@article{oai:tsukuba.repo.nii.ac.jp:00041807,
 author = {瀬尾, 由広 and 山本, 昌良 and 石津, 智子 and 青沼, 和隆 and Seo, Yoshihiro and Iida, Noriko and Yamamoto, Masayoshi and Machino-Ohtsuka, Tomoko and Ishizu, Tomoko and Aonuma, Kazutaka},
 issue = {5},
 journal = {Journal of the American Society of Echocardiography},
 month = {May},
 note = {Background
Long-axis images of the inferior vena cava (IVC) have limitations as surrogates for IVC morphology in grading central venous pressure (CVP) by two-dimensional echocardiography (2DE), because of the various cross-sectional morphologies and the translational motion of the IVC induced by sniffing. On the basis of the relationship between venous pressure and compliance, it was hypothesized that the cross-sectional morphology of the IVC, which was obtained using three-dimensional echocardiography, might estimate CVP more accurately compared with standard grading by 2DE.
Methods
Sixty consecutive patients who underwent right-heart catheterization studies were prospectively enrolled. Echocardiography was performed <24 hours before catheterization. From three-dimensional data sets, a cross-section of the IVC was determined that was perpendicular to the long-axis reference of the IVC. Short diameter (SD), long diameter (LD), the ratio of SD to LD (S/L) as the sphericity index, and area were measured on this cross-sectional IVC image.
Results
CVP correlated moderately with SD (r = 0.69, P < .001), strongly with S/L (r = 0.75, P < .001), and modestly with area (r = 0.47, P < .001) but not with LD (r = 0.24, P = .17). The largest areas under the curve by receiver operating characteristic analyses to detect CVP ≥ 10 mm Hg were 0.98 (95% CI, 0.97–1.0; P < .001) for S/L, 0.83 for SD (95% CI, 0.74–0.94; P < .001), and 0.70 for area (95% CI, 0.56–0.84; P = .02). If a cutoff value of 0.69 for S/L was used, the sensitivity, specificity, and accuracy to detect CVP ≥ 10 mm Hg were 0.94, 0.95, and 0.95 and for CVP grading by 2DE were 0.59, 0.98, and 0.85, respectively. Estimations of CVP were more accurately reclassified using S/L rather than grading by 2DE (net reclassification improvement, 0.38; 95% CI, 0.31–0.44; P < .001).
Conclusions
S/L of an IVC cross-section measured using three-dimensional echocardiography may be a reliable parameter to estimate CVP compared with standard grading by 2DE.},
 pages = {461--467},
 title = {Estimation of Central Venous Pressure Using the Ratio of Short to Long Diameter from Cross-Sectional Images of the Inferior Vena Cava},
 volume = {30},
 year = {2017}
}