Unveiling Diagnostic Challenges: A Case of Giant Coronary Artery Aneurysm Masquerading as a Diaphragmatic Hernia

Author: Zooha Altaf
Program: Research Scholar
Mentor(s): Mohit Bhasin, MD
Poster #: 145
Session/Time: A/2:40 p.m.

Abstract

Introduction:

Giant coronary artery aneurysms, though rare, can present with a wide spectrum of clinical manifestations, often mimicking other medical conditions due to their unusual size and anatomical locations. In this case report, we describe an extraordinary instance of a patient presenting with symptoms that were consistently misattributed to a diaphragmatic hernia throughout their life. The colossal dimensions of the coronary artery aneurysm, exceeding the size of the heart itself on imaging studies, contributed to this diagnostic challenge. The case sheds light on the critical importance of considering atypical cardiovascular pathologies in the differential diagnosis of seemingly unrelated clinical presentations. Additionally, it underscores the significance of utilizing advanced imaging techniques and interdisciplinary collaboration to ensure accurate diagnosis and appropriate management for patients with complex and potentially life-threatening conditions. Through this report, we aim to highlight the complexities associated with diagnosing and managing giant coronary artery aneurysms, emphasizing the need for heightened clinical suspicion and a comprehensive approach to patient evaluation.

Case Report:

A 70-year-old patient with a past medical history of chronic diastolic heart failure with preserved ejection fraction, hypertension, morbid obesity (BMI 53), gastroesophageal reflux disease (GERD), obstructive sleep apnea (OSA was presented to emergency department (ED) with severe shortness of breath (SOB) and right shoulder pain. The patient states that he has had progressive dyspnea on minimal exertion for about 1.5 weeks. On admission EKG was stable, CXR with no findings, and troponins were negative. The patient underwent CTA to rule out PE, but the study was significant for giant right coronary artery aneurysm (no evidence of leaking from vessel). The cardiothoracic surgery was consulted. The patient had a history of wheezing, which had resolved, and a persistent cough. The patient denied any history of asthma or chronic obstructive pulmonary disease (COPD) and stated that he had never smoked. Respiratory symptoms were managed using Tessalon, Flonase, and Mucinex. The patient's chronic diastolic heart failure with preserved ejection fraction was managed using IV Lasix and intake/output monitoring. Hypertension was treated with amlodipine and metoprolol, GERD with a PPI, and obstructive sleep apnea with a CPAP device. A giant right coronary artery was identified on CT scan, measuring approximately 14 x 12 cm.Additionally, minimal atelectasis towards the lung bases and a small right effusion were noted. The diagnosis of coronary artery disease was also confirmed. A cardiac MRI was subsequently performed, which showed a massive 14 x 14 x 17 cm superior-inferior right coronary artery aneurysm with partial thrombosis. This aneurysm was observed to be compressing the right ventricle (RV) and superior vena cava (SVC).Left heart catheterization was carried out, revealing significant findings in various coronary arteries. The left main artery showed no significant disease. The left anterior descending artery (LAD) exhibited moderate calcification and irregularity with a 40% mid-stenosis, without significant obstructive disease. The diagonal branch displayed a 30% calcified stenosis. The intermediate marginal artery exhibited an 80% ostial narrowing, supplying a large caliber vessel. The left circumflex artery showed 40% ostial tapering but no significant obstructive disease. The right coronary artery (RCA) had an 80% proximal stenosis and fed the enormous aneurysm. Unfortunately, the distal RCA could not be visualized due to the inability to fill the aneurysm with antegrade injections. Cardiology recommended surgery to address the ramus intermediate artery. It was noted that there might be a distal vessel to bypass based on calcification of the posterior descending artery (PDA) as seen on CT scans. Due to the significant size and expansion of the aneurysm in the right coronary artery, surgical intervention was deemed necessary. The procedure began with the challenging task of mobilizing the right ventricle away from the aneurysm mass. This feat was successfully accomplished by gently peeling the pericardium off the mass, creating separation between the right ventricle and the right atrium. Despite these efforts, complete removal of the mass was not feasible at that juncture. Adjustment of the venous cannulae and snaring of the SVC and IVC were performed to achieve caval exclusion. Identification of the proximal and distal ends of the right coronary artery indicated its disintegration from the mass, aligning with the pseudoaneurysm observed in imaging. Both ends were securely closed using pledgeted 4-0 Prolene and running 5-0 Prolene sutures. Subsequently, the right ventricle and right atrium were detached from the mass, unveiling a 2 x 3 cm defect in the right ventricle. Skillful repair of this defect ensued, involving the use of horizontal mattress 4-0 Prolene sutures through a bovine pericardial patch. Addressing the coronary artery bypass, attention was turned to the posterior descending artery (PDA) and the calcified right coronary artery. Despite the calcification, a vulnerable area in the PDA enabled bypass, and a reverse saphenous vein graft was anastomosed. The same technique was applied to the ramus intermedius. The patency of both grafts was verified through testing. To mitigate the risk of postoperative dysrhythmias and anticoagulation-related complications, a 50 mm AtriClip was positioned on the left atrial appendage. The heart was de-aired, and meticulous management of bleeding points was executed using pledgeted 4-0 Prolene sutures. Successful weaning of the patient off cardiopulmonary bypass was achieved.

