Cardiac Resynchronization Therapy-Induced Cardiac Index Increase Measured by Three-Dimensional Echocardiography Can Predict Decreases in Brain Natriuretic Peptide

Objectives First, to examine the perioperative association between increased cardiac index (CI) measured using three-dimensional echocardiography (CI 3D ), two-dimensional echocardiography (CI 2D ), and FloTrac/Vigileo (CI FT ) (Edwards Lifesciences, Irvine, CA) after cardiac resynchronization therapy (CRT) and decreased brain natriuretic peptide (BNP) 6 months after CRT. Second, to evaluate the accuracy and tracking ability of CI 2D and CI FT . Design A prospective clinical study. Setting A cardiac surgery operating room in a single cardiovascular center. Participants Forty-five patients undergoing elective CRT lead implantation. Interventions CI FT and CI 2D were determined simultaneously before and after CRT using CI 3D as the reference method. Measurements and Main Results BNP was measured before CRT and 6 months after CRT. Areas under the receiver operator characteristic curves (AUCs) were calculated for each method of measurement to predict BNP decrease. AUC was largest for CI 3D (AUC = 0.735, p = 0.017). Bland-Altman analysis revealed that the percentage error was 58% for CI FT and 28% for CI 2D. A polar plot analysis showed that the mean angular bias was -7.26° and 0.64°, the radial limits of agreement were 70° and 29.4°, and the concordance rate was 67.7% and 93.8% for CI FT and CI 2D, respectively. Conclusions CI significantly increased after CRT in patients whose BNP level decreased 6 months after CRT. However, only CI 3D could predict decreases in BNP 6 months after CRT. Although CI 2D was acceptable compared with CI 3D , the tracking ability of CI changes was just below acceptable. CI FT has a wide limit of agreement with CI 3D, with a poor tracking ability.