Print this page Email this page
Users Online: 2945
Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2015  |  Volume : 5  |  Issue : 3  |  Page : 137-142

The relationship between infrarenal and suprarenal transverse aortic diameter on ultrasound among adults in Zaria, Nigeria


1 Department of Radiology, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria
2 Department of Medicine, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria
3 Department of Radiology, University of Calabar Teaching Hospital, Calabear, Nigeria

Date of Web Publication19-Oct-2015

Correspondence Address:
Dr. Bello Omuya Usman
Department of Radiology, Ahmadu Bello University Teaching Hospital, Zaria
Nigeria
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2278-9596.167496

Rights and Permissions
  Abstract 

Background: Cardiovascular disease (CVD) is now a public health problem due to its high prevalence and associated high morbidity and mortality. Measurement of aortic diameters can help in predicting CVD in patients. The objective of this study was to determine the normal value of infrarenal and suprarenal transverse aortic diameter and their relationship on ultrasound among adults in Zaria, Nigeria
Patients and Methods: Three hundred consecutive Nigerian adults without CVD attending ultrasound unit of Radiology Department of Ahmadu Bello University Teaching Hospital, Zaria, were recruited for this study. Routine protocol for scanning the abdomen in the transverse, longitudinal and craniocaudal planes were used to scan the aorta for supra- and infrarenal dimensions.
Results: The mean suprarenal aortic diameter (SAD) of the subjects was 1.79 ± 0.25 cm with a range of 1.15-2.61 cm. The mean infrarenal aortic diameter (IAD) was 1.63 ± 0.23 cm with a range of 1.01-2.46 cm. The mean ratio of infra- and supra-renal diameter was 0.91 (±0.04), in male subjects, it was 0.92 (±0.04) and in female subjects, it was 0.90 (±0.05). IAD, IAD/SAD ratio, and weight were independent predictors of SAD on multilinear regression analysis. SAD, IAD/SAD ratio, age and body mass index were also independent predictors of IAD.
Conclusion: This study has established the normal ratio values of infrarenal to suprarenal transverse aortic diameter in healthy adults and the factors that correlate with transverse aortic diameter, as well as independent predictors of transverse aortic diameter in Zaria. These values would be of help to radiologists, surgeons, and other clinician in the diagnosis, management, and follow-up of cardiovascular patients.

Keywords: Body mass index, infrarenal aortic diameter, suprarenal aortic diameter


How to cite this article:
Usman BO, Ibinaiye PO, Abdulaziz U, Inah GB. The relationship between infrarenal and suprarenal transverse aortic diameter on ultrasound among adults in Zaria, Nigeria. Arch Int Surg 2015;5:137-42

How to cite this URL:
Usman BO, Ibinaiye PO, Abdulaziz U, Inah GB. The relationship between infrarenal and suprarenal transverse aortic diameter on ultrasound among adults in Zaria, Nigeria. Arch Int Surg [serial online] 2015 [cited 2024 Mar 28];5:137-42. Available from: https://www.archintsurg.org/text.asp?2015/5/3/137/167496


  Introduction Top


Aortic diameter at various levels has been documented in Caucasian but because of the paucity of such study in Africa, their values are used as reference. This contributes to increase in morbidity and mortality in cardiovascular disease (CVD) in the tropic. The normal infrarenal aortic diameter (IAD) in Caucasian is 2.3 cm in the young male, 1.9 cm in the young female; 2.5 cm for suprarenal diameter and 1.2 for infra- and supra-renal ratio. [1] The various imaging modalities in use to image abdominal aorta are plain film, ultrasound Doppler scan, angiography, computed tomography (CT), CT angiography (CTA), magnetic resonance imaging (MRI), and magnetic resonance angiography (MRA). However, they all have pitfalls and limitations. Plain film is very good in picking up calcification but not useful in the assessment of the lumen and aortic wall. Angiography assesses the aortic lumen but is invasive and requires a high level of expertise and has the side effect of contrast reaction. [2] CT/CTA with reformatted and volume rendering images give a very good assessment of the aortic wall and lumen, but it involves high ionizing radiation. MRI/MRA is one of the best modalities to image abdominal aorta; however, it is very expensive and not readily available in most centers in Nigeria. Aortic Doppler Ultrasound is a valuable diagnostic procedure that can be performed in the clinic or hospital setting using standard units with the appropriate frequency transducer. It is a useful tool for assessing aortic size, disparity or widening of the aorta.

