardiac cycle. Because this procedure takes no account of the lower velocity component of the flow profile, the blood velocity values in this review have potentially been overestimated. On the basis of this physiological phenomenon, the above-mentioned measure of mean blood velocity, which expresses the averaged speed for all red blood cells within the vessel, is more precise; however, the present procedure used to determine blood velocity also provides acceptable data.

Recent developments in ultrasound instrumentation include an auto-tracing programme for determining mean and maximum blood velocity (outer envelope). Maximum (envelope) blood velocity in the femoral artery is previously reported as being ~1.53 [20] and 1.3-1.8 [21,22] times higher than mean blood velocity. An in vitro study that used a silicon tube to model the conduit artery found that maximum (envelope) blood velocity was approximately 1.75 times higher than mean blood velocity [23].

Measurement procedure of blood velocity, vessel diameter, and blood flow in the arteries

For each participant, measurement was conducted between approximately 7 and 9 am, while fasting. Prior to measurement, colour Doppler was used to check for unsuspected pathology in each conduit artery. For each of the three conduit arteries, blood velocity was measured for 2-3 minutes and vessel diameter for 1-2 minutes via image observation using a wide expanded view in longitudinal section, by a single operator (the author). Blood velocity was analysed by integrating the outer envelope of the maximum velocity values from the flow profile for each beat, for approximately 20-40 beats [10,24-26]. Blood velocity and vessel diameter analyses were performed using the phase that demonstrated similar heart rate and blood pressure values among measurements from the three conduit arteries. The systolic and diastolic vessel diameter of each conduit artery was measured in relation to the electrocardiograph displayed on the monitor of the ultrasound unit.

Vessel diameter was also measured under perpendicular insonation and calculated in relation to the temporal duration of the electrocardiography recording curve, as follows: [(systolic vessel diameter × 1/3) + (diastolic vessel diameter × 2/3)] [15-17]. The mean vessel diameter for each beat was calculated over approximately 20-40 beats. Blood flow was determined by multiplying the cross-sectional area [area = π × (vessel diameter/2)2] by the amplitude (signal intensity)-weighted blood velocity (time- and spatial-averaged outer envelope of the maximum velocity). To determine BFAb precisely, blood pressure and heart rate should remain in a steady state during measurement of the three target arteries.

Determination of comprehensive BFAb

Blood flow in the Ao, LFA, and RFA is defined as BFAo, BFLFA, and BFRFA, respectively. BFAb was calculated by subtracting the sum of BFRFA and BFLFA from BFAo, as follows: BFAb = [BFAo - (BFLFA + BFRFA)] [10-14].


Consideration of the physiological aspect of the three arterial blood flows and BFAb
Day-to-day reliability and variability in hemodynamics of the three arteries and BFAb via repeated measurements

Hemodynamic measurements (blood velocity, vessel diameter, and blood flow) in the three arteries were performed on three consecutive days by a single operator. BFAb can then be determined for each day by the formula BFAo - (BFLFA + BFRFA), with blood flow calculated by multiplying blood velocity by the cross-sectional area. Variability in the values of blood velocity, vessel diameter, and blood flow in the three arteries may be valuable information for determining BFAb.

First, relative reliability was estimated by analysing the three hemodynamic measurements repeated on three different days, for 60 healthy male participants [12]. As shown in Table 1, F-test revealed no significant difference in blood velocity, vessel diameter, or blood flow values among the three measurements. Consequently, the single-measure intra-class correlation coefficient was significantly high for relative reliability estimated by repeated hemodynamics measurements [27]. This indicates that Doppler assessment of hemodynamic parameters in the three target arteries has potential as a stable and acceptable procedure for determining BFAb.

Second, Bland-Altman analysis [28] was used for statistical analysis of mean values (x-axis) and difference values (y-axis) in hemodynamics (blood velocity, vessel diameter, and blood flow) between two measurements over three different days (Figure 2). Figure 2 shows that no systematic bias (fixed bias and proportional bias) was found between any two measurements over three different days. The limits of agreement (mean ± 1.96 SD) in terms of the difference between two hemodynamics measurements and the 95% confidence interval also indicate validity in the present study population within an acceptable and permissible range and true mean values (Table 2). Bland-Altman analysis revealed that the acceptable range in difference (bias) between two measurements may be less than 8.9 cm/s for Ao and less than 5.3 cm/s for blood velocity in the femoral arteries; less than 1.5 mm for Ao and less than 0.95 mm for vessel diameter in the femoral arteries; and less than 1.0 l/min and less than 0.18 l/min for blood flow in the Ao and femoral arteries, respectively. It is considered that this range takes into account day-to-day physiological variation as well as measurement error. The present results for repeated measurements on three different days reveals that the range in blood flow values in the three arteries remained similar for individual participants under similar testing conditions; thus, mean BFAb is considered a reliable value with the acceptable range in difference (bias) between two measurements may be less than 0.9 l/min for blood flow in the Ab. (Tables 1, 2; Figure 3).

