|Year : 2017 | Volume
| Issue : 1 | Page : 36-40
Does populational difference influence the size of adult human coronary arteries?
Arun Dhakal1, Sushma Pandey2, Arun Maskey3, Shekhar Yadav4
1 Department of Anatomy, Chitwan Medical College, Bharatpur, Nepal
2 Department of Oral Medicine and Radiology, BPKIHS, Dharan, Nepal
3 Shahid Gangalal National Heart Center, Bansbari, Nepal
4 Department of Anatomy, Institute of Medicine, Kathmandu, Nepal
|Date of Web Publication||9-Aug-2017|
Department of Anatomy, Chitwan Medical College, Bharatpur
Source of Support: None, Conflict of Interest: None
Introduction: Many articles have measured the coronary artery size and compared with similar studies to verify the differences between populations. This study also compares its finding with other identical studies with an attempt to integrate them to evaluate earlier conclusions made on population differences.
Materials and Methods: Normal coronary angiograms from the preexisting database of patients who underwent cardiac catheterization were analyzed for their sizes using catheter tip as calibrating object.
Results: The measurements of left main coronary artery, left anterior descending artery, circumflex artery (CX), and right coronary artery (RCA) were 2.53 ± 0.26 mm, 1.86 ± 0.19 mm, 1.77 ± 0.27 mm, and 1.80 ± 0.22 mm, respectively, after being adjusted to body surface area. Coronary vessel sizes were compared between Indians, Nepalese, and the Caucasians. The RCA was significantly larger in the Indians as compared to Nepalese and Caucasians whereas Nepalese left anterior descending and CX arteries were significantly larger than both Indians and Caucasians while the left main artery was significantly larger among Nepalese than Indians.
Conclusion: After evaluating our findings with various other similar studies, this study concludes that coronary artery diameter varies with populations.
Keywords: Coronary artery, ischemic heart disease, population differences
|How to cite this article:|
Dhakal A, Pandey S, Maskey A, Yadav S. Does populational difference influence the size of adult human coronary arteries?. J Exp Clin Anat 2017;16:36-40
|How to cite this URL:|
Dhakal A, Pandey S, Maskey A, Yadav S. Does populational difference influence the size of adult human coronary arteries?. J Exp Clin Anat [serial online] 2017 [cited 2018 Sep 26];16:36-40. Available from: http://www.jecajournal.org/text.asp?2017/16/1/36/212636
| Introduction|| |
There have been many articles published focusing on the coronary artery sizes of various populations (Lip et al., 1999; Cheemalapati et al., 2006; Kim et al., 2005; Ghaffari et al., 2015; and Dhakal et al., 2015). Other articles have compared the coronary diameter of one population to the other together with clinical conditions and outcomes (Tillin et al., 2008; Toor et al., 2011; Dhawan and Bray 1994; and Silbiger et al., 2013). Majority of these articles were based on comparison of sizes of coronary vessels of South Asians and Caucasians due to the higher prevalence of coronary disease in the South Asian (Lip et al., 1999; Zindrou et al., 2006; Ghaffari et al., 2015; Tillin et al., 2008; Toor et al., 2011; and Dhawan and Bray, 1994). In addition, these articles concluded that vessel size of South Asians are relatively small as compared to the Caucasians contributing to the development of atheromatous plaque (Virmani et al., 2000) with corresponding higher mortality and morbidity seen within this population in relation to other racial group (Makaryus et al., 2005; Dhawan and Bray, 1995).
This study investigates coronary artery size among adult Nepalese and compares the findings with those of adult Caucasians of European origin: the North Americans, Indians, Immigrant Indians, and the Iranians published in different articles. Due to the lack of data on normal coronary artery size of South Americans, Chinese, African, and other racial pool of human population, it was not possible to incorporate these for this study.
| Materials and Methods|| |
This study analyzed 100 randomly selected normal coronary angiograms from the preexisting database of patients (male 57, female 43, age 56 ± 10.8 years) who underwent cardiac catheterization in Shahid Gangalal National Heart Centre, Bansbari, Kathmandu, Nepal between May and June of 2012.
