Atherosclerotic Coronary Artery Disease in a Younger Adult With Transseptal Anomalous Left Coronary Artery

Abstract

We present a case of extensive coronary atherosclerotic disease in a younger patient with an anomalous left coronary artery with transseptal course and show the utility of multimodality evaluation to determine the culprit lesion in patients presenting with this rare association. (Level of Difficulty: Intermediate.)

Central Illustration

History of Presentation

A 23-year-old diabetic male presented with pressure-like substernal chest pain triggered by routine home activities and associated with dyspnea. Vital signs included heart rate 100 beats/min, blood pressure 109/79 mm Hg, respiratory rate 21 breaths/min, and oxygen saturation 99%. Physical exam and electrocardiogram revealed sinus tachycardia. Significant labs included troponin 17 ng/mL peaking to 28 ng/mL, glucose 209 mg/dL, and hemoglobin A1c 11%. Complete blood count and basic metabolic panel were normal.

Learning Objectives

• •To recognize that anomalous coronary arteries have a wide range of clinical presentations, from asymptomatic to symptomatic with malignant courses.
• •To use advanced imaging to diagnose and manage patients with anomalous coronary arteries and acute coronary syndrome.
• •To understand that the association of atherosclerotic coronary artery disease and anomalous coronary arteries is a challenging clinical dilemma that requires multi-modality evaluation to determine the best management approach.

Past Medical History

The patient had uncontrolled diabetes type 1 complicated by diabetic ketoacidosis. Patient reported history of congenital coronary anomaly but was uncertain of further details.

Differential Diagnosis

Because of chest pain with elevated troponin, non–ST-segment elevation myocardial infarction was the primary working diagnosis. Ischemic presentation of possibly underlying congenital coronary anomaly was also considered.

Investigations

Cardiac catheterization revealed anomalous left main coronary artery (LM) originating from the right coronary artery, Lipton classification is RIIB.¹ Angiogram showed extensive multivessel stenosis: 90% stenosis of the first diagonal, 70% stenosis of the first obtuse marginal (OM) of the left circumflex, 80% stenosis of the second obtuse marginal, and 100% stenosis of the distal left circumflex. The right coronary artery showed 80% stenosis of the right posterolateral branch (Figure 1). There was no evidence of ostial stenosis.

Figure 1.

Cardiac Angiography Showing Atherosclerotic Disease

To further delineate the course of the left main LM, cardiac computed tomography angiography (CCTA) was performed. CCTA showed a single coronary artery coming off the right cusp with transseptal, rather than interarterial, course of the LM (Figures 2, 3, and 4). Transthoracic echocardiogram showed normal ejection fraction (60% to 65%) and mild hypokinesis. The patient had triple-vessel disease in the setting of a single-vessel coronary artery. To further evaluate the extent of myocardial injury, cardiac magnetic resonance imaging (CMR) was performed. CMR showed hypokinesis and transmural delayed enhancement in the basal to mid anterolateral wall with areas of microvascular obstruction, consistent with recent myocardial infarction (MI) (Figure 5). Three-dimensional printing also helped demonstrate the course of the artery (Figure 6).

Figure 2.

Cardiac Computed Tomography Angiography

The left main coronary artery (LM) coursing between the aortic root and the right ventricular outflow tract.

Figure 3.

Cardiac Magnetic Resonance Imaging: Anomalous Left Coronary Artery

The transseptal course of the anomalous left coronary artery.

Figure 4.

Cardiac Computed Tomography Angiography: 3-Dimensional Reconstructed Image

Figure 5.

Cardiac Magnetic Resonance Imaging

Transmural delayed enhancement in the basal/mid-anterolateral wall with areas of microvascular obstruction, consistent with infarcted tissue.

Figure 6.

3-Dimensional Image of the Heart Showing Anomalous Left Coronary Artery

Management

Given that the patient had triple-vessel disease in a single coronary artery with limited cardiac damage and already infarcted tissue, the risks outweighed the benefits of percutaneous intervention (PCI) of the culprit coronary lesion. Because transseptal anomalous coronary arteries are generally benign, revascularization with coronary artery bypass graft (CABG) was also not recommended. Nonpharmacological functional stress imaging with stress CMR ischemic testing was considered on an outpatient basis to assess for stress-induced myocardial ischemia. Finally, because of his uncontrolled diabetes, severe atherosclerosis, and chest pain – free status without hemodynamic instability, the patient was medically managed on guideline-directed medical therapy until he was optimized for possible later revascularization.

