DIFFERENCES IN ESTIMATED CARDIAC OUTPUT IN RELATION TO CARDIAC RISK FACTORS

摘要

While multiple methods have been used to assess cardiac output (CO) in various clinical settings, these may not be practical inprimary care or research settings. Recent investigations have indicated simple equations, like the Liljestrand and Zanderformula (COest=PP/(SBP+DBP)*HR), to be moderately correlated when comparing the estimated CO (COest) and otheraccepted methods of determining CO like echocardiographic derived CO (COecho). COest can be adjusted by a constant (k)derived by dividing CO by COest (k=CO/COest). Following adjustment of k, the new estimate (COest-adj) is more comparableto directly measured COecho. The purpose of this investigation was to replicate recent findings in a larger sample and determinewhich cardiometabolic risk factors may account for the variation in this formula in 1,410 African American participants (71%female, aged 62+9 years, 80% hypertensive, 29% diabetic, and 14% smokers) enrolled in the Genetic Epidemiology Networkor Arteriopathy (GENOA) completing an echocardiography exam (2000-2004). While COest-adj and COecho values weremoderately correlated (Pearson’s r= 0.43, p<0.001), there was variation in participants with cardiometabolic risk factors.Overall, COest-adj was 0.3 L lower compared to COecho, was slightly overestimated in females by 0.6 L, and wasunderestimated in males by 0.5 L. Further analyses revealed COest-adj was 0.4 L higher in hypertensives, 0.7 L higher indiabetics, and 0.1 L higher in smokers compared to COecho. These findings suggest that the adjusted Liljestrand and Zanderformula can be an inexpensive tool in the primary care and research settings for estimating CO in the presence of risk factors,but further adjustments may need to be developed to improve accuracy and precision.