Ultrasound of the abdominal aorta using lower frequency transducers (2.5-5 MHz) visualizes the wall and the lumen while the higher frequency transducers (5-10 MHz) are for Doppler interrogation. Scans can be performed in any plane, but are usually obtained in transverse (axial) and longitudinal (sagittal) planes. The lumen appears as an anechoic tubular space. The wall is echogenic and easily defined. [1] The incidence of the abdominal aortic disease is 1.4-8.2% in unselected population. It is 6% in those above 80 years of age. It is 6-20% in patients with the clinical sign of atherosclerotic disease. Males are more commonly affected than females and whites more than blacks (3:1). [2] There are more than 12 million deaths per year worldwide attributable to CVD. [2] The mortality in the developed, and developing countries combined accounted for approximately 50% of deaths that are related to CVD. [2] In Africa, Western and Southern Asia, there are 20 million death per year, 20% of which are related to CVDs. [3] In Kenya, aortic disease like aneurysm showed abdominal segment predominance and occurs 10-15 years earlier than in white population and carry high mortality from rupture. [3] In Nigeria Udemezue et al. [4] demonstrated that there is an increase in the prevalence of cardiovascular dysfunction within the last decade. In Zaria, Danbauchi et al. [5] showed that the aortic valvular disease is still prevalent in the developing countries, and its prevalence is put at 0.3-18.6%.

There are various imaging methods for the aorta, but ultrasonography appears to be most common and most readily used, as it is cheap, affordable, does not involve ionizing radiation and is noninvasive. It is, therefore, important that normal values for aortic diameter and its relationship with sex, age, body size, and supra- and infra-renal transverse aortic diameter ratio be established for the Nigeria population. The objective of this study was to determine the normal value of infrarenal and suprarenal transverse Aortic diameter and their relationship to age, sex, and body mass index (BMI) among adults in Zaria, Nigeria. This would serve as references in our locality instead of relying on established foreign references.


  Patients and Methods Top


This study was conducted over a period of 6 months from 6 th January 2012 to 6 th June 2012, after approval was given by the ethical committee of Ahmadu Bello University Teaching Hospital (ABUTH), at the Department of Radiology, ABUTH, Zaria, Nigeria. Informed written consents were obtained from the participants before the examination. Three hundred consecutive Nigerian adults without CVD attending ultrasound unit of the ABUTH were recruited for this study. The study subjects fasted for 8-12 h. Relevant cardiovascular history was elicited, weight and height of patients were measured and BMI calculated. Blood pressure was measured using adult size cuff of mercury sphygmomanometer. Routine protocol for scanning the abdomen in the transverse, longitudinal and craniocaudal planes were used to scan the aorta for supra- and infrarenal dimensions. The aortic diameter was measured using 3.5 MHZ grayscale curvilinear transducer of the Mindray DC-6 diagnostic ultrasound unit.

Inclusion criteria

normal consenting adults of 18 years and above on routine medical checkup, normal consenting staff, normal consenting students and patients for ultrasonography without CVDs.

Exclusion criteria

Subjects with previous history or clinical evidence of cardiac disorder, hypertension, renal disease, hepatobiliary disease, vascular diseases, cerebrovascular accident, diabetic mellitus, all pregnant women, subjects below the age of 18 years, cigarette smokers and those that declined consent.

