Introduction

Coiling (or looping) of the artery is a rare morphologic entity, most frequently described in the internal carotid artery. In other arteries, coiling is rarely reported because it remains asymptomatic and without clinical relevance unless inadvertently injured, as for diagnostic or monitoring purposes(₁). The internal mammary artery is the most frequently used bypass conduit for the left anterior descending coronary artery in patients treated with bypass surgery, with excellent long-term patency rates. However, the mammary artery may also be affected by functionally significant stenoses. Most stenoses of the mammary artery are secondary to the surgical procedure at the anastomosis site, but atherosclerotic lesions may also develop(₂).

Case Presentation

Our case was a 43-year-old male. His past medical history was significant for 3-vessel CABG and concomitant mitral ring annuloplasty at a different health facility 4 years ago. He was suffering from chest pain for 3 months. His coronary angiogram revealed stenoses in saphenous venous graft to the right coronary artery, in the native circumflex and left anterior descending arteries at postanastomotic segments. Percutaneous approach was planned for treatment. But during rehospitalization period, he suffered from fever and investigations identified a subacute bacterial endocarditis including the mitral valve (moderate mitral regurgitation and a vegetative mass of 1.9x0.9 cm on atrial face of mitral anterior leaflet). He was then referred to our clinic for re-CABG and mitral valve exploration. His coronary angiogram showed a lesion of left internal mammarian artery graft consistent with coiling at right anterior oblique position (Figures 1&2).

Figure 1

Figure 1

Figure 2

Figure 2

However, this lesion was identified as kinking at left anterior oblique position (Figures 3&4).

Figure 3

Figure 3

Figure 4

Figure 4: No luminal irregularity or indentation was shown

Discussion

Kinking of an ITA graft that's seen on the early postoperative angiography might improve without surgery or intervention. The natural course of ITA graft kinks should be considered when detecting these kinks on the early postoperative angiography when the patient is asymptomatic(₃).

Skeletonization of the internal thoracic artery (ITA) has several advantages: sequential bypass grafting can be easily performed, and a graft of increased length can make the distal coronary artery accessible. However, kinking of the grafts has been observed on postoperative angiograms in a few cases(₄).

In the study of Imamaki et al.,they investigated whether there were significant differences in the frequency of graft kinking and stenosis degree at the kink site between pedicled and skeletonized grafts. When the ITA had a kink, the stenosis degree at the kink site was significantly higher in the skeletonized group than in the pedicled group(4).

The role of marked bends in bypass grafts could deserve selective studies to determine whether they are associated with the development of functional stenosis. This information may be useful when performing mammary artery bypass graft surgery for avoiding extremely twisted vessel courses(₂). Immediate intervention need not always be performed if the patient has no angina caused by a stenotic lesion at the kink site(₄).