Noriko Iida

Transmural Compensation of Myocardial Deformation to Preserve Left Ventricular Ejection Performance in Chronic Aortic Regurgitation

BACKGROUND In patients with chronic aortic regurgitation (AR), systolic wall stress and volume overload affects left ventricular (LV) systolic function and remodeling. The aim of this study was to assess transmural rearrangements of myocardial deformation to preserve LV ejection performances using speckle-tracking echocardiography in patients with chronic AR. METHODS Ninety patients with AR were enrolled. On LV short-axis images, total, inner, and outer radial strain and circumferential strain at the inner, mid, and outer layers were calculated. On apical four-chamber images, endocardial longitudinal strain was calculated. End-systolic wall stresses were calculated using previous methods. RESULTS AR severities were classified as moderate in 31 patients, severe and preserved LV ejection fraction (LVEF) (≥50%) in 42 patients, and severe and reduced LVEF (<50%) in 17 patients. Longitudinal strain was decreased even in the moderate AR group, despite normal end-systolic wall stress. Inner radial strain progressively decreased with increasing end-systolic wall stress, whereas outer radial strain in the moderate and severe AR and preserved LVEF groups was higher than in the control group. Consequently, total radial strain was preserved even in the severe AR and preserved LVEF groups with increased end-systolic wall stress. Similarly, despite reduced inner circumferential strain, outer circumferential strain was higher in the severe AR and preserved LVEF group than in the control group. All strain parameters were lower in the severe AR and reduced LVEF group with dramatically increased end-systolic wall stress than in other groups. CONCLUSIONS Transmural strain analysis revealed that subendocardial dysfunction accompanied by increased wall thickening at the subepicardium may be a compensatory mechanism of wall thickening to preserve LVEF in patients with chronic AR.

Estimation of Central Venous Pressure Using the Ratio of Short to Long Diameter from Cross-Sectional Images of the Inferior Vena Cava

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.

Endothelial Dysfunction of Conduit Arteries in Patients with Repaired Coarctation of the Aorta

Adult patients with repaired coarctation of the aorta (r-CoA) show high prevalence of late hypertension, but the exact mechanisms of this phenomenon are unknown. Endothelial dysfunction has been implicated in this paradoxical hypertension. We evaluated the endothelial function of both conduit and resistance arteries by using flow-mediated dilation (FMD) and digital peripheral artery tonometry (PAT).Seventeen patients with r-CoA and one patient with repaired interrupted aortic arch (r-CoA group) aged 22.0 ± 6.9 years (5 females) underwent FMD of the right brachial artery, PAT of the right finger, blood marker tests, ambulatory blood pressure monitoring, echocardiography, carotid ultrasonography, and brachio-ankle pulse wave velocity measurement. The median age at aortic arch reconstruction was 2.0 months (interquartile range: 15 days to 7.0 years). Results were compared with 17 age-matched healthy subjects (control group).Eight (44%) patients of the r-CoA group were hypertensive (5 received antihypertensive drugs). Patients in the r-CoA group showed significantly lower FMD (3.8 ± 1.5 versus 6.6 ± 2.5%, P < 0.001), larger intima-media thickness (0.63 ± 0.17 versus 0.47 ± 0.09 mm, P = 0.001), and higher left ventricular mass index (91.4 ± 24.6 versus 73.4 ± 17.3 g/m2, P = 0.017) than those in the control group. There were no significant differences in PAT (refractory hyperemia index, 1.86 ± 0.43 versus 1.99 ± 0.59, P = 0.48) and brachio-ankle pulse wave velocity between the two groups.Vascular dysfunction in r-CoA patients, particularly endothelial dysfunction, tends to occur more significantly in conduit arteries than in resistance arteries.