Transcatheter aortic valve-in-valve post-dilatation as an overlooked risk factor of delayed coronary obstruction: a case report.

Background The risk of coronary obstruction during transcatheter aortic valve-in-valve replacement (VIV-TAVR) in patients deemed at high risk for surgical re-intervention is still a concerning issue. Case summary A 78-year-old woman with a past medical history of hypertension, chronic kidney disease, and rheumatoid arthritis was referred for a symptomatic and severely stenotic surgical Mitroflow n.21 bio-prosthesis and was subsequently recommended for a VIV procedure. Multiple anatomical risk factors for coronary occlusion required a pre-emptive coronary chimney stenting protection. The implantation of an Evolut-R 23 mm valve resulted in a gradient of 21 mmHg thus, a post-dilatation with an 18 mm balloon was performed. Both electrocardiographic and haemodynamic parameters remained excellent, however, a hazardous leaflet dislodgment became evident. Regardless, a prophylactic chimney stenting was performed because of the operator's perceived high risk of late coronary occlusion. Discussion The implantation of transcatheter valves inside failed surgically implanted aortic bio-prosthesis is broadly recognized as a safe and less-invasive alternative to repeated high-risk surgery. Although procedural success is achieved in the great majority of patients, this therapy may be jeopardized by rare but serious complications such as impending or established acute coronary occlusion. Several specific anatomical and procedural risk factors have been identified and primary coronary prevention strategies are often mandatory when they arise. Valve-in-valve post-dilation has been overlooked in its role as an additional risk factor of late coronary obstruction. Therefore, chimney stenting, performed after balloon post-dilation to prevent delayed coronary obstruction, even if the acute coronary event does not occur intra-procedurally, is strongly advisable.