Rupture of Giant Coronary Artery Aneurysm into Left Atrium Causing Acute Congestive Heart Failure

Abbreviations

CAA, Coronary artery aneurysm

CABG, Coronary artery bypass grafting

CHF, Congestive heart failure

CT, Computed tomography

GCAA, Giant CAA

HIV, Human immunodeficiency virus

KD, Kawasaki disease

LA, Left atrium

LCX, Left circumflex

LM, Left main

MDCT, Multidetector computed tomography

PDA, Posterior descending artery

INTRODUCTION

A coronary artery aneurysm (CAA) is defined as dilatation of more than 1.5 times the diameter of a normal adjacent artery. There is currently no consensus regarding the definition of a giant CAA (GCAA); a cutoff value of 20 mm, 40 mm, 50 mm, or 4 times the diameter of the reference artery have been proposed.¹ A scientific statement from the American Heart Association proposed that CAAs with a diameter greater than 8 mm could be called GCAAs in Kawasaki disease (KD).² We present a case of GCAA complicated with fistula formation, distal embolization, arrhythmia, and congestive heart failure (CHF). The patient was treated successfully with surgery.

CASE PRESENTATION

A 48-year-old male visited the emergency department with left upper abdominal pain. Splenic infarction was confirmed on computed tomography (CT) scan. Significant medical history included human immunodeficiency virus (HIV) infection. Atrial fibrillation with rapid ventricular response, shown on electrocardiogram, was presumed to be the cause of splenic embolization. A loud continuous heart murmur was heard over the left lower sternal border. Due to elevation of troponin-I levels (1.27 ng/ml), coronary angiography was done, which showed rapid dissipation of contrast medium from the left coronary artery, a faint aneurysmal silhouette, and left atrium (LA) opacification (Figure 1). Echocardiography showed a giant aneurysm of the left circumflex (LCX) coronary artery with mural thrombi, coursing posteriorly along the left atrioventricular groove, and a coronary-cameral fistula draining into the LA (Figure 1). Moderate-to-severe mitral regurgitation, left ventricle dilatation with impaired systolic function, and pulmonary arterial hypertension were also noted. During hospitalization the patient developed symptoms and signs of CHF including orthopnea, pulmonary edema, tachycardia, and hypotension. Multidetector computed tomography (MDCT) was done for pre-operative study, which showed giant aneurysmal dilatation from left main (LM) to LCX coronary artery, and posterior descending artery (PDA) originating from the distal part of the aneurysm. The aneurysm was around 3.5 cm in greatest diameter and over 6 cm in length (Figure 1). The patient received coronary aneurysmectomy, coronary cameral fistula repair, coronary artery bypass grafting (CABG), mitral valve replacement, and left auricle amputation. After initiation of cardiopulmonary bypass and aortic crossclamp, the heart was arrested with retrograde cardioplegia. The LA was entered from behind the Waterston’s groove, and the fistula opening was visualized at the left posterior atrial wall near the mitral annulus. It was about 1 cm in diameter and was suture-closed primarily. The coronary aneurysm was opened longitudinally to better visualize all the branch openings, which were also suture-closed. The LM orifice was closed from within the aorta. Then the aneurysm wall was plicated and closed. CABG was done with a great saphenous vein graft from the ascending aorta to the left anterior descending artery, with a Y-graft to the obtuse marginal and PDA, with proximal coronary suture-ligated to prevent backflow into the aneurysm. An attempt to repair the mitral valve failed as the annulus was relatively fixed by the external aneurysm. Thus, mitral valve replacement with a bioprosthesis (Carpentier-Edwards PERIMOUNT Magna Mitral Ease pericardial valve, 31 mm, Model 7300 TFX, Edwards Lifesciences) was done. Postoperative CT showed obliteration of the aneurysm without contrast medium enhancement (Figure 2). The patient had an uneventful postoperative recovery and was discharged 13 days after surgery.

Figure 1.

