Right ventricular ejection fraction derived from intraoperative three-dimensional transesophageal echocardiography versus cardiac magnetic resonance imaging.

Abstract

Right ventricle (RV) assessment is critical during cardiac surgery. Traditional assessment consists of visual estimation and measurement of validated parameters. Cardiac magnetic resonance imaging (cMRI) is the gold standard for RV analysis, and transthoracic three-dimensional (3D) echocardiography is validated against this. We aimed to show that intraoperative 3D transesophageal echocardiography (TEE) RV assessment is feasible and can produce results that correlate with cMRI. We recruited cardiac surgery patients who underwent cMRI within the preceding twelve preoperative months. An anesthetic protocol was followed pre-sternotomy and a 3D RV data set was acquired. We used TOMTEC 4D RV-Function to derive RV end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF). We compared these data with the corresponding MRI values. Twenty-five patients were included. Transesophageal echocardiography EDV and ESV differed from MRI measurements with a mean bias of -53mL (95% confidence interval [CI], -80 to 26) and -21mL (95% CI, -34 to -9). Transesophageal echocardiography EF did not differ significantly, with a mean bias of -4% (95% CI, -8 to 1). Results were unchanged after excluding MRIs older than 180days. Correlation coefficients for EDV, ESV, and EF were r = 0.85, 0.91, and 0.80, respectively. Interclass correlation coefficients for EDV, ESV, and EF were 0.86, 0.89, and 0.96, respectively. Intraoperative TEE RV, EDV, and ESV are underestimated relative to cMRI because of analysis, anesthetic, and ventilation factors. The EF showed a low mean difference, and all values showed strong correlation with MRI. Reproducibility and feasibility were excellent and increased use in clinical practice should be considered.