Capability of CT aortic regurgitant orifice to predict aortic regurgitation severity with cardiovascular magnetic resonance as reference

Regurgitant orifice area (ROA) measurements by cardiac CT have not been extensively compared with a quantitative classification of aortic regurgitation (AR) severity based on regurgitant fraction (RF) by phase-contrast cardiovascular magnetic resonance (PC-CMR) [1–3].

To evaluate ROA diagnostic accuracy by 256-slice CT for predicting severe AR with PC-CMR as reference.

We consecutively enrolled 57 patients with AR prior to surgery assessed by echocardiography, PC-CRM, and CT. Mean age 67.3±15.3 (84% males). Cardiac CT data sets were reconstructed at 75–78% of the R-R interval to measure ROA. According to previous data (4), a cut-off value of 33% by PC-CMR defined severe AR. Receiver operating curve (ROC) were calculated to detect the best CT-ROA cut-off to predict severe AR by CMR.

There were no differences between both groups of AR patients in terms of age, gender, or anthropometric measures. CT-ROA was significantly smaller in patients with RF<33% by PC-CMR (0.24±0.09 vs 0.49±0.22; p<0.001). AR etiology, jet eccentricity, ascending aorta diameters and ejection fraction (LVEF) also were not significantly different according to AR-RF group (Table 1).

CT-ROA significantly correlated with the RF>33% by PC-CMR (Pearson's correlation coefficient (R)=0,48, p<0.001) (Figure 1A).

In the ROC curve analysis to predict significant RF, a CT-ROA cut-off of 0.27 cm² correctly classified 93% of patients with sensitivity of 97.6% (CI95%:87,7–99,6); specificity of 73.33% (CI95%:48–89); PPV 95,3% (CI95%: 84,5–98,7); NPV 91,7% (CI95%: 64,6% a 98,5%) and area under the curve (AUC) of 0.93 (CI95%: 0.85–1.00; p<0.001) (Figure 1B).

CT-RAO could be useful to distinguish AR severity determined by PC-CMR with a cut-off value of 0.27 cm² as best predictor.

Type of funding sources: None.