Can a ‘branch-first’ approach to aortic arch replacement be safely utilized in Stanford type A acute aortic syndromes? Open Access

Summary

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: ‘Can a “branch-first” approach to aortic arch replacement be safely utilized in Stanford type A acute aortic syndromes?’ Altogether 64 papers were found using the reported searches, of which 10represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. All papers included in this BET reported acceptable mortality and/or neurological outcomes in comparison to currently published standards for traditional repair. We conclude that while there is a need for larger series, direct comparison and long-term follow-up, the ‘branch-first’ approach to aortic arch replacement has been safely performed in several centres in the setting of acute aortic syndromes with results demonstrating acceptable mortality, neurological outcomes and mid-term survival.

INTRODUCTION

A best evidence topic was constructed according to a structured protocol. This is fully described in the ICVTS [1].

THREE-PART QUESTION

In [Stanford type A acute aortic syndrome], does [a ‘branch-first’ approach] result in [acceptable mortality and neurological outcomes].

CLINICAL SCENARIO

A 56-year-old male presents to your emergency department with an acute Standford type A aortic dissection (AD) extending into his aortic arch. You are familiar with the outcomes of traditional surgical repair of type A AD and the known complications of prolonged periods of deep hypothermic circulatory arrest as this is the usual approach your department takes to such cases. Surgeons in your department have been performing elective aortic arch replacement surgeries utilizing an ‘branch-first’ approach and are advocating the benefits of continuous cerebral perfusion and reduced hypothermic arrest time. You are unsure if this technique has an established safety in aortic dissection and you resolve to check the literature for evidence.

SEARCH STRATEGY

The literature search was performed in MEDLINE from 1946 to September 2023 using the Ovid interface using the search terms: [Aortic Aneurysm, Thoracic/or aortic arch replacement.mp. or Aortic Dissection/] OR [aortic arch.mp.] OR [aortic arch repair.mp.] OR [aortic arch surgery.mp.] OR [aort* dissection.mp.] AND [branch first.mp.]. A second search was performed using only the search term: [branch first.mp]. A review of references of all papers was performed.

SEARCH OUTCOME

A total of 35 papers were found utilizing the first search. From these, 10 papers were identified that provided the best evidence to answer the clinical question. Sixteen papers were excluded as they did not address the clinical question or discussed only surgical technique without patient results. Eight papers were excluded as they presented early results from the same centre (Austin Health, Australia). One paper was excluded as it was not in the English language. Given the limited papers yielded from this initial search, a second search as described above, was performed. This search yielded 64 papers. On review, no new papers meeting the criteria were identified. One further paper was identified on review of references however it was excluded as it was performed with traditional circulatory arrest.

RESULTS

Abt et al. [2] provide a direct comparison between the outcomes of the ‘branch-first’ technique and traditional aortic arch replacement. They present a retrospective analysis from a single centre of 144 patients, of which 76 (52.8%) underwent a ‘branch-first’ aortic arch replacement. In this group, 31 patients (41%) had acute aortic syndrome or dissection, compared to 35 (51%) in the traditional repair group (P = 0.23). ‘Brach-first’ patients were cooled to 27.4 (±3.5)°C, with a median cardiopulmonary bypass (CPB) time of 189 (Interquartile range (IQR) 154–238) min, cross-clamp time 87 (IQR 62–135) min with antegrade cerebral perfusion utilized in both groups. The presentation of the results does not allow for separation of type A AD from the aneurysm patients. Given the significant variation in the baseline clinical status of these 2 patient populations, inclusion of aneurysm patients may have an impact upon the reported complication rate and must be noted if comparison is made to other reported outcomes in type A AD cohorts. This paper shows a significant reduction in 30-day mortality (P = 0.004) with no significant difference in stroke (P = 0.2), postoperative dialysis (P = 0.45) or length of stay (P = 0.42) in the ‘branch-first’ group, supporting the safe utilization of the procedure.