Validity of target arterial blood flows and BFAb compared with previous findings
Abdominal aorta

Values for vessel diameter, estimated cross-sectional area, and blood flow of the upper abdominal aorta obtained in the present review were 15.6 ± 1.2 mm, 1.91 ± 0.29 cm2, and 2951 ± 767 ml/min, respectively (Table 3).

The present values for diameter and cross-sectional area are similar to those of 15.5-17.6 mm and 1.88-2.43 cm2, respectively, measured by Gabriel and Kindermann [29]. Nimura et al. [7] reported blood flow values obtained by Doppler ultrasound of the upper abdominal aorta and the sum total blood flow of the coeliac, superior mesenteric and both renal arteries as 2470-3246 ml/min and 2450-3549 ml/min, respectively. These values are similar to those for BFAo expressed in the present review.

Femoral artery

The present values for the diameter of the femoral arteries were 9.0 ± 0.7 mm in the LFA and 9.1 ± 0.7 mm in the RFA (Table 3), which is in the same range as the previously reported values of 7.5 ± 0.3 mm measured using angiography [30] and 8.1 ± 0.11 mm measured by Duplex Doppler [31]. In the present review, cross-sectional area of the femoral arteries was 0.65 ± 0.1 cm2 in the LFA and 0.65 ± 0.11 cm2 in the RFA. Mean blood velocity in the femoral arteries was 8.3 ± 2.4 cm/s in the LFA and 8.1 ± 2.1 cm/s in the RFA; these values are in the same range as that of 10.2 ± 0.39 cm/s previously measured by pulsed Doppler [31]. Blood flow in the femoral arteries was 316 ± 97 ml/min in the LFA and 313 ± 83 ml/min in the RFA. These values are in the same range as those of 450-886 ml/min [32], 301 ± 81 ml/min [33], and 390 ± 20 ml/min [34] measured using indicator dilution; and 376 ± 154 ml/min [35], 226.5 ± 28.6 ml/min [31], 344 ml/min [36], and 350-367 ml/min [37] measured by Doppler ultrasound. Furthermore, Ganz et al. [38] reported a value of 383-766 ml/min by thermodilution, and Vänttinen [39] reported a value of 239 ml/min using electromagnetic flowmetry. These values are in the same range in those of the present review, despite differences in the method of measurement. Blood flow may also be influenced by the subject's position during measurement and local blood flow per body weight, as well as thigh muscle mass [40].

Blood flow in the lower abdomen

There is lack of comparative BFAb data measured by other valid methods (gold standard) such as the thermodilution technique or the cardiovascular magnetic resonance method. However, ultrasound Doppler is also an acceptable valid measure for determining blood velocity/flow in the conduit artery.

Including the results of previous reports [12], the range of BFAb over the three different days was 1153-4401 ml/min in the 60 participants. Furthermore, the mean value of BFAb was 2630 ± 649 ml/min in 18 of the participants (age range, 20-38 years) in the previous reports [10].

Based on the general anatomical features shown in Figure 1, the BFAb values are considered to indicate the sum of blood flow to the coeliac artery; mesenteric arteries; the bilateral renal, suprarenal, gonadal, and internal iliac arteries; and some lumbar arteries.

Previous studies [41-44] reported average splanchnic blood flow (including that of the coeliac trunk, superior mesenteric, and inferior mesenteric arteries) as approximately 1500 ml/min, corresponding to 20%-30% of cardiac output. The sum of the blood flow values in the two renal arteries is approximately 1000-1200 ml/min, which corresponds to 20% of cardiac output [45]. In addition, blood flow is 1400 ml/min in the liver, gastro-intestine, and spleen (the so-called splanchnic organs), and 1100 ml/min in the kidney [46]. The range of values for the sum of blood flow in the "splanchnic" and the "two renal arteries" reported in previous studies is similar to the BFAb values obtained using the present method. However, the wide range in BFAb may also be related to individual physical features such as body surface area and body weight.

Relationship of blood flows to body surface area and to body weight

Previous studies have shown that cardiac output increases in proportion to body surface area [46,47], which means that cardiac output is regulated throughout life in almost direct proportion to overall metabolic activity. Furthermore, a positive correlation has been demonstrated between cardiac output and abdominal-splanchnic blood volume, using whole-body scintigraphy [48]. BFAb is expected to be closely related to body surface area, because the splanchnic system receives ~30% of cardiac output.

A significant positive relationship exists between BFAb and both body surface area and body weight (Figure 4). The formula used to calculate body surface area is widely used in the target population [49]. Furthermore, an increase in BFAb with increasing body weight may be reasonable, taking into consideration the total weight of the lower abdomen. This relationship is based on the concept that blood flow distribution is associated with a higher flow per weight to the liver and intestine compared with skeletal muscle at rest [50]. An expected additional finding was that peripheral blood flow at each conduit artery also had a positive linear relationship (p < 0.05) with body surface area as well as with body weight (Figure 4). This correlation is in agreement with evidence concerning the relationship between cardiac output supply and peripheral arterial blood flow, with cardiac output being closely related to body surface area [46,47].

