Giant aneurysm of an aortocoronary venous bypass graft treated by an endovascular approach

Aneurysmal transformation of a venous coronary bypass graft is a rare (incidence of 0.07%), yet potentially fatal complication of coronary artery bypass grafting. It is postulated > 5 years following coronary artery bypass graft (CABG) multiple factors contribute to the development of graft aneurysm, including atherosclerosis, endothelial dysfunction, changes in smooth muscle orientation in the proximity of valves [1] and trauma during surgical handling of the vein [2]. Establishing the final diagnosis is hampered by unspecific clinical presentation (chest pain, dyspnea), with nearly 1/3 of cases being diagnosed incidentally [1]. In consequence, patients undergo extensive and time-consuming cardiological workup prior to treatment. Despite cardiac surgery remaining the mainstay of treatment for coronary bypass graft aneurysms, minimally invasive endovascular procedures constitute an accepted and effective alternative for patients with multiple comorbidities without mechanical complications [1–3].
We hereby present a unique case of a 71-year-old patient with a giant aneurysmal transformation of an SVG-OM graft resulting in worsening dyspnea due to pulmonary trunk compression, successfully treated by endovascular embolization.
A patient with an implantable cardioverter-defibrillator and a past history of multiple coronary arterial bypass grafting (Ao-DIAG-LAD, Ao-RCA, SVG-OM, LITA-LAD) and angioplasty of the Ao-DIAG-LAD graft was admitted due to worsening dyspnea. Coronary computed tomography (CT) angiography revealed the presence of a partially thrombosed SVG-OM bypass graft aneurysm, measuring 73 × 66 × 61 mm and causing pulmonary trunk narrowing to 11 mm in the anteroposterior (AP) view (Figure 1 A); another fully thrombosed, smaller aneurysm was visible at the occluded distal segment of the graft. A third aneurysm was detected at the proximal Ao-DIAG-LAD graft; full patency of the previously stented graft with no filling of the aneurysm was observed. Although patients with mechanical complications of coronary graft aneurysms, e.g. compression of adjacent vascular structures, are routinely treated by classic cardiac surgery [1], it was decided to refer our patient for less invasive endovascular exclusion of the partially filling SVG-OM graft aneurysm due to extensive post-operative retrosternal fibrosis and signs of cardiac insufficiency (ejection fraction (EF) = 28%). Based on distal graft impatency and severe compression symptoms, occlusion of the afferent graft segment was chosen as the best treatment option in order to promote aneurysm shrinkage. Deployment of a vascular plug seemed to be the method of choice due to a short (< 15 mm) landing zone, rapid, single-device vessel occlusion and no additional mass to be left within the aneurysm sac. Amplatzer Vascular Plug 4 (AVP4 – St. Jude Medical, MN, USA) 6 × 11 mm was selected as the most appropriate device. Consecutive stages of the embolization procedure performed under local anesthesia are presented in Figures 1 B and C. Control angiography confirmed proper positioning of the occluder and lack of contrast filling in the bypass graft and aneurysm sac.
Coronary CT angiograms obtained at 3 and 12 months (Figure 1 D) follow-up confirmed effective occlusion of the bypass graft with complete thrombosis of the aneurysm sac. Aneurysm sac shrinkage to 67 × 63 × 58 mm and 60 × 62 × 51 mm was observed at 3 and 12 months follow-up, respectively. This was accompanied by pulmonary trunk decompression to 19 mm in the AP dimension at the 12-month follow-up, and symptom resolution.

Conflict of interest

The authors declare no conflict of interest.

References

1. Ramirez FD, Hibbert B, Simard T, et al. Natural history and management of aortocoronary saphenous vein graft aneurysms: a systematic review of published cases. Circulation 2012; 126: 2248-56.
2. Dieter RS, Patel AK, Yandow D, et al. Conservative vs. invasive treatment of aortocoronary saphenous vein graft aneurysms: treatment algorithm based upon a large series. Cardiovasc Surg 2003; 11: 507-13.
3. Weintraub WS, Jones EL, Morris DC, et al. Outcome of reoperative coronary bypass surgery versus coronary angioplasty after previous bypass surgery. Circulation 1997; 95: 868-77.

Corresponding author:
Dr. Maryla Kuczyńska, Department of Interventional Radiology and Neuroradiology, Medical University of Lublin, 8 Jaczewskiego St, 20-954 Lublin, Poland, phone: +48 607 141 921, e-mail: maryla.kuczynska@gmail.com
Received: 9.01.2019, accepted; 12.08.2019.