Case report
Life-saving necklace: collateral circulation from the conus artery to the anterior descending artery

Collateral circulation is important in preserving ventricular function, especially in coronary artery disease with total occlusion. The conus branch of the right coronary artery (RCA) has the capacity of angiogenesis and arteriogenesis [1, 2]. We report a case of hyperacute inferior myocardial infarction with life-saving collateral circulation from the conus artery to the left anterior descending artery (LAD). A 54-year-old man was referred to the emergency room with hyperacute inferior myocardial infarction. Coronary angiography demonstrated chronic total occlusion of the LAD at its proximal segment and acute total occlusion of the RCA at the proximal segment after the conus branch (Figure 1). The LAD was filled by the collateral circulation through a large conus artery that originated within the right sinus of Valsalva, very close to the ostium of the RCA. It coursed with the LAD at the medial segment (Figure 2). The circumflex artery was normal. Primary percutaneous transluminal coronary angioplasty of the occluded RCA was performed and one drug-eluting stent (2.75 mm × 30 mm) was implanted. Coronary artery bypass graft surgery was recommended for revascularisation of the LAD. Collateral circulation is an important factor in the pathophysiology of coronary artery disease. The symptoms and prognosis among these patients depend on the quality of the collateral circulation. This case shows the importance of collateral supply of conus branch circulation preventing cardiogenic shock in patients with chronic occlusion of the LAD and acute occlusion of the RCA.

References

 1. de Agustín JA, Marcos-Alberca P, Hernández-Antolín R, et al. Collateral circulation from the conus coronary artery to the anterior descending coronary artery: assessment using multislice coronary computed tomography. Rev Esp Cardiol 2010; 63: 347-351.

 2. Yamagishi M, Haze K, Tamai J, et al. Visualization of isolated conus artery as a major collateral pathway in patients with total left anterior descending artery occlusion. Cathet Cardiovasc Diagn 1988; 15: 985-988.