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

Abstract

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. 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. 25 patients (54±10year-old, 88% male) were studied, inclusive of 13 genetically mediated and 12 degenerative aneurysms: CMR and TEE were performed within 12±9days. 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±1.7cm2 vs 5.8±1.3cm2 , P=.004]) and end-systolic area (ESA [6.1±1.9cm2 vs 6.5±1.7cm2 , P=.10]), with significant correlations between the two modalities (r=.73, .76, P<.05 for all). 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.