Relation of Brain Natriuretic Peptide to Myocardial Performance Index in Adults With Congenital Heart Disease

Myocardial performance index (MPI) is an echocardiographic Doppler-derived measure of ventricular function previously validated in patients with congenital heart disease. It may be preferred over conventional noninvasive measures of ventricular function in patients with complex anatomy because it is dependent on neither geometric shape nor heart rate. Brain natriuretic peptide (BNP) is a predictor of systolic and diastolic dysfunction in anatomically correct hearts. The correlation of BNP to MPI in patients with congenital heart disease was determined. Fifty-four adults with congenital heart disease were evaluated. BNP was measured using standardized assays. Doppler echocardiography was performed within 6 months of BNP assay. There were no changes in clinical status during this interval. An experienced observer was blinded and evaluated all echocardiographic images, and MPI and ejection fraction (EF) were determined. Left ventricular (LV) or univentricular MPI was calculated in 34 patients and right ventricular (RV) MPI was calculated in 23 patients. Pearson’s correlation coefficient test showed that BNP significantly correlated with LV/univentricular MPI (r = 0.461, p = 0.006) and RV MPI (r = 0.748, p <0.0001), whereas LV/univentricular EF and RVEF had no significant correlation with BNP (r = −0.189, p = 0.172; r = 0.066, p = 0.729, respectively). In patients with congenital heart disease, BNP correlated significantly with MPI, but not with LV, RV, or univentricular EF. This is particularly true in patients with geometrically variable right ventricles in which EF may be more difficult to assess. In conclusion, these findings emphasize the unique ability of both BNP and MPI to assess global ventricular function in geometrically complex hearts.