Angiography showing dissipation of contrast medium from the left coronary artery, aneurysmal silhouette (A and B), and LA opacification (C). Echocardiography showing the coronary aneurysm located at the left AV groove with thrombus content (D). The aneurysm can be traced to the LM coronary artery (E). Color Doppler shows blood flow between the aneurysm and LA (F). MDCT and 3D reconstruction depicting aneurysmal dilatation from LM to LCX coronary artery, with fistula to LA (G, H, and I). “*” Labels the aneurysm. AV, atrioventricular; LA, left atrium; LCX, left circumflex; LM, left main; MDCT, multidetector computed tomography; 3D, 3-dimensional.

Figure 2.

Intraoperative photo of the bulging aneurysm when the heart is retracted toward the patient’s right side (A). Postoperative CT shows no contrast media in the residual aneurysm sac (B and C). “*” Labels the aneurysm. CT, computed tomography.

DISCUSSION

GCAAs are usually asymptomatic and discovered incidentally.¹ Previously reported complications of GCAAs included myocardial infarction, arrythmias, distal embolization, spontaneous rupture, fistula formation, or compression of the cardiac chambers.³ Timely intervention could prevent these potentially fatal consequences. CAAs can be treated with percutaneous coronary interventions in simple cases when the anatomy is suitable.^3,4 Endovascular strategies include various occluder devices, coils, and covered stents. For GCAAs, surgical correction has the additional advantage of excising the aneurysm sac. It is preferrable in cases with multivessel or left main coronary artery involvement, mechanical complications, and in those requiring concomitant valve surgery.^3,5 Surgical methods adopted comprised of aneurysm ligation, resection, or marsupialization with an interposition graft.⁶ The GCAA in our patient was treated by closing the LM orifice, incising the aneurysm sac, and closing the efferent vessel openings with bypass grafting of the distal branches. This procedure has also been reported by other authors.^6,7

The fistula opening in the LA was around 1 cm, and the edges appeared jagged and irregular. Judging from this and the recent development of CHF, we hypothesize that the fistula was a result of the GCAA rupturing into the LA, and not a congenital coronary-cameral fistula. The large shunt ultimately resulted in pulmonary edema, cardiac dysfunction, hypotension, and atrial fibrillation.

The large aneurysm and shunting of coronary blood to the low-pressure LA could also cause a coronary steal phenomenon. This could explain the slight elevation of cardiac enzymes seen in our patient. His other coronary arteries appeared relatively normal with no significant coronary artery disease.

The etiology of the GCAA in our case is unknown. The most common cause of CAAs is atherosclerosis, which has been linked to 50% of CAAs diagnosed in adults.⁸ Our patient did not have diabetes, was not a smoker, and had never suffered from a myocardial infarction in the past. KD causes vasculitis in the coronary arteries and is the most common cause of CAAs in childhood.⁹ KD, being the second most common cause of CAAs in adults, could not be ruled out as an etiology in our patient. However, it commonly involves multiple aneurysms of the coronary and the systemic arteries.¹⁰ Other uncommon causes of CAAs include vasculitic disorders such as Takayasu arteritis, systemic lupus erythematosus, polyarteritis nodosa, rheumatoid arthritis, and hereditary connective tissue disorders such as Marfan syndrome and Ehlers-Danlos disease.⁹ Unfortunately, we did not have histological proof that our case of GCAA resulted from vasculitic or connective tissue disorders. The only risk factor we could identify in our patient was HIV infection. Bacterial, mycobacterial, fungal, syphilitic, Lyme, and HIV infections can also cause CAAs.⁹ Direct invasion of pathogens into the vessel wall, immune complex deposition, and anti-retroviral therapy are related to aneurysm formation. It has been reported that coronary artery aneurysms, ectasia, and stenosis are found in people living with HIV.¹¹

LEARNING POINT

GCAAs could present with devastating complications such as formation of a fistula between cardiac chambers, acute CHF, and thromboembolism. Timely, accurate diagnosis and surgery are effective in treating this disease.

DECLARATION OF CONFLICT OF INTEREST

All authors declare no conflicts of interest.