Considered founders of the technique, first described in 2011 [3, 4], Matalanis et al. [5] discuss their 15-year single-centre experience with the ‘branch-first’ technique. They present a retrospective analysis of 155 patients, 62 of whom had the procedure performed for type A AD. Cooling to a mean target of 25 (23.8–28)°C, they report a mean CPB time of 265.5 (220–320) min, cross-clamp time of 154.5 (117–202.5) min with no period of global cerebral arrest. Fifty-six percentage of cases were suitable for distal clamping requiring no distal ischaemia. Postoperatively they reported a 9.0% rate of dialysis, 3.2% rate of permanent cerebrovascular events, 1.9% rate of spinal ischaemia and 4.5% in hospital mortality rate. Of note, in the subgroup of uncomplicated dissections and elective cases, 1.9% of patients suffered a stroke, with no mortalities. This is the only paper captured by this BET that offers direct comparison between the outcomes of type A AD and aneurysm patients. The type A AD group had higher rates of dialysis (17.7% compared to 3.2%, P < 0.01), transfusion (4 zunits compared to 1 unit, P < 0.01), longer stays in the Intensive Care Unit (ICU) (101.5 compared to 45 h, P < 0.01), more ventilatory hours (27 compared to 13 h, P < 0.01) and longer hospital length of stay (14 compared to 9 days, P < 0.01) compared to aneurysm patients. Overall, the paper supports the safety of a ‘branch-first’ approach with acceptable mortality and neurological complication rates compared to standard published outcomes [6, 7].

Presenting on the same set of patients as Matalanis et al. [5], Sharma et al. [8] present the data as a comparison between emergency and elective cases and offer midterm results utilizing Kaplan–Meier analysis to assess freedom from mortality and reintervention. Of the elective patients, 21 (19.8%) were aortic dissection cases compared to 41 (83.7%) in the emergency group. The remainder were aortic aneurysms. Results show an acceptable mid-term mortality and reintervention rate (Table 1). When interpreting the results of this paper, it is important to note that while 10-year outcomes are presented, their study design specifies that follow-up data was collected until the last known follow-up, which is specified as a median of 38.9 (IQR 15.4–82.9) months. Overall, the paper supports the safety of a ‘branch-first’ approach with acceptable mid-term results.

Su et al. [9] present a retrospective analysis of 15 patients operated on over a 19-month time period utilizing the ‘branch-first’ approach to perform aortic arch replacement in acute type A AD. They report a mean CPB time of 133.4 ± 20.0 min, a mean aortic cross-clamp time of 68.1 ± 25.8 min and a mean lower body circulatory arrest time was 18.3 ± 5.5 (range 14–25) min. The mean bladder temperature of hypothermic circulatory arrest was 27.8 ± 0.85°C (range 26–29). Continuous antegrade cerebral perfusion was maintained on all patients during lower body circulatory arrest. Only 1 patient required temporary haemodialysis and there was no reoperation for bleeding. All patients survived and no patient had permanent neurological deficit, supporting the safe utilisation of a ‘branch-first’ approach.

Yang et al. [10] present a retrospective analysis of 108 patients with type A AD operated on over a 16-month period at a single centre. They offer comparison between 84 patients who underwent a traditional repair with the classical ‘Sun’s procedure’, a technique of total aortic arch replacement with a stented elephant trunk [11], compared to 24 patients who underwent the ‘branch-first’ approach. This provided the only direct comparison of outcomes between the 2 surgical approaches captured by this BET. The ‘branch-first’ group had significantly shorter CPB time (172.4 ± 29.9 min, compared to 194.9 ± 47.4 min, P = 0.04), significantly shorter ICU stay [17.0 (14.6–38.2) h compared to 42.1 (19.7–87.2) h, P < 0.01] and significantly shorter mechanical ventilation time [15.5 (11.9–40.0) h compared to 19.0 (17.0–45.6) h, P = 0.018]. There was no statistical difference demonstrated for in-hospital deaths (2 compared to 10, P > 0.99), red blood cell transfusion [0.0 (0.0–1.0) compared 0.0 (0.0–1.0), P = 0.26], neurological complications (2 compared to 13, P = 0.51) or postoperative dialysis (2 compared to 9, P > 0.99) between the ‘branch first’ and traditional group. Overall, this paper supported the safety of the ‘branch-first’ approach with no significant difference in mortality or neurological outcomes compared to the traditional approach to aortic arch replacement but lacked patient numbers to demonstrate statistically significant improvement in these outcomes.