Technique of infrarenal and suprarenal aortic diameter measurement using ultrasound

All subjects were examined in the supine position with the radiologist sitting to the right side of the patient. A coupling gel was adequately applied on the left lower chest and abdominal midline. The ultrasound examination involved visualization of the entire length of the abdominal aorta by using a 2.5-5 MHz curved array probe, viewing from the subxiphoid area to the umbilicus in the midline. The probe pointer was placed at 9 O'clock with firm pressure to the abdomen. Next step was to identify the anterior vertebral body which is densely hyperechoic, concave down, with posterior acoustic shadowing. Two vascular, anechoic structures are present immediately anterior to the vertebral body; with the probe indicator to the patient's right side, the aorta is on the right side of the ultrasound screen (patient's left) and the inferior vena cava is on the left side of the screen (patient's right). The aortic diameter was measured above and below the renal arteries in the transverse plane.

The measurements were made from outer wall to outer wall [Figure 1]a after the patient had been asked to inspire deeply and hold. The probe was placed perpendicular to the aorta, in order to maximize the angle of insonation and moved down the abdomen in 0.5-1 cm increments in the transverse plane. The probe was then turned clock-wise to 12 O'clock to obtain a longitudinal view of the aorta. This was followed from the mid-epigastrium to the bifurcation.
Figure 1

Click here to view


There are some technical limitations that made examination difficult especially when there are vessels angulations, but the coronal view was used as an alternative. Using the liver as an acoustic window, the probe was placed in the mid-axillary line at 12 O'clock. Imaging was done through the ribs, preferably below the costal margin.

Statistical methods

All measurements were statistically analyzed using Statistical Package for Social Sciences (SPSS) software version 17 (SPSS Inc., Released 2008. SPSS statistics for windows, Chicago). P ≤ 0.05 was considered as statistically significant and findings are presented in tables and graph.


  Results Top


In this study, 300 subjects were recruited, 153 (51%) of the subjects were females while 147 (49%) were males, given a male to female ratio of 1:1.04. Their mean age was 32.89 (±11.96) years, with a range of 18-80 years. The mean age for male and female subjects were 34.3 (±12.70) and 31.22 (±10.98) years respectively. The age group distribution of the subjects is as shown in [Figure 1]. The mean height of the subjects was 1.66 (±0.08) m, with a range of 1.47-1.88 m. The mean (standard deviation [SD]) height for male and female subjects was 1.73 (±0.07) cm and 1.61 (±0.06) cm, respectively. There was a significant difference between male and female heights (t = 12.24 and P = 0.000) as shown in Tables 1 and 2. The mean weight of the subjects was 64 (±9.72) kg, with a range of 42-92 kg and a median of 63 kg. The mean (SD) weight for male and female subjects was 65.52 (±9.12) kg and 65.53 (±10.08) kg, respectively. There is a significant difference between the weight of the males and females (t = 2.65 and P = 0.008) [Table 3] and [Table 4].

The mean suprarenal aortic diameter (SAD) of all subjects was 1.79 (±0.25) cm with a range of 1.15-2.61 cm and a median of 1.76 cm [Table 1]. The mean SAD in male is 1.88 (±0.23) cm, while the mean SAD in female subjects was 1.69 (±0.22) cm. There was a statistically significant difference between the mean SAD of male and female subjects (t = 7.27, P = 0.000). This was shown in basic descriptive of statistical features between male and female gender [Table 3] and [Table 4]. There was a positive correlation between the SAD and infra-aortic diameter of the subjects (r = 0.93, P = 0.000). The correlation of SAD was also shown in correlation matrix for SAD, IAD, and IAD/SAD ratio [Table 2].
Table 1: Summary of basic descriptive features of subjects


