Aims
Accurate echocardiographic assessment of left ventricular outflow tract (LVOT) and the aortic root is necessary for risk stratification and choice of appropriate treatment in patients with pathologies of the aortic valve and aortic root. Conventional 2D transthoracic echocardiographic (TTE) assessment is based on the assumption of a circular shaped LVOT and aortic root, although previous studies have indicated a more ellipsoid shape. 3D TTE and multidetector computed tomography (MDCT) applies planimetry and are not dependent on geometrical assumptions. The aim was to test accuracy, feasibility, and reproducibility of 3D TTE compared to 2D TTE assessment of LVOT and aortic root areas, with MDCT as reference.
Methods and results
We examined 51 patients with 2D/3D TTE and MDCT at the same day. All patients were re-examined with 2D/3D TTE on a different day to evaluate 2D and 3D re-test variability. Areas of LVOT, aortic annulus, and sinus were assessed using 2D, 3D TTE, and MDCT. Both 2D/3D TTE underestimated the areas compared to MDCT; however, 3D TTE areas were significantly closer to MDCT-areas. 2D vs. 3D mean MDCT-differences: LVOT 1.61 vs. 1.15 cm2, P = 0.019; aortic annulus 1.96 vs. 1.06 cm2, P < 0.001; aortic sinus 1.66 vs. 1.08 cm2, P = 0.015. Feasibility was 3D 76–79% and 2D 88–90%. LVOT and aortic annulus areas by 3D TTE had lowest variabilities; intraobserver coefficient of variation (CV) 9%, re-test variation CV 18–20%.
Conclusion
Estimation of LVOT and aortic root areas using 3D TTE is feasible, more precise and more accurate than 2D TTE.
BackgroundGlobal longitudinal strain (GLS) is a predictor of outcome after cardiac surgery. If integrated into clinical decision‐making and timing of surgery, it is important to evaluate the feasibility, reproducibility, and variation of GLS in this selection of patients, where poor image quality and nontraceable segments are frequent.Methods and resultsTwo‐dimensional strain analysis was performed on 250 patients planned to undergo open‐heart surgery. Intra‐ and inter‐examiner retest variability was assessed in 50 consecutive patients. All myocardial segments were traceable in 119 patients, and GLS of those served as a reference in comparison with alternative strain models with nontraceable segments. Global longitudinal strain estimation by the recommended method of a maximum of one nontraceable segment per view was only feasible in 64% of cases (mean GLS −16%). Reproducibility was moderate (intra‐observer coefficient of variation [CV] 8%; inter‐observer CV 10%) and variation of GLS showed bias ± 95% limits of agreement (LOA) of 0.6 ± 1.1 (P < .05). Accepting three nontraceable segments in total increased feasibility to 77% with similar reproducibility (intra‐observer CV 8%; inter‐observer CV 11%) and variation (bias ± LOA: 0.6 ± 1.3, P < .05). A model with a maximum of one apical, one mid, and one basal nontraceable segment increased feasibility to 72% with similar reproducibility (intra‐observer CV 8%; inter‐observer CV 10%) and variation (bias ± LOA: 0.4 ± 1.2, P < .05).ConclusionGlobal longitudinal strain estimation in patients prior to cardiac surgery is challenged by moderate feasibility, retest variation as well as variation in cases of nontraceable segments. We suggest alternative strain models with improved feasibility without compromising reproducibility and variation.
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