Percutaneous Repair of Coronary Artery Bypass Graft-Related Pseudoaneurysms Using Covered JOSTENTs

Spontaneous rupture of a saphenous vein graft with pseudoaneurysm formation is a rare occurrence after coronary bypass grafting. Until now, pseudoaneurysm formation from a native coronary artery at the site of a left internal thoracic to radial artery T-graft anastomotic site has not been reported. Although the recommended treatment of vein graft or native coronary artery pseudoaneurysms remains poorly defined, open surgical ligation with placement of a new conduit, percutaneous coil embolization, and now treatment with covered stents are among the therapies reported. We hereby report the use of polytetrafluoroethylene-covered JOSTENTs in the successful repair of a large pseudoaneurysm emanating from a 23-year-old saphenous vein graft, and repair of a pseudoaneurysm at the anastomotic site of a radial artery graft to the circumflex coronary artery 18 days after bypass surgery. These are, respectively, the oldest saphenous vein graft-related and earliest radial artery graft-related pseudoaneurysms to have been reported in literature to date. Methods Case Report #1. A 72-year-old Caucasian woman with active rheumatoid arthritis, marked joint deformities, and who was on chronic prednisone was referred to our institution for management of a large saphenous vein graft pseudoaneurysm. In 1979, the patient underwent coronary artery bypass grafting (CABG), consisting of a single saphenous vein graft to the left anterior descending artery (LAD). Except for balloon angioplasty of a right coronary artery (RCA) in 1991, she had been asymptomatic from a cardiac standpoint. On a routine chest x-ray a widened mediastinum was detected. A CT scan revealed a large saphenous vein graft-associated pseudoaneurysm contained within the pericardium (Figure 1). Subsequent cardiac catheterization revealed low-normal left ventricular ejection fraction, 70% proximal RCA stenosis, 100% proximal LAD and pulsatile flow into a large pseudoaneurysm (? 2 x 2.5 x 3.5 cm) arising from the mid-portion of the widely patent saphenous vein graft to the LAD. A much larger shadow was present encompassing the entire shell of the pseudoaneurysm (? 3 x 4 x 8 cm), which appeared to be at least five times larger than the opacificated portion (Figure 2). The patient declined repeat bypass surgery in favor of compassionate-use JOSTENT GraftMaster covered stent placement to treat the pseudoaneurysm, coupled with conventional stenting of the right coronary artery stenosis. Stenting of the saphenous vein graft was achieved using an 8 French (Fr) Taniuchi Umbrella Curve guide catheter (Cordis Corporation, Miami Lakes, Florida), a 0.014´´ Choice extra support wire (Boston Scientific, Natick, Massachusetts), and direct stenting with two 4.5 mm x 16 mm polytetrafluoroethylene-covered GraftMaster JOSTENTs (Jomed Inc.). The first JOSTENT was deployed at 16 atmospheres (ATM) and sealed off the superior rim of the pseudoaneurysm, but there continued to be flow into the pseudoaneurysm from its inferior position. A second, overlapping JOSTENT was deployed distally at 12 ATMs with the overlap site treated at 18 ATMs. This produced complete exclusion of the pseudoaneurysm site with no residual, dissection, or evidence of distal embolization. There was no pulsatile flow seen into what was formerly a freely communicating cavity (Figure 3). The RCA was also successfully treated using a non-covered stent. The patient was discharged home the following day on aspirin and clopidogrel daily. Case Report #2. A 66-year-old Caucasian woman with a history of hypertension, diabetes mellitus, hyperlipidemia and peripheral vascular disease underwent CABG with placement of a left internal mammary (LIMA) graft to the LAD, and a radial artery T-graft off the LIMA. The radial artery graft was anastomosed sequentially from the first diagonal to the first obtuse marginal. The patient did well postoperatively, but was readmitted 18 days later with a non ST-elevation MI and atrial fibrillation. Cardiac catheterization revealed a 75% mid-circumflex stenosis and an approximately 2 cm pseudoaneurysm originating from the first obtuse marginal just proximal to the radial artery anastomotic site (Figure 4). The radial artery graft was patent to the fist diagonal, but the sequential limb was occluded. It was elected to attempt percutaneous repair of the pseudoaneurysm using a covered JOSTENT. A 7 Fr Q 3.5 guide catheter (Boston Scientific) was used to cannulate the left main, and a 0.014´´ Choice floppy guidewire (Boston Scientific) was advanced into the first obtuse marginal. A 2.5 x 15 mm Maverick balloon (Boston Scientific) was advanced to the mid-circumflex artery lesion and inflated to 6 atmospheres for 45 seconds, leaving a 40% residual. Subsequently, the balloon was advanced distally into the first obtuse marginal, positioned at the apparent pseudoaneurysm origin site, and inflated to 3 atmospheres. Contrast injection showed no visible flow into the pseudoaneurysm, confirming the site of origin. Consequently, a 12 mm JOSTENT coronary stent graft (Jomed Inc.) was hand-mounted onto a 2.5 x 20mm Maverick balloon and deployed over the perforation site at 14 atmospheres. The site was post-dilated with a 2.75 x 9 mm Maverick balloon (Boston Scientific) to 18 atmospheres with a residual luminal diameter ? 