Malperfusion Syndrome in Patients Undergoing Repair for Acute Type A Aortic Dissection: Presentation, Mortality and Utility of the Penn Classification.

Background: The current study aims to report the presentation of the malperfusion syndrome in patients with acute Type A aortic dissection admitted to surgery and its impact on mortality.

Methods: Data were retrieved from the multicenter European Registry of Type A Aortic Dissection (ERTAAD). The Penn classification was utilized to categorize malperfusion syndromes. A machine learning algorithm was applied to assess the multivariate interaction's importance regarding in-hospital mortality.

Results: A total of 3,902 consecutive patients underwent repair for Acute Type A Aortic Dissection. Local malperfusion syndrome occurred in 1,584 (40.58%) patients. Multi-organ involvement occurred in 582 patients (36.74%) whereas 1,002 patients (63.26%) had single-organ malperfusion. The prevalence was the highest for cerebral (21.27%) followed by peripheral (13.94%), myocardial (9.7%), renal (9.33%), mesenteric (4.15%), and spinal malperfusion (2.10%). Multi-organ involvement predominantly occurred in organs perfused by the downstream aorta. Malperfusion significantly increased mortality risk (p < 0.001, OR 1.95 ± 0.29). The Boruta machine learning algorithm identified the Penn classification as significantly associated with in-hospital mortality (p< 0.0001, variable importance = 7.91), however, 8 other variables yielded higher prediction importance. According to the Penn classification mortality rates were for Penn A = 12.38%, Penn B = 20.71% Penn C = 28.90%, and Penn BC = 31.84% respectively.

Conclusions: Nearly half of the examined cohort presented with signs of malperfusion syndrome predominantly due to local involvement. More than one-third of patients with local malperfusion syndrome had a multivessel involvement. Furthermore, different levels of Penn classification can be used only as a first tool for preliminary stratification of early mortality risk.