Dual Conal Branch LAD Revascularization via Vieussens’ Ring on CCTA

We report a middle-aged woman with hypertension, dyslipidemia, and prior PCI with stents in the proximal LAD and a major diagonal who presented with exertional angina despite a negative stress ECG and underwent CCTA. CCTA demonstrated chronic total occlusion of the mid-LAD immediately distal to the proximal LAD stent, with distalperfusion entirely collateral-dependent. A conal branch from the right coronary ostium formed a Vieussens’ arterial ring and bifurcated: one branch entered the LAD at the junction between a normal-caliber segment and a subsequent long suboccluded tract, while the other revascularized the distal LAD. Additional collaterals arose from a large diagonalbranch. Both stents were patent. A severe ostial Left Circumflex artery stenosis was identified as the most likely culpritlesion. This case illustrates an uncommon dual conal-branch collateralization pattern and underscores the value of CCTA in complex CTO evaluation.