Relationship of BFAb to BFAo, BFLFA, and BFRFA in estimating BFAb

The distribution of BFAb may be influenced by the magnitude of both cardiac output and limb blood flows. Specifically, it is speculated that alterations in limb blood flow may play an important role in regulating BFAb via changes in the tone in the vascular bed of abdominal organs during low-intensity exercise when there is little fluctuation in the magnitude of BFAo [10]. Similarly, it is unclear whether BFAb or cardiac output at rest has a major impact on limb blood flow in a steady state of neural response.

Day-to-day coefficients of variation in blood flow were relatively high in the femoral arteries compared with BFAo, even though the absolute BFAo values were approximately 10 times higher than those of blood flow in both femoral arteries. Accordingly, BFAb was more strongly related to BFAo (r = 0.966) than to BFLFA (r = 0.303) or BFRFA (r = 0.281) (Figure 5). Alterations in BFAo that are closely related to cardiac output (except cerebral and arm blood flows) potentially have the greatest influence on BFAb, even if blood flow in the femoral arteries has less influence on BFAb, at least at rest; accordingly, BFAo potentially has the largest influence on BFAb as a central hemodynamic factor. Figure 5 shows that precise BFAb values may be unreliable when there are large variations in both BFLFA and BFRFA. Thus, evaluation of BFAb may be better expressed by the following formula: BFAb (l/min) = 0.85 × BFAo - 0.19, if Ao measurement alone is performed (Figure 5).

Effect of respiration and posture

Deep thoracic breathing in inspiration produces rapid acceleration of blood flow in veins located near the thorax, such as the hepatic vein, jugular vein, and inferior vena cava [51], while the blood velocity in these veins is reduced just as rapidly at the start of expiration [52]. Mechanical ventilation causing a higher positive end-expiratory pressure-induced increase in lung volume could impede venous return, thereby altering systemic hemodynamics and hepatic venous outflow [53]. In animal experiments, portal vein blood velocity and hepatic arterial blood velocity were shown to decrease with positive end-expiratory pressure as a result of a simple increase in the downstream pressure [54].

Also relevant to the present method are respiratory phase and posture, which are related to alteration in BFAb, as shown in Figure 6. The difference in BFAb was approximately 550 ml/min between inspiration and expiration in the sitting position; in the supine position, the difference was 480 ml/min. Blood flow was significantly less in inspiration compared with expiration in Ao, LFA, and RFA, in both the sitting and supine positions. BFAb was found to be lower in inspiration than in expiration, in both the sitting and supine positions. Respiration-related changes in the hemodynamics of the three conduit arteries potentially lead to alterations in BFAb. This result may be in partial agreement with the theory that respiratory-induced alteration of BFAb occurs with impedance of venous return in the splanchnic area.

The change in intra-abdominal pressure during breathing (thoracic-abdominal movement) possibly reflects transient changes in blood velocity in the Ao and femoral arteries. Higher values of venous outflow are found in the hepatic and portal veins in the supine rather than upright position, due to the effect of gravity [51]. In contrast, the reduction of BFAb in the inspiratory phase is similar between sitting and supine, and thus no postural effect on BFAb is seen in Figure 6. As the splanchnic circulation is intrinsically susceptible to the adverse effects of hydrostatic force [51,55], redistribution due to postural change between sitting and supine may differ between venous and arterial sites. Respiratory effects should be taken into account in evaluation of BFAb determined by measurements obtained in the three arteries. The present study demonstrated that changes in blood velocity between expiration and inspiration in the three conduit arteries may potentially indicate alterations in BFAb, and are only minimally influenced by posture. This phenomenon could be due to mechanical compression of vascular flow perfusion in comprehensive BFAb or via the vasovagal response. Because respiration and posture effects have an effect when organ perfusion is adequate, it is important not to confuse these effects as a sign of impaired organ perfusion. Evaluation of BFAb hemodynamics in the three conduit arteries should take respiratory effects into account.

Limitations

The disadvantages of the present methods are that measurement of the three target arteries cannot easily be performed in a short period of time, and that blood flow in the pelvis and other organs (except for the target splanchnic area) cannot be excluded. To avoid over- or underestimation of BFAb, measurement of the three target arteries should be performed under steady-state conditions at rest, with only minor changes in heart rate and blood pressure.

