Anomalous Intercoronary Communication in the Setting of Chronic Left Circumflex Occlusion

Intercoronary communication (ICC) is a rare coronary artery anomaly that can be mistaken for collateral flow in chronic occlusive disease, with implications for procedural planning. We report a 77-year-old woman with 2 h of retrosternal, burning chest pain, ischemic ST-segment depression, negative serial high-sensitivity troponins, and poorly controlled hypertension. Imaging showed coronary calcification and impaired left-ventricular diastolic function. On Day 3, angiography revealed no significant left main disease, diffuse proximal-mid LAD atherosclerosis, and an occluded left circumflex artery (LCx) distal to second obtuse marginal (OM2), alongside severe mid-right coronary artery stenosis. Contrast opacified the left system from the RCA via a large channel consistent with ICC. An antegrade strategy was prioritized while recognizing the ICC as a potential retrograde bailout. After plaque shift via OM2 predilation (1.5/2.0-mm balloons), intravascular ultrasound (IVUS)-guided stenting (2.75 × 26 mm) required a distal sealing stent (2.5 × 12 mm) for an edge hematoma. With microcatheter support, a Fielder XT wire crossed into the distal LCx, and true-lumen position was confirmed; subsequent dilatation improved flow, but a distal LCx dissection was identified and confirmed by IVUS. A reverse-crush two-stent strategy with final kissing inflations achieved optimal expansion and thrombolysis in myocardial infarction (TIMI) 3 flow. The patient was discharged on dual antiplatelet therapy and remained symptom-free at 1 month. This case underscores the need to differentiate ICC from collaterals and demonstrates an imaging-guided, stepwise strategy for bifurcation lesions when wiring is difficult, and complications such as edge hematoma or dissection arise.