Acute myocardial infarction in a patient with congenitally corrected transposition of the great arteries and complex coronary anatomy-a case report

Abstract

Background: Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart anomaly with atrioventricular and ventriculoarterial discordance that is often associated with other cardiac and coronary artery anomalies. Here, we report a case of a patient with ccTGA and non-ST elevation myocardial infarction (NSTEMI) with challenging coronary anatomy that was treated with stress-perfusion cardiac magnetic resonance imaging (spCMR) guided percutaneous coronary intervention (PCI).

Case summary: A 46-year-old male smoker with ccTGA, dyslipidaemia, diabetes Type 2 managed with dietary restrictions and a family history of premature myocardial infarction, presented with typical chest pain, elevated cardiac troponin levels and ECG-changes indicative of ischaemia. The patient was diagnosed with NSTEMI and underwent initial urgent coronary angiography (CA) without apparent significant stenosis, although the right coronary artery (RCA) could not be selectively investigated. The patient had coronary anatomy 1R-2LCX according to the Leiden convention, which is the usual anatomy in patients with ccTGA. Despite this, CA was challenging due to the different anatomy compared with individuals with normally positioned great vessels. The patient remained highly symptomatic with chest pain at moderate exertion. To improve identification of the anatomic location and extent of ischaemia, we performed spCMR with adenosine. This revealed a limited septal infarction (likely embolic) in the right ventricle and reversible ischaemia in two inferior right ventricular segments. A second angiography, selectively investigating RCA demonstrated a significant stenosis in the distal RCA that was successfully treated with a drug-eluting stent. Fractional flow reserve (FFR) measurements of the left coronary arteries demonstrated hemodynamically non-significant stenosis. The patient's symptoms resolved, and he remained asymptomatic at one month follow-up.

Discussion: This ccTGA patient had multiple risk factors for coronary artery disease and presented with NSTEMI. Diagnosis and treatment were challenging due to complex cardiac anatomy and associated different origins of the coronary arteries. We highlight the importance of careful evaluation of the coronary anatomy and functional testing using for example spCMR and FFR to target the culprit coronary vessel(s) in ccTGA complicated by NSTEMI.

Keywords: Acute myocardial infarction; Case report; Congenitally corrected transposition of the great arteries; Coronary artery anomalies.

Figure 1

Cardiac magnetic resonance images of the patient. (A) Systemic RV and Amplatzer ASD device indicated by arrow. (B) Late gadolinium enhanced short axes view at the basal level showing systemic RV, LV, and a minimal anteroseptal infarction (likely embolic) with microvascular obstruction (arrow). (C) Perfusion image of the systemic RV at rest. (D) Perfusion image of the systemic RV during quantitative spCMR with adenosine. Arrows highlight hypoperfused infero-septal segments of the RV. We want to point out that the RV seems dilated during stress (D) compared with the rest image (C). However, there was no right ventricular dilatation when comparing right ventricular volumes in four-chamber view and therefore this is likely explained by patient movement or excessive breathing during stress and not by right ventricular dilatation.

Figure 2

Electrocardiogram of the patient. Ischaemic electrocardiographic changes in anterior leads (arrows) upon presentation with NSTEMI (A) compared with a two-year-old ECG when the patient was asymptomatic (B).

Figure 3

Coronary angiogram of the patient. Left (A) and unselective proximal right (B) coronary artery at the initial coronary angiography. (C) Right coronary artery with significant stenosis in distal portion (indicated by arrow). (D) Right coronary artery after PCI.

Figure 4

Schematic visualization of the coronary arteries. (A and C) Usual coronary anatomy in normally aligned great arteries. (B and D) Coronary anatomy in our patient with ccTGA. A and B from a surgical point of view. (C and D) from imaging point of view. A = Anterior. P = Posterior. L = Left. R = Right. Orientation according to the Leiden convention is done either through surgical point of view or imaging point of view. In the surgical case, we assume that an observer takes place in the non-facing (NF) aortic sinus, looking at the pulmonary trunk (PT). The sinus to the right of the observer is called number 1, and to the left is called number 2. In the imaging case, we assume that the observer also takes place in the NF aortic sinus, but turning his back towards the PT. Now in the same way, the sinus to the right of the observer is called number 1, and to the left is called number 2, making it possible for both surgeons and cardiologists to use the same coding system.

Figure 5

Reconstructed cardiac magnet roentgen image showing origins of the coronary arteries in a short axes view. PT, pulmonary trunk; A = anterior; P = posterior; L = left; and R = right.