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Table of Contents
ORIGINAL ARTICLE
Year : 2022  |  Volume : 12  |  Issue : 3  |  Page : 119-122

Coronary artery dimensions in normal adult Indian population by computed tomography coronary angiography


1 Department of Cardiology, Sir Ganga Ram Hospital, New Delhi, India
2 Department of Radiology, Sir Ganga Ram Hospital, New Delhi, India

Date of Submission20-Apr-2021
Date of Decision09-May-2021
Date of Acceptance23-Jun-2021
Date of Web Publication14-Sep-2022

Correspondence Address:
Dr. Vyom Mori
Department of Cardiology, Sir Ganga Ram Hospital, Old Rajinger Nagar, New Delhi - 110 060
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jicc.jicc_19_21

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  Abstract 


Introduction: In any given population, coronary artery diameter is highly variables. It has been postulated that Indians have an increased risk of coronary artery disease (CAD) due to smaller diameter of arteries in them. However, small diameter can be due to smaller body surface area (BSA). Hence, we tried to assess whether smaller coronary artery dimensions in Indians are due to their smaller BSA or not. Methodology: In this observational study, patients undergoing computed tomography coronary angiography and having normal angiogram were included in this study. Patients' coronary artery diameters in major epicardial vessels were measured and indexed to BSA. Analysis was done to assess for any significance compared to Caucasians. Results: A total of 250 patients were part of this study. The mean diameters of proximal left main (LM), distal LM, left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) were 4.27 ± 0.78, 4.26 ± 0.79, 3.47 ± 0.6, 2.99 ± 0.64, and 3.33 ± 0.63 mm, respectively. On indexing to BSA, the measurements in proximal LM, distal LM, LAD, LCX, and RCA were 2.31 ± 0.4, 2.31 ± 0.4, 1.89 ± 0.32, 1.62 ± 0.35, and 1.81 ± 0.34 mm/BSA, respectively. When they were compared to other Indian and Caucasian studies, the diameters were not found to be statistically significant. Conclusion: Thus, the authors conclude that Indians do not have an increased risk for CAD because of their smaller diameters, but it is because of their smaller BSA. This study helped us evaluate the reference range of major epicardial vessel diameters in Indian population.

Keywords: Body surface area, computed tomography coronary angiography, small coronary artery


How to cite this article:
Mori V, Mohanty A, Yadav A, Makhija A, S. Sawhney JP, Kandpal B, Passey R, Vivek B S, Manchanda S C, Mantri RR. Coronary artery dimensions in normal adult Indian population by computed tomography coronary angiography. J Indian coll cardiol 2022;12:119-22

How to cite this URL:
Mori V, Mohanty A, Yadav A, Makhija A, S. Sawhney JP, Kandpal B, Passey R, Vivek B S, Manchanda S C, Mantri RR. Coronary artery dimensions in normal adult Indian population by computed tomography coronary angiography. J Indian coll cardiol [serial online] 2022 [cited 2022 Oct 2];12:119-22. Available from: https://www.joicc.org/text.asp?2022/12/3/119/356059




  Introduction Top


Coronary artery dimensions are highly variable in the given population. Multiple variables such as age, sex, body weight, body surface area (BSA), cardiac mass, and ethnicity affect the normal coronary artery dimensions.[1] Indians have smaller coronary artery diameters which might be a risk factor for increased incidence of coronary artery disease (CAD).[2],[3] Some studies have suggested that when indexed to BSA, there is no difference in dimensions between different populations. Hence, smaller coronary artery can possibly be due to smaller BSA.[4] In addition, coronary artery dimensions play an important role in deciding the need for revascularization, stent and balloon sizing, minimal luminal area, and postdilatation measurements. These factors play an important role in long-term stent-related prognosis such as stent thrombosis, lesion revascularization, and in-stent restenosis. The diameter measured by intracoronary imaging has been used as a cutoff for deciding the need for revascularizing left main (LM) coronary artery but not for other epicardial arteries.[5] The main reason for this is the extensive geographic variation in diameter of coronary arteries.[6],[7] This study was done to estimate the size of normal coronary arteries in Indian population, index it to BSA, and see if there is any significant difference when compared to the Caucasian population. This study also might provide some insight into the use of diameters indexed to BSA as a cutoff for deciding the need for revascularization.