Potential clinical usefulness and application

Evaluation of BFAb as a quantitative assessment, encompassing physiologic flow, is a potentially useful indicator of 1) reserve blood volume and 2) blood flow in redistribution in the lower abdominal circulation in cardiovascular and hepato-gastrointestinal disease, shock, multiple organ failure, and stressful conditions such as following physical exercise and in the postprandial period. The advantage of the present method is that it enables evaluation of comprehensive BFAb without interference from intestinal bowel gas, because the three target conduit arteries can be detected relatively easily. It may also be useful for examining pathological hemodynamics, which may influence the abdominal circulation under the conditions of 1) extraordinary hemodynamics associated with abdominal aneurysm; 2) collateral circulation in abdominal-iliac peripheral arterial disease, as well as comparison with the post-operative state; and 3) intestinal neurological dysfunction associated with spinal disorder, in cerebrovascular disease, and in orthostatic hypotension with vasovagal syncope.

Although Doppler methods are less commonly used for quantifying flow in the three target arteries compared with other techniques, the measurement procedure used in the present method is potentially clinically viable. However, because it can be time-consuming to perform routine hemodynamic measurements for the three conduit arteries, measurement may be limited to the region of the femoral arteries around the inguinal ligament close to the genital area, which may not be an acceptable method for general use. It is possible that Doppler ultrasound evaluation of BFAb using a single vessel (Ao) may enable the necessary information to be obtained (Figure 5).

Also of note, because BFAb values are potentially related to many factors, including mean arterial blood pressure and/or cardiac index, it has potential use as a surrogate parameter for central venous saturation in the clinical setting.


Conclusions

The advantage in the described procedure for the determination of splanchnic hemodynamics is that it may potentially enable evaluation of the whole lower abdominal blood flows, assessed by non-invasive measurement using cardiovascular ultrasound. In contrast, it has the disadvantage that measurement of the three target arteries during steady heart rate and blood pressure can be time-consuming, and in measuring blood flow in the target splanchnic area, blood flow of pelvic and other organs cannot be excluded. Respiration and posture related to alterations in BFAb should be taken into account when measuring the three arteries. Determination of BFAb by evaluating three-conduit arterial hemodynamics using the technique described in this review may provide a valid measurement that encompasses the comprehensive physiologic arterial blood inflow to multiple abdominal organ systems.


Abbreviations

BF: Blood flow; Ao: Upper abdominal aorta; LFA: Left femoral artery; RFA: Right femoral artery; BFAo: Blood flow in the upper abdominal aorta; BFRFA: Blood flow in the right femoral artery; BFLFA: Blood flow in the left femoral artery; FAs: Both femoral arteries; BFAb: Comprehensive blood flow in the lower abdomen.


Competing interests

The author declares that they have no competing interests.


Acknowledgements

The author would like to express gratitude to the deceased Professor Hisao Iwane, as a previous supervisor; Professor Takafumi Hamaoka, as previous co-supervisor at Ritsumeikan University; Dr. Ayumi Sakamoto, as the director of the Tokyo Therapeutic Institute; Mr. Yukihiro Yamamoto of GE Healthcare Japan for his kind support in the initial studies; colleagues Dr. Norio Murase and Dr. Ryotaro Kime; and Professor Toshihito Katsumura, as the present departmental supervisor. I would also like to thank all of the participants in the studies.


