Introduction: Echo-based coronary artery (CA) Z-value is the current standard for the case definition of CA dilatation (Z>2.5) in KD. Extrapolating Z-value equations to selective angiography has not been evaluated. CA to aortic valve (AV) ratio is stable versus BSA (Figure).
Methods: CA measurements from selective angiography were compared to echo measurements within 3 months interval, late after KD. Measurements were performed 3-5 mm from CA ostium for patients without aneurysms, and proximal to the aneurysm for the remainder. The AV was measured in the echo long axis and the angio frontal views. Z-values and CA/AV ratios were compared between angio and echo measurements.
Results: There were 22 cases with and 55 without CA sequelae. Echo measurements overestimated the smallest CA segments (intercept 0.75 mm), with an error attenuation for larger coronaries (slope 0.74, r2 0.45). In contrast, CA/AV ratio had a better correlation for all CA size range (intercept 0.04, slope 0.87, r2 0.55). There was a disagreement between echo and angio for the case definition of coronary dilatation for the Z-value equations (p value 0.02 and 0.04), but not for the CA/AV ratio (p value 0.1 and 0.27). The best sensitivity and specificity of echo to predict angio-based CA status were obtained with the CA/AV (100 and 93 percent for the right and 50 and 87 percent for the left coronary, versus 36 and 93 percent and 44 and 87 percent, respectively).
Conclusion: CA/AV is a better representative of the angiographic CA status compared to echocardiography based Z-value calculations.