  Methodology Top


This was an observational study done between November 2018 and December 2019. Patients who presented with chest pain and underwent computed tomography (CT) coronary angiography were included in the study. Patients' history for risk factors such as diabetes mellitus, hypertension, smoking, or family history of cardiovascular disease was noted. Indication for undergoing CT and body measurements were recorded. Patients with coronary artery calcium score (CACS) >400, prior history of revascularization, valvular heart disease, the presence of coronary anomalies (e.g., abnormalities of ostia/ectasia, anomalous origin, and anomalous course), plaque at measuring points (as it may distort diameter due to positive remodeling), and >50% stenosis in one of the major epicardial arteries were excluded from the study. After assessing the eligibility for CT coronary angiography and establishing the heart rate of 60–70 beats/min, with the use of beta-blockers, the scan was performed. CT was performed on a 128-slice multidetector computed tomography using retrospective electrocardiography (ECG)-gated acquisition after intravenous injection of nonionic contrast. After the image acquisition, diameters of the major epicardial vessels were measured at end-diastole. Six measurements were taken: three for LM – one point 5 mm distal to the ostium, the second point 10 mm before the bifurcation, and the third at polygon of confluence – and the other three points were taken in the left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) 10 mm distal to the ostia of these arteries [Figure 1]. All the measurements were then indexed to the BSA. These measurements were compared with other Indian and Caucasian studies of normal coronary artery dimensions to see for any significant difference between the two.
Figure 1: Axial computed tomography sections showing points of measurement for left main, left anterior descending, left circumflex, and right coronary arteries

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Statistical analysis

Categorical variables were presented in number and percentage (%) and continuous variables were presented as mean ± standard deviation and median. Normality of data was tested by Kolmogorov–Smirnov test. If the normality was rejected, then nonparametric test was used. Quantitative variables were compared using independent t-test/Mann–Whitney test (when the data sets were not normally distributed) between the two groups. P < 0.05 was considered statistically significant.


  Results Top


A total of 850 patients were initially screened to be part of the study. After exclusion, 250 patients were included. Exclusion was mainly due to CACS >400 (350) and the presence of >50% stenosis in epicardial arteries (130) followed by history of revascularization and plaque at measuring point. The mean age of the population was 47.04 ± 9.47 years. Age and sex distribution, mean BSA, and indication for CT are enumerated in [Table 1]. 51% were hypertensive, 18% were diabetic, 4% were smoker, 28% were dyslipidemic, and 26% had a family history of CAD. The mean diameters of proximal LM, distal LM, LAD, LCX, and RCA were 4.27 ± 0.78, 4.26 ± 0.79, 3.47 ± 0.6, 2.99 ± 0.64, and 3.33 ± 0.63, respectively (mm). When the vessel diameters were indexed to BSA, the measurements in the proximal LM, distal LM, LAD, LCX, and RCA were 2.31 ± 0.4, 2.31 ± 0.4, 1.89 ± 0.32, 1.62 ± 0.35, and 1.81 ± 0.34, respectively (mm/BSA). Gender-related variations in mean diameters of vessels are mentioned in [Table 2]. On comparison of the diameters indexed to body surface with other Caucasian and Indian studies, the P > 0.05 [Table 3]. The study also provides a reference size of LM at proximal (4.22 ± 0.78 mm), distal (4.24 ± 0.69 mm), polygon of confluence (4.8 ± 0.55 mm), and major epicardial vessels in Indian population [Table 4].
Table 1: Demographics of the study population (n=250)

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Table 2: Gender-related variations in coronary artery diameters

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Table 3: Comparison of measurements after indexed to body surface area with other Indian and Caucasian studies

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Table 4: Dimensions of coronary artery in Indians

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  Discussion Top


In this study, we observed that diameters of vessels indexed to BSA when compared to other Indian and Caucasian studies based on quantitative coronary angiography as well CT coronary angiography had shown no statistical difference [Table 3]. The mean vessel diameters for males were significantly larger than those for females, but when indexed to BSA, these values are not significant. There had been assumption that Asians and particularly Indians have increased risk for atherosclerosis because of their small coronary artery diameters. However, from our observational study, it is proved that the coronary artery dimensions in Indian population are not small, but it is due to their small BSA. Thus, the rationale for small dimensions being a risk factor for CAD is not valid in Indian population.

