Management of Undeflatable Coronary Balloons During Percutaneous Coronary Intervention: A Case-Based Review and Practical Bailout Algorithm.

Background: Undeflatable coronary balloons during percutaneous coronary intervention (PCI) are rare but particularly hazardous because persistent intracoronary inflation can cause abrupt coronary occlusion, ischaemia, and haemodynamic collapse. We aimed to synthesise the published experience to define mechanistic patterns, identify recurring predisposing factors, and propose a practical bailout algorithm. Methods and Results: We performed a case-based review of PubMed, the Cochrane Library, and EBSCO from inception to February 2026. Eligible reports described balloons that could not be deflated while positioned in a coronary artery. A total of 15 coronary cases (2011-2025) met the inclusion criteria. Events occurred most often during post-dilatation or after stent deployment in complex anatomy, frequently involving severe calcification, aorto-ostial segments, chronic total occlusion-like lesions, and settings with limited guide engagement. Mechanistic patterns clustered into (i) intact-system non-deflation, where restoration of an exit pathway (system checks, sustained negative suction, and contrast dilution), followed by controlled decompression (wire puncture or mechanical- or energy-assisted disruption), was feasible; (ii) shaft-compromised events (fracture or detachment), where management shifted from decompression to mechanical retrieval, with surgery reserved for percutaneous failure. Conclusion: Undeflatable coronary balloons represent distinct failure modes with different viable rescue options. Outcomes appear to be driven by rapid restoration of perfusion and early recognition of shaft integrity. A structured escalation approach prioritising stabilisation, low-risk troubleshooting, controlled decompression, and decisive transition to retrieval, exclusion, or surgery when decompression is impossible could reduce secondary iatrogenic harm.