Cardiac tamponade due to rupture of a giant coronary artery aneurysm with a coronary arteriovenous fistula: a case report

Coronary artery aneurysm (CAA) is defined as dilatation exceeding 1.5 times the width of the normal adjacent coronary artery segments. Those with a diameter > 20 mm are referred to as giant CAA [1]. CAA usually causes few symptoms, and rupture is rare, but can be lethal due to cardiac tamponade when it does occur.

We describe a patient with acute cardiac tamponade caused by spontaneous rupture of giant CAA with a coronary arteriovenous fistula (CAVF), who underwent successful emergency surgery.

CAA is quite rare, occurring in 0.15–4.9% of patients undergoing coronary angiography [1, 2]. Giant CAA is even more infrequent. This abnormality is thought to originate in different ways. Atherosclerosis is the chief cause of CAA in adults, followed by Kawasaki disease. Other underlying conditions include connective tissue disease, arteritis, and CAVF [3], defined as an abnormal communication between a coronary artery and a cardiac chamber, great artery, or vena cava. Dilatation of the CAVF is common, and although 19% of these may become aneurysmal [4], rupture of the aneurysm appears very rare. CAA with CAVF > 30 mm in diameter is at risk of rupture [5]. CAA > 50 mm in diameter shows an association with CAVF in 21.4% of cases [6]. That is, one of the causes of giant CAA is CAVF. In the present case, we considered that these CAAs derived from CAVF.

Coronary angiography is essential for establishing the diagnosis of CAA with CAVF. Newer imaging modalities, such as multidetector-row CT (MDCT), can be useful for demonstrating CAVF. MDCT is also well suited to noninvasively evaluating communications between CAA and the vessels in CAVF [7]. In the present case, CT was undertaken at a nearby hospital, not our hospital. MDCT was therefore not performed in this case.

Acute cardiac tamponade is often caused by acute aortic dissection, free wall rupture due to acute myocardial infarction, or a traumatic thoracic accident. The present experience indicates that rupture of CAA with CAVF should be considered as one potential cause of acute cardiac tamponade. Few reports have described ruptured CAA with CAVF resulting in cardiac tamponade [2, 8]. A review of published reports described the risk factors for rupture of CAA with CAVF as female gender, saccular aneurysm, Asian ethnicity, origin of the aneurysmal fistula in the left coronary artery, and hypertension [9].

We have here reported a case of ruptured CAA with CAVF in which the patient developed presyncope, back pain, and subsequent cardiac tamponade, but emergent surgical treatment was successfully performed.

We started to perform emergency surgery for aneurysm excision, and blood was observed oozing from the boundary around the giant CAA of the RCA and CAVF. Ligation of the fistula and excision of the giant aneurysm were initially considered necessary, but were not performed because the aneurysm of the LAD was < 10 mm in diameter. The patient remained well at the 4-year follow-up with no expansion of the small coronary aneurysm. Previous reports of ruptured CAA have noted diameter over 30 mm [2, 10]. Furthermore, CAA and CAVF in this case did not cause other symptoms such as angina or dyspnea. Complete surgical repair, including exclusion of the smaller LAD aneurysm and coronary revascularization to a graftable branch in the left anterior descending area combined with ligation of the associated fistula, is quite challenging and sometimes fatal because of the risk of broad anterior myocardial infarction without revascularization due to the lack of graftable branches. Accordingly, only the two giant CAAs of the RCA were operated on.

The 5-year survival rate of patients with aneurysms was 71% in one report that defined CAA as an aneurysm over double the size of the normal coronary artery or more than 8 mm in diameter [11]. We consider careful follow-up as important for this case.

We successfully performed surgical treatment for a ruptured giant CAA. On the basis of this case, we propose that rupture of a CAA should be considered as one cause of cardiac tamponade.