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A Novel Diastolic Doppler Index Less Affected by Aortic Arch Anomalies Co-existing with Coarctation
Arash Ghorbannia1,2, Andrew D Spearman3, Shahd Sawalhi4
1Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, WI, USA. ghorbannia@outlook.com.
Insights
Continuous flow pressure gradient (CFPG) shows better diagnostic performance than conventional Doppler indices for assessing coarctation of the aorta (CoA), even in complex cases with aortic arch anomalies.
Area of Science:
- Cardiovascular Medicine
- Medical Imaging
- Hemodynamics
Background:
- Coarctation of the aorta (CoA) severity assessment is difficult due to complex anatomical variations and limitations of Doppler-based methods.
- Continuous flow pressure gradient (CFPG) shows potential but its efficacy in complex CoA remains unstudied.
Purpose of the Study:
- To evaluate the impact of complex CoA and associated hemodynamics on CFPG diagnostic performance compared to conventional Doppler indices.
- To compare the diagnostic accuracy of CFPG and conventional Doppler indices in discrete versus complex CoA.
Main Methods:
- Retrospective analysis of patients with discrete juxtaductal CoA (n=25) and complex CoA (n=43).
- Comparison of arm-leg systolic blood pressure gradients (BPG) with BPG derived from conventional Doppler indices and CFPG.
- Utilized echocardiography Z-scored aortic diameters and computational simulations from a preclinical CoA model.
Main Results:
- Conventional Doppler indices showed significantly reduced diagnostic performance in complex CoA compared to discrete CoA.
- CFPG exhibited only a modest decrease in diagnostic indicators for complex CoA versus discrete CoA.
- Simulations indicated that CFPG is less influenced by aortic arch anomalies than conventional Doppler indices.
Conclusions:
- CFPG demonstrates superior and more consistent diagnostic performance in coarctation of the aorta, particularly in complex cases with concomitant aortic arch anomalies.
- CFPG offers a more reliable method for severity assessment in coarctation of the aorta when compared to conventional Doppler indices, especially in the presence of anatomical complexity.
Abstract:
Severity assessment for coarctation of the aorta (CoA) is challenging due to concomitant morphological anomalies (complex CoA) and inaccurate Doppler-based indices. Promising diagnostic performance has been reported for the continuous flow pressure gradient (CFPG), but it has not been studied in complex CoA. Our objective was to characterize the effect of complex CoA and associated hemodynamics on CFPG in a clinical cohort. Retrospective analysis identified discrete juxtaductal (n = 25) and complex CoA (n = 43; transverse arch and/or isthmus hypoplasia) patients with arm-leg systolic blood pressure gradients (BPG) within 24 h of echocardiography for comparison to BPG by conventional Doppler indices (simplified Bernoulli equation and modified forms correcting for proximal kinetic energy and/or recovered pressure). Results were interpreted using the current CoA guideline (BPG ≥ 20 mmHg) to compare diagnostic performance indicators including receiver operating characteristic curves, sensitivity, specificity, and diagnostic accuracy, among others. Echocardiography Z-scored aortic diameters were applied with computational simulations from a preclinical CoA model to understand aspects of the CFPG driving performance differences. Diagnostic performance was substantially reduced from discrete to complex CoA for conventional Doppler indices calculated from patient data, and by hypoplasia and/or long segment stenosis in simulations. In contrast, diagnostic indicators for the CFPG only modestly dropped for complex vs discrete CoA. Simulations revealed differences in performance due to inclusion of the Doppler velocity index and diastolic pressure half-time in the CFPG calculation. CFPG is less affected by aortic arch anomalies co-existing with CoA when compared to conventional Doppler indices.
