In-stent restenosis of left main chimney stent with successful percutaneous coronary intervention with drug-coating balloon: a case report and literature reviews.

Background: Coronary artery obstruction (CAO) is a critical complication in transcatheter aortic valve replacement (TAVR). Coronary artery obstruction arises from mechanical obstruction of coronary ostia by displaced native or bioprosthetic valve leaflets. Despite the growing adoption of chimney stenting, data on long-term outcomes are sparse. We introduced a patient who had undergone a very late in-stent restenosis (ISR) over the left main (LM) chimney stent and its successful management using a cutting balloon (CB) and drug-coating balloon (DCB). Case summary: A patient experienced angina symptoms 2 years after receiving TAVR with LM chimney stent placement. Coronary angiography revealed ISR of LM chimney stent in neosinus proportion. The patient was successfully treated by CB and DCB angioplasty. Discussion: The chimney stent technique, initially developed as a bailout technique, is increasingly used prophylactically in anatomically high-risk cases. Lacking large-scale studies on chimney stent ISR limits our understanding. Besides CABG or repeat stenting, CB plus DCB may offer a potential opinion to achieve long-term benefits in such cases. With rapid increasing of TAVR patient, further studies may be needed to guide the possible complication with chimney stent in CAO cases.