Assessment of the left ventricular outflow tract during cardiac anaesthesia with biplane transoesophageal echocardiography: An observational study.

BACKGROUND: Assessment of left ventricular outflow tract (LVOT) area is a key component of quantification of aortic stenosis and stroke volume. Current international guidelines recommend measurement of the LVOT diameter with two-dimensional (2D) echocardiography and assume a circle. This may lead to erroneous measures of aortic valve area and adversely affect peri-operative decision making. Multiplane orthogonal (biplane) and three-dimensional (3D) echocardiography imaging may allow more accurate calculation of LVOT, aortic valve area and stroke volume. OBJECTIVE: To evaluate the shape and area of the LVOT with conventional 2D diameter, short axis cross-sectional planimetry with biplane imaging and 3D multiplane reconstruction in patients undergoing cardiac surgery with transoesophageal echocardiography (TOE). DESIGN: A retrospective observational study. SETTING: A single centre university hospital. PATIENTS: 119 patients undergoing cardiac surgery with TOE. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Measurements of the shape and area of the LVOT with standard 2D TOE, short axis biplane imaging and 3D TOE. RESULTS: The LVOT shape is elliptical in 70% of patients. The (mean ±â€ŠSD, [range]) LVOT cross-sectional area with 2D TOE was 4.29 cm2 ±â€Š0.98, [2.46 to 6.70], with biplane was 4.68 cm2 ±â€Š1.03, [2.92 to 7.30] and with 3D was 4.59 cm2 ±â€Š0.99, [2.78 to 7.10]. There was a statistically significant difference (P < 0.001) in the three pairwise comparisons. 2D LVOT area had large bias (7 to 9%) and wider limits of agreement (LOA) with both biplane and 3D LVOT area (-17 to 36%). Biplane and 3D LVOT areas had small bias (1.8%) with relatively narrow LOA (-8 to 11%). CONCLUSIONS: 2D diameter measures of the LVOT assuming a circle underestimate LVOT area, underestimate aortic valve area and increase the apparent severity of aortic stenosis. This may lead to inappropriate aortic valve intervention. In a busy operating room environment, we suggest that for the calculation of stroke volume and aortic valve area, LVOT area is measured with biplane imaging. TRIAL REGISTRATION: Observational study with no interventions so trial not registered.

The effect of pericardial incision on right ventricular systolic function: a prospective observational study.

BACKGROUND: Echocardiographic longitudinal markers of right ventricular (RV) systolic function are commonly depressed after coronary artery bypass graft surgery (CABG) despite an uncomplicated course and good clinical recovery. The exact timing and cause of these changes is unknown. The aim of this observational study was to monitor echocardiographic markers of RV systolic function intraoperatively during CABG. We used angle-independent speckle tracking to measure the primary endpoints of tricuspid annular plane systolic excursion (TAPSE) and tricuspid annular systolic velocity (S') before and after pericardiotomy. METHODS: Twenty-four patients undergoing elective on-pump CABG were enrolled in the study. Speckle tracking-derived TAPSE, S', free wall systolic strain, RV outflow tract strain, colour tissue Doppler-derived isovolumic acceleration (IVA) and two-dimensional RV dimensions and fractional area change (FAC) were measured at three intraoperative time points: 1) after sternotomy immediately prior to pericardiotomy; 2) after pericardiotomy and placement of pericardial retraction sutures; and 3) following cardiopulmonary bypass after chest closure. RESULTS: Adequate image quality to perform speckle tracking measurements was obtained in twenty-one patients. We found that there were no significant changes to echocardiographic parameters of RV systolic function between pre- and post-pericardiotomy. The mean (SD) of the primary endpoints were: TAPSE [28.1 (5.1) mm vs 27.7 (7.4) mm, respectively; mean difference, -0.4 mm; 97.5% confidence interval (CI), -4.0 to 3.1; P = 0.76] and S' [10.4 (2.1) cm·sec-1 vs 10.8 (1.9) cm·sec-1, respectively; mean difference, 0.4 cm·sec-1; 97.5% CI, -0.9 to 1.7; P = 0.48]. Significant reductions in the parameters of RV systolic function were found only after cardiopulmonary bypass and chest closure. CONCLUSION: Pericardial opening and suspension had no significant effect on the indices of RV systolic function derived from speckle tracking or colour tissue Doppler.