Comparison of invasive and non-invasive pressure gradients in aortic arch obstruction

Abstract

Background Aortic arch obstruction can be evaluated by catheter peak-to-peak gradient or by Doppler peak instantaneous pressure gradient. Previous studies have shown moderate correlation in discrete coarctation, but few have assessed correlation in patients with more complex aortic reconstruction. Methods We carried out retrospective comparison of cardiac catheterisations and pre- and post-catheterisation echocardiograms in 60 patients with native/recurrent coarctation or aortic reconstruction. Aortic arch obstruction was defined as peak-to-peak gradient ≥25 mmHg in patients with native/recurrent coarctation and ≥10 mmHg in aortic reconstruction. Results Diastolic continuation of flow was not associated with aortic arch obstruction in either group. Doppler peak instantaneous pressure gradient, with and without the expanded Bernoulli equation, weakly correlated with peak-to-peak gradient even in patients with a normal cardiac index (r=0.36, p=0.016, and r=0.49, p=0.001, respectively). Receiver operating characteristic curve analysis identified an area under the curve of 0.61 for patients with all types of obstruction, with a cut-off point of 45 mmHg correctly classifying 64% of patients with arch obstruction (sensitivity 39%, specificity 89%). In patients with aortic arch reconstruction who had a cardiac index ≥3 L/min/m2, a cut-off point of 23 mmHg correctly classified 69% of patients (71% sensitivity, 50% specificity) with an area under the curve of 0.82. Conclusion The non-invasive assessment of aortic obstruction remains challenging. The greatest correlation of Doppler indices was noted in patients with aortic reconstruction and a normal cardiac index.

Treating a 20 mm Hg gradient alleviates myocardial hypertrophy in experimental aortic coarctation

“…The Doppler peak instantaneous BPG across the narrowing is then estimated by the modified Bernoulli equation. However, invasive cardiac catheterization measuring the peak-to-peak gradient across the CoA represents the gold standard in the pediatric population(13, 14). Although Doppler-measured BPG tends to overestimate catheter-measured BPG in many cases, Doppler peak instantaneous BPG correlates reasonably well with catheter peak-to-peak BPG in patients with native or recurrent CoA that do not have collateral vessels or retrograde flow during diastole.…”

“…Peak instantaneous BPG was estimated using the modified Bernoulli equation (4×V 2 ). Peak instantaneous BPG values by ultrasound were only used in the current study to determine when absorption of the dissolvable Vicryl sutures used in creating CoA for the Corrected group of rabbits had occurred, since BPG by catheterization obtained as discussed below represents the gold standard and preferred method, when available(13, 14). Weekly ultrasound imaging revealed that the BPG remains elevated in Corrected rabbits for 34±2 days after surgical induction of the coarctation (range 32–37 days; Figure 2).…”

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

“…Peak instantaneous gradient by echocardiogram is used commonly in clinical practice. However, multiple studies have highlighted its poor correlation with peak‐to‐peak gradient at catheterization …”

Simplified Bernoulli's method significantly underestimates pulmonary transvalvular pressure drop

“…[4][5][6][7][8][9][10][11] Several studies have investigated the correlation between MRI measurements and echocardiography with catheterization for the estimation of the pressure drop in pulmonary circulation. The results have been inconsistent.…”