Volume 12 Supplement 1

Abstracts of the 13th Annual SCMR Scientific Sessions - 2010

Open Access

Diagnosis of coarctation with MR using carotid-subclavian artery index

  • Yu-Po Chen1,
  • Aoife Keeling1 and
  • James C Carr1
Journal of Cardiovascular Magnetic Resonance201012(Suppl 1):P23

https://doi.org/10.1186/1532-429X-12-S1-P23

Published: 21 January 2010

Introduction

Aortic coarctation is a common condition defined as the narrowing of the aorta, usually just distal to the origin of the left subclavian artery, and often associated with other conditions such as bicuspid aortic valve or ventricular spetal defect [1]. Dodge-Khatami, et al. introduced the use of carotid-subclavian artery index as an alternative way of predicting coarctation independent of other variables in neonates and infants [2]. The index's validity with modalities other than echocardiography and in adults has not been explored, however.

Purpose

In this study, we test the hypothesis that the carotid-subclavian artery index can be used with MR in adults to predict the presence of aortic coarctation.

Methods

Patients and controls were selected retrospectively from the database at NMH according to IRB-approved protocols. We identified and selected patients who had a diagnosis of aortic coarctation or history of coarctation repair and underwent contrast enhanced magnetic resonance angiography (CE-MRA) between 2006 and 2009. Patients with comparable age-distribution and normal MR images of their aortas were chosen from the same database as controls. The MR imaging protocol has been previously published [3]. For each subject, we measured the following aortic dimensions on user-defined multiplanar reformats (MPR) and thin MIPs: distance between the origin of the brachiocephalic trunk and the origin of the left carotid artery (d1), distance between the origin of the left carotid artery and the origin of the left subclavian artery (d2), the aortic arch diameter at the origin of the left carotid artery (d3), and the descending aorta diameter (d4). The carotid-subclavian artery index is defined as the ratio of d3 to d2.

Results

The carotid-subclavian artery index is significantly smaller in the coarctation group compared to the control. The data suggest that a cutoff of 1.5 for using the carotid-subclavian artery index to diagnose coarctation provides the best sensitivity and specificity simultaneously. The area under the ROC curve is 0.955, suggesting that the carotid-subclavian artery index has excellent accuracy. See figures 1 and 2 and Tables 1, 2 and 3
Table 1

Demographic Data of Coarctation Patients and Controls

 

Coarctation Patients (n = 28)

Controls (n = 26)

Male/Female

14/14

14/12

Median age (yrs)

33

31.5

Mean age (yrs)

35.4

35.6

Standard deviation (yrs)

11.7

12.3

Table 2

Aortic Dimensions and Carotid-Subclavian Artery Index: Comparison. Mean(Standard Deviation)

 

Coarctation Patients (n = 28)

Controls

(n = 26)

p value

CSAI (d3/d2)

1.08 (0.33)

3.45 (2.61)

<0.00001

d1(cm)

1.22 (0.29)

0.40 (0.07)

<0.00001

d2(cm)

2.03 (0.62)

0.81 (0.12)

<0.00001

d3(cm)

1.82 (0.20)

2.31 (0.07)

0.000012

d4(cm)

2.24 (0.31)

1.91 (0.05)

0.0056

Table 3

Sensitivity and Specificity Values for Various Cutoffs.

CSAI-Cutoff

1.0

1.3

1.5

1.7

2.0

Sensitivity %

53.57

78.57

82.14

85.71

85.71

Specificity %

100.00

100.00

100.00

96.15

76.92

PPV %

100.00

100.00

100.00

96.00

80.00

NPV %

66.67

81.25

83.87

86.21

83.33

Figure 1

Measurements of Aortic Dimensions.

Figure 2

ROC Curve.

Conclusion

We have demonstrated that the carotid-subclavian artery index is a useful tool for diagnosing aortic coarctation in adults with MRA. With a cutoff value of 1.5, the index provides high sensitivity and specificity. It can lead to early diagnosis of mild coarctation and other congenital conditions such as bicuspid aortic valve.

Authors’ Affiliations

(1)
Northwestern University Feinberg School of Medicine

References

  1. Secchi F: 2009Google Scholar
  2. Dodge-Khatami A: 2005Google Scholar
  3. Bireley WR: 2007Google Scholar

Copyright

© Chen et al; licensee BioMed Central Ltd. 2010

This article is published under license to BioMed Central Ltd.

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