In coronary angiograms, left anterior oblique view was used to measure the right coronary artery (RCA) and right anterior oblique view was used to measure the left coronary artery. Angiograms showing entire proximal occlusions or anomalous arteries and patients below 18 years of age were excluded from the study. Catheter used for angiography itself was employed as the object of calibration by automated edge detection system (Judkins, 1967). For the vessel size measurement, the known diameter of catheter tip was used as a reference [Figure 1].
|Figure 1: Selecting the size of catheter (French-size of 6 being selected)|
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Measurements of the left coronary artery system was taken, which is the left main coronary artery (LMCA) [Figure 2], the left anterior descending artery (LAD) [Figure 3] prior to the beginning of the first septal branch, and the proximal circumflex (CX) [Figure 4] before origin of the first obtuse marginal. The RCA included proximal RCA [Figure 5] before the beginning of acute marginal artery. For all the measured vessels, the diameters of the largest dimension in each segment were selected. Body surface area (BSA) was calculated using the Mosteller method: BSA (m 2) = square root of (height [cm] × weight [kg]/3600) (Mosteller, 1987). Coronary diameters were adjusted by dividing them with BSA.
|Figure 2: Quantitative analysis of the arteriogram performed by digital analysis system (showing the reference diameter of left main coronary artery: 4.14 mm in|
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|Figure 3: Quantitative analysis of the arteriogram performed by digital analysis system (showing the reference diameter of left anterior descending artery: 3. 98 mm in this case)|
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|Figure 4: Quantitative analysis of the arteriogram performed by digital analysis system (showing the reference diameter of circumflex artery: 2. 54 mm in this case)|
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|Figure 5: Quantitative analysis of the arteriogram performed by digital analysis system (showing the reference diameter of right coronary artery: 2. 94 mm in this case)|
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Continuous variables were expressed as mean with standard deviation. Comparison of means was made using the Student's t-test. P < 0.05 was considered statistically significant.
| Results|| |
Normal coronary angiograms of 100 Nepalese (body surface area: 1.74 ± 0.28 m 2) were analyzed for the sizes of different arteries. The angiograms were assessed by two independent observers with interobserver variability of 0.287 with limits of agreement spanning between 0.913 mm and 1.61 mm. The measurements of LMCA, LAD artery, CX artery, and RCA were 2.53 ± 0.26 mm, 1.86 ± 0.19 mm, 1.77 ± 0.27 mm, and 1.80 ± 0.22 mm, respectively, after being adjusted to body surface area.
The body surface area of the Nepalese population obtained from our study was compared with similar data available of the native Indians (Cheemalapati et al., 2006) and the Caucasians of North America (Hasan et al., 2011) [Table 1]. Body surface area of the Caucasians was significantly larger (P< 0.05) than the Indians and the Nepalese with no statistically significant difference (P > 0.05) when compared between the latter two. In addition, same populations were compared for their coronary artery sizes after they were normalized to body surface area [Table 2]. The RCA was significantly larger (P< 0.05) in the Indians as compared to Nepalese and Caucasians whereas Nepalese LAD and CX arteries were significantly larger (P< 0.05) than both Indians and Caucasians while the left main artery was significantly larger among Nepalese than Indians.
|Table 2: Coronary artery size normalized for body surface area and compared with other series (mean diameter mm/m2 body surface area)|
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| Discussion|| |
The sizes of human coronary arteries are highly variable in the normal population (Hermiller et al., 1992; Restrepo et al., 1973; and Lewis et al., 1970). Various studies have linked body surface area, sex, age, genetic factors, racial factors, and weight of the heart with the anatomy of coronary vessels (Dhawan and Bray, 1994; Hutchins et al., 1977; Wilsens et al., 1966; Dodge et al., 1992; and Leung et al., 1991). As these studies were done on dissected and postmortem specimens and weight of the heart and diameter of the vessel lumen being determined from them, there seems to be an error in these studies due to factors such as fixation, preservation, and analysis of dissected specimens. To avoid such fallacy, quantitative coronary angiography was used for geometric evaluation of the arteries in this study.
