Evaluation of Ventricular dP/dt Before and After Open Heart Surgery Using Transesophageal Echocardiography

Non-geometric echocardiographic indices of ventricular function in patients with a Fontan circulation

BACKGROUND

Complex anatomy and limited windows complicate echocardiographic assessments of ventricular function in Fontan patients. For the Pediatric Heart Network Fontan Cross-Sectional Study, data were acquired from which mean ventricular pressure change during isovolumetric contraction (dP/dt(ic)), Tei index, and maximal systolic annular velocity (S') could be measured. The purpose of this study was to compare these nongeometric indices of ventricular function to cardiac magnetic resonance (CMR) measurements of ventricular ejection fraction (EF).

METHODS

Echocardiographic and CMR studies were performed prospectively using standardized protocols; measurements were completed by core laboratories. Data from both modalities were available from 137 patients.

RESULTS

A weak but statistically significant correlation was observed between mean dP/dt(ic) and CMR-derived EF (r = 0.20, P = .022). This correlation was strengthened when preload was taken into account (r = 0.30, P = .001). Statistically significant correlations did not exist between CMR-derived EF and the Tei index or S'.

CONCLUSIONS

Among Fontan patients, the correlation between CMR-derived EF and nongeometric echocardiographic indices of ventricular function is not strong. Of the indices evaluated, however, mean dP/dt(ic) appears to be the best.

Comparison Between the Mean dP/dt During Isovolumetric Contraction and Other Echocardiographic Indexes of Ventricular Systolic Function

Echocardiographic assessments of ventricular function derived from estimates of the mean dP/dt during isovolumetric contraction (mean dP/dt(ic)) were compared with those obtained from measurements of the shortening fraction and the stress-velocity index (SVI). Mean dP/dt(ic) correlated well with the shortening fraction, r = 0.74, P < 0.0001. Furthermore, 10 out of 11 patients with mean dP/dt(ic) below 800 had a shortening fraction < 0.28, whereas all patients with a mean dP/dt(ic) > 1000 mmHg/sec had a shortening fraction > 0.28. A good correlation also existed between mean dP/dt(ic) and the SVI, r = 0.73, P < 0.0001. Nine out of 11 patients with a mean dP/dt(ic) < 800 mmHg/sec had an SVI > 2 standard deviations below normal, whereas all patients with mean dP/dt(ic) > 1000 mmHg/sec had normal or increased SVI. The correlation between mean dP/dt(ic) and the SVI was strengthened when mean dP/dt(ic) was adjusted for heart rate and preload. Hence, assessments of ventricular function derived from measurements of mean dP/dt(ic) appear to agree well with those provided by the shortening fraction and SVI. Because the determination of mean dP/dt(ic) is not hampered by unusual anatomy or wall motion (conditions which compromise the validity of the shortening fraction and SVI), mean dP/dt(ic) may be a good index of ventricular function in cases where measurements of the shortening fraction and SVI would be unreliable.