Future Directions
Percutaneous cardiac procedure volumes have exploded in recent years as
technical capabilities grow and more devices come to market. The primary
goals of any procedure should be safety and efficacy. Efficiency and low
cost must also be the aims as healthcare expenditures continue to grow
ever higher. As procedures have expanded, so have correlating imaging
techniques to enhance planning and meet those essential objectives. In
LAAO procedures in particular, the critical information imaging
modalities provide is the relevant anatomy of the LAA and how that
impacts device selection. Given the excellent structural resolution of
CMR and the data demonstrated by Dallan et al., CMR should be a safe and
effective option in the future. We would suspect that with more
experience, sizing accuracy would approach that of CT, improving the
average number of devices needed per case and thereby lowering
associated costs.
The cost of CMR may come down over time, and availability should
improve. CMR certainly has the advantage of availability for patients
with renal disease unable to receive significant contrast loads and can
be obtained without general anesthesia. It may be of particular use when
a patient with renal disease desires same-day discharge or has an
aversion to TEE. The authors highlight CMR’s added information over CT,
such as myocardial fibrosis and structural remodeling. It may be that
CMR has enhanced utility in combined procedures, for instance, where an
LAAO is performed with an ablation [9].
Beyond strictly procedural planning, CMR may have a use in the overall
assessment of the LAA. There have been efforts to define better stroke
risk based on imaging of the LAA [10], and CMR would seem to be an
unexplored modality in this regard. CMR may also be helpful in post-LAAO
follow-up, explicitly looking for device leaks, device thrombus, or
evidence of endothelialization [11].
For the immediate future, CT is likely to remain the most utilized
modality for LAAO planning. However, with more investigation, CMR should
become a viable alternative and another tool for LAAO procedural
planning.
References
1. Reddy, V.Y., et al., 5-Year Outcomes After Left Atrial
Appendage Closure. Journal of the American College of Cardiology, 2017.70 (24): p. 2964-2975.
2. Khalil, F., et al., Utilization and procedural adverse outcomes
associated with Watchman device implantation. Europace, 2021.23 (2): p. 247-253.
3. Beigel, R., et al., The Left Atrial Appendage: Anatomy,
Function, and Noninvasive Evaluation. JACC: Cardiovascular Imaging,
2014. 7 (12): p. 1251-1265.
4. Möbius-Winkler, S., et al., Percutaneous left atrial appendage
closure: Technical aspects and prevention of periprocedural
complications with the watchman device. World J Cardiol, 2015.7 (2): p. 65-75.
5. Rajwani, A., et al., CT sizing for left atrial appendage
closure is associated with favourable outcomes for procedural safety.European Heart Journal - Cardiovascular Imaging, 2016. 18 (12):
p. 1361-1368.
6. Korsholm, K., et al., Expert Recommendations on Cardiac
Computed Tomography for Planning Transcatheter Left Atrial Appendage
Occlusion. JACC: Cardiovascular Interventions, 2020. 13 (3): p.
277-292.
7. Nadeem, F., et al., A New WATCHMAN Sizing Algorithm Utilizing
Cardiac CTA. Cardiovascular Revascularization Medicine, 2021.33 : p. 13-19.
8. Dallan, L.A.P., et al., Novel Cardiac Magnetic Resonance
Imaging-Based Sizing for Left Atrial Appendage Closure. Journal of
Cardiovascular Electrophysiology, 2022.
9. Kuchynka, P., et al., The Role of Magnetic Resonance Imaging
and Cardiac Computed Tomography in the Assessment of Left Atrial
Anatomy, Size, and Function. Biomed Res Int, 2015. 2015 : p.
247865.
10. Yaghi, S., et al., Left Atrial Appendage Morphology Improves
Prediction of Stagnant Flow and Stroke Risk in Atrial Fibrillation.Circ Arrhythm Electrophysiol, 2020. 13 (2): p. e008074.
11. Hong, S.N., et al., Cardiac Magnetic Resonance Imaging and the
WATCHMAN Device. Journal of the American College of Cardiology, 2010.55 (24): p. 2785-2785.