Frozen elephant trunk: What can the Salerno experience tell us?

Field: Medicine (Health Sciences)

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. Open access funding enabled and organized by Projekt DEAL.