Feasibility study of a synchronized diastolic injection with low contrast volume for proper quantitative assessment of aortic regurgitation in porcine models

Objectives To evaluate the in vivo feasibility of aortography with one accurately timed diastolic low‐volume contrast injection for quantitative assessment of aortic regurgitation (AR) post transcatheter aortic valve replacement (TAVR). Background With the rise of a minimalistic approach for TAVR, aortography (re)emerges as a pragmatic tool for AR assessment. In a mock circulation system, we have validated the accuracy of a single diastolic injection triggered by electrocardiogram (ECG) with low‐contrast volume. Methods Two‐phase experiment: first, a series of aortograms were performed in a porcine model, with 8 mL of contrast using the synchronized (SYNC) and the conventional non‐synchronized (NS) injections. In a second phase, we developed a model of AR by inserting partially unsheathed Wallstents of 6–10 mm of diameter across the pig's aortic valve, performing SYNC injections with 8 mL of contrast and NS injections with 8 mL and 15 mL (rate: 20 mL/sec). Respective accuracies of SYNC vs. NS were assessed using Passing‐Bablock regression. An angiography core laboratory performed quantitative AR assessment with videodensitometry (VD‐AR). Results The SYNC injections produced higher opacification of the aortic root compared with NS injections ( P = 0.04 for density). In the second phase, a regression line for predicting VD‐AR based on the SYNC injection resulted in a lower intercept and a slope closer to the line of identity (y = 11.9 + 0.79x, P < 0.001, r 2 = 0.94) with the NS‐8 mL than with the NS‐15 mL injection (y = 26.5 + 0.55x, P < 0.001, r 2 = 0.81). Conclusion Synchronized diastolic injection with low contrast volume produced denser images in the aortic root and more accurate than the conventional injection; thus, may be an appealing alternative for assessment of AR post TAVR.