The management of aortic disease, in both its chronic and acute presentations, has always been a fascinating challenge for the cardiac surgeon. This complexity stems from its multifaceted diagnostic nature, its potential simultaneous involvement of various sections of the aorta (ascending, aortic arch, and/or descending), and the time constraints it imposes on precise surgical planning. Consequently, it is essential to approach it optimally in the shortest possible timeframe.
The preferred approach for acute type A aortic dissection is strongly endorsed by the consensus of various medical societies, with surgical intervention considered an immediate necessity. This urgency elevates perioperative morbidity and mortality rates. Without intervention, the natural course of the disease results in a short-term mortality rate ranging from 70% to 90%.
However, there is a subset of patients who progress unusually to a chronic stage without undergoing acute management, deviating from the typical natural course of the disease. In these cases, the condition is often incidentally detected due to diagnostic failure or the absence of medical consultation after the initial acute episode. This variation in presentation results in histopathological changes in the affected tissues, notably fibrosis development, which imparts greater stability. This phenomenon could predict more favorable perioperative outcomes in both short and long-term periods.
In previous years, Elefteriades et al. described certain clinical situations where medical management prevails over surgical intervention, which is deferred or disregarded. These scenarios include a critical condition at initial assessment (with multiorgan involvement) associated with severe comorbidities, patients in their eighties, and a “delayed” presentation, defined as hospital consultation occurring 48-72 hours after symptom onset, and/or a history of previous aortic surgery (vascular or valvular).
The article “Contemporary Midterm Outcomes After Primary Repair of Chronic Type A Aortic Dissection” retrospectively analyzes data from a cohort of 205 patients obtained from a single center between 1990 and 2021. These patients underwent primary repair for “chronic” type A dissection, defined as repair conducted over 60 days after symptom onset or when the onset time was uncertain, based on imaging or intraoperative findings that suggested chronicity.
The technical aspects of the procedures varied considerably over the long period covered by this cohort. Nonetheless, all patients were approached via median sternotomy. A recommendation is made for arterial cannulation at the innominate artery, offering the advantage of selective antegrade systemic or cerebral perfusion. However, femoral cannulation was the primary site in 41% of the cohort, with only 14% undergoing cannulation at the innominate, likely reflecting the historical nature of the cohort. Hypothermia and circulatory arrest were used in 91% (186) of cases, with 44% receiving antegrade cerebral perfusion, 31% retrograde, and the remaining patients managed with bilateral or combined perfusion at low temperatures between 22 and 24ºC. The extent of resection was tailored to the diseased aorta section, with most patients undergoing ascending aorta and hemiarch replacement (72%), unless additional criteria for full arch replacement were met, accounting for 18% of cases:
- Arch diameter exceeding 5 cm.
- Severe compression of the true lumen by the false lumen within the arch.
- Tear originating in or affecting the major curvature or supra-aortic trunk region.
Results showed a relatively young patient population, with a median age of 66 years. Most patients presented with DeBakey type I dissection (52% of the cohort) and were generally younger than those with type II (64 vs. 68 years; p < 0.01). Males were predominant (73%), and 64% had a symptomatic clinical course. Initial acute episodes led to a chronic classification in 40% of patients. Regarding history, 46% had prior cardiac surgeries, with significant differences between DeBakey classifications (type I: 37% vs. type II: 57%; p < 0.05). Among these, 35% had previously undergone coronary revascularization, the most common prior procedure. Ischemia and perfusion times showed no statistical significance between dissection types; however, circulatory arrest time varied by DeBakey classification (type I: 31 minutes vs. type II: 27 minutes; p < 0.01).
Early postoperative outcomes did not show significant adverse event differences among DeBakey types, except for postoperative arrhythmia rates (type I: 28% vs. type II: 42%; p < 0.04). The overall mortality was 7%, which was notably lower than the rates reported in the literature. Absence of complications such as paraplegia, very low rates of paraparesis, and minimal persistent renal dysfunction requiring replacement therapy were remarkable findings. Long-term follow-up (median of five years, ranging from 2 to 11 years) documented a reoperation rate of 3% and reoperation-free survival of 61%.
The authors conclude that durable repair is achievable with acceptable perioperative risks. Although some postoperative variations are noted between aortic dissection subtypes, mid-to-long-term outcomes are comparable. They emphasize the need for individualized therapeutic approaches. However, the management of “evolved” aortic dissection is associated with reduced rates of persistent neurological complications, even lower than in the acute management of this pathology.
COMMENTARY:
This article is highly valuable as it establishes a clear definition of the “chronic” or delayed phase of this pathology, providing crucial insights for patients presenting in this manner. The extensive timeframe of the study and large cohort enable observations of evolving surgical techniques. Despite this, global analysis shows no statistically significant sociodemographic or clinical differences, indicating that these factors did not influence postoperative outcomes or have any significant clinical impact.
The percentage of patients experiencing an episode of type A aortic dissection with a prior surgical history is noteworthy. This is uncommon in routine clinical practice and may be linked to specific surgical techniques used in this single-center cohort (cannulation strategies, clamping, proximal coronary anastomoses, perioperative blood pressure control, etc.).
Due to the single-center retrospective nature of the data analysis, some results should be interpreted cautiously. Nevertheless, this remains one of the most extensive series examining this form of type A dissection, where “natural selection” yields superior outcomes not directly comparable to those in acute presentations.
REFERENCE
Zea-Vera R, Green SY, Amarasekara HS, Orozco-Sevilla V, Preventza O, LeMaire SA, Coselli JS. Contemporary Midterm Outcomes After Primary Repair of Chronic Type A Aortic Dissection. Ann Thorac Surg. 2023 Sep;116(3):459-466. doi: 10.1016/j.athoracsur.2022.12.016.