Anomalous Right Coronary Artery From Pulmonary Artery Presenting as Inferior Wall Ischemia: A Case Report

Abstract

We illustrate the case of a 62-year-old man with a symptomatic anomalous right coronary artery from pulmonary artery (ARCAPA). Our patient had presented with dyspnea on exertion with electrocardiogram showing pronounced inferior Q waves and marked inferolateral ST-T wave changes. The patient had a nuclear stress test which showed inferior wall ischemia. Subsequently, the patient underwent coronary angiography which showed an ARCAPA. The patient underwent surgical repair with reimplantation of the right coronary artery to the ascending aorta which was tolerated well. Our case illustrates ARCAPA presenting late in adulthood with ischemic symptoms that was treated with corrective surgery.

Introduction

Congenital anomalies of the coronary circulation are a rare occurrence in the adult population with an incidence of <1%.^1,2 There are multiple coronary artery anomalies, one of them being anomalous right coronary artery from pulmonary artery (ARCAPA) which is estimated to account for about 0.1% of all coronary artery anomalies.^3,4 As the name suggests, it refers to the origin of the right coronary artery (RCA) from the pulmonary artery instead of the right sinus of Valsalva. While the clinical presentation of ARCAPA is variable, it is often asymptomatic, especially in children. Among symptomatic individuals, it has a bimodal age distribution with a first peak near birth and a second between 40 and 60 years of age. ⁵ In this case report, we illustrate the case of a 62-year-old man with a symptomatic ARCAPA presenting as discomfort on exertion, which was managed surgically.

Case Presentation

The patient is a 62-year-old man with a medical history notable for hypertension, hyperlipidemia, and type 2 diabetes who presented to his outpatient cardiologist for a routine follow-up for hypertension. Two years before the presentation, the patient had been referred for a treadmill stress test given nonspecific ST segment changes and premature ventricular contractions (PVCs) seen on electrocardiogram (ECG). The treadmill stress test was aborted due to baseline inferolateral ST-T segment changes rendering it non-interpretable. The patient subsequently underwent a nuclear stress test (NST), which showed no evidence of inducible ischemia and normal wall motion. At the current visit, the patient reported discomfort only with climbing stairs and walking up an incline but otherwise could walk as far as he wanted to. He was found to have an abnormal ECG with pronounced inferior Q waves and more marked inferolateral ST-T wave changes and thereby underwent another NST to follow up on the abnormal ECG and was found to have mild inferior wall ischemia and mild inferior wall hypokinesis. There was no evidence of an infarct on the NST. The patient subsequently had a coronary angiography which showed an ARCAPA that was filling distally with collaterals from the distal left circumflex artery (Qp/Qs of 1.68; Supplemental Videos 1 and 2). The patient was referred to cardiac surgery for surgical repair of the ARCAPA, which was performed with reimplantation of the RCA to the ascending aorta (Figure 1). The patient tolerated the procedure well and has been doing well to date.

Figure 1.

Diagram illustrating surgical reimplantation of right coronary artery from pulmonary artery to ascending aorta.

Discussion

In this case report, we illustrate an ARCAPA presenting with ischemic symptoms, which was repaired by surgical reimplantation of the RCA to the ascending aorta. Anomalous right coronary artery from pulmonary artery may present with symptoms around 8 weeks (about 2 months) of life with declining pressures in the pulmonary artery leading in turn to decreased left coronary artery flow. ¹ Presentation in the adult population varies drastically from an incidental left parasternal murmur to severe complications including cardiac arrest and sudden death. ¹ While data on ARCAPA are limited mostly to case reports, a systematic review of case reports has shown that even in asymptomatic patients, surgical repair of the RCA is opted for by most patients. ⁵ The reason to pursue surgical repair of ARCAPA in asymptomatic cases is to prevent ischemic symptoms and cardiac dysfunction which occurs secondary to coronary steal.^5,6 The pathophysiology behind this coronary steal phenomenon involves the creation of a low-pressure system involving the pulmonary circulation that results in a left to right shunt leading to symptoms of ischemia. ²

The 2018 AHA Adult Congenital Heart Disease guidelines have a Class I recommendation for surgical repair of ARCAPA in symptomatic adults and a Class IIa recommendation for asymptomatic adults with ventricular dysfunction or myocardial ischemia attributable to ARCAPA. ⁷ In our case, ARCAPA presented with ischemic symptoms late in adulthood. While it has been postulated that clinical presentation of ARCAPA in this age group is triggered by atherosclerotic disease in the left coronary system, in our patient, there was only minimal atherosclerotic coronary artery disease found in the mid left anterior descending artery on angiography.

While cardiac angiography was pursued in our patient which led to diagnosis of ARCAPA, a coronary computed tomographic angiography (CCTA) would have been a reasonable non-invasive alternative to the same. ⁸ Echocardiography also assists with the diagnosis of the same with features like extensive collateralization between the left and right coronary systems and increased flow between RCA and pulmonary artery highly suggestive of ARCAPA.^5,6 In our case, the patient was found to have pronounced Q waves in inferior leads and inferior-lateral ST-T wave changes which prompted ischemic work up with a NST demonstrating inferior wall hypokinesis and the diagnosis of ARCAPA being made on cardiac angiography. Prior case reports have also shown T-wave inversions in inferior leads and findings suggestive of Left Ventricular Hypertrophy (LVH) on ECG in patients with ARCAPA.^3,6 In the pediatric population, patients undergoing surgical ARCAPA repair have been shown to have excellent long-term outcomes. ⁹ However, such data is lacking for adult patients undergoing surgical repair of ARCAPA. It is important to report on the long-term outcomes of these patients due to there being potential for long-term complications after the procedure including RCA thrombosis. There are multiple explanations for this complication, including kinking of the RCA at the site of implantation and the transition from a high to a low flow coronary system after the procedure.^3,5,10 Right coronary artery thrombosis is typically treated with warfarin given that data on using direct oral anticoagulants is lacking for this population. Fortunately, in our case, the patient has had an uncomplicated course thus far.

Conclusions

In this case report, we illustrate ARCAPA, which presented late in adulthood with ischemic symptoms and was treated with corrective surgery which the patient tolerated well. Studies on long-term outcomes of adult patients undergoing medical or surgical treatment of ARCAPA are lacking. These studies are required and will help better inform the management of patients with ARCAPA.