Descending aortic strain quantification by intra-operative transesophageal echocardiography: Multimodality validation via cardiovascular magnetic resonance.

BACKGROUND: Whereas cardiac magnetic resonance (CMR) imaging provides high temporal resolution imaging of aortic distensibility (strain), transesophageal echocardiography (TEE) is widely used for intra-operative aortic imaging and provides a clinical alternative for aortic assessment. We tested intra-operative global circumferential aortic strain (GCS) measured on TEE in relation to the reference of CMR-derived strain among patients undergoing surgical graft repair of ascending aortic aneurysms.
METHODS: CMR (3T) was prospectively performed in patients scheduled for aortic repair. TEE was performed intra-operatively; images were co-localized with MRI. GCS on CMR and TEE was quantified independently, blinded to results of the other modality.
RESULTS: 25 patients (54 ± 10 year-old, 88% male) were studied, inclusive of 13 genetically mediated and 12 degenerative aneurysms: CMR and TEE were performed within 12 ± 9 days. Pulse pressure (PP)-adjusted descending aortic TEE-derived GCS strongly correlated with cine-CMR-derived GCS (r = .75, P = .002) though absolute GCS and PP-adjusted values were slightly lower (5.40 ± 1.11 vs 6.49 ± 1.43% and 11.55 ± 3.04 vs 13.99 ± 4.53%, respectively). Similarly, TEE yielded slightly lower end-diastolic area (EDA [5.1 ± 1.7 cm2 vs 5.8 ± 1.3 cm2 , P = .004]) and end-systolic area (ESA [6.1 ± 1.9 cm2 vs 6.5 ± 1.7 cm2 , P = .10]), with significant correlations between the two modalities (r = .73, .76, P < .05 for all).
CONCLUSIONS: This exploratory study supports feasibility of TEE for assessing aortic GCS in a surgical at-risk population, as well as magnitude of agreement between intra-operative TEE and preoperative CMR. We found that there is a significant correlation between GCS and EDA and ESA aortic areas, but that TEE-derived parameters underestimated CMR values by a small but significant amount.