Fibrinolysis and Coronary Stenting for Treatment of an Acute Inferior Myocardial Infarction after Ascending Aortic Aneurysm Repa

Anastamotic complications of the coronary ostia after successful Bentall-type surgery for aortic root replacement have been reported, with an estimated incidence of 5–6%.¹ These problems are usually minimized by coronary artery bypass graft surgery. We report a case of a patient with an acute inferior myocardial infarction that developed 18 months after Bentall repair surgery for a type-A aortic dissection, and which was treated with percutaneous coronary stenting. Case Report. A 64-year-old male previously underwent repair of a type-A aortic dissection. Resection and graft replacement of the ascending aorta was performed using a 30 mm Hemashield woven Dacron tube graft. The aortic valve was replaced using a 27 mm composite Freestyle™ porcine valve conduit (Medtronic, Inc., Minneapolis, Minnesota). Reattachment of the coronary ostia was performed using 12 mm Hemashield woven Dacron tube grafts (modified Carbol technique), one for the left main and one for the right coronary artery. His postoperative course was uncomplicated and he was discharged home. Sixteen months after this surgery, the patient underwent radical prostatectomy for stage IIa prostate carcinoma, and had an unremarkable hospital course. Eighteen months after his aorta surgery, the patient called emergency services (EMS) after suffering 3 hours of midsternal chest discomfort. Initial electrocardiography (ECG) by the EMS revealed an acute inferior ST-segment elevation myocardial infarction (STEMI). He was treated according to local protocol with a prehospital thrombolytic regimen and was brought urgently to our cardiac catheterization laboratory. After thrombolytic therapy, his chest discomfort had partially improved, but ST-segment elevation persisted on the ECG. Coronary angiography, performed via the femoral route, showed a patent Dacron tube graft to the left main with no significant stenoses in the left coronary circulation (Figure 1). The right coronary Dacron tube graft had a severe stenosis at the anastamosis of the graft with the right coronary artery (Figure 2). A 6 Fr multipurpose guide catheter was then used to cannulate the right coronary graft. Abciximab bolus and infusion was given intravenously, and a 0.014 inch Luge™ guidewire (Boston Scientific Corp., Natick, Massachusetts) was advanced through the guide catheter and maneuvered into the distal right coronary artery. A 2.5 x 15 mm Maverick® over-the-wire balloon (Boston Scientific) was used to predilate the right coronary ostium (15 seconds at 15 atm). A second inflation was done just distal to the first (15 seconds at 10 atm). We then chose a 4.0 x 15 mm Liberté™ stent (Boston Scientific) and deployed it in the right coronary ostium — distal Dacron graft site (50 seconds at 10 atm). A second inflation in the proximal right coronary artery was done (30 seconds at 10 atm). A 5.0 x 12 mm Quantum™ Maverick® balloon (Boston Scientific) was then used to postdilate the Liberté stent (30 seconds a 14 atm). Intravascular ultrasound was used to confirm apposition of the stent to the ostium of the right coronary artery as well as the Dacron tube graft. The distal stent edge was noted to be not well apposed and subsequently was postdilated again with the 5.0 mm balloon (25 seconds at 14 atm). The final angiogram revealed TIMI 3 flow with no residual stenosis (Figure 3). The patient had an uneventful hospital course following the procedure and was discharged home on hospital day 4, following a submaximal stress test and reevaluation by the vascular surgery group who had done the aortic repair. Discussion. Coronary stenosis after ascending aortic aneurysm repair and coronary reimplantation have been reported and may be due to imperfect suture technique, causing kinking or stretching of the vessel, or to the direct instrumentation of the coronary ostia for the direct antegrade cardioplegia. The use of tissue glue has also been suggested as being the cause of delayed coronary stenosis due to an inflammatory and/or proliferative response.² This patient presented with an acute STEMI, and differentiating between atherosclerosis and a proliferative response within the coronary graft and artery is difficult. Due to the nature of his presentation, it is suspected that there was a thrombotic component in addition to the proliferative response which can occur in reimplanted coronary arteries. To our knowledge, this is the first case of percutaneous stent treatment of an acute STEMI after complete aortic root replacement. Although coronary angiography and intervention in patients with history of aortic root repair may pose technical challenges,^3–4 specifically coronary graft cannulation, catheter backup support and ease of proper stent deployment, coronary stenting likely is a feasible option in these cases.

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