References
Katz LN,Rodbard S,The integration of the vasomotor responses in the liver with those in other systemic vesselsJ Pharmacol Exp TherYear: 193967407422
Qamar MI,Read AE,Effects of exercise on mesenteric blood flow in manGutYear: 19872858358710.1136/gut.28.5.5833596339
Alvarez D,Vazquez H,Bai JC,Mastai R,Flores D,Boerr L,Superior mesenteric artery blood flow in coeliac diseaseDig Dis SciYear: 1993381175118210.1007/BF012960648325179
Danse EM,Van Beers BE,Jamart J,Hoang P,Laterre PF,Thys FC,Kartheuser A,Pringot J,Prognosis of ischemic colitis: comparison of color Doppler sonography with early clinical and laboratory findingsAJR Am J RoentgenolYear: 20001751151115411000181
Groszmann RJ,Hyperdynamic circulation of liver disease 40 years later. Pathophysiology and clinical consequencesHepatologyYear: 1994201359136310.1002/hep.18402005387927273
Waaler BA,Hisdal J,Eriksen M,Circulatory responses to a meal in patients with a newly transplanted heartActa Physiol ScandYear: 200217410110810.1046/j.1365-201X.2002.00934.x11860371
Nimura Y,Miyatake K,Kinoshita N,Okamoto M,Kawamura S,Beppu S,Sakakibara H,Lerski RA, Morley PNew approach to noninvasive assessment of blood flow in the major arteries in the abdomen by two-dimensional Doppler echographyUltrasound 82. Proceedings of 3 rd Meeting of the World Federation for Ultrasound in Medicine and Biology, 5th World Congress of Ultrasound in Medicine and Biology, (Brighton, England, 26-30 July 1982)Year: 1983Oxford: Pergamon447451
Jäger K,Bollinger A,Valli C,Ammann A,Measurement of mesenteric blood flow by duplex scanningJ Vasc SurgYear: 198634624693512856
Nakamura T,Moriyasu F,Ban N,Nishida O,Tamada T,Kawasaki T,Sakai M,Uchino H,Quantitative measurement of abdominal arterial blood flow using image-directed Doppler ultrasonography: superior mesenteric, splenic, and common hepatic arterial blood flow in normal adultsJ Clin UltrasoundYear: 19891726126810.1002/jcu.18701704062523903
Osada T,Katsumura T,Hamaoka T,Inoue S,Esaki K,Sakamoto A,Murase N,Kajiyama J,Shimomitsu T,Iwane H,Reduced blood flow in abdominal viscera measured by Doppler ultrasound during one-legged knee extensionJ Appl PhysiolYear: 1999867097199931212
Osada T,Iwane H,Katsumura T,Murase N,Higuchi H,Sakamoto A,Hamaoka T,Shimomitsu T,Relationship between reduced lower abdominal blood flows and heart rate in recovery following cycling exerciseActa PhysiolYear: 201220434435310.1111/j.1748-1716.2011.02349.x
Osada T,Murase N,Kime R,Shiroishi K,Shimomura K,Nagata H,Katsumura T,Arterial blood flow of all abdominal-pelvic organs using Doppler ultrasound: range, variability, and physiological impactPhysiol MeasYear: 2007281303131610.1088/0967-3334/28/10/01417906396
Osada T,Nagata H,Murase N,Shimomura K,Kime R,Shiroishi K,Nakagawa N,Katsumura T,Hemodynamics relationships among upper abdominal aorta and femoral arteries: basis for measurement of arterial blood flow to abdominal-pelvic organsMed Sci MonitYear: 200915CR332CR34019564822
Osada T,Nagata H,Murase N,Kime R,Katsumura T,Determination of comprehensive arterial blood inflow in abdominal-pelvic organs: impact of respiration and posture on organ perfusionMed Sci MonitYear: 201117CR57CR6621278689
Osada T,Muscle contraction-induced limb blood flow variability during dynamic knee extensorMed Sci Sports ExercYear: 2004361149115810.1249/01.MSS.0000132272.36832.6A15235318
Rådegran G,Ultrasound Doppler estimates of femoral artery blood flow during dynamic knee extensor exercise in humansJ Appl PhysiolYear: 199783138313889338449
Osada T,Rådegran G,Femoral artery inflow in relation to external and total work rate at different knee extensor contraction ratesJ Appl PhysiolYear: 2002921325133011842074
Osada T,Rådegran G,Femoral artery blood flow and its relationship to spontaneous fluctuations in rhythmic thigh muscle workloadClin Physiol Funct ImagingYear: 20092927729210.1111/j.1475-097X.2009.00868.x19486343
Gill RW,Measurement of blood flow by ultrasound: accuracy and sources of errorUltrasound Med BiolYear: 19851162564110.1016/0301-5629(85)90035-32931884
Holland CK,Brown JM,Scoutt LM,Taylor KJ,Lower extremity volumetric arterial blood flow in normal subjectsUltrasound Med BiolYear: 1998241079108610.1016/S0301-5629(98)00103-39833575
Osada T,Rådegran G,Alterations in the rheological flow profile in conduit femoral artery during rhythmic thigh muscle contractions in humansJpn J PhysiolYear: 200555192810.2170/jjphysiol.R207415796786
Osada T,Rådegran G,Alterations in the blood velocity profile influence the blood flow response during muscle contractions and relaxationsJ Physiol SciYear: 20065619520310.2170/physiolsci.RP00290516839453
Moriyasu F,Ban N,Nishida O,Nakamura T,Miyake T,Uchino H,Kanematsu Y,Koizumi S,Clinical application of an ultrasonic duplex system in the quantitative measurement of portal blood flowJ Clin UltrasoundYear: 19861457958810.1002/jcu.18701408022945835
Leyk D,Eßfeld D,Baum K,Stegemann J,Influence of calf muscle contractions on blood flow parameters measured in the arteria femoralisInt J Sports MedYear: 19921358859310.1055/s-2007-10245711487343