There has been a recommendation of deciding the need for revascularization based on the minimum luminal area by intracoronary imaging in those with borderline CAD. This has been valid for the LM interventions but not for other epicardial vessels in view of wide variations in the population.[5],[6] Using diameters indexed to BSA as a cutoff for deciding revascularization in epicardial vessels can be considered. This is just hypothesis generating and needs to be validated with further studies as the dynamics of CAD depends on multiple other factors and microcirculatory functions.

We have also measured the average size of major epicardial vessels at proximal points along with measurements of LM at three points. They serve as a reference in diffuse coronary disease, various pathological states, optimization of stent, and selection of stent size.

The limitations of the study are small number of patients, observational study, and population restricted only to North India. CT-based measurements can be variable compared to angiography or intracoronary imaging based.


  Conclusion Top


We conclude that Indians do not have smaller coronary arteries when compared to Caucasians, but it is attributed to their smaller BSA. Therefore, the smaller vessel diameters are not a justified reason for increased atherosclerotic burden in Indians and some other more plausible traditional risk factor needs to be identified. Moreover, vessel diameters indexed to BSA should be considered for cutoffs rather than the naïve diameters.[10]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Dodge JT Jr., Brown BG, Bolson EL, Dodge HT. Lumen diameter of normal human coronary arteries. Influence of age, sex, anatomic variation, and left ventricular hypertrophy or dilation. Circulation 1992;86:232-46.  Back to cited text no. 1
    
2.
Vallapuri S, Gupta D, Talwar KK, Billie M, Mehta MC, Morise AP, et al. Comparison of atherosclerotic risk factors in Asian Indian and American Caucasian patients with angiographic coronary artery disease. Am J Cardiol 2002;90:1147-50.  Back to cited text no. 2
    
3.
Balarajan R. Ethnic differences in mortality from ischaemic heart disease and cerebrovascular disease in England and Wales. BMJ 1991;302:560-4.  Back to cited text no. 3
    
4.
Raut BK, Patil VN, Cherian G. Coronary artery dimensions in normal Indians. Indian Heart J 2017;69:512-4.  Back to cited text no. 4
    
5.
D'Ascenzo F, Barbero U, Cerrato E, Lipinski MJ, Omedè P, Montefusco A, et al. Accuracy of intravascular ultrasound and optical coherence tomography in identifying functionally significant coronary stenosis according to vessel diameter: A meta-analysis of 2,581 patients and 2,807 lesions. Am Heart J 2015;169:663-73.  Back to cited text no. 5
    
6.
Gonzalo N, Escaned J, Alfonso F, Nolte C, Rodriguez V, Jimenez-Quevedo P, et al. Morphometric assessment of coronary stenosis relevance with optical coherence tomography: A comparison with fractional flow reserve and intravascular ultrasound. J Am Coll Cardiol 2012;59:1080-9.  Back to cited text no. 6
    
7.
Usui E, Yonetsu T, Kanaji Y, Hoshino M, Yamaguchi M, Hada M, et al. Efficacy of optical coherence tomography-derived morphometric assessment in predicting the physiological significance of coronary stenosis: Head-to-head comparison with intravascular ultrasound. Euro Intervention 2018;13:e2210-8.  Back to cited text no. 7
    
8.
Mahadevappa M, Hegde M, Math R. Normal proximal coronary artery diameters in adults from india as assessed by computed tomography angiography. J Clin Diagn Res 2016;10:C10-3.  Back to cited text no. 8
    
9.
Hasan RK, Ginwala NT, Shah RY, Kumbhani DJ, Wilensky RL, Mehta NN. Quantitative angiography in South Asians reveals differences in vessel size and coronary artery disease severity compared to Caucasians. Am J Cardiovasc Dis 2011;1:31-7.  Back to cited text no. 9
    
10.
Lip GY, Rathore VS, Katira R, Watson RD, Singh SP. Do Indo-Asians have smaller coronary arteries? Postgrad Med J 1999;75:463-6.  Back to cited text no. 10
    


    Figures

  [Figure 1]
 
 
    Tables

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



 

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