Hyperdominant Left Circumflex Artery Challenging Conventional Paradigms and Current Guideline Recommendations: A Comprehensive Literature Review and Case Series

Figures

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  FIGURE 1. ECG of IPMI mimicking NSTEMI in the first patient. The 12‐lead ECG of the patient at our hospital showed transient subtle STD in lateral precordial leads (thin red arrows).

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  FIGURE 2. Coronary angiography findings in the first patient, immediate CAG revealed: (A) RAO caudal view and (B) AP cranial view showing a large thrombotic occlusion (thick yellow arrows) in the left PDA following contrast injection. (C) LAO cranial view showing a markedly enlarged hyperdominant‐LCx with a disproportionately large caliber relative to the other coronary arteries and an extended course reaching and covering the left ventricular apex, as well as a moderate atherosclerotic plaque (thin red arrow) in the proximal segment of the LAD. (D) LAO view showing a nondominant right coronary artery with multiple significant ostioproximal stenoses. AP, anteroposterior; CAG, coronary angiography; LAD, left anterior descending artery; LAO, left anterior oblique; RAO, right anterior oblique.

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  FIGURE 3. Percutaneous coronary intervention findings in the first patient. During PCI it was observed that (A) RAO caudal view and (B) LAO cranial view demonstrating restoration of antegrade flow in the left PDA following guidewire crossing (thick yellow arrow). (C–E) Balloon angioplasty (red arrows) of the proximal PDA was performed, resulting in improved luminal diameter and enhanced distal flow. LAO, left anterior oblique; PCI, percutaneous coronary intervention; RAO, right anterior oblique.

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  FIGURE 4. 12‐Lead ECG in the second patient. One of the initial 12‐lead ECG in the second patient was entirely normal. PDA, posterior descending artery.

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  FIGURE 5. Coronary angiography findings in the second patient. CAG revealed: (A) LAO cranial view showing the proximal portion of the large LCx artery; its ostium is well visualized, and a total occlusion (complete flow interruption) is present at the origin of the left PDA following contrast injection (yellow thick arrow). (B) RAO caudal view showing a patent left main coronary artery without significant stenosis; however, a concentric ostioproximal stenosis (yellow thick arrow) is evident in the OM1. The proximal segment of the LAD artery exhibits mild plaque extension (B: red thick and C: red yellow arrow). RAO cranial view demonstrating a total eccentric occlusion (thick yellow arrows) in its distal segment involving the left PDA. (D) LAO view depicting a diminutive RCA without significant stenosis or atherosclerotic plaque. LAD, left anterior descending artery; LAO, left anterior oblique; LCx, left circumflex artery; OM1, first obtuse margin branch; RAO, right anterior oblique.

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  FIGURE 6. Percutaneous coronary intervention findings in the second patient. During PCI, (A) LAO cranial view and (B) RAO caudal view demonstrate successful coaxial crossing of the guidewire through the LCx artery into the left PDA (yellow thick arrow). (C) LAO cranial view demonstrating balloon angioplasty (red thin arrows) of the proximal segment of the left PDA. (D) after balloon dilatation showing improve luminal diameter and enhanced distal flow. (E–G) LAO cranial and RAO caudal views after successful stent deployment in the PDA (white thin arrows), confirming successful implantation and restoration of TIMI 3 flow. Owing to its markedly large caliber relative to the other epicardial coronary arteries and its extended distribution into myocardial territories normally supplied by the RCA, the LCx was classified hyperdominant. LAO, left anterior oblique; LCx, left circumflex artery; PDA, posterior descending artery; RAO, right anterior oblique.

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  FIGURE 7. A suggested diagnostic approach based on our clinical experience to prevent overlooking concealed IPMI particularly in left‐dominant coronary circulation. *We suggested that performing an initial 15‐lead ECG, including posterior leads in all symptomatic patients with suspected ACS; however, this may not always be feasible at the FMC. λAt this point, we recommend recording a 15‐lead ECG, including posterior leads (V7–V9) within 90 min of the initial ECG, in all patients.