Covered Stent: A Novel Percutaneous Treatment of Iatrogenic Aortic Dissection During Coronary Angioplasty

Aortic dissection is a rare complication of percutaneous coronary intervention (PCI).^1,9 It can be life-threatening and warrants immediate diagnosis and treatment, which may be conservative,^1,3 surgical, or stenting.^4–6,8,9 We describe a patient in whom retrograde aortic dissection appeared during PCI to the right coronary artery which was successfully treated by a covered stent implantation. Case Report. A 74-year-old Caucasian male was admitted to the hospital because of unstable angina. Eleven years previously, this patient presented with stable angina pectoris and an abnormal ergometry test. An echocardiogram at the time had revealed normal left ventricular systolic function. Coronary angiography had demonstrated a small left anterior descending artery (LAD) with a non-critical proximal stenosis and a complete occlusion of the mid-portion, and a critical proximal stenosis of the first obtuse marginal artery (OM1). A normal, large, dominant right coronary artery (RCA) supplied collaterals to the distal LAD. The patient was referred for coronary artery bypass grafting (CABG). At surgery, since the saphenous veins were unsuitable for grafting due to previous thrombophlebitis, and the anterior wall of the left ventricle was found to have multiple scarring, it was decided to use a single left internal mammary artery (LIMA) graft to the OM1. The patient was in good condition for 11 years, but was hospitalized with unstable angina in 1999. A recent thallium 201 perfusion scan had revealed evidence of ischemia in the anteroseptal, inferior and apical segments of the left ventricle. An echocardiogram revealed severe left ventricular dysfunction. Coronary angiography revealed a 90% mid-RCA stenosis, in addition to an occluded LAD and a 90% mid-stenosis of the OM1. The LIMA graft to the OM1 was patent. A decision was made to dilate the stenosis in the RCA. However, after insertion of a 7 French (Fr) Zuma guiding catheter (Medtronic, Minneapolis, Minnesota) and a floppy 0.014” guidewire (Biotronic GmbH, Germany), spasm was noted at the tip of the catheter, and contrast media was noted in the adjacent aortic wall. This was followed by a dissection in the ostial RCA that propagated retrogradely into the ascending aorta, causing staining with the contrast media (Figure 1). The patient complained of chest pain, but was stable hemodynamically. At this stage, a decision had to be made between emergency CABG and PCI. Because of the previous CABG and the phlebitic saphenous veins, it was decided to attempt PCI. Without changing the guiding catheter or the guidewire, the dissection was first closed off with a covered, 4.0 x 12.0 mm stent (Jostent, JOMED GmbH, Germany) and an additional 4.0 x 16.0 mm stent (Jostent) was deployed distally to the covered stent. Subsequent injection showed reduced contrast medium staining of the aortic wall (Figure 2). A third, 3.0 x 20 mm stent (Cordis, Miami Lakes, Florida) was successfully deployed into the original target RCA stenosis. The patient remained stable hemodynamically throughout the procedure, and his chest pain resolved. The patient remained asymptomatic throughout the rest of his stay in the hospital. No elevation of cardiac enzymes was noted. A transesophageal echocardiogram revealed a small haematoma in the aortic sinus wall, but no evidence of dissection. The patient was discharged from the hospital 3 days after his admission, in good condition. A follow-up effort thallium 201 perfusion scan revealed no evidence of ischemia in the RCA territory. Discussion. To our knowledge, this is the first case in which an acute dissection of the ascending aorta (complicating PCI) was treated with a covered stent to seal the entry site. The true incidence of aortic dissection during coronary angiography or angioplasty is not known. An incidence of 0.03% has been suggested.^7,8 However, this may be an underestimation, due to a tendency not to publish iatrogenic complications. The exact mechanism responsible for this complication during PCI is also not known, although several have been suggested. These include vigorous manual injection of contrast material into the subintimal space, aggressive attempts to re-canalize total occlusions by the subintimal passage of particularly stiff wires, and the use of guiding catheters that are either wedged or in a non-coaxial position relative to the proximal segment of the coronary artery.