Total aortic arch replacement has been and remains one of the most complex procedures in cardiovascular surgery. Since the first successful arch repair in the 1950s,¹ the risks for cerebrospinal complications and mortality have been reduced but not eliminated. The introduction of hypothermic circulatory arrest² and antegrade cerebral perfusion³ were critical to improving the outcome of the arch repair. Since many patients require a second-stage procedure, the invention of the elephant trunk procedure was another milestone in simplifying future operations on the descending aorta.⁴

The combination of an arch prosthesis and a stent-graft for the descending aorta is nowadays known as the “frozen elephant trunk.” It has the potential to treat complex aortic pathologies in a single-stage procedure.⁵ The Thoraflex™ Hybrid graft was introduced in Europe almost a decade ago and currently awaits its commercial availability in the United States. Four-branched hybrid grafts simplify selective anastomoses of the supra-aortic vessels.

In this issue of the Journal of Cardiac Surgery, Masiello et al.⁶ present their single-center experience with the Thoraflex™ Hybrid prosthesis. In this retrospective study, the authors report on 70 patients who underwent total aortic arch replacement with the frozen elephant trunk technique over a time period of approximately 2 and a half years. The early mortality was acceptable and the rates of perioperative stroke and spinal ischemia were extremely low.

The early mortality was 14.2% in the present study and involves both elective and emergent cases for aortic dissection. Therefore, the mortality is comparable to the results of other centers.^7-11 The incidence of stroke and spinal ischemia were low in the Salerno experience. Neurologic complications have always been an issue with operations on the aortic arch, especially in high-risk patients.¹² Generally speaking, we have to put more effort into further reducing this risk. The authors' surgical approach relies on “debranching” the supra-aortic vessels on the beating heart and they attribute the low stroke rate (partially) to this technique. I find this approach promising.

Also, the risk for spinal ischemia can be a problem with the frozen elephant trunk procedure. The Salerno group performs the distal anastomosis in Zone 2. The proximalization of the distal anastomosis is thought to reduce the risk for spinal cord injury and is nowadays widely performed.¹³ In addition, their usage of a short stent-graft helped to minimize the risk for spinal ischemia.

The present study advocates for the usage of the frozen elephant trunk in dedicated aortic centers.⁶ While I support the authors' suggestions that complex aortic operations should be performed in specialized centers, it might be difficult for such centers to be simultaneously geographically accessible. More geographically dispersed smaller centers might not be able to perform the frozen elephant trunk procedure with adequate results. Especially in acute aortic dissection, a simpler operation might be more appropriate to prevent a deadly outcome in these cases. In elective situations, it might be advisable to refer complex aortic cases to specialized aortic centers.

In summary, the present study by Masiello et al.⁶ demonstrates how the frozen elephant trunk procedure can be applied with excellent results. The Salerno group does a lot of things right and is rewarded with good outcomes. Total arch replacement will never be an operation that can be easily performed in every center, but the present study demonstrates that four-branched hybrid off-the-shelf solutions have the potential for easy adoption into clinical practice in dedicated aortic centers.

全主动脉弓置换术一直是并且仍然是心血管手术中最复杂的手术之一。自 1950 年代第一次成功的足弓修复以来，¹脑脊椎并发症和死亡率的风险已经降低但并未消除。引入低温停循环²和顺行脑灌注³对于改善足弓修复的结果至关重要。由于许多患者需要第二阶段手术，象鼻手术的发明是简化未来降主动脉手术的另一个里程碑。⁴

用于降主动脉的弓形假体和支架移植物的组合现在被称为“冷冻象鼻”。它有可能在单阶段程序中治疗复杂的主动脉病变。⁵ Thoraflex™ Hybrid 移植物大约十年前在欧洲推出，目前正在等待其在美国的商业供应。四分支混合移植物简化了主动脉上血管的选择性吻合。

在本期《心脏外科杂志》中，Masiello 等人。⁶人展示了他们使用 Thoraflex™ Hybrid 假肢的单中心体验。在这项回顾性研究中，作者报告了 70 名患者在大约 2 年半的时间里使用冷冻象鼻技术接受了全主动脉弓置换术。早期死亡率是可以接受的，围手术期卒中和脊髓缺血的发生率极低。

在本研究中，早期死亡率为 14.2%，涉及主动脉夹层的择期和紧急病例。因此，死亡率与其他中心的结果相当。^7-11在萨勒诺的经验中，中风和脊髓缺血的发生率很低。神经系统并发症一直是主动脉弓手术的一个问题，尤其是在高危患者中。¹²一般而言，我们必须付出更多努力来进一步降低这种风险。作者的手术方法依赖于使跳动心脏上的主动脉上血管“脱支”，他们将低中风率（部分）归因于这种技术。我发现这种方法很有前途。

此外，脊髓缺血的风险可能是冷冻象鼻手术的一个问题。Salerno 组在 2 区进行远端吻合术。远端吻合术的近端化被认为可以降低脊髓损伤的风险，并且现在被广泛执行。¹³此外，他们使用短支架移植物有助于将脊髓缺血的风险降至最低。

本研究提倡在专门的主动脉中心使用冷冻的象鼻。⁶虽然我支持作者的建议，即复杂的主动脉手术应该在专门的中心进行，但这些中心可能难以同时在地理上可达。地理上更分散的较小中心可能无法以足够的结果执行冷冻象鼻手术。特别是在急性主动脉夹层中，在这些情况下，更简单的手术可能更适合防止致命的结果。在选择性情况下，建议将复杂的主动脉病例转诊到专门的主动脉中心。

总之，Masiello 等人的本研究。^{图 6}展示了如何应用冷冻象鼻手术并取得优异的效果。Salerno 小组做了很多正确的事情，并获得了良好的结果。全弓置换永远不会是在每个中心都可以轻松进行的手术，但本研究表明，四分支混合现成解决方案有可能在专门的主动脉中心轻松应用于临床实践。