Rethinking Aortic Risk: The Potential Impact of Novel, Adjusted, and Combined Aortic Measures in the Prediction of Aortic Dissection

BACKGROUND: Indications for pre-emptive aortic surgery are based on ascending aortic diameter. In this study we assessed the diagnostic test properties of novel unadjusted, adjusted, and combined measures of aortic geometry. METHODS: This study comprised an international multicentre analysis of patients undergoing contrast-enhanced computed tomography angiography (CTA) before acute type A aortic dissection (ATAAD). A historical cohort of nonaneurysmal patients and patients with known aneurysmal disease (TAA) were included as a control group. Receiver operating characteristic (ROC) curves were applied to evaluate the aortic measures' diagnostic accuracy (for [un]adjusted aortic diameter, length, and volume), with sensitivity analyses performed in a matched sample. Clinically intuitive measures, such as the number needed to reclassify (NNR) to identify an additional patient at risk of ATAAD, were calculated. RESULTS: Eighty patients underwent CTA before ATAAD occurred, in 5 centres in The Netherlands and Germany. The control group encompassed 333 patients. The specificity of all measures was 98.8%, 97.0%, and 94.9% at contemporary diameter thresholds of 55 mm, 52 mm, and 50 mm. The sensitivity of diameter, length, or volume was 4.1%, 6.8%, and 14.9% at the 98.8% specificity threshold (NNR volume vs diameter: 9.3, P = 0.008). The combination of diameter, length, and volume as a new criterion resulted in an increased sensitivity at the 55-mm and 52-mm thresholds (18.9%, NNR = 6.8, P = 0.001; 23.0%, NNR = 9.3, P = 0.008). Results were consistent in matched samples. CONCLUSIONS: These newly introduced aortic measures seem promising to identify patients at risk of ATAAD, but their net benefit needs to be validated in real-world cohorts.