Ruptured Giant Right Coronary Artery Aneurysm Percutaneously Plugged

Case Report

A 55 year-old male city mayor presented with chest discomfort. His past medical history was remarkable for disabling childhood polio requiring iron-lung therapy and chronic renal insufficiency. His cardiac history began at age 41 with acute inferior myocardial infarction. Cardiac catheterization at that time showed three-vessel coronary artery disease with multiple giant fusiform coronary aneurysms including the proximal right coronary (RCA), the proximal and mid-left anterior descending (LAD) arteries and the proximal left circumflex artery. Left ventricular (LV) systolic function was normal. He had no known childhood history of Kawasaki’s disease. Coronary bypass surgery was performed after his initial presentation in 1990, with a right internal mammary artery graft to the right posterior descending artery and ligation of the mid-RCA distal to the coronary aneurysm, a left internal mammary artery graft to LAD, and sequential saphenous vein graft to the first diagonal and first obtuse marginal branches. Cardiac catheterization performed after non-Q-wave myocardial infarction in 1997 showed aneurysmal dilatation of the proximal RCA with mid-vessel occlusion, proximal and mid-LAD and proximal left circumflex aneurysmal disease similar to that found in 1990. There were left-to-right collaterals to the distal RCA. The mammary grafts were occluded. The sequential vein graft was widely patent. Medical management with aspirin and warfarin was continued. The patient’s LV function remained normal.
The patient now presents with 3 weeks of atypical chest discomfort not related to exertion but responsive to sublingual nitroglycerin. Warfarin was held and enoxaparin dosed for mild renal insufficiency was initiated in anticipation of outpatient cardiac catheterization. A more severe chest pain episode prompted hospital admission. The patient’s electrocardiogram was unchanged from baseline. Initial CK-MB was normal followed by a rise to 8 U/L on the second set. The initial hematocrit was 39%. On the second hospital day, anterior chest wall ecchymosis developed, hypotension with systolic blood pressure of 70 mmHg requiring dopamine and the patient’s hematocrit decreased to 21%. Fresh frozen plasma, vitamin K and packed red blood cells were administered. Emergency contrast-enhanced chest computed tomography demonstrated hemomediastinum and left pleural effusion. A large proximal right coronary aneurysm was visualized with suspected rupture and leak (Figures 1A and B). Urgent cardiac catheterization was performed, demonstrating a large calcified right coronary aneurysm (Figure 2). The ostial and proximal right coronary segment leading into the aneurysm was estimated to be 4.8 mm in diameter and 17 mm in length by quantitative coronary analysis. Cineangiography suggested active contrast extravasation from the superior aspect of the aneurysm, but this could not be definitively demonstrated. The patient’s left coronary and graft anatomy were unchanged from 1997.
After detailed discussion with the cardiac surgeon, family and patient, it was agreed to occlude the proximal right coronary artery percutaneously with cardiac surgical standby. A 6 Fr hockey stick guiding catheter was advanced into the proximal RCA. Two 6 mm x 7 mm Amplatzer Vascular Plugs (AGA Medical Corp., Golden Valley, Minnesota) were deployed in the proximal RCA. At the conclusion of the procedure, there was no contrast penetration into the aneurysm sac (Figures 3A, B and C). Additionally, the previous contrast swirling in the aneurysm ceased with deposition of stagnated contrast (stained thrombus) in the dependent portion of the aneurysm consistent with thrombosis. The patient’s hematocrit and blood pressure stabilized. The left pleural effusion was drained (1100 cc of bloody fluid), and he was released after several days of observation. At 1- and 3-month office follow-up visits, the patient was free of chest discomfort or shortness of breath and had a normal hematocrit.

Discussion

The prevalence of coronary aneurysms is unknown, but is felt to be rare. Aneurysms may arise secondary to atheromatous disease, vasculitis, collagen-vascular disease or Kawasaki’s disease.¹ They may result in myocardial ischemia, development of the adjacent stenoses, distal thromboembolism, myocardial infarction and sudden death.² Coronary aneurysms have been diagnosed with echocardiography, CT, magnetic resonance imaging, coronary angiography and necropsy. One analysis suggests that presence of a coronary aneurysm(s) is an independent predictor of mortality, with a 5-year survival rate of 71%.³ Symptomatic coronary aneurysms have been managed with medical therapy, surgical excision or ligation with coronary bypass and covered stents.⁴ Prophylactic treatment of asymptomatic coronary aneurysms is controversial due to the inherently limited information to predict the natural history or to guide management.
Reports of documented rupture have been extremely rare, with pericardial tamponade and/or cardiogenic shock as the previously reported presentations.^5–7 Our patient experienced hemomediastinum and left pleural effusion likely due to the lack of an intact pericardium given his prior coronary surgery. Our case has the additional unusual feature of the RCA that had been previously ligated to prevent distal embolization from the aneurysm at the time of coronary artery bypass graft surgery. This allowed us to occlude the inflow to the aneurysm without producing myocardial ischemia or infarction. In the more typical of these rare situations, we and others have excluded symptomatic coronary aneurysms with covered stents to maintain distal vessel patency.
To our knowledge, this is the first report of the percutaneous treatment of a leaking coronary aneurysm with a vascular occluder device. The Amplatzer Vascular Plug used in this case is a self-expandable, cylindrical device made from 144 nitinol mesh wire secured on both ends with platinum marker bands.⁸ There is no fabric on the plug. The plug is preloaded and attached by a microscrew to a 135 cm delivery cable and can be delivered through a 6 Fr guiding catheter. The mesh of the plug gradually thromboses, leading to occlusion of the vessel. While we considered deploying coils directly into the aneurysm sac or into the ostial and proximal right coronary segment supplying the aneurysm, we felt that obstructing the roughly 5 mm diameter proximal segment with the vascular plug device would be a safer, more effective and efficient endovascular treatment. Our patient, like many with an acute life-threatening cardiac illness, had several comorbidities including being wheelchair-bound from childhood polio, acute chronic renal insufficiency, obstructive coronary artery disease and prior cardiothoracic surgery, These, as well as the substernal location of the giant aneurysm which would complicate surgical access, led our highly experienced cardiac surgical consultant to estimate a 20–30% operative and perioperative mortality risk. Our hope (and fortunately our experience) was that the endovascular approach we applied would be (and was) successful, with minimal morbidity.

References

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