# Invasive Right Anomalous Coronary Arteries Assessment: Intravascular Ultrasound and Adenosine vs Dobutamine Fractional Flow Reserve

## TL;DR

This study compares methods to assess blood flow in a rare heart condition, finding that adenosine-based FFR and IVUS can help reduce the need for more complex testing.

## Contribution

The study introduces a potential alternative to complex dobutamine FFR testing for assessing right anomalous coronary arteries.

## Key findings

- FFRAdenosine reliably ruled in hemodynamically relevant R-AAOCA with 100% specificity and positive predictive value.
- IVUS-MLA effectively ruled out hemodynamically relevant R-AAOCA with 100% sensitivity and negative predictive value.
- One-quarter of patients with R-AAOCA had hemodynamically relevant disease.

## Abstract

In the right anomalous aortic origin of a coronary artery (R-AAOCA), invasive fractional flow reserve during dobutamine (FFRDobutamine) allows to assess dynamic interarterial/intramural compression that may lead to ischemia. However, FFRDobutamine requires expertise and is procedurally complex. Therefore, a simpler alternative is needed, but it remains uncertain whether routine intravascular ultrasound (IVUS) and standard FFR during adenosine (FFRAdenosine) can reliably determine hemodynamic relevance.

This study aimed to compare the diagnostic accuracy of FFRAdenosine and IVUS-based minimal lumen area (IVUS-MLA) against the reference standard of FFRDobutamine for identifying hemodynamically relevant R-AAOCA.

Consecutive patients of a single center were prospectively enrolled over 5 years (June 2020-June 2025) with R-AAOCA and interarterial/intramural course. All patients underwent FFRDobutamine, FFRAdenosine, and resting IVUS-MLA of the proximal anomalous segment. Hemodynamically relevant R-AAOCA was defined as FFRDobutamine ≤0.80. Diagnostic performance was assessed using receiver-operating characteristic analysis.

A total of 73 patients (mean age 51 ± 13 years; 34% female) were included. Seventeen patients (23%) had hemodynamically relevant R-AAOCA. FFRAdenosine ≤0.80 predicted FFRDobutamine ≤0.80 with 100% specificity and positive predictive value, 29% sensitivity and 82% negative predictive value (area under the curve: 0.81). IVUS-MLA ≤5.5 mm2 predicted hemodynamic relevance with 100% sensitivity and negative predictive value, 68% specificity, and 49% positive predictive value (area under the curve: 0.88).

In adults with newly diagnosed R-AAOCA and interarterial and intramural course, one-quarter were hemodynamically relevant. FFRAdenosine could reliably rule-in, while IVUS-MLA could effectively rule-out relevant R-AAOCA, potentially reducing the need for FFRDobutamine testing.