Click here to view
Table 2: Correlation matrix of SAD, IAD, and IAD/SAD ratio


Click here to view
Table 3: Basic descriptive statistics in male subjects


Click here to view
Table 4: Basic descriptive statistics in female subjects


Click here to view


The mean ± SD IAD of all subjects was 1.63 (±0.23) cm with a range of 1.01-2.46 cm and a median of 1.60 cm. The mean IAD in male was 1.73 (±0.23) cm, while the mean IAD in female subjects was 1.53 (±0.20) cm. There was a statistically significant difference between the mean IAD of male and female subjects (t = 8.43, P = 0.000). There was a positive correlation between the IAD of the subjects and their SAD (r = 0.92, P = 0.000). There was a positive correlation between the height of the subjects and supra-aortic diameter(r = 0.365, P = 0.000). Likewise, there was a positive correlation between infra-aortic diameter and height of the subjects (r = 0.384, P = 0.000). The correlation of height is shown in correlation matrix for SAD, IAD, and IAD/SAD ratio [Table 2].

Factors that correlated with SAD were: Weight (r = 0.43, P = 0.000), height (r = 0.37, P = 0.000), BMI (r = 0.24, P = 0.000), IAD (r = 0.93, P = 0.000), and age (r = 0.55, P = 0.000). The other factors did not show significant correlation with SAD. Factors that correlated with IAD in this study were: Weight (r = 0.41, P = 0. 000), height (r = 0.38, P = 0.000), BMI (r = 0.20, P = 0.000), SAD (r = 0.93, P = 0.) and age (r = 0.58, P = 0.000). The summary of factors that are associated with IAD is shown [Table 2]. The mean ± SD IAD/SAD of all subjects was 0.90 ± 0.04, with a range of 0.75-1.00 and a median of 0.92. The mean IAD/SAD ratio in male was 0.91(±0.04), while the mean IAD/SAD in female subjects was 0.90 (±0.05). There was a significant difference between the mean IAD/SAD of male and female subjects (t = 2.65, P = 0.009). The IAD/SAD of the subjects was noted to be positively correlated with both the supra-aortic diameter (r = 0.0137, P = 0.018) and height (r = 0.1222, P = 0.035).

Multilinear regression analysis showed that IAD, weight, and infra- and supra-aortic diameter ratio are independent predictive factors for SAD. The independent predictive factors for SAD are shown in the coefficient for SAD [Table 5]. The scatter plot with regression line for the SAD and weight of the subject is shown in [Figure 2]. Multilinear regression analysis was done, where factors that correlated with IAD were entered in a stepwise backward method. The model showed that age, BMI and SAD, and infra- and supra-aortic diameter ratio are independent predictive factors for IAD. The independent predictive factors for IAD are shown in the coefficient for IAD [Table 6]. The scatter plot with regression line for the SAD and weight of the subject is shown in [Figure 3].
Figure 2: Scatter plot and regression line of infra- and supra-renal aortic diameter

Click here to view
Figure 3: Scatter plot and regression line of weight and supra-renal aortic diameter

Click here to view
Table 5: Coefficient table for supra-aortic diameter


Click here to view
Table 6: Coefficient for IAD


Click here to view



  Discussion Top


The mean SAD in this study was 1.79 (±0.25) cm. It was higher in males with a mean of 1.88 cm while in females it was 1.69 cm. The observed mean SAD in this study is less than the values given in other studies [1],[6] done in Uppsala Sweden. The disparity could be explained by the difference in the methodology because they used MRI and inclusion criteria for age was restricted to 70-year-old men and women. Similarly, in a CT study of 70 adult patients aged 17-89 years (mean - 50 years) without CVD, Hager et al. [7] found the mean diameter of the aorta to be 2.5 cm. Of all the factors that were found to correlate with SAD in this study, three were noted to be independently predictive factors in linear regression model namely: IAD, infra and SAD ratio and weight. The findings in this study are largely in keeping with earlier studies where factors that are predictive of SAD had been noted to include weight, [8] IAD, and SAD ratio. [9],[10],[11]

