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Updated: Aug 8, 2026
Morphological and Functional Assessment of the Right Ventricle Using 3D Echocardiography
Published on: October 28, 2020
The association between right coronary artery morphology and endothelial function
Yaron Arbel1, Danny Dvir, Micha S Feinberg
1Heart Institute, Chaim Sheba Medical Center, Tel Hashomer, Israel.
Insights
The study found that sigma-shaped right coronary arteries (RCAs) have better endothelial function than C-shaped RCAs, even without existing atherosclerosis. This suggests C-shaped RCAs may be more prone to developing artery disease.
Area of Science:
- Cardiovascular Research
- Vascular Biology
- Medical Imaging
Background:
- Two right coronary artery (RCA) shapes, sigma and C, are known.
- C-shaped RCAs are linked to atherosclerosis, but sigma-shaped RCAs are not.
- The link between RCA shape and vascular endothelial function is unstudied.
Purpose of the Study:
- To assess the association between right coronary artery (RCA) morphology and flow-mediated endothelium-dependent dilation (FMD).
- To investigate endothelial function in patients with normal coronary arteries but different RCA shapes.
Main Methods:
- Prospective assessment of FMD in 49 patients with non-specific chest pain and normal coronary angiography.
- Brachial artery FMD and nitroglycerin-mediated vasodilation (NTG) measured via ultrasound.
- Patients categorized by RCA morphology (sigma vs. C) by blinded readers.
Main Results:
- The C-shaped RCA group showed significantly lower FMD than the sigma-shaped group (9.0+/-4.2% vs. 14.3+/-4.7%, p<0.04).
- Nitroglycerin-mediated vasodilation (NTG) was similar between groups.
- No significant differences in other measured variables were observed.
Conclusions:
- Endothelium-dependent FMD is greater in sigma-shaped RCAs compared to C-shaped RCAs.
- This finding suggests a potential mechanism for C-shaped RCAs being predisposed to atherosclerosis.
- RCA morphology may influence vascular endothelial function independently of overt atherosclerotic lesions.
Background:
Two distinct right coronary artery (RCA) morphologies have been previously described: sigma- and C-shaped RCAs. While the C-shaped RCA was significantly associated with atherosclerosis, the sigma-shaped was not. The association of RCA morphology and vascular endothelial function has not yet been assessed.
Methods:
To evaluate the association between the RCA's morphology and flow-mediated endothelium-dependent dilation (FMD) in patients without evidence of atherosclerotic lesions, we prospectively assessed FMD in 49 consecutive patients with non-specific chest pain, who were referred to our laboratory 30+/-10 days after corroboration of normal coronary arteries on coronary angiography. Endothelium-dependent brachial artery FMD and endothelium-independent nitroglycerin-mediated vasodilation (NTG) were assessed using high resolution (15 MHz) linear array ultrasound. The patients were divided into 2 groups according to their RCA morphology on coronary angiograms (sigma and C) which were analyzed by 2 independent readers who were blinded to the patients' FMD results.
Results:
The C-shaped group exhibited a significantly lower FMD compared to the sigma-shaped group (9.0+/-4.2% vs. 14.3+/-4.7%, p<0.04, respectively), while NTG was the same in both groups. There were no significant group differences in other variables.
Conclusions:
Endothelium-dependent FMD in the brachial artery is significantly greater in sigma- compared to C-shaped RCA in coronary arteries without overt atherosclerotic lesions, suggesting a potential mechanism whereby C-shaped RCA are predisposed to atherosclerosis.
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