SS–16 Left Circumflex CTO Resistant to Sequential Plaque Modification Techniques

Abstract

Introduction and Aim: Severely calcified chronic total occlusion (CTO) lesions are among the most technically challenging complex coronary lesions encountered during percutaneous coronary intervention (PCI), with relatively low technical success rates. We present a case of a complex, severely calcified left circumflex (LCx) CTO in which revascularization could not be achieved despite the sequential use of advanced plaque modification techniques.

Case Report: A 60-year-old man presented to the emergency department with pain originating in the epigastric region and radiating to the back. Four months earlier, an exercise stress test had been discontinued due to symptoms, and although coronary angiography had been recommended, the patient had not undergone further evaluation. He was admitted with a preliminary diagnosis of unstable angina. His medical history included hypertension, coronary artery disease, and active smoking. Electrocardiography showed sinus rhythm with supraventricular extrasystoles. Echocardiography revealed a left ventricular ejection fraction of 40–45%, with hypokinesia of the lateral and anterior walls. Coronary angiography demonstrated diffuse 40–50% stenosis in the right coronary artery (RCA), 50–60% stenosis in the distal left anterior descending artery (LAD), a chronic total occlusion of the first diagonal branch (D1), and a severely calcified CTO in the proximal LCx.

First Session (April 5, 2026): The LCx was engaged from the left main coronary artery. Despite the use of different coronary guidewires and balloon support, the CTO segment could not be crossed intraluminally. Subsequently, a guidewire was advanced into the obtuse marginal (OM) branch. The proximal calcified segment was sequentially dilated using 1.5×9 mm, 1.5×20 mm, 2.5×25 mm, 2.75×15 mm, 2.75×18 mm, and 2.75×23 mm non-compliant (NC) balloons, followed by a 2.5×20 mm scoring balloon and a 2.5×15 mm cutting balloon. Although the cutting balloon ruptured at 14 atm, adequate plaque modification could not be achieved. Given the development of a limited dissection with preserved TIMI grade 3 flow and the absence of symptoms, the procedure was terminated, and rotational atherectomy was planned.

Second Session (April 8, 2026): The lesion was successfully crossed with the support of a microcatheter. Following predilation, rotational atherectomy was performed using a 1.75-mm burr. Subsequent high-pressure dilations with a 3.25-mm cutting balloon, a 3.0×12 mm NC balloon inflated up to 34 atm, and a 3.5×15 mm NC balloon inflated up to 26 atm failed to achieve adequate lumen expansion. The lesion was considered balloon-undilatable, and repeat intervention with either intravascular lithotripsy (IVL) or an OPN balloon was planned. Following the procedure, new-onset atrial fibrillation developed, and oral anticoagulation therapy was initiated.

Third Session (April 27, 2026): The previously rotablated resistant lesion was re-crossed with a guidewire. A 2.5×15 mm OPN balloon was inflated up to 40 atm, followed by additional high-pressure dilation with a 3.0×20 mm NC balloon. Despite these interventions, persistent balloon waist was observed, and adequate lumen expansion could not be achieved. No perforation, no-reflow phenomenon, or hemodynamic instability occurred during the procedure. Given the failure to achieve technical success despite sequential plaque modification techniques, further attempts at revascularization were abandoned, and optimal medical therapy was pursued. The patient was discharged without cardiac symptoms.

Conclusion: In severely calcified CTO lesions, technical success may not always be achieved despite the sequential use of advanced plaque modification techniques, including rotational atherectomy, cutting balloons, and ultra-high-pressure balloons. This case highlights that balloon-undilatable calcified CTO lesions represent one of the most challenging scenarios in interventional cardiology. Intravascular imaging-guided procedural planning and the timely use of emerging calcium-modification technologies, such as IVL, may represent potential strategies to improve procedural success in similar cases.