Early outcomes with a hybrid technique for repair of a non-A non-B aortic dissection

Non-A Non-B Acute Aortic Dissection: Is There Some Confusion in the Radiologist's Mind?

BACKGROUND

The aim of this study is to define and determine the rate of acute non-A-non-B aortic dissections, and to evaluate CT angiography findings and possible complications, as well as to discuss management strategies and currently available therapy. Non-A non-B type of aortic dissection is still a grey area in the radiologist's mind, such that it is not entirely clear what should be reported and completed in terms of this disease.

METHODS

A retrospective single-center study including 36 pre-treatment CT angiograms of consecutive patients (mean age: 61 years) between January 2012 and December 2022 with aortic dissection involving the aortic arch with/without the thoracic descending/abdominal aorta (type non-A non-B).

RESULTS

According to the dissection anatomy, we identified three modalities of spontaneous acute non-A-non-B anatomical configurations. Configuration 1 (n = 25) with descending-entry tear and retrograde arch extension (DTA entry). Configuration 2 (n = 4) with Arch entry tear and isolated arch involvement (Arch alone). Configuration 3 (n = 7) with Arch entry and anterograde descending (±abdominal) aorta involvement (Arch entry). CT angiogram findings, management, and treatment options are described.

CONCLUSIONS

Acute non-A non-B dissection represents an infrequent occurrence of aortic arch dissection (with or without involvement of the descending aorta) that does not extend to the ascending aorta. The complete understanding of its natural progression, distinct CT angiography subtypes, optimal management, and treatment strategies remains incomplete. Within our series, patients frequently exhibit a complex clinical course, often necessitating a more assertive approach to treatment compared to type B dissections.

Current knowledge and contemporary management of non-A non-B aortic dissections

Non-A non-B aortic dissection (AAD) is an infrequently documented condition, comprising of only a small proportion of all AADs. The unique anatomy of the aortic arch and the failure of the existing classifications to adequately define individuals with non-A non-B AAD, have led to an ongoing controversy around the topic. It seems that the clinical progression of acute non-A non-B AAD diverges from the typical type A and B dissections, frequently leading to serious complications and thus mandating early intervention. Currently, the available treatment methods in the surgical armamentarium are conventional open, endovascular techniques and combined hybrid methods. The optimum approach is tailored in every individual case and may be determined by the dissection’s location, extent, the aortic diameter, the associated complications and the patient’s status. The management of non-A non-B dissections still remains challenging and a unanimous consensus defining the gold standard treatment has yet to be reached. In an attempt to provide further insight into this perplexing entity, we performed a minireview of the literature, aiming to elucidate the epidemiology, clinical course and the optimal treatment modality.

Surgical treatment patterns and clinical outcomes of type B aortic dissection involving the aortic arch

OBJECTIVE

In the present report, we have described the outcomes of endovascular repair, hybrid arch repair, and open surgical repair for type B dissection involving the aortic arch (B_{1-2, D}).

METHODS

Cases of endovascular repair, hybrid arch repair, and open surgical repair performed between January 2015 and December 2019 for aortic dissection designated as B_{1-2, D} by the Society for Vascular Surgery/Society of Thoracic Surgeons classification were retrospectively analyzed. The primary end point was all-cause mortality at follow-up. The secondary end points included early mortality, early morbidities, and aortic-related late events. Kaplan-Meier curves were created to analyze survival from all-cause mortality and freedom from aortic-related late events in the endovascular, hybrid, and open groups. Propensity score matching and stratification (stratified by proximal dissection extension: B_{1, D} and B_{2, D}) were performed as sensitivity analyses to compare the outcomes among the three treatment patterns after controlling for major confounders.

RESULTS

The present study included 151 patients (men, 79.5%; mean age, 47.3 ± 10.5 years), with 72 (47.7%) in the endovascular group, 46 (30.5%) in the hybrid group, and 33 (21.8%) in the open group. No significant difference was noted in early mortality between the endovascular, hybrid, and open groups (1.4% vs 2.2% vs 3.0%; P = .791). The incidence of early endoleak was significantly greater (33.3% vs 13.0% vs 6.1%; P = .002) and the incidence of renal function deterioration was less (4.2% vs 26.1% vs 24.2%; P = .001) after endovascular repair vs hybrid arch repair and open surgery. After a median follow-up of 40.0 months (range, 0-84.0 months), no significant differences were found in all-cause mortality (5.6% vs 4.3% vs 3.0%; P = 1.0), aortic-related late events (16.7% vs 15.2% vs 12.1%; P = .834), or late endoleak (9.7% vs 4.3% vs 6.1%; P = .630) after endovascular, hybrid, and open surgery. The propensity score matching and stratification analyses displayed consistent outcomes for early mortality, all-cause mortality, and aortic-related late events among the three groups.

CONCLUSIONS

The mid- to long-term outcomes after endovascular repair, hybrid arch repair, and open surgical repair for type B dissection involving the aortic arch (B_{1-2, D}) were favorable and comparable in selected patients. Extensive experience and multidisciplinary teamwork are prerequisites for individualized strategies for repair of B_{1-2, D}.

Non-A non-B aortic dissection: A literature review

Non-A non-B aortic dissections are an infrequent occurrence and represent a small proportion of aortic dissections. Treating this life-threatening medical emergency often requires surgeons to undertake some one of the most challenging surgical or endovascular cases in medicine. This literature review aims to define and classify non-A non-B dissections, describe their epidemiology as well as their pathology. This review also aims to discuss the range of surgical techniques employed in their treatment and management and to investigate the patient outcomes associated with each technique.