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Cardiac output determined by echocardiography in patients with cirrhosis: comparison with the indicator dilution
Ulrik B Andersen1, Søren Møller, Flemming Bendtsen
1Department of Clinical Physiology, Hvidovre Hospital, University of Copenhagen, Denmark.
Insights
Doppler echocardiography accurately measures group cardiac output in cirrhosis patients, but individual results vary. Reproducibility is acceptable, though less precise than indicator dilution methods.
Area of Science:
- Cardiology
- Medical Imaging
- Hepatology
Background:
- Cardiac output measurement in hyperkinetic cirrhosis patients using Doppler echocardiography lacks validation.
- This study addresses the need to validate Doppler echocardiography against a gold standard for cardiac output assessment in this population.
Purpose of the Study:
- To compare simultaneous cardiac output measurements between Doppler echocardiography (CO(d)) and indicator dilution technique (CO(I)) in patients with cirrhosis.
- To assess the accuracy and reproducibility of Doppler echocardiography for cardiac output determination in this specific patient group.
Main Methods:
- Simultaneous cardiac output measurements were performed in twelve cirrhosis patients.
- Doppler echocardiography (CO(d)) calculated output from outflow tract velocity, area, and heart rate.
- Indicator dilution technique (CO(I)) used 125I and 99mTc albumin with atrial injection and femoral artery sampling.
Main Results:
- Mean CO(d) and CO(I) were comparable (7.20 vs 7.15 l/min).
- A strong correlation (r=0.86, P<0.0001) existed between CO(d) and CO(I), with a slope of 0.91.
- Doppler measurements showed higher variability (SD 0.79 vs 0.30 l/min; CV 10.5% vs 4.2%) and individual disagreements, despite group accuracy.
Conclusions:
- Doppler echocardiography provides accurate group mean cardiac output in cirrhosis patients.
- Significant individual over- and underestimations necessitate caution when interpreting single Doppler measurements.
- The reproducibility of Doppler echocardiography is acceptable but inferior to the indicator dilution technique.
Background/Aims:
Measurement of cardiac output in hyperkinetic patients with cirrhosis by Doppler echocardiography is increasingly reported, but has not been validated. We have compared simultaneous measurements of cardiac output by Doppler echocardiography (CO(d)) and by the indicator dilution technique (CO(I)).
Methods:
Twelve patients with cirrhosis were studied. CO(d) was measured as the spatial mean velocity of the left ventricular outflow tract, multiplied by the cross-sectional area and the heart rate. CO(I) was determined by the standard indicator dilution technique after injection of 125I albumin and 99mTc albumin into the right atrium and subsequent sampling from the femoral artery.
Results:
The mean CO(d) and CO(I) were similar (7.20 vs 7.15 l/min, NS). A highly significant correlation was present between CO(d) and CO(I) (r = 0.86, P < 0.0001; slope 0.91, Y(0) = 0.78 l/min). However, the mean squared difference between CO(d) and CO(I) was 2.3 (l/min)2. A Bland-Altman plot revealed no trend with the level of cardiac output. The standard deviation (0.79 vs 0.30 l/min, P < 0.01) and the coefficient of variation (10.5 vs 4.2%, P < 0.01) of duplicate measurements were significantly higher with the Doppler technique.
Conclusion:
Doppler measurements of cardiac output in groups of patients with cirrhosis are accurate with respect to the group mean, but marked disagreements of over- and underestimation were seen in individual patients. The reproducibility of the Doppler technique is acceptable, although not as good as that of the indicator dilution technique.