Iatrogenic aortic root and left main dissection during non-emergency coronary surgery: a solution applicable to heavily calcified coronary arteries†

Abstract

Dissection of the left main coronary artery during coronary artery bypass graft (CABG) surgery is a rare, potentially lethal complication, usually diagnosed at post-mortem. During the cross-clamp period of a 4-vessel coronary artery bypass graft procedure in a 74-year old hypertensive woman, retrograde dissection occurred in a diffusely diseased marginal artery when perfused with cardioplegic solution at a pressure of 140-150 mmHg through a vein graft. The dissection extended back to the left main artery, included the posterior proximal ascending aorta and then down the left anterior descending artery (LAD). Transoesophageal echocardiography (TOE) confirmed the left main dissection and showed anterior-septal-lateral akinesis in a previously normally functioning left ventricle (LV). The circumferentially calcified proximal LAD was grafted with a saphenous vein by carving an oval area of calcium creating an elliptical opening in the artery wall. Normal LV function returned and, in the area of the left main dissection, there was only thickening with no colour flow. Eight months postoperatively cardiac catheterization showed normal LV function, patent vein grafts to the right coronary artery and proximal LAD, left internal mammary artery to distal LAD and an occluded sequential marginal vein graft. Twelve years postoperatively, the patient is well with Class I angina, on medication. There is no previous documentation of a diagnosed and successfully treated left main dissection during CABG surgery. Since this case using the technique of creating an oval opening in a circumferentially calcified coronary artery (with an otherwise satisfactory lumen), the author has been using this technique to bypass otherwise non-bypassable arteries; this technique may be useful to help patients with severe calcific coronary artery disease.

Keywords: Aortic root; Coronary artery bypass graft surgery; Dissection; Left main.