Echocardiographic correlates of pressure-volume-derived indices: Advancing intraoperative assessment of right ventricular function.

OBJECTIVES

To evaluate the relationship between intraoperative 3-dimensional (3D) echocardiographic measures of right ventricular (RV) function and invasively derived RV-pulmonary arterial (RV-PA) coupling metrics obtained from single-beat end-systolic pressure-volume analysis, identify echocardiographic surrogates capable of discriminating impaired RV-PA coupling during cardiac surgery.

METHODS

In a prospective observational study of 78 adult patients undergoing cardiac surgery with transesophageal echocardiography and pulmonary artery catheter monitoring, RV volumes and functional indices were quantified using 3D TEE, whereas RV-PA coupling (Ees/Ea) was calculated using the V0 single-beat method. Patients were stratified by coupling status using an Ees/Ea cutoff of 0.8. Relationships between echocardiographic variables and coupling metrics were analyzed using Spearman correlation, receiver operating characteristic analysis, and multivariable logistic regression adjusted for Society of Thoracic Surgeons risk score and perfusion time.

RESULTS

Patients with impaired RV-PA coupling (28.2%) demonstrated significantly larger 3D end-systolic volume and reduced 3D ejection fraction (EF) and 4-dimensional-derived fractional area change (FAC) compared with those with preserved coupling. 3D EF showed the strongest correlation with coupling (ρ = 0.94, P < .001) and significant discriminative performance (area under the curve = 0.94; optimal cutoff <44.2%). Indexed end-systolic volume and 3D FAC also reliably identified impaired coupling, whereas TAPSE and TAPSE/PASP did not. Exploratory analyses showed that low Ees/Ea and reduced 3D FAC/right ventricular systolic pressure were associated with prolonged postoperative vasopressor/inotrope use.

CONCLUSIONS

Intraoperative 3D volumetric indices, particularly 3D EF and FAC, may closely reflect invasively measured RV-PA coupling and potentially identify patients with impaired coupling. These findings may support the use of 3D echocardiography as a practical surrogate for intraoperative RV-PA coupling assessment during cardiac surgery.