Discussion
One of the most fearsome complication that can occur during percutaneous coronary intervention is an iatrogenic acute aortic dissection that could extend retrogradely into the ascending aorta. A diseased vessel wall with multiple calcification and atherosclerotic plaques seems to be the most important predisposing factor. In most cases coronary dissection is easily diagnosed during the coronary angiography, which usually reveals a true and a false lumen, separated by a radiolucent intimal flap and a dye staining persistently localized. [3]
The process underlying IAAD is not yet completely clear; in fact there are different mechanisms involved. Firstly, the dissection may be caused by the high-pressure injection of contrast medium on a pre-existing dissection breach. Secondly shearing forces during systole and diastole could explain the propagation of the dissection in a retrograde sense. Finally, the entry breach could also be created by direct trauma of the angiographic catheters and increased by forced injection of contrast medium. [4]
The type of treatment is different depending on the type and extension of the dissection. For IAAD that remains localized at the level of the Valsalva sinus during the procedure and that extend in a retrograde form it is preferable to maintain a conservative attitude, as most tend to spontaneously regress with the collaboration of the antegrade aortic blood flow. [5]
If the dissection extends less than 40 mm from the coronary ostia into the ascending aorta and progresses in an antegrade fashion then it is preferable to intervene by stenting the affected coronary artery so as to close the breach and prevent the dissection from spreading. [6] The third type of strategy consists in an emergency ascending aorta replacement and is recommended if the dissection extends more than 40 mm from the coronary artery ostium, if the patient is hemodynamically unstable, presents with severe aortic insufficiency, has hemopericardium or if the guidewire fails to cross the occluded lesion. Coronary stenting can be useful in these cases as a ”bridge to the surgery ” and can avoid or reduce the progression of the dissection.
In conclusion, the goal in the treatment of IAAD should be closing the intimal tear as quickly as possible in order to prevent the progression of dissection and to avoid damage to neurological system and other end-organs. A percutaneous attempt is always recommended if suitable, but if it does not achieve a satisfactory result a prompt ascending aortic replacement is mandatory.