Balloon Over-the-Wire Opposing Support (BOOST) Technique: The Sawah-Sabry Approach for Retrieval of a Stuck Retrograde Microcatheter in Chronic Total Occlusion PCI-A Case Report.

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) remains one of the most technically demanding areas in interventional cardiology, and although the retrograde approach has improved procedural success, rare complications such as retrograde microcatheter (MC) entrapment present a serious challenge with limited bailout options. We report the case of a 67-year-old male farmer with diabetes mellitus and hypertension who presented with refractory typical chest pain and a failed right coronary artery CTO PCI 3 months earlier. His J-CTO score was 4, with a prior failed attempt, blunt stump, and severe angulation. A retrograde Gaia 2nd wire successfully crossed the distal cap and entered the antegrade guiding catheter; however, the retrograde MC became entrapped at a heavily calcified bend, forming a complete LAD-RCA loop and resisting conventional retrieval maneuvers. A novel bailout strategy, the Balloon Over-the-wire Opposing Support (BOOST) Technique-Sawah-Sabry Approach-was applied using an antegrade 2.5 × 20 mm balloon advanced within the MC to generate forward counterforce, combined with minimal retrograde traction and GuideLiner support. The MC was gradually released and retrieved safely, allowing successful implantation of three drug-eluting stents with restoration of TIMI III flow.