Diastolic velocity half time is associated with aortic coarctation gradient at catheterization independent of echocardiographic and clinical blood pressure gradients

Objective: The most accurate noninvasive parameter to predict whether a patient with aortic coarctation will meet interventional criteria at catheterization remains elusive. We aim to determine the best independent echocardiographic predictors of a coarctation peak-to-peak pressure gradient ≥20 mm Hg at catheterization, the accepted threshold for intervention.

Design: Retrospective query of our catheterization database from 1/2007 to 7/2016 for the diagnostic code of aortic coarctation was performed. Multiple echocardiographic measurements and blood pressure gradients prior to cardiac catheterization were collected. Univariate correlation of variables with the continuous catheterization peak were calculated using Spearman's rho. Univariate association with peak-to-peak gradient at catheterization ≥20 mm Hg was tested using Mann-Whitney U test and the Pearson chi-square test or Fisher's exact test. Multivariable logistic regression assessed the independent association of the clinically relevant metrics with gradient at catheterization ≥20 mm Hg.

Results: Sixty-eight patients met study criteria (median age 9.25 years), of whom 84% underwent intervention at catheterization. Echocardiographic peak and mean coarctation velocity, indexed systolic and diastolic velocity half times (SVHTi, DVHTi), and blood pressure gradient all had moderate correlation (Spearman's rho = 0.529-0.617, P < .001) with the continuous catheterization gradient and were significantly associated with the binary outcome of catheterization peak ≥20 mm Hg (P < .001). Logistic regression found echocardiographic mean systolic gradient (OR 1.213 [95% CI 1.041-1.414]) and DVHTi (OR 1.039 [95% CI 1.004-1.074]) independently associate with catheterization peak ≥20 mm Hg after controlling for blood pressure gradient (OR 1.066 [0.987-1.150]).

Conclusions: Most echocardiographic estimates show moderate correlation with arch gradient at catheterization. Noninvasive four extremity blood pressure gradient is significantly associated with peak-to-peak gradient ≥20 mm Hg. DVHTi may provide a unique independently associated echocardiographic estimate of coarctation severity. Further study of these variables with larger cohorts may allow for development of predictive models to direct catheterization.