^8,9 In our case, the first proposed mechanism seems the most likely culprit, although the non-coaxial position of the guiding catheter may have damaged the aortic wall at the ostium of the narrowed coronary artery. An antegrade dissection of the aortic wall may proceed in two ways. When the dissection is limited to a few centimeters beyond the aortic valve, the patient usually remains hemodynamically stable. A conservative approach that includes follow-up with non-invasive methods is often sufficient in such cases. However, if the dissection progresses towards the aortic arch, it may extend into the descending aorta. Such cases have the potential for complications, such as acute aortic regurgitation and acute myocardial infarction, and warrant a more aggressive therapeutic approach. Percutaneous sealing of the entry site using stents is an option when the progression of the dissection is slow and the anatomy of entry is suitable for stenting.^2,4,5 A surgical approach is more appropriate for dissections with a potential risk of immediate involvement of the entire aorta, especially when the anatomy is not optimal for sealing the entry site with stenting. In our patient, the dissection progressed up the ascending aorta causing a flow-limiting dissection of the RCA that resulted in acute myocardial ischemia. Since the patient was not a good candidate for surgery, we decided to seal the entry site of the aortic dissection first, with consequent treatment of the RCA dissection. Due to the location of the entry site at the right aortic cusp, our concern was that because of the presence of cells in a standard stent, it might not fully cover the site of entry of the dissection. A covered stent was chosen in order to ensure that the entry site was totally sealed. The coronary stent graft (covered stent) consists of two coaxially aligned stainless steel stents, securing a polytetrafluoroethylene (PTFE) membrane between them in a sandwich-like manner. The stent was deployed so that its edge protruded one millimeter into the aortic cusp, and a large balloon was inflated within both the stent and the aortic cusp. We suggest that in cases where the entry site of the dissection is well beyond the coronary ostium, the use of standard stents may be sufficient. However, when the entry site is formed at the coronary ostium itself and proceeds towards the ascending aorta, the use of a covered stent is preferable.

1. Sutton AG, Aggarwal RK, de Belder MA. Type A dissection of the ascending thoracic aorta during percutaneous coronary intervention. J Invas Cardiol 2000;12:147–150. 2. Al-Saif SM, Liu MW, Al-Mubarak N, et al. Percutaneous treatment of catheter-induced dissection of the left main coronary artery and adjacent aortic wall: A case report. Cathet Cardiovasc Intervent 2000;49:86–89. 3. Pentousis D, Toussaint M, Zheng H, et al. Conservative management for an extensive type A aortic dissection complicating coronary angioplasty. J Invas Cardiol 2000;12:320–323. 4. Seifein HB, Missri JC, Warner MF. Coronary stenting for aortocoronary dissection following balloon angioplasty. Cathet Cardiovasc Diagn 1996;38:222–225. 5. Bae JH, Kim KB, Kim KS, Kim YN. A case of aortocoronary dissection as a complication during a percutaneous transluminal coronary angioplasty (PTCA). Int J Cardiol 1998;66:237–240. 6. Moles VP, Chappuis F, Simonet F, et al. Aortic dissection as complication of percutaneous transluminal coronary angioplasty. Cathet Cardiovasc Diagn 1992;26:8–11. 7. Alonso F, Almeria C, Fernandez-Ortiz A, et al. Aortic dissection occurring during coronary angioplasty: Angiographic and transesophageal echocardiographic findings. Cathet Cardiovasc Diagn 1997;42:412–415. 8. Geraci AR, Krishnaswami V, Selman MW. Aortocoronary dissection complicating coronary angiography. J Thorac Cardio Surg 1973;65:695–698. 9. Pande AK, Gosselin G, Leclerc Y, Leung TK. Aortic dissection complicating coronary angioplasty in cystic medial necrosis. Am Heart J 1996;131:1221–1223.