Native coronary artery dissection possibly due to intracoronary shunt tube for off-pump coronary artery bypass grafting

Abstract

A 70-year-old woman with left main (LM)/3-vessel disease (Suppl Fig. 1) undergone off-pump coronary artery bypass grafting (CABG) surgery [left internal thoracic artery (LITA)–left anterior descending coronary artery (LAD), aorta-saphenous vein graft (SVG)–posterior descending branch, aorta-free right internal thoracic artery–intermediate branch, aorta-SVG-posterior lateral branch]. On the postoperative day 1, value of CPK-MB increased up to 223 IU/L, and emergency coronary angiography (CAG) revealed an occlusion of native LAD just beyond the LITA anastomosis site (Fig. 1A, B), and the all patent grafts. After advancing a floppy guidewire with a micro catheter backup from the native LM/LAD into the distal LAD with some difficulty, an antegrade flow appeared (Fig. 1C). Pre-procedural optical frequency domain imaging (OFDI) revealed intimal dissection with thrombus just distal to the LITA anastomosis site (Fig. 1D–H, Suppl Movie 1). Then we crossed another wire into the septal perforator just distal to the culprit lesion as a marker wire, and directly implanted a drug-eluting stent (Ultimaster Tansei 2.5/9, TERUMO) under guidance of OFDI and the marker wire (Fig. 1I). Post-procedural OFDI confirmed an optimal stent placement without jailing the LITA anastomosis site (Fig. 1J, Suppl Movie 2), and final CAG showed an acceptable result (Fig. 1K, L). Most of peri-procedural myocardial infarction (MI) after CABG are usually based on biomarker elevation alone, and infrequently accompanied by specific findings, such as new ischemic electrocardiographic change, documented vessel occlusion or imaging evidence of myocardial injury, suggesting that surgical revascularization-associated whole heart injury, such as elective cardiac arrest, cardioplegia, or sequential multi-vessel transient occlusion during offpump grafting might contribute to the peri-procedural MI following CABG [1]. For off-pump CABG surgery, an intracoronary shunt tube within the anastomotic vessel has been generally used to maintain distal perfusion, reduce intraoperative myocardial ischemia, and prevent myocardial dysfunction [2, 3], while several reports have shown that intracoronary shunt tube has a potential to cause endothelial denudation [4, 5]. In the present case, the exact mechanism of native coronary dissection just beyond the graft anastomosis site remains unclear; however, there is a possibility that the intraluminal shunt tube during bypass grafting might cause the coronary dissection, leading to the peri-procedural MI. Compared with intravascular ultrasound imaging, optical coherence tomography (OCT)/OFDI has the more potential to delineate the details of coronary vessel structure, particularly superficial plaque morphology including leading edge of intima, through its high-resolution power, and can therefore, detect even minor intimal dissections more clearly [6]. Moreover, 3-dimensional reconstructed OCT/ OFDI image can depict precise location of stent struts jailing the side-branch ostium, and plays an important role in the stent optimization for bifurcation lesions [7]. Through these clinical utilities, OFDI greatly contributed to confirmation of native coronary dissection and optimal stent placement in the present case.