Ascending Aorta Dissection Before 5.5 cm Diameter; "It Wasn't Raining When Noah Built the Ark".

Introduction: The aim of this study was to compare mean maximum ascending aortic diameter at the time of acute aortic dissection with the current surgical threshold for elective ascending aortic operations on non-syndromic thoracic aortic aneurysms.

Material And Methods: All consecutive non-syndromic adult patients admitted for acute type A aortic dissection in a single tertiary centre were prospectively enrolled from April 2020 to March 2021. The primary endpoint was the difference between mean maximum aortic diameter at the time of dissection and the 5.5 cm threshold for elective repair. Secondary endpoints included 30-day/in-hospital mortality, aortic length and comparison with normal controls, length/height ratio index, "actual" preoperative Euroscore II and "predicted" Euroscore II if electively operated.

Results: Among 31 patients ageing 67.3±12.03 years on average, mean maximum aortic diameter at the time of dissection was 5.13±0.66 cm, significantly lower than the guidelines-derived surgical threshold of 5.5 cm (p=0.004). Mean aortic length was 11±1.47 cm, also significantly longer compared normal controls reported in the literature (p<0.001). The 30-day/in-hospital mortality was 35.5%. Mean length/height ratio index was 6.18±0.76 cm/m. Finally, mean "actual" preoperative Euroscore II was 10.43±4.07 which was significantly higher than the 1.47±0.57 "predicted" Euroscore II (p<0.05).

Conclusions: The maximum aortic diameter at the time of acute type A aortic dissection of non-syndromic cases was significantly lower than the current recommendation for elective repair. Lowering of the current diameter-based surgical threshold of 5.5 cm may be profitable in terms of prevention, but further investigations should be undertaken. Length-based thresholds could also add to timely aortic dissection prevention.