This study showed the mean infra-aortic diameter was 1.63 (±0.23) cm. It was found to be higher in male with a mean of 1.73 cm than female with a mean of 1.53 cm. The finding in this study has similarities and differences from previous studies done in Nigeria [12],[13],[14],[15] and among Caucasian. [1],[8] The mean IAD was within the range 1.2-2.7 cm in the previous study done in Europe by Sonesson et al. [8] .The larger value of 4.7 cm ± 0.5 cm noted earlier in Nigerian studies was due to the difference in methodology (radiograph), mean age, and the level of the measurement (aortic arch). However, it confirmed the earlier studies which showed that the aortic diameter is greater in males than females. [12],[13],[14],[15],[16]

Another important observation in the present study was that mean IAD and SAD ratio was 0.91 (±0.04) with a range of 0.75-1.0; ratio was 0.92 for males and 0.90 for females. It is noteworthy that 97.5% of all measurements of infrarenal and suprarenal aortic ratio is below 1.0. This finding is in agreement with earlier studies [7],[17] that showed the IAD and SAD ratio to be 0.9 in males and 0.8 in females. However, Wanhainen et al. [17] noted a small difference in female gender due to the inclusion of fewer female subjects. In the study done by Alcorn et al., [18] using older patients with aneurysm, the IAD/SAD ratio was 1.4. The higher ratio noted in the Alcorn et al. [18] study is likely due to the older age of the patients used (mean age = 67 years) and the diseased state of their blood vessels. Age and CVDs have been shown by several studies to be a significant contributing factor for higher IAD/SAD ratio. [9],[18],[19]

Age, SAD, IAD and SAD ratio and BMI were noted to be independent predictive factors of IAD in this study. These findings are in agreement with the earlier studies by Sonesson et al. [8] and Collin et al. [10] IAD and SAD ratio was noted to be an independent predictive factor of SAD and IAD.

Limitations of the study

There was difficulty in cases of bowel gas interference with ultrasound signals. Vessel angulations were noted to be an important constraint.


  Conclusion Top


The mean ± (SD) SAD was 1.79 (±0.25) cm. The mean IAD was 1.63 (±0.23) cm. The mean (±SD) ratio of infra- and suprarenal diameter was 0.91 (±0.04), in male subjects it was 0.92 (±0.04) and in female subjects it was 0.90 (±0.05). This study showed infra- and supra-aortic diameter ratio, IAD, and weight were independent predictive factors for SAD. Infra- and supra-aortic diameter ratio, BMI, SAD, and age were an independent predictive factor for IAD.


  Recommendations Top


  1. The nomogram established from this study will be recommended as a guide to help clinicians in the diagnosis, treatment, and follow-up of patient with the aortic disease.
  2. In CVD ultrasound screening, measurement of aortic diameter should be part of the routine workup for the patients.
  3. All patients who are incidentally found to have abnormal aortic diameter measurement should be investigated appropriately.
  4. This study examined only healthy individuals who had no clinical history or evidence of renal or systemic disease. Further studies need to be done in patients with CVD to establish the sensitivity of this value, using this nomogram as a baseline study.
  5. Further studies are also required on other systemic diseases that can affect aortic diameter.


 
  References Top

1.
Mok KL. Ultrasound of abdominal aorta. Acad Emerg Med 2009;5:412.  Back to cited text no. 1
    
2.
Dahnert W. Radiology Review Manual. 6 th ed. Philadelphia: Lippincott William & Wilkin; 2007. p. 614-5.  Back to cited text no. 2
    
3.
Ogeng′o JA, Olabu BO, Kilonzi JP. Pattern of aortic aneurysms in an African country. J Thorac Cardiovasc Surg 2010;140:797-800.  Back to cited text no. 3
    
4.
Udemezue OO, Akpuaka PC, Anibeze CI. Body habits and abdominal aortic sizes among south Nigerians. J Exp Clin Anat 2000;1:22-5.  Back to cited text no. 4
    
5.
Danbauchi SS, Alhassan MA, David SO, Wammada R, Oyati IA. Spectrum of rheumatic heart disease in Zaria, Northern Nigeria. Ann Afr Med 2004;3:17-21.  Back to cited text no. 5
    
