Acute type A aortic dissection is a condition with a high mortality rate. Without immediate intervention, mortality increases by 1-2% per hour from the onset of symptoms. The treatment of choice is emergency surgery, where rapid diagnosis and the implementation of urgent medical management are essential to optimize the patient’s condition upon arrival for surgery.

Despite advances in surgical outcomes over the years improving survival rates, mortality remains high. Malperfusion signs at diagnosis present a major complication that greatly impacts short- and long-term surgical outcomes, resulting in poorer morbidity and mortality outcomes.

This study’s objective is to determine whether the elapsed time from symptom onset to surgery and the location of malperfusion syndrome influence survival in type A aortic dissection surgery. A 300-minute cutoff was established to divide patients into two groups: those who underwent early versus delayed intervention. All patients presenting to the hospital with acute type A aortic dissection between 2003 and 2019 at the Japanese Red Cross Kobe center were studied. In total, 463 subjects were included, excluding those who died in transit and those who were not operated on. Among the remaining 331 patients, 25% (84) presented with malperfusion syndrome, diagnosed clinically and by CT angiography upon arrival at the emergency department.

Kaplan-Meier analysis with a log-rank test was used to evaluate survival. Cox proportional hazards analysis was performed to identify predictive elements, focusing on factors with a p < 0.1 level of significance in the univariable analysis (shock upon emergency department arrival, coronary malperfusion, time exceeding 300 minutes until intervention, and preoperative cardiopulmonary arrest).

No statistically significant differences were found in preoperative variables between groups. In patients with malperfusion, the time from symptom onset to transfer to the operating room was significantly longer (209 vs. 976 minutes). Comparing patients presenting without malperfusion symptoms to those with them, the latter group experienced higher postoperative morbidity and 30-day mortality. However, despite this, no long-term survival differences (mean follow-up of 5 years) were observed among survivors. There was higher survival among patients transferred to the operating room early, regardless of clinical malperfusion presentation. Multivariate analysis indicated that patients with coronary malperfusion and shock upon emergency department arrival experienced higher long-term mortality.

The authors concluded that, in patients diagnosed with acute type A aortic dissection associated with malperfusion, those who underwent early surgical intervention—within five hours from symptom onset—demonstrated higher long-term survival. Additionally, among the regions affected by malperfusion syndrome, coronary ischemia was associated with higher short- and long-term mortality. Finally, patients who experienced shock prior to surgery had poorer long-term survival.

COMMENTARY:

Malperfusion syndrome encompasses all situations that compromise blood flow to an organ, resulting in ischemia and/or dysfunction. It can arise from various causes: dissection of aortic branches, dynamic or static obstruction, thrombosis in the false lumen, or a combination thereof. Multiple therapeutic options have been described to address this issue, such as fenestration or extra-anatomical arterial bypasses, but their efficacy remains uncertain. Whether coronary intervention should precede ascending aorta repair in malperfusion patients is particularly controversial, as suggested by the authors of this study. This action could worsen outcomes, as it delays patients’ transfer to the operating room and does not seem to offer a clear survival advantage. Therefore, caution is needed when extrapolating this approach to our practice, since preoperative coronary angiography is not customary, and, in most cases, ischemia arises from ostial-proximal coronary vessel involvement by the dissection itself. Aortic surgery resolves dynamic obstruction in a large proportion of cases by redirecting flow into the true lumen. This underscores the importance of minimizing delays in transferring a patient with acute ascending aortic dissection to the operating room.

This study highlights the importance of early surgical intervention, yet this should always align with rapid diagnosis and a hospital protocol that facilitates effective, safe, and efficient patient transfers. The tolerance for malperfusion varies between organs, affecting postoperative morbidity differently. For example, myocardial or cerebral tolerance times are generally shorter. However, visceral organs have better tolerance, although established mesenteric involvement has a very high mortality rate in these patients.

The number of patients included in the study is remarkable, yet one limitation of this article is the small number of patients with mesenteric, renal, peripheral, and spinal malperfusion; this would have helped to clarify specific management for each type of pathology and its impact on short- and medium-term survival. The same research group published results in 2011 on surgical intervention for acute aortic dissection complicated by cerebral coma. Demonstrating the importance of early surgical intervention despite the presence of cerebral malperfusion with a comatose neurological state.

In conclusion, acute type A aortic dissection with associated malperfusion syndrome is a pathology with high morbidity and mortality. Additionally, it can trigger severe systemic complications, with emergency surgery being one of the few effective options to prevent fatal complications and improve long-term outcomes. We must aim for the earliest possible surgical intervention from diagnosis in these patients and minimize decision-making time.

REFERENCE:

Nakai C, Izumi S, Haraguchi T, Henmi S, Nakayama S, Mikami T, et al. Impact of time from symptom onset to operation on outcome of repair of acute type A aortic dissection with malperfusion. J Thorac Cardiovasc Surg. March 2023;165(3):984-991.e1. doi: 10.1016/j.jtcvs.2021.03.102