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Quantitative assessment of ventricular function in children with single ventricles using the Doppler myocardial
R V Williams1, S Ritter, L Y Tani
1Department of Pediatrics, Primary Children's Medical Center and the University of Utah, Salt Lake City 84113, USA. pcrwilli@ihc.com
Insights
The Doppler myocardial performance index (MPI) is higher in children with single ventricles, indicating reduced function. MPI improved after bidirectional cavopulmonary anastamosis (BCPA) in infants, suggesting better ventricular function post-surgery.
Area of Science:
- Pediatric Cardiology
- Echocardiography
- Congenital Heart Disease
Background:
- Assessing ventricular function in single ventricle physiology is challenging due to complex geometry.
- The Doppler myocardial performance index (MPI) offers a potential method for evaluating ventricular function regardless of geometry.
Purpose of the Study:
- To compare MPI in normal children versus those with single ventricles.
- To assess MPI changes before and after bidirectional cavopulmonary anastamosis (BCPA) in single ventricle patients.
Main Methods:
- Retrospective review of echocardiograms from patients undergoing BCPA (1994-1998).
- Calculation of MPI using Doppler inflow and outflow tracings.
- Comparison of MPI between single ventricle patients and age-matched controls.
Main Results:
- Patients with single ventricles had significantly higher MPI than controls (0.67 vs 0.32, p < 0.001).
- Overall MPI showed no significant change before and after BCPA (0.70 vs 0.66).
- Infants (<1 year) undergoing BCPA demonstrated a significant MPI decrease post-surgery (0.71 vs 0.61, p = 0.01), indicating improved function.
Conclusions:
- Elevated MPI in single ventricle patients suggests impaired ventricular function.
- MPI may serve as an objective tool for assessing ventricular function in single ventricle patients.
- BCPA in infants may improve ventricular function, as indicated by MPI changes.
Abstract:
Assessment of ventricular function in patients with functionally single ventricles and unusual ventricular geometry is difficult. The Doppler myocardial performance index (MPI) may provide a method of assessing function in these patients. The purposes of this study were to compare the MPI in normal children and in children with a functionally single ventricle, and to compare the MPI in patients with single ventricles before and after bidirectional cavopulmonary anastamosis (BCPA). Echocardiograms of all patients who underwent BCPA between January 1994 and December 1998 were reviewed before and after surgical palliation. Age-matched normal subjects (n = 30) served as controls. The MPI was calculated from Doppler tracings of ventricular inflow and outflow. Of the 60 patients with single ventricles who underwent BCPA, 41 had adequate preoperative Doppler studies to allow calculation of the MPI, and 21 of 41 had adequate studies before and after BCPA. The MPI was higher in patients with single ventricles than in normal controls (0.67 +/- 0.14 vs 0.32 +/- 0.10, p < 0.001). There was no significant difference in the MPI in patients with single ventricles before and after surgery (0.70 +/- 0.16 vs 0.66 +/- 0.15). However, patients who had a BCPA at < 1 year of age had a significant decrease in the MPI after surgery (0.71 +/- 0.10 vs 0.61 +/- 0.11, p = 0.01). Compared with controls, the MPI was significantly higher in patients with single ventricles suggesting an altered hemodynamic state consistent with decreased ventricular function. The MPI decreased in patients who underwent BCPA at < 1 year of age, suggesting an improvement in ventricular function. The MPI provides an objective method of assessing and following ventricular function in patients with single ventricles that is independent of ventricular geometry.