Isnard R,Lechat P,Kalotka H,Chikr H,Fitoussi S,Salloum J,Golmard J-L,Thomas D,Komajda M,Muscular blood flow response to submaximal leg exercise in normal subjects and in patients with heart failureJ Appl PhysiolYear: 199681257125799018508
Osada T,Katsumura T,Murase N,Sako T,Higuchi H,Kime R,Hamaoka T,Shimomitsu T,Post-exercise hyperemia after ischemic and non-ischemic isometric handgrip exerciseJ Physiol Anthropol Appl Human SciYear: 20032229930910.2114/jpa.22.299
Fleiss JL,Statistical methods for rates and proportionsYear: 19812New York: John Wiley & Sons
Bland JM,Altman DG,Statistical methods for assessing agreement between two methods of clinical measurementLancetYear: 1986184763073102868172
Gabriel H,Kindermann W,Ultrasound of the abdomen in endurance athletesEur J Appl PhysiolYear: 19967319119310.1007/BF00262831
Callum KG,Gaunt JI,Thomas ML,Browse NL,Physiological studies in arteriomegalyCardiovasc ResYear: 1974837338310.1093/cvr/8.3.3734415073
Fitzgerald DE,O'Shaughnessy AM,Cardiac and peripheral arterial responses to isoprenaline challengeCardiovasc ResYear: 19841841441810.1093/cvr/18.7.4146744361
Agrifoglio G,Thorburn GD,Edwards EA,Measurement of blood flow in human lower extremity by indicator-dilution methodSurg Gynecol ObstetYear: 196111364164513859664
Folse R,Application of the sudden injection dye dilution principle to the study of the femoral circulationSurg Gynecol ObstetYear: 19651201194120614289621
Wahren J,Jorfeldt L,Determination of leg blood flow during exercise in man: an indicator-dilution technique based on femoral venous dye infusionClin Sci Mol MedYear: 1973451351464594233
Reagan TR,Miller CW,Strandness DE Jr,Transcutaneous measurement of femoral artery flowJ Surg ResYear: 19711147748210.1016/0022-4804(71)90064-35111054
Lewis PJ,Psaila JV,Morgan RH,Davies WT,Woodcock JP,Common femoral artery volume flow in peripheral vascular diseaseBr J SurgYear: 19907718318710.1002/bjs.18007702202317678
Hussain ST,Smith RE,Wood RFM,Bland M,Observer variability in volumetric blood flow measurements in leg arteries using duplex ultrasoundUltrasound Med BiolYear: 19962228729110.1016/0301-5629(95)02050-08783460
Ganz VA,Hlavová A,Fronek A,Linhart J,Prerovsky I,Measurement of blood flow in the femoral artery in man at rest and during exercise by local thermodilutionCirculationYear: 196430868914197841
Vänttinen E,Electromagnetic measurement of the arterial blood flow in the femoropopliteal regionActa Chir ScandYear: 1975141353359127496
Rådegran G,Saltin B,Human femoral artery diameter in relation to knee extensor muscle mass, peak blood flow, and oxygen uptakeAm J Physiol Heart Circ PhysiolYear: 2000278H162H16710644595
Bradley SE,The hepatic circulationHandbook of PhysiologyYear: 1963Bethesda, MD: American Physiological Society13871438 Circulation, sect. 2, Volume II. chapter 41.
Greenway CV,Stark RD,Hepatic vascular bedPhysiol RevYear: 19715123655543903
Hultman E,Blood circulation in the liver under physiological and pathological conditionsScand J Clin Lab InvestYear: 196618Suppl, 922741
Rowell LB,Human cardiovascular adjustments to exercise and thermal stressPhysiol RevYear: 197454751594587247
Hollenberg NK,Zelis RThe renal circulationThe Peripheral CirculationYear: 1975New York: Grune & Stratton131150
Ganong WF,The heart as a pumpReview of Medical PhysiologyYear: 1998Chapter 2921New York: Lange Medical Books/McGraw-Hill Company567578
Guyton AC,Hall JE,Cardiac output, venous returns, and their regulationTextbook of Medical PhysiologyYear: 1995Chapter 209Pennsylvania Philadelphia: WB Sanders Company24153
Kiszka-Kanowitz M,Henriksen JH,Moller S,Bendtsen F,Blood volume distribution in patients with cirrhosis: aspects of the dual-head gamma-camera techniqueJ HepatolYear: 20013560561210.1016/S0168-8278(01)00175-111690706
Fujimoto S,Watanabe T,Sakamoto A,Yukawa K,Morimoto K,Studies on the physical surface area of Japanese. Part 18: Calculation formulas in three stages over all age [in Japanese]Jpn J HygYear: 19682344345010.1265/jjh.23.443
Rodahl K,Physiological bases of exerciseTextbook of work physiologyYear: 19863New York: McGraw-Hill book company
Hsia TY,Khambadkone S,Redington AN,Migliavacca F,Deanfiels JE,de Leval MR,Effects of respiration and gravity on infradiaphragmatic venous flow in normal and Fontan patientsCirculationYear: 200010219suppl IIIIII-14815311082378
Abu-Yousef MM,Mufid M,Woods KT,Brown BP,Barloon TJ,Normal lower limblood velocityenous Doppler flow phasicity:Is it cardiac or respiratory?AJR Am J RoentgenolYear: 1997169172117259393197
Matuschak GM,Pinsky MR,Rogers RM,Effects of positive end-expiratory pressure on hepatic blood flow and performanceJ Appl PhysiolYear: 198762137713832954939
Gioia FR,Harris AP,Traystman RJ,Rogers MC,Organ blood flow during high-frequency ventilation at low and high airway pressure in dogsAnesthesiologyYear: 198665505510.1097/00000542-198607000-000083524318
Cullbertson JW,Wilkins RW,Ingelfinger FJ,Bradley SE,The effect of the upright posture upon hepatic blood flow in normotensive and hypertensive subjectsJ Clin InvestYear: 19513030533110.1172/JCI10244514824281

