The surgical techniques for acute type A aortic dissection (ATAAD) vary significantly. While indications for certain approaches are sometimes clear, in other cases, selecting the optimal surgical strategy is more complex.

The aim of this study was to analyze outcomes based on the chosen surgical approach for ATAAD: a conservative approach with ascending aorta and hemiarch replacement in higher-risk patients, or a more aggressive technique with root and/or total aortic arch replacement in lower-risk patients. Patients undergoing conservative repair (group 1) were compared to those undergoing extensive repair (group 2) using univariable and multivariable analysis. From 1997 to 2019, 343 patients underwent ATAAD repair. Of these, 240 received conservative repairs, while 103 received extensive repairs. Group 1 was older and presented more comorbidities such as hypertension, previous myocardial infarction, and renal dysfunction. Group 2 had a higher prevalence of connective tissue disease (2.1% vs. 12.6%; p = 0.01), aortic insufficiency, and longer intraoperative times. The incidence of individual postoperative complications was similar regardless of approach. However, the composite of significant adverse events (surgical mortality, myocardial infarction, stroke, dialysis, or tracheostomy) was higher in the conservative group (15.1% vs. 5.9%; p = 0.03). Surgical mortality was 5.6% and showed no difference between groups. Ten-year survival rates were similar with either surgical approach. The cumulative 10-year reintervention risk was higher in group 2 (5.6% vs. 21%; p < 0.01). In multivariable analysis, ejection fraction and diabetes were predictors of major adverse events, but extensive repair was not. Extensive repair was, however, a predictor of late reintervention (OR = 3.03; p = 0.01).

The authors conclude that a customized conservative approach for ATAAD leads to favorable surgical outcomes without compromising durability.

COMMENTARY:

There is no doubt that treating type A aortic dissection represents a surgical challenge with significant mortality. Both the chosen surgical strategy and the expertise of the surgeons play a decisive role in the outcome. Lau et al. present their personal experience from a specialized aortic surgery center, encompassing a considerable number of patients over a 22-year period. In two-thirds of cases, a conservative strategy was adopted, avoiding root and total arch replacement, primarily in elderly, frail patients with significant comorbidities. The remaining group of patients underwent a more extensive root and/or aortic arch surgery. Notably, regardless of the chosen surgical strategy, the observed operative mortality was very low, and the long-term results were excellent.

When reviewing the literature comparing hemiarch surgery versus complete aortic arch replacement in ATAAD, there is a wide variation in outcomes. Pending results from the first randomized trial (HEADSTART) underway, the latest meta-analysis shows no significant differences in mortality or long-term reoperation rates. However, other studies present diverse outcomes, likely due to the challenge of homogenizing study groups in this type of disease. In the series analyzed by Lau et al., the conservative approach group showed, somewhat paradoxically, a higher incidence of adverse events than the extensive repair group. This outcome highlights the appropriate decision to limit aggressive surgery in higher-risk patients. In terms of long-term outcomes, ten-year survival was notably high in both groups, exceeding 60%, which is commendable. On the other hand, the higher incidence of late distal reintervention in the extensive surgery group reflects a more severe pathology rather than incomplete treatment. Conversely, the lower reoperation rate during follow-up in the conservative group might be attributed to unknown factors such as deaths from non-aortic causes, contraindications for reintervention due to age/comorbidities/frailty, or other factors.

Achieving these excellent outcomes required a combination of factors that are not always possible. The systematically adopted strategy of performing less aggressive surgery in older patients with severe comorbidities is a key component, but probably more crucial was the degree of specialization achieved at this center in the surgical treatment of aortic dissection. This allowed the surgeons to acquire all necessary skills (surgical experience, consistent decision-making, etc.) to optimize these results. Increasingly, many cardiac surgery centers have begun establishing multidisciplinary teams specialized in this pathology, enabling them to gain experience with a relatively rare condition that involves continuously evolving technological resources and complex surgical treatment.

In any case, as with many things in life, these decisions are rarely black and white but rather shades of gray. A long, complex surgery, even if performed technically to perfection, may not be tolerated by an elderly and frail patient. Conversely, a more conservative approach might not be sufficient long-term in a younger patient with connective tissue disease. This article reflects the philosophy followed by many centers, where the approach should be guided by the patient’s condition rather than the disease itself, and the primary goal in cases of aortic dissection should always be, above all, to save the patient’s life.

REFERENCE:

Lau C, Robinson NB, Farrington WJ, Rahouma M, Gambardella I, Gaudino M, et al. A tailored strategy for repair of acute type A aortic dissection. J Thorac Cardiovasc Surg. 2022 Dec;164(6):1698-1707.e3. doi: 10.1016/j.jtcvs.2020.12.113.