Surgical outcomes in acute type A aortic dissection: the effect of 5-hour time window on malperfusion syndrome

BACKGROUND: While a 5-hour time window for central aortic repair has been proposed to improve outcomes in acute type A aortic dissection (ATAAD) complicated by malperfusion, its efficacy relative to the number and nature of involved organs remains unclear. METHODS: Patients who underwent surgical repair for ATAAD with malperfusion between January 2013 and December 2019 were enrolled and stratified by the number of malperfusion sites. Surgical outcomes were then compared between patients who received central repair within a 5-hour window and those treated beyond this timeframe. RESULTS: Preoperative organ malperfusion was present in 22.5% (237/1053) of patients. Among them, 62.4% (148/237) had single-organ involvement, while 37.6% (89/237) presented with multi-organ involvement (≥ 2 organs). An exploratory receiver operating characteristic (ROC) curve analysis identified a statistical cutoff of 4.5 h for predicting in-hospital mortality, conceptually supporting the 5-hour clinical window. Proximal malperfusion (coronary, cerebral) was common in the multi-organ group and was associated with a significantly worse prognosis. Central repair within the 5-hour window significantly improved long-term outcomes for patients with single-organ malperfusion. For those with multi-organ involvement, this strategy significantly improved early surgical outcomes, although the benefit diminished as the number of malperfused sites increased. Furthermore, for patients with proximal malperfusion, adhering to the 5-hour window helped mitigate irreversible damage to vital organs, increasing the likelihood of survival and functional recovery. CONCLUSIONS: The 5-hour time window serves as a clear clinical intervention threshold, enabling clinicians to make rapid decisions during the acute phase, optimize treatment plans, and fundamentally improve patient outcomes.