Figures

[Figure ID: F1]
Figure 1 

Anatomical region for measurement and blood velocity profiles of the three arteries. Blood flow (BF) measurements were obtained for the upper abdominal aorta (Ao) above the coeliac artery bifurcation and for the bilateral femoral arteries (right and left femoral arteries; RFA and LFA, respectively). Comprehensive BF in the lower abdomen (BFAb) was calculated by subtracting bilateral femoral arterial flow (BFLFA + BFRFA) from BFAo. The splanchnic gastrointestinal blood vessels include the renal (RA) and coeliac arteries (CA), and the superior and inferior mesenteric arteries (SMA and IMA, respectively). Figure modified from Osada et al. [12], reproduced with permission from IOP Publishing Ltd.



[Figure ID: F2]
Figure 2 

Bland-Altman analysis of three arterial hemodynamics for repeated measurement. The difference (y-axis) and mean (x-axis) are shown for hemodynamics (blood velocity, vessel diameter, and blood flow, respectively) in the three arteries between two measurements obtained over three different days. Results are based on 180 samplings (comparison between 1st and 2nd, 2nd and 3rd, and 3rd and 1st measurements) in 60 participants. The solid line indicates bias (close to zero) and the dashed lines are the limits of agreement of ± 1.96 SD (± 2 SD on the figure). The open circles correspond to 1st vs. 2nd measurement. The grey circles correspond to 2nd vs. 3rd measurement. The closed circles correspond to 3rd vs. 1st measurement. All measurements were obtained by a single operator, using the same ultrasound instrument. Thus, no systematic bias (fixed bias or proportional bias) exists between two measurements. Ao, abdominal aorta; LFA, left femoral artery; RFA, right femoral artery. Material reproduced with additional data in the adapted figure, with Bland-Altman analysis, from Osada et al. [12], with permission from IOP Publishing Ltd.



[Figure ID: F3]
Figure 3 

Bland-Altman analysis of blood flow in the lower abdomen for repeated measurements. Bland-Altman analysis revealed no systematic bias (fixed bias or proportional bias) between two measurements. The difference (y-axis) and mean (x-axis) in blood flow in lower abdomen (Ab) between two measurements over three different days. Results are based on 180 samplings (comparison between 1st and 2nd, 2nd and 3rd, and 3rd and 1st measurements) in 60 participants. The solid line indicates bias and the dashed lines are the limits of agreement of ± 1.96 SD (± 2 SD on the figure). The open circles correspond to 1st vs. 2nd measurement. The grey circles correspond to 2nd vs. 3rd measurement. The closed circles correspond to 3rd vs. 1st measurement. Material reproduced, with data added to the figure adapted from Osada et al. [12], with permission from IOP Publishing Ltd.



[Figure ID: F4]
Figure 4 

Relationship of blood flows to body surface area and to body weight. A significant (p < 0.05) positive linear correlation was observed between measured blood flow, and body surface area and body weight for Ao, LFA, RFA, and Ab (n = 50). Note overlapping of the circular regression lines for blood flow in LFA and RFA. Ao, abdominal aorta; LFA, left femoral artery; RFA, right femoral artery; Ab, lower abdomen. Figure adapted from Osada et al. [13], reproduced with permission from The International Science Literature, Inc.



[Figure ID: F5]
Figure 5 

Relationship of blood flow in lower abdomen to the three arteries. BFAb was more strongly related to BFAo (r = 0.966, p < 0.0001) than to BFLFA or BFRFA (r = 0.303, p = 0.0327 in LFA; r = 0.281, p = 0.0482 in RFA) (n = 50). Ao, abdominal aorta; LFA, left femoral artery; RFA, right femoral artery; Ab, lower abdomen. Blood flow in the Ao, LFA, RFA and Ab is defined as BFAo, BFLFA, BFRFA, and BFAb respectively. Figure adapted from Osada et al. [13], reproduced with permission from The International Science Literature, Inc.



[Figure ID: F6]
Figure 6 

Blood flow in the three arteries and lower abdomen in relation to respiration and posture. Blood flow was significantly less in inspiration compared with expiration in Ao, LFA, and RFA, in both sitting and supine positions. Consequently, blood flow in Ab was lower in inspiration than in expiration, in both sitting and supine positions (n = 10). Values are expressed as the mean ± standard error (SE). Ao, abdominal aorta; LFA, left femoral artery; RFA, right femoral artery; Ab, lower abdomen. Figure adapted from Osada et al. [14], reproduced with permission from The International Science Literature, Inc.