Discussion

To our knowledge, this is the first reported case of extensive atherosclerotic coronary disease in a younger patient with a transseptal anomalous left coronary artery and single coronary vessel. Multimodality imaging played an important role in elucidating the correct anatomy and guiding our management approach.

Clinically significant coronary anomalies in the general population are estimated to be between 0.1% and 1.0% in both adults and children, with many anomalies going undiagnosed and found incidentally during echocardiogram or angiogram.² Symptomatic patients can present with chest pain, exertional syncope, arrhythmias, sudden cardiac death, or aborted sudden cardiac death. Diagnosis of coronary anomalies has traditionally been performed with coronary angiography; however, angiography is invasive, with risk of morbidity (1.5%) and mortality (0.15%), and has poor spatial resolution.³ Electrocardiogram-gated multidetector computed tomography and magnetic resonance imaging have emerged as noninvasive imaging modalities that can provide 3-dimensional information of the aberrant vessels.³

Whether anomalous coronary arteries are more subject to atherosclerosis is an area of ongoing debate, with previous anecdotal reports answering in both the affirmative and negative.4, 5, 6 Those studies were anecdotal and without matched controls. However, 1 study by Click et al⁷ matched patients with anomalous coronary arteries to patients with native coronary arteries and found that only anomalous circumflex coronary arteries had a significantly greater degree of stenosis than matched control counterparts. Although at 3 years there was a trend for poorer survival in those with the anomalous circumflex coronary artery, at 7 years there was no significant difference in survival.⁷ The reported cases were in older patients, whereas our patient was in his 20s. In our case, the patient’s poor health literacy and poorly controlled diabetes were more likely contributors to his atherosclerotic disease rather than the anomalous artery itself. Furthermore, the patient had significant stenosis of his normal right coronary artery, further showing that the patient’s overall poor health was a greater contributor to the stenosis than the anomalous artery.

Diabetes is a known risk factor for cardiovascular events and plays a significant role in microvasculopathy. It has previously been shown that diabetic patients with acute MIs who undergo PCI fail to obtain or sustain microvascular myocardial reperfusion and are still at risk for later cardiovascular events.⁸ One large multicenter study between diabetic and control patients showed that despite similar rates of Thrombolysis In Myocardial Infarction flow grade 3 post PCI, diabetic patients continued to have poor myocardial perfusion.⁸ The mechanism is thought to be multifactorial, secondary to increased risk for thrombosis and inflammation, increased endothelial damage from oxidative stress, and reduced acute coronary collateral recruitment.⁹ In the present case, revascularization success was thought to be further diminished because of the appearance of completed infarct of the basal-mid anterolateral wall with microvascular obstruction.

Several factors played into why we chose medical management for our patient. First, the patient had uncontrolled diabetes that, despite his younger age, made him a less than ideal surgical candidate. Second, his single coronary artery made PCI a high-risk procedure. Third, the CMR showed a small area of infarction that, if reperfused, would not significantly improve his condition.⁹ As transseptal anomalous coronary arteries have a relatively benign course, surgical intervention of anomalous coronary was not recommended. Thus, the decision was made to medically manage the patient on guideline-directed medical therapy. Nonpharmacological functional stress imaging with stress CMR ischemic testing was considered on an outpatient basis to assess for stress-induced myocardial ischemia per European Society of Cardiology guidelines.¹⁰

Follow-Up

At 6-month follow-up after optimization of intense medical therapy, there was subjective improvement in overall functional capacity and no recurrent chest pain. Patient was lost to follow-up, but he has not returned to our facility for recurrent MI or any other major cardiovascular event.

Conclusions

Atherosclerotic cardiovascular disease in patients with anomalous coronary arteries presents a diagnostic and management challenge, particularly in patients with uncontrolled comorbidities. Advanced imaging with CCTA and CMR can be helpful in mapping the anatomy and guide decision making in these complex patients.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.