Intravascular Ultrasound Assessment of Coronary Arteries at High Risk for Obstruction Following TAVR: The ICARO Study

In patients at high risk for coronary artery obstruction (CAO), intravascular ultrasound (IVUS) assessment of coronary ostia after transcatheter aortic valve replacement (TAVR) may detect signs of impending CAO.

The aim of this study was to evaluate the feasibility and safety of IVUS assessment in this context and its capacity to indicate chimney stenting.

This was a prospective, multicenter, observational study. Both native and valve-in-valve procedures presenting ≥2 radiological predefined high-risk characteristics for CAO were included. The primary endpoint was the feasibility and safety of IVUS assessment after TAVR. Secondary endpoints included the rate of chimney stenting deferral after IVUS, the description of IVUS-based features leading to chimney stenting, and major adverse cardiovascular and cerebrovascular events.

Among 32 enrolled patients (40 vessels), 2 experienced sudden CAO requiring urgent chimney stenting. IVUS was feasible and safe in all remaining cases (38 vessels). On the basis of IVUS, chimney was deferred in 24 of 38 cases (63%; 95% CI: 50%-78.9%). IVUS features guiding the decision to stent were the minimal cross-sectional area at the ostial-paraostial space and the distance of the displaced leaflet from the coronary ostium. After a median follow-up period of 366 days (Q1-Q3: 119-780 days), major adverse cardiovascular and cerebrovascular events did not differ between patients receiving stents and those deferred (1 of 16 [6.2%] vs 1 of 16 [6.2%]; 95% CI: 0%-15.6%; P = 0.958).

This first multicenter investigation on the IVUS use in the setting of CAO during TAVR suggests that the technique is both feasible and safe. Implementing IVUS in decision making on the need for chimney stenting may provide additional information, helping operators limit stent implantation only when really needed.