Marked changes in right ventricular contractile pattern after cardiothoracic surgery: Implications for post-surgical assessment of right ventricular function
Longitudinal shortening accounts for the majority of right ventricular (RV) contraction in normal hearts. This finding accounts for the correlation between longitudinal measures of RV contraction such as tricuspid annular plane systolic excursion (TAPSE) and global RV function. We hypothesized that, after cardiac surgery, there are major differences in the RV contractile pattern relative to normal hearts.
We retrospectively studied 2 cardiac surgical cohorts who underwent cardiopulmonary bypass (CPB) with pericardial incision (OHT, n = 54; CABG, n = 23) and compared them with a lung transplant cohort (n = 25). We compared TAPSE, RV fractional area change (RVFAC) and relative change in RV transverse and longitudinal area in the surgical cohorts with data from normal subjects (n = 84).
RVFAC was lower in the surgical groups compared with the normal group, yet still in the normal range (37% to 42% vs 47%; p < 0.01). TAPSE was markedly lower in OHT (15 � 3 mm) and CABG (16 � 4 mm) than in normal (26 � 4 mm) subjects (p < 0.01), as was the relative contribution of longitudinal area change (OHT group 51 � 11%, CABG group 54 � 13%, normal group 78 � 14%; p < 0.01). The ratio of TAPSE to RVFAC was markedly lower in CABG (40 � 14 mm/%FAC) and OHT (37 � 10 mm/%FAC) patients than in normal (56 � 14 mm/%FAC) subjects (p < 0.001). However, OLT patients had a higher TAPSE (18 � 3 mm) than OHT (15 � 3 mm) and CABG (16 � 4 mm) patients (p < 0.01) and a higher relative contribution of longitudinal area change: OLT 67 � 10%; OHT 51 � 11%; and CABG 54 � 13% (p < 0.01).
After cardiac surgery, the RV contractile pattern changes, with a relative loss of longitudinal shortening and gain in transverse shortening despite normal global RV function. These findings have major implications for quantitative assessment of RV function after cardiac surgery, suggesting that global measures of RV function assessment may be preferred in this setting and that lower normative ranges should be used when measurement of RV function is performed with longitudinal methods.