Discussion:

The phenomenon of coronary artery aneurysms (CAA) was initially documented in postmortem observations by Morgagni in 1761. CAA is characterized by localized dilation of coronary segments, exceeding 1.5 times the dimensions of adjacent normal segments. Additionally, the term coronary artery ectasia (CAE) is employed to describe more diffuse lesions. Notably, giant coronary artery aneurysms present a distinctive challenge due to their exceptional size, often surpassing typical dimensions. This remarkable enlargement can engender diagnostic confusion, resembling different medical conditions due to their substantial mass and distinct anatomical location. A pertinent illustration can be observed in this case where symptoms were consistently misattributed to a diaphragmatic hernia. The intricacies in identifying giant coronary artery aneurysms underscore the necessity for comprehensive evaluations, a heightened clinical suspicion, and the utilization of advanced imaging modalities. Clinical manifestations of these aneurysms span a spectrum, ranging from serendipitous discoveries on cardiac imaging to instances of acute coronary syndrome. The underlying origins and associations of such aneurysms often encompass genetic predisposition, coronary artery disease, and certain vasculitic and connective tissue disorders like Kawasaki disease and Marfan syndrome. Instances of post-infectious CAAs have been documented, potentially arising from direct wall invasion or immune complex deposition. In clinical practice, coronary angiography remains a prevalent imaging technique for assessing aneurysmal or ectatic coronary arteries. However, challenges such as delayed antegrade contrast filling, segmental backflow, and contrast stasis in the dilated segments can impede clear imaging during angiography. Employing intravascular ultrasound (IVUS) can prove invaluable, offering enhanced visualization of vessel wall structures and enabling differentiation between true aneurysms, pseudoaneurysms, and segments exhibiting aneurysmal appearance due to plaque rupture or adjacent stenosis. Moreover, IVUS aids in precise sizing of the aneurysm and any neighboring stenoses, facilitating appropriate stent selection if percutaneous coronary intervention (PCI) is considered. As an emerging technique, coronary computed tomography is gaining traction in assessing these cases due to its ability to provide more accurate evaluation of aneurysm size, thrombus presence, and calcification compared to invasive angiography. Managing patients with CAA poses substantial challenges for various reasons. The natural course of coronary aneurysms is inadequately understood, thus complicating decisions surrounding the management of incidentally detected CAA or coronary ectasia in the absence of concurrent stenosis or occlusion. Atherosclerosis is implicated in a significant portion of CAA cases, particularly among older patients, underscoring the critical role of aggressive risk factor modification in this demographic. The role of dual antiplatelet therapy or therapeutic anticoagulation in managing patients with CAA or CAE, particularly in cases incidentally identified, remains a subject of ongoing debate.

Conclusion:

In conclusion, the Case Report highlights the challenges associated with diagnosing and managing giant coronary artery aneurysms, emphasizing the importance of clinical suspicion, interdisciplinary collaboration, and the utilization of advanced imaging techniques. This case serves as a reminder that exceptional clinical scenarios require an integrated approach that accounts for both cardiovascular and non-cardiovascular factors, ultimately leading to accurate diagnosis, effective management, and improved patient outcomes. Further research and reporting of such cases are essential to enrich our understanding of this rare yet clinically significant condition.