Zheng et al. [12] present a retrospective analysis of 36 patients performed over an 18-month period at a single centre. Of these, 26 patients had type A AD and 10 had aortic aneurysms. The presentation of the results does not allow the type A AD patients to be separately analysed. They cooled patients to 28 ± 1.1°C with a mean CPB time of 172.4 ± 43.3min, a cross-clamp time of 94.3 ± 24.3min and a moderate hypothermic circulatory arrest time of 23 ± 6 min. They had a total of 2 postoperative mortalities, 1 (2.8%) cerebral infarction and 2 temporary episodes of paraplegia. They offer comparison to previous results at their centre with the classic ‘Sun’s procedure’ approach, with the ‘branch-first’ approach showing an improvement in mortality rate from 7.8% to 5.6%, a reduction in mean CPB time from 201 to 174 min and a reduction in cross-clamp time of 111 to 94 min. Overall it supports an improvement in mortality outcomes.

Li et al. [13] present a retrospective analysis of 12 patients operated on over an 11-month period at a single centre. All patients had type A AD and underwent surgical repair via a ‘branch-first’ approach. Cooling their patients to 28–30°C, they report a CPB time of 223 ± 32 min, a cross-clamp time of 110 ± 22 min and a circulatory arrest time 65 ± 22 s. In their series, they reported no hepatorenal or coagulopathy complications and no mortalities or neurological complications. While a small sample, this paper supports the safe application of the technique with acceptable mortality and neurological outcomes.

Gao et al. [14] present a brief retrospective description of 41 of their patients on which they performed a ‘branch-first’ aortic arch replacement, with 36 of these patients having undergone the procedure for management of acute type A AD. The presentation of the results does not allow the type A AD patients to be separately analysed. They state they targeted moderate hypothermia of 28–32°C and that the procedures were performed ‘within ∼4 h’, but no further details are provided within the text regarding cross-clamp or lower body circulatory arrest time. The only outcome reported within the paper is ‘no surgical deaths’ with no data presented regarding neurological outcomes. While the absence of surgical mortality is of note, no other outcomes from the ‘branch-first’ approach can be extracted. Overall, this paper supports the safety of the ‘branch-first’ approach but has limited evidence presented.

Zheng et al. [15] present a single case experience of a 62-year-old male who underwent the branch-first approach for the management of a penetrating aortic ulcer located at junction of the ascending aorta and arch. The patient survived with no neurological complication. They had a hypothermia target of 28°C, a CPB time of 107 min, a cross-clamp time of 58 min and a circulatory arrest time of 13 min, with cerebral perfusion maintained throughout. While only a single case, this paper helps to support the use of the technique for a pathology other than the aneurysms and dissections captured in the other papers.

Robertson et al. [16] report on the results of a single case experience with a 64-year-old female with a retrograde type A AD presenting on imaging following initial endovascular intervention of a type B dissection. The patient was cooled to 25°C and had a CPB time of 236 min, cross-clamp time 135 min and a lower body circulatory arrest time of 46 min. There was no mortality or significant neurological deficits reported and she was alive at 6-month follow-up. While limited to a single case, this report does serve to demonstrate the successful replication of the procedure outside of major aortic units.

CLINICAL BOTTOM LINE

We conclude that while there is a need for larger series, direct comparison and long-term follow-up, the ‘branch-first’ approach to aortic arch replacement has been safely performed in several centres in the setting of acute aortic syndromes with results demonstrating acceptable mortality, neurological outcomes and mid-term survival.

Conflict of interest: none declared.

Funding

No funding to declare.

DATA AVAILABILITY

No new data sets were created or analysed during this study. All articles referenced are available via Ovid Medline.

Reviewer information

Interdisciplinary CardioVascular and Thoracic Surgery thanks Yasunori Iida, Thierry Caus and the other anonymous reviewer(s) for their contribution to the peer review process of this article.

REFERENCES