A Rare Form of Communication between the Left Internal Thoracic Artery and the Left Anterior Descending Artery

Case Report. A 59-year-old male with exertional angina pectoris had undergone coronary angiography in 1998. Selective left coronary angiography showed that his left anterior descending artery (LAD) was totally occluded at the proximal site without any significant intercoronary collaterals, with a huge apical aneurysm on left ventriculography. Left internal thoracic artery (LITA) angiography was not performed. An *aneurysmectomy procedure with bypass grafting to the first diagonal and first obtuse marginal branch was planned. During the operation, only a saphenous vein graft was used for sequential anastomosis from the aorta to the first diagonal and first obtuse marginal branch with an apical plication procedure. The left internal thoracic artery (LITA) was not used as a graft and no anastomosis was applied to the LAD which was in the aneurysm area. Five years later, the patient experienced exertional angina again and coronary angiography was performed for control. It revealed that the LAD, first diagonal and first obtuse marginal branch were still occluded (Figure 1), and selective LITA angiography showed that the distal area of the LAD was visualized via “multiple extracardiac collaterals” from the untouched LITA (Figure 2). Discussion. Extracardiac collaterals generally from the bronchial and internal thoracic arteries to the myocardial circulation have been described in case reports and in experimental studies.^1–3 Also, collateral development between coronary and pulmonary arteries due to the adhesions of the pericardial space was reported after heart transplantation.⁴ In this case, we present an extremely rare form of communication between the LITA and the LAD. Because preoperative LITA angiography was not performed, we could not demonstrate that the collaterals did not exist prior to surgery. However, it is much more likely that the collaterals developed as a result of cardiopulmonary bypass-related inflammation, opened pericardium and narrowed retrosternal area due to the postoperative adhesions.

1. Ishihata T, Takeda H, Katohno E, et al. An adult case of Bland-White-Garland Syndrome with collaterals from the bronchial artery. Heart Vessels 1994;9:218–222. 2. White FC, Carroll SM, Magnet A, Bloor CM. Coronary collateral development in swine after coronary artery occlusion. Circ Res 1992;71:490–500. 3. Unger EF, Sheffield CD, Epstein SE. Heparin promotes the formation of extracardiac to coronary anastomosis in a canine model. Am J Physiol 1991;260:H1625–1634. 4. Balfour IC, Tinker K, Singh GH, et al. Coronary artery to pulmonary artery collaterals after heart transplantation. J Heart Lung Transplant 1999;18:1027–1029.