Abstract BACKGROUND Intraoperative transesophageal echocardiography (iTEE) has an important role in mitral valve (MV) surgery, but may have dissimilar parameters from postoperative echocardiography (post-TTE). We aimed to evaluate iTTE Doppler flow profile and compare with the post-TTE in MV surgery. METHODS We conducted a prospective, observational study of 126 patients that underwent MVsurgery during 2 years. iTEE evaluated mean pressure gradient (MPG) and functional area. Patients were re-evaluated with TTE, 72 hours after surgery (post-TTE). iTEE and post-TTE Doppler values were compared and correlated. Preoperative TTE (pre-TTE) parameters were also determined. RESULTS The mean age was 59 ± 18 years and 55% were female. The prevalence of severe mitral regurgitation (MR) was 77.6% and severe mitral stenosis (MS) 23.7%. Globally, mitral valve repair was performed in 71%cases (83% for MR and 15% for MS) and replacement in 29% (64% for MR and 46% for MS). Left ventricular ejection fraction (LVEF), systolic pulmonary artery pressure (sPAP), tricuspid annular plane systolic excursion (TAPSE) assessed in pre-TTE and post-TTE, as also MPG and functional area in post-TTE and iTEE are depicted on table 1. There was a higher numerical difference in iTEE vs post-TTE MPG values in mechanical valves (n = 5) (3.5 ± 1.2 to 5.2 ± 1.6, difference of 1.65 ± 2.4mmHg), than in biological valves (n = 17) (3.1 ± 1.1 to 3.9 ± 1.5, difference of 0.8 ± 1.7mmHg). Globally, iTEE-derived MPG and functional area were strongly correlated with their post-TTE values (r2 0.7 and 0.8,p < 0.001). CONCLUSIONS iTEE Doppler parameters were strongly correlated with postoperative TTE parameters, with minimal differences: postoperative MPG were +0.4 ± 1mmHg higher in MV repair and +1.0 ± 1.8mmHg in MV replacement. There was a global improvement in sPAP. Our study demonstrates the usefulness of iTEE and its importance in stablishing possible reference values for postoperative follow-up. MR MS pre-TTE post-TTE P value pre-TTE post-TTE P value LVEF (± SD,%) 57 ± 9 52 ± 10 <0.001 58 ± 6 56 ± 7 <0.001 sPAP (± SD,mmHg) 42 ± 17 33 ± 9 <0.001 47 ± 18 35 ± 6 <0.001 TAPSE (± SD,mm) 18 ± 2 14 ± 3 <0.001 18 ± 2 14 ± 3 <0.001 MV repair MV replacement iTEE post-TTE P value iTEE post-TTE P value MPG (± SD, mmHg) 2.8 ± 1.5 3.1 ± 1.4 0.084 3.2 ± 1.4 4.2 ± 1.6 0.016 Functional Area (± SD, cm2) 2.8 ± 0.6 2.8 ± 0.7 0.665 2.8 ± 0.6 2.7 ± 0.8 0.653