JCM | Free Full-Text | Factors Associated with Early Mortality in Acute Type A Aortic Dissection—A Single-Centre Experience

Aortic dissection involving the ascending aorta and/or the aortic arch, defined as type A aortic dissection according to the Stanford classification, remains an acute, critical pathology requiring emergent surgical treatment. Although diagnostic and treatment protocols have been continuously improved and optimized through the years, the associated mortality rates are still significant (17.7% to 22% in-hospital mortality and a 65% survival rate over the following 10 years) [1,2]. Many aspects of the surgical management of acute aortic dissections type A (AADA), such as the extent of distal aortic reconstruction and management of the aortic root, among others, remain the subject of debate among clinicians [3], since reducing the complexity of surgery may improve early outcomes on the one hand, but may lead to increased risk of reoperation on the other [4].

Furthermore, complications in the postoperative phase after this challenging procedure may lead to adverse events, potentially affecting the patients’ prognosis and survival [5]. Prompt identification of patients at risk for complications and early intervention may improve outcomes and reduce in-hospital mortality.

Despite modern advancements in its detection and treatment, AADA remains a challenging aortic pathology, with relevant mortality rates. A recent study investigating the epidemiologic characteristics of AADA in the Danish population revealed an incidence rate of 2.2/100.000 and a 30-day mortality rate of 22% [27], confirming the rather uncommon but fatal nature of the disease. The risk factors usually associated with AADA are hypertension, atherosclerosis, aneurysmatic degeneration of the aorta, and connective tissue disease [2,28]. In this retrospective, observational study, we examined the pre- and perioperative parameters of patients admitted with AADA in our centre, as well as their postoperative course and complications, in order to elucidate the correlations of the parameters associated with poor outcomes and identify the patients at risk.

Regarding the preoperative characteristics of our patient cohort, hypertension was the most common comorbidity (64% of all patients), and it was significantly correlated with mortality (p = 0.02). This observation is in line with the findings of Wang et al., who described hypertension as an independent risk factor for long-term modality [29]. Another factor associated with early mortality is atrial fibrillation [30]. Patients with atrial fibrillation and acute aortic syndrome reportedly have a higher in-hospital mortality than do those without atrial fibrillation [30]. These patients are often on oral anticoagulation, which has also been described as a risk factor for bleeding and haemodynamic instability after AADA surgery [31]. In line with these findings, our results indicated both atrial fibrillation (p = 0.04) and oral anticoagulation (p = 0.04) to be strongly associated with mortality. Postoperative bleeding was observed in 25% of the non-survivors in our cohort and was a relevant complication in 19 patients requiring surgical revision.

The duration of extracorporeal circulation correlates with patients’ survival [5,32]. Survivors in our study showed a trend for shorter reperfusion times (minutes: 83.3 ± 40.6 vs. 98.4 ± 40.5; p = 0.25) and total CBP times (minutes: 215.8 ± 73.6 vs. 256.2 ± 125.9; p = 0.26) with a significantly shorter total operation time (minutes: 364.6 ± 97.1 vs. 449.1 ± 141.7; p = 0.002). Longer applications of extracorporeal circulation reflect the severity of the dissection on the one hand and the patients’ cardiovascular capacity to negotiate reperfusion on the other. Moreover, CBP disrupts the integrity of red blood cells, causing haemolysis; in this way, it may affect microcirculation and organ perfusion [33]. To improve patient outcomes, understanding and optimizing the underlying mechanisms of extracorporeal circulation remain of paramount importance. Simplifying the operation technique might influence the patient’s outcome; in particular, the indication for patients treated with FET should be well justified. In the new era of acute aortic surgery, the application of FET in case of AADA without an entry in the aortic arch is a matter of ongoing discussion.

Organ dysfunction during the postoperative phase may severely affect patient recovery and is associated with adverse outcomes. In our cohort, cardiogenic shock was the most common cause of death, accounting for 30% of all fatal outcomes. In all, 45% of non-survivors were diagnosed with acute heart failure, which was strongly associated with mortality (p p 5]. AKI after aortic surgery is potentially limiting in terms of patients’ prognosis [34,35,36,37]. In line with this, patients with preoperatively impaired renal function [38] or those with renal malperfusion [39] carry a higher risk of postoperative renal failure. Furthermore, based on the results of the current cohort, chronic kidney disease was not a relevant factor for mortality, and both survivors and non-survivors had comparable serum creatinine levels at admission (survivors: 1.2 ± 1.2 mg/dL; non-survivors: 1 ± 0.4 mg/dL). These findings underline the importance of early detection of postoperative AKI [40] and undeferred initiation of nephroprotective measures to contain damage to the kidney tissue and allow for a quick organ recovery.

Persistent focal neurological deficits and postoperative stroke were also significantly associated with mortality (p = 0.02 for both). Multivariate regression analysis revealed an odds ratio of 5.8 for a fatal outcome in cases of focal neurological deficits. Although the interpretation of this analysis is limited due to the small sample size of the presented cohort, it is in line with clinical observations in the literature. Neurological deficits, with or without evidence of stroke, complicate the patient’s recovery and are associated with high mortality and hospitalization [16], particularly in the elderly [41]. Although intraoperative protocols have been adjusted to monitor and contain cerebral malperfusion, through tedious blood pressure management and intraoperative NIRS monitoring, postoperative neurological complications remain a significant cause of morbidity and mortality [42]. Procedures involving the aortic arch display increased stroke rates [43], and the different arterial cannulation sites have not been found to bring certain benefits in stroke prevention [44]. Identifying and treating affected patients early in the postoperative phase with an interdisciplinary team may improve the overall outcome during the hospital stay and after the patient’s discharge.