Discussion
Open aortic arch surgery is a complex surgical procedure requiring meticulous planning and strict collaboration of surgical, anesthetic and perfusionist teams. Specifically, in this type of surgery temporary circulatory arrest is key to enable the replacement of the enlarged aortic segment. Consequently, during open aortic arch surgery, protection is required not only for myocardium (as during standard classical cardiac surgery) but also for central nervous system and vital organs. Our analysis shows that patients undergoing aortic arch surgery are older (median 64 years (54-69)) with many co-existing conditions of the heart and the aorta, often implicating the expansion of the scope of planned surgery.
After having analyzed our 10-year outcomes of open aortic arch surgery, we were struck by the high early mortality of 11.6%, significantly higher than the mortality of 5.5% reported in the literature to date [13]. Therefore, we decided to break up those 10 years into two 5-year periods.
The analysis of the first 5 years (group A) revealed that the early learning curve period is associated with outcomes significantly worse than those reported in literature. Particularly noticeable are early mortality of 20% and stroke rate of 24%, whereas Thomas et al. [13] report rates of 5.5% and 5% respectively after elective surgery. These results can be regarded as even poorer, keeping in mind that in most cases (68%) the surgery of aortic arch was limited to only partial replacement (hemiarch). In this type of approach Lima et al. [14] report early mortality of 2.9% and stroke rate of 4.1%. Worse surgical outcomes in group A are reflected by longer ICU stay, longer time of mechanical ventilation and more acute kidney failure and pneumonia in comparison to group B. Another important factor affecting the postoperative outcome was the central nervous system protection, which in as many as 24% of patients was limited to deep hypothermic circulatory arrest. This translated into high rate of stroke (24%).
With experience gained the number of operated patients increased from 25 patients (29%) in group A to 61 patients (71%) in group B, and the scope of surgeries became more extended (from 32% total arch replacements in group A to 66% in group B). Additionally, descending aorta and aortic root became more frequently addressed. Frozen elephant trunk with the use of the E-vita OPEN PLUS system (Jotec, Hechingen, Germany) became the preferred technique for surgeries involving the descending aorta.
In the second study group, complementary surgical procedures on aortic root (valve sparing aortic root replacement (VSARR)) and aortic valve, even though technically demanding and time consuming, were not avoided. Of note is the rising ratio of repaired aortic valves from 50% in group A to 79% in group B. The extending scope of surgery resulted in longer CPB time in group B: 200 minutes vs 163 minutes (P =0.003) .
Despite the fact that patients in group B underwent more complex aortic arch surgery, had more additional coronary and valvular procedures, and more redo surgeries, the outcomes were significantly better than in group A. The early mortality of 8.2% is similar to the data reported by Patel et al [15] in his large series of 721 patients, and even better than the early mortality of 15% reported from another polish center by Hirnle et al [16].
Meticulous central nervous system protection contributed to the reduction of stroke ratio to 1.6%, which is an excellent result, better than the numbers reported by Patel et al. [15] (4.8%) and Hirnle et al. [16] (9%). This low ratio of stroke is related to the implementation of selective brain perfusion with cerebral oxygenation monitoring in the majority of operated patients (96.7%), whereas DHCA was used in only 2 patients (3.3%).
To summarize it seems that the key factor impacting the outcomes of open aortic arch surgery is the experience of the team, which translates into reproducible results on par with those reported by other surgical teams specializing in the surgery of aortic arch. Estimated 5-year survival of 81% after open aortic arch surgery makes it a reliable and reproducible cardiac surgical procedure, associated with good long-term outcomes.