Contrasting effect of different cardiothoracic operations on echocardiographic right ventricular long axis velocities, and implications for interpretation of post-operative values

Background Patients undergoing coronary artery bypass grafting (CABG) experience a reduction in right ventricular long axis velocities post surgery. Objectives We tested whether the phenomenon of right ventricular (RV) long axis velocity decline depends on the chest being opened fully by mid-line sternotomy, pericardial incision, or on the type of operation performed. Method By intraoperative transoesophageal echocardiography (TEE) we recorded serial right ventricular (RV) systolic pulse-wave tissue Doppler velocities during 6 types of elective procedure: 53 CABG surgery, 15 robotic-assisted minimally-invasive CABG (RCABG), 28 aortic valve replacement (AVR), 8 minimally-invasive aortic valve replacement (mini-AVR), 5 mediastinal mass excision, and 1 left atrial myxoma excision. Pre and post operative transthoracic echocardiography (TTE) were also conducted. Results Surgery without substantial opening of the pericardium did not significantly reduce RV systolic velocities (RCABG 13±1.8 versus 12.4±2.7cm/s post; mini-AVR 11.9±2.3 versus 11.1±2.3cm/s; mediastinal mass excision 13.9±3.1 versus 13.8±4cm/s). In contrast, within 5min of pericardial incision those whose surgery involved full opening of the pericardium had large reductions in RV velocities: 54±11% decline with CABG (11.3±1.9 to 5.1±1.6cm/s, p<0.0001), 54±5% with AVR (12.6±1.4 to 5.7±0.6cm/s, p<0.001) and 49% with left atrial myxoma excision (11.3 to 15.8cm/s). This persisted immediately after pericardial opening to the end of surgery (61±11%, p<0.0001; 58±7%, p<0.0001; 59% respectively). Conclusions It is full opening of the pericardium, and not cardiac surgery in general, which causes RV long axis decline following cardiac surgery. The impact is immediate (within 5min) and persistent.