Right Ventricle-Pulmonary Artery Coupling and Major Morbidity and Operative Mortality After Cardiac Surgery.

BACKGROUND

The right ventricle-pulmonary artery (RV-PA) coupling ratio provides an assessment of RV function indexed to PA afterload. A low preoperative RV-PA ratio has been associated with increased mortality after transcatheter procedures. In patients undergoing cardiac surgery, we hypothesized that a lower preoperative RV-PA ratio is independently associated with a higher risk of major morbidity and operative mortality (MMOM).

METHODS

We conducted a retrospective cohort study of adult patients who underwent coronary artery bypass graft and/or valve surgery (aortic, mitral, and tricuspid). The RV-PA ratio was calculated using the ratio of tricuspid annular plane systolic excursion (TAPSE) to PA systolic pressure (PASP). The primary outcome was MMOM as defined by the Society of Thoracic Surgeons (STS). The Youden index was used to determine the optimal cutoff to classify into low versus high TAPSE/PASP ratio groups. Multivariable analysis was performed to test the association of TAPSE/PASP ratio with MMOM and other clinical outcomes with P- value <0.05 used for statistical significance.

RESULTS

One hundred and twenty-four (14.3%) of the 868 patients who met inclusion criteria had the primary outcome of MMOM. Patients in the low TAPSE/PASP group were more likely to have MMOM (90 (22.0%) vs 34 (7.4%); P < .001) as well as longer intensive care unit length of stay (ICU-LOS), hospital LOS (H-LOS), and mechanical ventilation time (MVT). By multivariable analysis, TAPSE/PASP ratio <0.52 mm/mm Hg was associated with a significant increase in the risk of MMOM (odds ratio [OR] 1.77, 95% confidence interval [CI], 1.10-2.83, P = .018). In the analyses of secondary outcomes, for every 0.1 mm/mm Hg increase in TAPSE/PASP ratio, there was a 4% reduction in ICU-LOS and MVT, and a 3% reduction in H-LOS.

CONCLUSIONS

TAPSE/PASP ratio <0.52 mm/mm Hg was associated with a significant increase in the risk of MMOM. Low preoperative TAPSE/PASP ratio was also associated with longer ICU-LOS, H-LOS, and MVT, even when adjusting for STS risk score for MMOM and cardiopulmonary bypass time.