Marfan syndrome (MFS) is the most common genetic disorder of the connective tissue [1]. The most life-threatening complication in MFS is aortic adverse events (AAEs). Preventing AAEs requires accurate indicators for risk stratification and timely prophylactic surgery. 

Although aortic root and ascending aorta dilatation are well-known risk factors for aortic dissection and rupture [2], thoracic aorta dissections can occur with diameters that do not reach the known threshold for prophylactic surgery [3]. 

As previous studies demonstrated that the risk of AAEs increased when the diameter of the ascending aorta reached 6 cm, it is recommended that an aortic diameter of 5.5 cm is the threshold for preventive surgery in current guidelines [4]. However, many (AAEs) occur in patients with aortic diameters smaller than 5.5 cm. This discrepancy highlights a contradiction, creating uncertainty about the optimal size criteria for surgical intervention in patients with ascending thoracic aortic aneurysms (ATAA) [5-8]. 

Further studies have reported that for every centimetre increase in aortic length, the risk of adverse aortic events (AAEs) increases fivefold. Moreover, the probability of AAEs is 12.4 times higher in aortas longer than 13 cm compared to those shorter than 9 cm [9], [10]. This highlights the importance of aortic length as a significant risk factor in the occurrence of AAEs. Therefore, aortic length can sharply increase the risk of AAEs, even when the aortic diameter remains relatively small. 

The ascending aorta diameter, whether absolute or personalised, has proven insufficient to reliably identify at-risk populations. As a result, recent studies have introduced alternative indicators. Our study aims to underscore the importance of alternative thoracic aorta measurements using CT scan.