Challenging Diagnosis of Myocardial Infarction Due to Anomalous Left Circumflex Artery

Keywords
Myocardial Infarction / Diagnosis; Coronary Artery Anomalies; Coronary Angiography; Cardiac Magnetic Resonance

A 45-year-old male without past medical history presented with retrosternal chest pain and ST-segment elevation in inferolateral leads at ECG. Invasive coronary angiography, along with optical coherence tomography performed as part of the clinical study, showed normal coronaries, and myocardial infarction with non-obstructive coronary arteries (MINOCA) was diagnosed (Figure 1 A-B). Due to ongoing chest pain, triple-rule-out computed tomography angiography (CTA) was undertaken to exclude aortic dissection and pulmonary embolism. Incidentally, anomalous left circumflex artery (LCx) originating from the right sinus of Valsalva with a suspicion on severe stenosis was detected (Figure 1 C-E). Selective angiography of the LCx confirmed severe lesion in the distal vessel segment (Figure 1 F), however given the resolution of patient's symptoms, a decision on medical therapy with dual antiplatelet agents was undertaken. At discharge, cardiac magnetic resonance disclosed mildly reduced left ventricular ejection fraction (53%) with myocardial edema and transmural infarction of the basal-to-mid lateral wall (Figure 1 G-H).

Figure 1
Coronary angiography, coronary computed tomography angiography and cardiac magnetic resonance findings of the patient with challenging diagnosis of myocardial infarction and anomalous left circumflex artery.

LCx arising from the right aortic sinus is the most frequent coronary artery anomaly (CAA) found in up to 0.7% of the population. Although anomalous LCx is considered benign, the severe angle and tortuous vessel course may predispose it to accelerated atherosclerosis. Herein, the anomalous LCx was overlooked due to super-selective cannulation of the right coronary artery, and a large intermediate branch was incorrectly classified as LCx leading to deferred revascularization and irreversible myocardial injury. This case highlights that CAA could be included in the differential diagnosis of MINOCA, and unveils the potential for triple-rule-out CTA in detecting CAA.

• Sources of Funding
  This study was partially funded by Research Grant "Iuventus Plus" from the Polish Ministry of Science and Higher Education [IP2014 034073].
• Study Association
  This study is not associated with any thesis or dissertation work.

References

• ¹
  Kang JW, Seo JB, Chae EJ, Jang YM, Do KH, Lee JS, et al. Coronary Artery Anomalies: Classification and Electrocardiogram-Gated Multidetector Computed Tomographic Findings. Semin Ultrasound, CT MRI. 2008;29(3):182-194.
• ²
  Wilkins CE, Betancourt B, Mathur VS, Massumi A, De Castro CM, Garcia E, et al. Coronary Artery Anomalies: A Review of More than 10,000 Patients from The Clayton Cardiovascular Laboratories. Texas Heart Inst J. 1988;15(3):166-173.

Publication Dates

• Publication in this collection
  June 2018

History

• Received
  19 Aug 2017
• Reviewed
  12 Dec 2017
• Accepted
  12 Dec 2017