Accuracy of a new method for semi-quantitative assessment of right ventricular ejection fraction by cardiovascular magnetic resonance: Right ventricular fractional diameter changes

Tricuspid annular plane systolic excursion is dependent on right ventricular volume in addition to function

BACKGROUND

Tricuspid annular plane systolic excursion (TAPSE) is an effective parameter for assessing right ventricular (RV) function in echocardiographic studies. The preload dependency of TASPE has not been explored.

METHODS

We retrospectively reviewed 380 cardiac magnetic resonance (CMR) exams. RV ejection fraction (EF) and end-diastolic volume (EDV) were measured from short-axis cine images. TAPSE was measured as the difference of the perpendicular distance of the tricuspid annulus to the RV apex during diastole and systole. RV dysfunction was defined as RVEF <47%. The relationship of TAPSE, RVEF, and indexed RVEDV (RVEDVi) were evaluated. The TAPSE cut-off values derived from CMR were tested in a validation group (n = 46) with an echocardiographic exam performed within 1 month of the CMR.

RESULTS

TAPSE had a good linear correlation with RVEF (r = .69, P < .001). In normal RVEF patients, TAPSE had a positive correlation with RVEDVi (r = .208, P = .014). Receiver operating characteristic analysis revealed a higher TAPSE cut-off value of 2.4 cm in the top normal to mildly dilated RV volume group for identifying RV dysfunction with lower predictive accuracy (sensitivity 80%, specificity 67%, area under the curve = 0.78, P < .001) as compared with 2.0 cm for the normal RV size or moderate to severely dilated RV groups. The higher TAPSE cutoff showed improved sensitivity (73% vs 43%) and Youden index (0.55 vs 0.43) in our validation cohort.

CONCLUSIONS

Tricuspid annular plane systolic excursion not only correlates with RVEF, but also is dependent on RV volume. The cut-off value and predictive accuracy of TAPSE for detecting RV dysfunction vary with different RV volumes.

Validation of cardiac magnetic resonance tissue tracking in the rapid assessment of RV function: a comparative study to echocardiography

AIM

To investigate the accuracy of cardiac magnetic resonance (CMR) tissue tracking (CMR-TT) and speckle tracking echocardiography (STE) against CMR determined right ventricular (RV) ejection fraction (RVEF) and to identify an optimal cut-off value for STE and CMR-TT to determine RVEF <45% and compare this to other conventional methods for estimating RVEF in dilated cardiomyopathy (DCM) patients.

MATERIALS AND METHODS

Twenty-nine DCM patients were recruited prospectively. CMR and echocardiography were performed within 48 hours and four-chamber views were used for strain analysis. Contoured CMR short axis images provided RVEF. Intraclass correlation coefficient (ICC), bias, levels of agreement, and receiver operating characteristic (ROC) curve analyses were performed.

RESULTS

CMR-TT RV free-wall longitudinal strain (FLS) and STE RV global longitudinal strain (GLS) showed the best correlation with RVEF (r=-0.68, r=-0.82, p<0.001 respectively). There was moderate correlation between echocardiography RV GLS and CMR RV FLS (r=0.64, p<0.001). CMR-TT FLS showed excellent intra-observer and interobserver reliability (ICC=0.980; ICC=0.968 respectively). STE GLS correlated better with RVEF than with peak systolic annular velocity (S'; r=0.45), tricuspid annular plane systolic excursion (TAPSE; r=0.56), and fractional area change (FAC; r=0.78). CMR-TT RV FLS had better correlation with RVEF than CMR TAPSE (r=0.69 versus 0.40). ROC analysis demonstrated the optimal cut-off value for CMR-TT RV FLS and STE GLS in detection of RVEF <45% was ≥-24.4% (area under the curve=0.87, 100% sensitivity, 66.7% specificity) and ≥-20.9% (area under the curve=0.88, 100% sensitivity, 60% specificity) respectively.

CONCLUSION

CMR-TT FLS and STE GLS showed potential to provide rapid assessment of RV function and had superior correlation with RVEF compared to conventional parameters.