# Updated 2022 ACC/AHA Guideline Improves Concordance Between TTE and CT in Monitoring Marfan Snydrome and Related Disorders, but Relevant Measurement Differences Remain Frequent

## TL;DR

The 2022 ACC/AHA guideline improves agreement between TTE and CT measurements in Marfan syndrome patients, but significant differences still remain.

## Contribution

First demonstration that the 2022 ACC/AHA guideline improves concordance between TTE and CT measurements in Marfan syndrome.

## Key findings

- The 2022 guideline reduced measurement differences outside clinical agreement limits for aortic sinus and ascending aorta.
- Mean differences in measurements were smaller with the 2022 guideline compared to the 2010 guideline.
- Despite improvements, frequent differences >2 mm persist, potentially affecting surgical decisions.

## Abstract

Patients diagnosed with Marfan syndrome or a related syndrome require frequent aorta monitoring using imaging techniques like transthoracic echocardiography (TTE) and computed tomography (CT). Accurate aortic measurement is crucial, as even slight enlargement (>2 mm) often necessitates surgical intervention. The 2022 ACC/AHA guideline for Aortic Disease Diagnosis and Management includes updated imaging recommendations. We aimed to compare these with the 2010 guideline.

This retrospective study involved 137 patients with Marfan syndrome or a related disorder, undergoing TTE and ECG-triggered CT. Aortic diameter measurements were taken based on the old 2010 guideline (TTE: inner edge to inner edge, CT: external diameter) and the new 2022 guideline (TTE: leading edge to leading edge, CT: internal diameter). Bland-Altman plots compared measurement differences.

Using the 2022 guideline significantly reduced differences outside the clinical agreement limit from 49% to 26% for the aortic sinus and from 41% to 29% for the ascending aorta. Mean differences were –0.30 mm for the aortic sinus and +1.12 mm for the ascending aorta using the 2022 guideline, compared to –2.66 mm and +1.21 mm using the 2010 guideline.

This study demonstrates for the first time that the 2022 ACC/AHA guideline improves concordance between ECG-triggered CT and TTE measurements in Marfan syndrome patients, crucial for preventing life-threatening aortic complications. However, the frequency of differences >2 mm remains high.

Accurate aortic diameter measurement is vital for patients at risk of fatal aortic complications. While the 2022 guideline enhances concordance between imaging modalities, frequent differences >2 mm persist, potentially impacting decisions on aortic repair. The risk of repeat radiation exposure from ECG-triggered CT, considered the ‘gold standard’, continues to be justified.