Expanding giant right coronary artery aneurysm: an acute need for new management strategies.

Angiography use has become increasingly common worldwide. Coronary artery aneurysm may be an incidental finding during angiography. Occasionally it might be symptomatic or may become symptomatic over the course of time. Rupture of aneurysm may lead to disastrous complications. Here we present a case in which aneurysm was asymptomatic but surgical intervention was done because of rapid increase in the size of aneurysm. This is to drive home the point that timely surgical intervention is instrumental in preventing complications associated with possible rupture of the aneurysm.

INTRODUCTION

Coronary artery aneurysms (CAA) may be detected incidentally during angiography. About 1.2-4.9% of patients undergoing cardiac catheterization are discovered to have at least one aneurysm, with right coronary artery (RCA) lesions accounting for 50% of the total.[1234] Aneurysm of the left main coronary artery is rare, less than 1% of all CAA. Coronary artery aneurysms greater than 2 cm in diameter are called giant aneurysms and represent those that are most likely to develop complications.[56]

Majority of patients with CAA are asymptomatic from any of the clinical effect of the aneurysm which is detected during angiography while investigating for some other pathology. Giant aneurysms, however, may become symptomatic; size and location determine their manifestation. CAA's can present with myocardial ischemia due to thrombosis secondary to sluggish blood flow in the aneurysm.

Rupture of CAA can lead to hemo-pericardium, tamponade and sudden death. CAA can also impinge on surrounding structures with case reports of fistula formation to cardiac structures including the right atrium, pulmonary artery and coronary sinus.[47]

CASE REPORT

A 52-year-old man presented with a history of hypertension and coronary artery disease (CAD). The patient previously had stents placed in Left anterior descending (LAD) artery in 2001 and in the Right Coronary Artery in 2004. An implantable cardioverter-defibrillator (ICD) was placed two years back for an episode of ventricular tachycardia. Left ventricular systolic dysfunction with an EF of 24% was demonstrated at that time.

Patient developed exertional chest pain and a cardiac catheterization was scheduled. Angiography revealed an 80%-90% in-stent restenosis in left anterior descending (LAD) and a patent stent in the distal RCA. There was a 2.2 cm by 3.2 cm aneurysm in the proximal RCA and another measuring 1.4 cm by 1.5 cm in the mid RCA [Figure 1]. Ventriculography demonstrated antero-apical hypokinesia. A cardiac catheterization two years earlier had demonstrated an aneurysm of 1.2 by 2.5 cm in proximal RCA and 1.2 cm by 1.2 cm in mid RCA [Figures 2 and 3]. At that time he was started on Coumadin due to CAA and left ventricular dysfunction. Although, patient appeared asymptomatic from the RCA aneurysm, he required revascularization of the LAD territory. Given the rapidly increasing size of aneurysm, he was referred for surgical intervention.

Figure 1

Aneurysm of coronary artery

Figure 2

Coronary angiogram done from 2010 demonstrating 2 aneuryms in the right coronary artery

Figure 3

Coronary angiogram done in 2008 demonstrating aneurysms in the Right coronary artery

After median sternotomy and the institution of cardiopulmonary bypass with cardioplegic arrest, the aneurysms were inspected and found to be impinging on the right atrium but not communicating with any cardiac chamber. The RCA was ligated proximal and distal to the aneurysms and a free radial artery graft was placed to the posterior descending branch of the RCA. In addition, the left internal mammary artery was grafted to the left anterior descending coronary artery.

The patient's post-operative course was complicated by atrial fibrillation with a rapid ventricular rate followed by ventricular tachycardia about six hours post-operatively. Normal sinus rhythm was regained after electrical counter shock and he was placed on an amiodarone infusion for 24 h. An intra-aortic balloon pump was placed at that time. The apparent trigger for ventricular tachycardia was myocardial ischemia secondary to atrial fibrillation with rapid ventricular response. Right ventricular ischemia due to sacrifice of right ventricular branch by ligation of the RCA aneurysm was considered. However, electrocardiograms done before and immediately post-cardioversion did not show any ischemic changes. Electrolytes were normal at the time of ventricular tachycardia. Transesophageal echocardiogram done shortly after the event showed an EF of 20% with akinesia of the inferior wall and hypokinesia of posterior, lateral and septal walls, essentially unchanged from preoperatively.

DISCUSSION

Increased recognition of CAA's parallels the widespread use of coronary angiography. Atherosclerosis is the most common cause of CAA. Other causes include Kawasaki disease, congenital, mycotic, post syphilitic, connective tissue disorders or pseudo aneurysm secondary to vessel injury following percutaneous intervention.[4578910] Recently there have been reports of CAA formation following placement of a drug eluting stent.[10] In the current case, there was a stent placed in RCA about nine years earlier but the CAA developed in a non-stented area. Thus, its cause is most likely secondary to atherosclerosis. The aneurysm was not resected and therefore not subjected to pathologic examination.

Due to the sporadic nature of giant CAA's, there is no standard surgical approach. The goals of surgical therapy are to eliminate intraluminal pressure which would encourage further aneurysm expansion and to provide adequate coronary blood flow distally. Percutaneous approaches with covered stents are not routinely available at this time. However, covered stents such as Jostent PTFE covered balloon expandable coronary stent graft have been shown to be an effective device for percutaneous management and exclusion of CAA, especially in patient at high risk for coronary surgical intervention surgery.[7] Self expandable PTFE stents have more utility in coronary aneurysms without angulation and large diameter. Only limited experience is available at this time. Medical therapy for CAA consists of anticoagulation with Coumadin to prevent thrombosis and coronary artery occlusion.[1]

Indications for surgical therapy are size greater than 2.0 cm in diameter or documented increase in size.[6] Ligation of smaller aneurysms may be considered when concomitant surgery is planned, but smaller, asymptomatic lesions do not require intervention. Surgical treatment options include coronary artery bypass grafting, in conjunction with proximal or distal ligation.[1112] Other surgical options include resection with end-to-end anastomosis or interposition vein graft.[9] End-to-end native artery anastomosis is always not practical. Proximal aneurysm of the left main coronary artery may require aortotomy and patch closure of the orifice to gain proximal control.[67]

Our case was interesting and unique because of the documented rapid enlargement of the aneurysm over two years. Despite the giant CAA, the patient remained asymptomatic from the aneurysm. He was successfully treated surgically despite an episode of post-operative ventricular tachycardia. He subsequently did well and has returned to normal activities. With increasing recognition of such cases, it becomes mandatory to adopt and formulate universal approaches for their management and surgical resection is the definite answer to such scenarios. Otherwise, catastrophic complications are always possible for any delayed therapeutic decision.