Nepalese and Indian people belong to the South Asian population. In this study, we have taken the native Indians (Cheemalapati et al., 2006) and Nepalese population to compare the interpopulation variation of South Asians in coronary artery sizes. As shown in [Table 1], the difference in body surface area between the Nepalese and the Indians was insignificant. In [Table 2], most of the major arteries of the Nepalese were significantly larger than the Indians with Indians having significantly larger right coronary arteries. Cheemalapati et al. (2006) in their study compared the differences of the coronary artery sizes between the native Indians and immigrant Indians to the UK demonstrating some branches of the left being significantly greater in the immigrants with right branches being significantly larger in the native Indians. These findings demonstrated that though these three groups belong to the same South Asian population, there is a significant variation in their coronary vessel sizes. Zindrou et al. (2006) did not find any significant difference in the coronary artery diameters between the Caucasian and South Asians in UK-based study further adding to the conclusion drawn above.
Coronary artery diameter in Indians has been shown to be significantly smaller when compared to the Western population (Lip et al., 1999; Dhawan and Bray, 1994; Hasan et al., 2011; and Brown et al., 1977). Most of these studies referred to body surface area of South Asians, which is smaller than that of Caucasians, as the main factor behind the smaller coronary vessel size seen in South Asians. This fact is in agreement with our findings when body surface area between these two groups was compared as shown in [Table 1]. However, Cheemalapati et al. (2006) in their study concluded that the dimensions of the RCA of the Native Indians are greater contradicting the general perception that Indians have smaller coronary arteries. To extend the discussion further, Caucasian coronary vessel size taken from the study of Hasan et al. (2011) is incorporated for comparison in our study as shown in [Table 2]. All the vessels except the LMCA of the Nepalese population were significantly larger than that of the Caucasians. Native Indians as compared to the Caucasians had significantly larger RCA with only the left main coronary vessel being significantly larger among the Caucasians. The original comparison done by Hasan et al. (2011) between the Caucasians and South Asian population concluded that South Asians did have smaller coronary artery sizes. With these findings after comparison, we can highlight the fact that different groups of people belonging to the same population group of South Asians showed variety of outcomes enforcing our hypothesis of inconsistency in coronary vessel size within populations distributed in large geographical region but included within the same population group.
Taking and comparing the proximal diameter of all the main branches of coronary arteries between the data of Caucasian coronary artery diameters from Birmingham study (Lip et al., 1999; Hasan et al., 2011), we found that except the LMCA, all the other arteries were significantly greater of the Caucasians of Birmingham study (Lip et al., 1999). These findings also add to the fact of intra-population difference of coronary artery size when same population is considered. Here, it must be noted that human populations as Caucasians, South Asians, Africans, etc., each represent a large segment of human population. To draw conclusions from studies conducted in a segment of population representing a vast population is intrinsically flawed. Our findings confirms this and questions the claims made by earlier studies (Dhawan and Bray, 1995; Lip et al., 1999; Makaryus et al., 2005; and Hasan et al., 2011) in regard to significant populational differences in human coronary artery diameters.
Middle East represents a different group of people. Study on this group by Ghaffari et al. (2015) on coronary artery dimensions of Iranian population concluded that Iranian population had larger coronary diameters in contrast to Caucasians or South Asians reflecting the variety of coronary sizes that can be expected in human population. In addition, further study within this group as well as other various groups of different regions of the globe should help us reveal the real scenario of this preliminary discussion.
It is possibly because of variety of findings of coronary artery size in different studies that Standring (2016) mentions only the range of coronary vessels size by stating that “the caliber of coronary arteries, both main stems and larger branches, based on measurements of arterial casts or angiograms, ranges between 1.5 and 5.5 mm for the coronary arteries at their origins.”
| Conclusion|| |
This study shows that coronary artery diameter is highly variable within the population of humans though larger study incorporating clinical status, demographic data, larger number of angiograms, and more population variation is needed for proper validation. Surgeons must be prepared to encounter variations in the caliber of coronary artery irrespective of the racial and regional origin of the patient. Developing a database of coronary artery sizes of and between different populations for further study is recommended.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2]