3 mm. Subsequent angiography demonstrated TIMI 3 flow, no residual stenosis and no flow visible into the pseudoaneurysm. The mid-circumflex stenosis was treated with a non-covered stent (Figure 5). The patient did well post-procedure and was discharged home on the fifth hospital day without further even on aspirin and clopidogrel. Discussion There have been numerous reports in the literature of early and late pseudoaneurysm formation related to coronary artery bypass grafting but few on percutaneous treatment. Usually, vein graft pseudoaneurysms develop in the setting of local infection, inflammation as in our patient with rheumatoid arthritis, in diffusely diseased grafts, at anastomotic sites, at areas of weakness such as at vein valves, at a site of intraoperative trauma, or postoperative trauma from percutaneous intervention.1 In addition to angiography, alternate imaging modalities such as echocardiography, computer tomography or magnetic resonance imaging is often needed to fully delineate the pseudoaneurysm anatomy. Fistulous connection to the anterior chest wall, right atrium and right ventricle has been reported.2,3 The natural history of bypass graft pseudoaneurysms includes thrombosis, embolization and/or rupture. These complications may be life-threatening, and unfortunately occur at unpredictable time points. Traditionally, treatment of bypass graft-related pseudoaneurysms has been achieved by open surgical repair with ligation and placement of a new conduit. However, a variety of less invasive alternate methods have been reported. Percutaneous coil embolization has been used, but usually at the undesirable cost of graft patency.4 Attempts to deliver coils through the sidewall of a stent into the pseudoaneurysm in and effort to preserve the graft lumen have to date not been favorable. Less commonly reported methods of therapy include graft sclerosis with heated contrast.5 We have successfully utilized a slow infusion of thrombin into a left mammary artery pseudoaneurysm to effect thrombosis.6 Recently, covered stents, which exclude the pseudoaneurysm from the graft lumen, have become the favored percutaneous route of therapy. Early reports included the use of a saphenous vein allograft attached to a biliary stent to exclude the pseudoaneurysm neck.7 The arrival of covered stents has made this approach more readily available.8 The JOSTENT coronary stent graft is a composite stent with an ultra-thin layer of expandable polytetrafluoroethylene sandwiched between two stainless steel stents. It is available in a pre-mounted version (JOSTENT GraftMaster), and a bare version (JOSTENT Coronary Stent Graft UA), which is hand-crimped onto a delivery balloon. Although these are not the first case reports of JOSTENTs applied to the percutaneous treatment of coronary artery or bypass graft pseudoaneurysms, our case reports are unique for several reasons. First, this represents the oldest vein graft to have deployed an associated pseudoaneurysm reported in the literature to date. Although pseudoaneurysms typically develop in a diffusely diseased graft or at a site or prior trauma, our patient exhibited no other angiographically significant vein graft disease, and there was no history of antecedent trauma. This pseudoaneurysm arose discretely from the mid-body of the vein graft, and not at the typical anastomotic-related site. There have been reports of pseudoaneurysm formation associated with mediastinal infection postoperatively, but our patient was free of infection. Of note, our patient had rheumatoid arthritis, a systematic inflammatory process, and was chronically treated with prednisone — this may have predisposed her to spontaneous graft rupture. At least one other report exists describing vascular fragility and rupture complicating percutaneous transluminal angioplasty in a patient on long-standing steroids.9 Although saphenous vein graft pseudoaneurysm formation has been reported as early as 11 days postoperatively, our second case is notable in that it is the earliest reported case of a pseudoaneurysm related to radial artery T-graft bypass grafting. Here, pseudoaneurysm formation was likely related to intraoperative trauma or suture-related defects at the anastomotic site. Treatment was successful with a hand-mounted JOSTENT, which are typically utilized for vessels 2.5 mm or smaller in diameter. Although focal rupture of the PTFE layer of the JOSTENT has been reported as a cause of poor long-term durability, to date, neither patient has exhibited evidence of JOSTENT rupture.10 These case reports illustrate the diversity of application of covered JOSTENTs in the treatment of coronary artery or bypass graft perforation or pseudoaneurysm formation, from early postoperative complications, to very late vein graft rupture.

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