Transesophageal two-dimensional echocardiographic analysis of right ventricular systolic performance indices during coronary artery bypass grafting

Sixteen patients (aged 59 ± 14 years) undergoing coronary artery bypass surgery were evaluated to delineate the intra-operative course of transesophageal echocardiographic right ventricular (RV) systolic performance indices. Pre-induction data included thermodilution RV ejection fraction (RVEF TD), 0.43 ± 0.13, RV end-diastolic volume index (EDVI), 110 ± 33 mL/m 2, cardiac index (CI), 3.4 ± 1.0 L/min/m 2, RV enddiastolic pressure (EDP), 7.1 ± 4.2 mmHg, and mean pulmonary artery pressure ( PAP ), 21 ± 6 mmHg. Eleven patients had significant right coronary artery (RCA) disease (>70% occlusion). Five patients arrived with an ongoing nitroglycerin infusion (1 to 3 μg/kg/min), which was maintained intraoperatively. Echocardiographic measurements included longitudinal-axis (LA) and short-axis (SA) planimetered area excursion fractions (2D LA and 2D SA, respectively) and LA maximal major and minor axis shortening fractions (max major LA and max minor LA, respectively). Hemodynamic measurements included RVEF TD, EDVI, CI, EDP, and PAP . Measurements were determined following induction/ endotracheal intubation, following sternotomy/pericardiotomy, and after cardiopulmonary bypass (CPB) with the chest open. All patients were maintained on vasodilator therapy post-CPB (nitroglycerin, 1 to 3 μg/kg/min [N = 16] and nitroprusside, 0.5 to 4.5 pg/kg/min [N = 4]) post-CPB. Two patients received inotropic support (epinephrine, 0.2 to 0.3 μg/ kg/min). CPB was associated with significant decreases in max major axis LA and 2D LA ( P < 0.05) as compared to measurements determined prior to CPB. Maximum major axis LA values pre-CPB were 0.35 ± 0.06 and 0.33 ± 0.08 versus post-CPB values of 0.24 ± 0.08. 2D LA values were 0.50 ± 0.16 and 0.47 ± 0.10 versus post-CPB values of 0.37 ± 0.11. 2D SA was maintained (values 0.43 ± 0.17 and 0.44 ± 0.18 versus post-CPB 0.52 ± 0.18). The pre-CPB maximum major axis LA/ maximum minor axis LA relationship was significant (γ = 0.71). There was no correlation between these variables post-CPB. Maximum major axisLA changes were unrelated to CPB duration, aortic cross-clamp time, cardioplegia dose, antecedent RV function, and the presence/ absence of RCA disease. Significant changes were also unrelated to changes in heart rate. There was no significant change in EDVI, EDP, and PAP measurements. These findings may indicate regional inhomogeneity of RV function or a spectrum of differing sensitivities to changes in RV performance of the respective meas