DISCUSSION
IACD complicating coronary interventions is extremely rare and a few cases have been reported. The rapid propagation of aortocoronary dissection may become immediately life-threatening via several sequelae, including hemorrhage into the pericardium resulting in cardiac tamponade, occlusion of the contralateral coronary ostium or propagation of the dissection into the descending aorta.7 Most reported iatrogenic aortocoronary dissections have been related to procedures in the RCA, especially during PCI for chronic total occlusions. The RCA is more easily dissected in the retrograde direction into the coronary sinus than the left main coronary artery(LMCA) because of the presence of more smooth muscle cells and a dense matrix of collagen type I fibers8 in the peri-ostial wall and sino-tubular junction of the LMCA. Its mechanism involves disruption of the coronary intima by mechanical trauma caused by aggressive manipulation of rigid or hydrophilic guide wires, followed by vigorous contrast injection, which, in turn, contributes to the subsequent retrograde extension of the dissection. Over 40% of the cases usually spread rapidly to the ascending aorta if the entry-door is not sealed rapidly, a “wait and see” approach may be too risky. To date, the optimal treatment of this rare entity has not been well established. Management depends on the status of the distal coronary circulation and the extent of aortic dissection. When possible dissection can be dealt with deployment of stents distal to the dissection and near the ostium, thus sealing off the entry port. Dunning et al.1categorized aortocoronary dissection according to the level of aortic involvement, where class I denotes dissection involving only the coronaries, class II extending up to <40 mm of the ascending aorta, and class III reaching >40 mm of the ascending aorta. As class I and II patients with limited involvement of the aorta can benefit from stenting of the coronary dissection entry point without the need for surgical intervention, it was found that urgent surgery is the treatment of choice for class III patients with extensive dissection or patients with hemodynamic instability and those with ischemia of one of the aortic branches.
Aortic dissection when localized may be followed up with ECG and CT scan if coronary blood flow has been corrected by stenting.8 However, if the above procedure fails or cannot be attempted without a high risk of further compromising of the coronary circulation as in our case, surgery is the only option.8 Surgery was also a preferred option in our case because of the extensive aortic dissection and co-existent coronary artery disease in RCA and LAD which was managed surgically by bypass grafting.