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

Area of Science:

• Cardiology
• Medical Imaging
• Hemodynamics

Background:

• Aortic arch obstruction assessment traditionally relies on invasive catheter peak-to-peak gradients.
• Non-invasive Doppler peak instantaneous pressure gradients are an alternative, but their accuracy in complex aortic conditions is less understood.
• Previous studies show moderate correlation in simple coarctation, but limited data exists for complex aortic reconstructions.

Purpose of the Study:

• To compare the accuracy of Doppler-derived pressure gradients with catheter-derived peak-to-peak gradients in evaluating aortic arch obstruction.
• To assess the correlation in patients with native/recurrent coarctation and those with aortic reconstruction.
• To determine the utility of Doppler indices in complex aortic pathologies.

Main Methods:

• Retrospective analysis of 60 patients undergoing cardiac catheterization and echocardiography.
• Comparison of peak-to-peak gradient (catheter) with Doppler peak instantaneous pressure gradient (echocardiography).
• Definition of aortic arch obstruction: peak-to-peak gradient ⩾25 mmHg (native/recurrent coarctation) and ⩾10 mmHg (aortic reconstruction).

Main Results:

• Doppler gradients showed weak correlation with catheter gradients, even with normal cardiac index (r=0.36-0.49).
• Receiver operating characteristic curve analysis yielded an area under the curve of 0.61 for all obstructions.
• In aortic reconstruction with normal cardiac index, a Doppler cut-off of 23 mmHg showed better classification (AUC 0.82).

Conclusions:

• Non-invasive Doppler assessment of aortic obstruction remains challenging.
• Doppler indices demonstrate the greatest correlation in patients with aortic reconstruction and a normal cardiac index.
• Further refinement of non-invasive methods is needed for accurate assessment of complex aortic arch obstruction.