Tables
[TableWrap ID: T1] Table 1 

Reliability and coefficients of variation in hemodynamics for repeated measurements


Hemodynamics variable Target artery 1st 2nd 3rd Mean CV (%) Relative reliability, SM-ICC F (2, 118, 0.05) p < 0.05

Mean SD Mean SD Mean SD
Blood velocity (cm/sec) Ao 26.0 6.6 26.2 6.3 26.0 7.0 4.9 0.94 0.18 ns
LFA 8.4 2.5 8.3 2.3 8.2 2.5 7.8 0.90 0.48 ns
RFA 8.4 2.5 8.2 2.2 8.3 2.6 8.7 0.85 1.15 ns

Vessel diameter (mm) Ao 15.5 1.3 15.6 1.2 15.5 1.2 1.3 0.95 3.63 ns
LFA 9.0 0.7 9.1 0.7 9.0 0.7 1.4 0.94 3.09 ns
RFA 9.1 0.8 9.1 0.7 9.0 0.8 1.2 0.97 1.35 ns

Blood flow (ml/min) Ao 2946 774 2989 740 2931 818 4.9 0.95 1.65 ns
LFA 322 104 324 105 317 113 8.6 0.90 0.66 ns
RFA 323 103 317 94 319 106 8.6 0.90 0.57 ns
Ab 2301 699 2348 666 2295 721 6.2 0.94 1.87 ns

Mean coefficients of variation (CV) in hemodynamics were obtained from the average CV values of 60 participants among three repeated measurements over three different days. Single-measure intra-class correlation coefficient (SM-ICC) was evaluated by three repeated measurements over three different days. All measurements were performed by a single operator. SD, standard deviation; ns, not significant; Ao, abdominal aorta; LFA, left femoral artery; RFA, right femoral artery; Ab, lower abdomen. This material is reproduced and additional data were provided for analysis from Osada et al. [12], with permission from IOP Publishing Ltd.


[TableWrap ID: T2] Table 2 

Bland-Altman analysis of acceptable range in difference (bias) in hemodynamics via three repeated measurements


Hemodynamics variable Ao LFA RFA Ab
Blood velocity (cm/sec) Limit of agreement 0.00 ± 8.93 0.00 ± 4.37 0.00 ± 5.24
95%CI 0.00 ± 0.67 0.00 ± 0.33 0.00 ± 0.39

Vessel diameter (mm) Limit of agreement 0.00 ± 1.49 0.00 ± 0.95 0.00 ± 0.77
95%CI 0.00 ± 0.11 0.00 ± 0.07 0.00 ± 0.06

Blood flow (ml/min) Limit of agreement 0.00 ± 1008.42 0.00 ± 186.78 0.00 ± 180.71 0.00 ± 922.08
95%CI 0.00 ± 75.16 0.00 ± 13.92 0.00 ± 13.47 0.00 ± 68.73

Results are based on 180 samplings (comparison between 1st and 2nd, 2nd and 3rd, and 3rd and 1st measurements) in 60 participants. All measurements were performed by a single operator. The mean difference (bias) in each hemodynamic parameter (blood velocity, vessel diameter, and blood flow) between two measurements almost corresponds to zero. Therefore, the limit of agreement is expressed as 0.00 ± 1.96 SD. The 95% of confidence interval (95%CI) is expressed as 0.00 ± 1.96 SE. Ao, abdominal aorta; LFA, left femoral artery; RFA, right femoral artery; Ab, lower abdomen; SD, standard deviation; SE, standard error. This material is reproduced and additional data were provided for analysis from Osada et al. [12], with permission from IOP Publishing Ltd.


[TableWrap ID: T3] Table 3 

Mean values and range for the three arterial hemodynamics and lower abdominal blood flow


Hemodynamics variable Ao LFA RFA Ab
Blood velocity (cm/sec) Mean ± SD 26.1 ± 6.5 8.3 ± 2.4 8.1 ± 2.1 --
Range 13.9–41.1 4.9–13.4 4.0–12.7 --
95%CI 24.4–27.7 7.7–8.9 7.6–8.7 --

Vessel diameter (mm) Mean ± SD 15.6 ± 1.2 9.0 ± 0.7 9.1 ± 0.7 --
Range 12.4–18.1 7.9–11.6 7.6–10.9 --
95%CI 15.2–15.9 8.9–9.2 8.9–9.2 --

Blood flow (ml/min) Mean ± SD 2951 ± 767 316 ± 97 313 ± 83 2323 ± 703
Range 1585–5274 178–558 168–481 1153–4401
95%CI 2757–3145 291–340 292–334 2145–2500

Mean values are shown for three repeated measurements over three different days in 60 participants. All measurements were performed by a single operator. Ao, abdominal aorta; LFA, left femoral artery; RFA, right femoral artery; Ab, lower abdomen; 95%CI, 95% of confidence interval; SD, standard deviation. This material is reproduced and additional data were provided for analysis from Osada et al. [12], with permission from IOP Publishing Ltd.



Article Categories:
  • Review

Keywords: Lower abdominal inflows, splanchnic blood flow, Doppler ultrasound.

Previous Document:  Adaptive evolution and functional constraint at TLR4 during the secondary aquatic adaptation and div...
Next Document:  Mist Separation and Sonochemiluminescence under Pulsed Ultrasound.