The use of IVUS to assess the coronary ostia at high risk for coronary artery obstruction (CAO) after TAVR is feasible, safe and potentially lifesaving, according to results from the ICARO study published May 12 in JACC: Cardiovascular Interventions.

Mattia Lunardi, MD, PhD, et al., conducted the first prospective, multicenter, observational study to evaluate IVUS in this context, as well as its capacity to indicate the need for chimney stenting, in patients diagnosed with symptomatic severe native aortic stenosis or clinically relevant degeneration of previously implanted surgical aortic valve bioprosthesis, with an indication to undergo TAVR. The study included both native and valve-in valve procedures presenting with two or more radiologically predefined high-risk CAO characteristics.

Of the 32 study patients (40 vessels), two experienced sudden CAO requiring emergency chimney stenting. Clinical follow-up occurred at one, 12 and 24 months to assess vital status, cause and date of death, occurrence and timing of any myocardial infarction, stroke, details and results of any subsequent repeat coronary angiography and any coronary intervention.

Results showed that IVUS was feasible and safe in the remaining cases (38 vessels). Based on IVUS findings, chimney stenting was deferred in 24 of 38 cases (63%). The minimal cross-sectional area at the ostial-paraostial space and the distance of the displaced leaflet from the coronary ostium on IVUS guided the decision to stent.

Additionally, at one year, 6.2% of the patients who did and did not have deferred chimney stenting experienced a major adverse cardiovascular and cerebrovascular events. Noting the comparable clinical outcomes between these groups, the authors write this suggests "the safety of IVUS assessment in avoiding chimney."

In an accompanying editorial comment, Jaffar M. Khan, MD, writes "Chimney stents come with inherent risks, including risk for long-term dual antiplatelet therapy, risk for stent thrombosis and difficulty reaccessing the coronary arteries. Safely reducing the need for these stents with integrated [computed tomography] modeling of coronary obstruction, more widespread use of BASILICA, and, finally, using IVUS should be encouraged, and the investigators should be congratulated for paving the way for wider use of this technique."