6.
Wanhainen A. How to define an abdominal aortic aneurysm - influence on epidemiology and clinical practice. Scand J Surg 2008;97:105-9.  Back to cited text no. 6
    
7.
Hager A, Kaemmerer H, Rapp-Bernhardt U, Blücher S, Rapp K, Bernhardt TM, et al. Diameters of the thoracic aorta throughout life as measured with helical computed tomography. J Thorac Cardiovasc Surg 2002;123:1060-6.  Back to cited text no. 7
    
8.
Sonesson B, Länne T, Hansen F, Sandgren T. Infrarenal aortic diameter in the healthy person. Eur J Vasc Surg 1994; 8:89-95.  Back to cited text no. 8
    
9.
Sterpetti AV, Schultz RD, Feldhaus RJ, Cheng SE, Peetz DJ Jr. Factors influencing enlargement rate of small abdominal aortic aneurysms. J Surg Res 1987;43:211-9.  Back to cited text no. 9
    
10.
Collin J, Araujo L, Walton J, Lindsell D. Oxford screening programme for abdominal aortic aneurysm in men aged 65 to 74 years. Lancet 1988;2:613-5.  Back to cited text no. 10
    
11.
Johnston K, Rutherford R, Tilson M, Shah D, Hollier L, Stanley J. Suggested standards for reporting on arterial aneurysms. J Vasc Surg 1991;13:452-8.  Back to cited text no. 11
    
12.
Anyanwu GE, Anibeze CI, Akpause FC. Transverse aortic arch diameter and relationship with heart size of Nigerians within the south east. Biomed Res 2007;2:115-8.  Back to cited text no. 12
    
13.
Ikeme AC, Ogakwu MA, Nwakonobi FA. The significance of the enlargement of the aortic shadow in adult Nigerians. Afr J Med Med Sci 1976;5:195-9.  Back to cited text no. 13
    
14.
Umerah BC. Unfolding of the aorta (aortitis) associated with pulmonary tuberculosis. Br J Radiol 1982;55:201-3.  Back to cited text no. 14
    
15.
Obikili EN, Okoye IJ. Aortic arch diameter in frontal chest radiographs of a normal Nigerian population. Niger J Med 2004;13:171-4.  Back to cited text no. 15
    
16.
Gustafson JE, Friedenberg MJ. Evaluation of left heart disease by statistical analysis of aortic parameters and transverse cardiac diameter. Am Heart J 1965;69:479-86.  Back to cited text no. 16
    
17.
Wanhainen A, Bylund N, Björck M. Outcome after abdominal aortic aneurysm repair in Sweden 1994-2005. Br J Surg 2008;95:564-70.  Back to cited text no. 17
    
18.
Alcorn HG, Wolfson SK Jr, Sutton-Tyrrell K, Kuller LH, O′Leary D. Risk factors for abdominal aortic aneurysms in older adults enrolled in The Cardiovascular Health Study. Arterioscler Thromb Vasc Biol 1996;16:963-70.  Back to cited text no. 18
    
19.
Akkersdijk GJ, Puylaert JB, Coerkamp EG, de Vries AC. Accuracy of ultrasonographic measurement of infrarenal abdominal aortic aneurysm. Br J Surg 1994;81:376.  Back to cited text no. 19
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]


This article has been cited by
1 Ultrasonographic study of the effects of essential hypertension on the luminal diameter and doppler velocimetric indices of the abdominal aorta in adults
JohnOluwafemi Adetokunbo, BolanleOlubunmi Ibitoye, AnthonyOlubunmi Akintomide, BukunmiMichael Idowu
Journal of West African College of Surgeons. 2022; 12(2): 88
[Pubmed] | [DOI]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Patients and Methods
Results
Discussion
Conclusion
Recommendations
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed4806    
    Printed249    
    Emailed0    
    PDF Downloaded258    
    Comments [Add]    
    Cited by others 1    

Recommend this journal