LIMA. RIMA and RA

Q: Which of the following arteries has the largest medial cross-sectional area? - select one

A) Left internal mammary artery (LIMA)

B) Radial artery (RA)

C) Right Internal Mammary Artery (RIMA)

Answer: B

Although the radial artery has a large medial cross-sectional area, it is used judiciously in coronary artery bypass surgery (CABG) because it is more prone to graft spasm. One in ten patients may experience it and require vasodilator agents, such as calcium channel blockers, immediately postoperatively. Additionally, many of these patients have underlying or impending renal failure, and the use of the radial artery as a graft may preclude the future construction of an arteriovenous graft (AVG) on the ipsilateral arm.

The Medial Cross-Sectional Area (mm²) of the Proximal Radial Artery is, on average, about 2.48, and that of the Distal Radial Artery is about 1.86. In comparison, the medial cross-sectional area (mm²) of the Left Internal Mammary Artery (LIMA) is, on average, about 0.54. Although, for technical reasons, the Right Internal Mammary Artery (RIMA) is used less frequently, it has a larger cross-sectional area than the LIMA, with an average of 0.67.

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References:

1. Gaudino M, Benedetto U, Fremes S, et al. Radial-Artery or Saphenous-Vein Grafts in Coronary-Artery Bypass Surgery. N Engl J Med 2018; 378:2069.

2. Iacò AL, Teodori G, Di Giammarco G, et al. Radial artery for myocardial revascularization: long-term clinical and angiographic results. Ann Thorac Surg 2001; 72:464.

3. Nappi F, Bellomo F, Nappi P, Chello C, Iervolino A, Chello M, Acar C. The Use of Radial Artery for CABG: An Update. Biomed Res Int. 2021 Apr 7;2021:5528006. doi: 10.1155/2021/5528006. PMID: 33928147; PMCID: PMC8049807.

4. Gaudino M, Tondi P, Benedetto U, Milazzo V, Flore R, Glieca F, Ponziani FR, Luciani N, Girardi LN, Crea F, Massetti M. Radial Artery as a Coronary Artery Bypass Conduit: 20-Year Results. J Am Coll Cardiol. 2016 Aug 9;68(6):603-610. doi: 10.1016/j.jacc.2016.05.062. PMID: 27491903.