Coronary Branch Diameter Calculator

for Bifurcations & Trifurcations

Calculate proximal main vessel diameter

Calculate distal vessel diameter

Calculate the proximal vessel size

Calculate the distal vessel size

Notes on use

This tool calculates the appropriate vessel size for coronary bifurcations and trifurcations. The main results use the Huo-Kassab law (DpMV^2.33 = DdMV^2.33 + DSB ^2.33) (1) , which was derived using the theory of minimum work. Several laws and equations for calculating the appropriate size of coronary arteries have been proposed. A recent meta-analysis of eighteen published studies and >1000 unique coronary trees (2) generated the Taylor-Morris exponent and law (DpMV^2.39 = DdMV^2.39 + DSB^2.39). This shows excellent agreement with the Huo-Kassab law for all bifurcation types. Finet’s equation (DpMV = 0.678 (DdMV + DSB)) describes a fractal relationship between the diameters of the main daughter vessel and side branch and was derived from an observational analysis of coronary intravascular ultrasound data (3). Finet’s equation is mathematically simpler to apply and agrees with both the Taylor-Morris and Huo- Kassab laws for symmetrical bifurcations (i.e. when the distal main vessel and side branch are similar in size), but agreement is not accurate for asymmetrical bifurcations. First described in 1926, Murray’s law was the original theoretical law of branching vascular trees (DpMV³ = DdMV³ + DSB³) (4) and also was derived from the principle of minimum work. Unlike the Huo-Kassab law, it considers bifurcations in isolation, and neglects the resistance of the distal tree. For symmetrical bifurcations (distal vessels similar in size), Murray’s law underestimates the size of the proximal main vessel compared with the other laws. These laws relate to vessel sizes in the healthy state, whereas diseased coronary arteries my undergo negative or positive remodelling. For this reason, the results of the calculator should be used with caution.

D

diameter

MV

main vessel

SB

side branch

d

distal

p

proximal

References

1. Huo Y, Kassab GS. Intraspecific scaling laws of vascular trees. J R Soc Interface. 2012;9(66):190-200.
2. Taylor DJ, Saxton H, Halliday I, Newman T, Hose D, Kassab GS, et al. A systematic review and meta- analysis of Murray's Law in the Coronary Arterial Circulation. American Journal of Physiology-Heart and Circulatory Physiology. 2024.
3. Finet G, Gilard M, Perrenot B, Rioufol G, Motreff P, Gavit L, et al. Fractal geometry of arterial coronary bifurcations: a quantitative coronary angiography and intravascular ultrasound analysis. EuroIntervention. 2008;3(4):490-8.
4. Murray CD. The physiological principle of minimum work: I. The vascular system and the cost of blood volume. Proceedings of the National Academy of Sciences. 1926;12(3):207-14.

The Coronary Branch Diameter Calculator provided above is for educational purposes only. The authors have made every effort to ensure the accuracy of the calculations, but accept no responsibility for any errors, omissions, or inaccuracies in the results generated. Use of this calculator is at the user’s own risk and results should not be considered a substitute for professional advice or judgment. The results of this calculator may be informative, and do not replace the judgement of a qualified clinical professional. By using this calculator, you agree to release the providers from any liability arising from or related to its use.