With improvements in the perioperative and postoperative management of acute type A aortic dissection (AADA), there has been a trend towards aggressive total arch replacement (TAR) rather than hemi-arch replacement to improve long-term outcomes, especially in DeBakey type I aortic dissection (1–5). However, it remains unclear whether to perform extended arch repair or limited hemi-arch replacement in patients with DeBakey type I AADA because surgical volume, surgical experience, and indications for extended arch repair vary among institutions (6–9). Therefore, clinical experiences regarding this question should be reported not only by large centers of excellence, but also by smaller centers, in order to better address this question in the real-world setting.

Our institute is in the northern Hokkaido and performs approximately 20 surgeries for AADA annually. At our institute, replacement of the ascending aorta with resection of the primary entry is the preferred surgical approach. TAR is performed only in cases of (1) an intimal tear localized along the greater curvature of the aortic arch, (2) malperfusion of the carotid arteries, (3) the critical stenosis of the true lumen, and/or (4) significant dilation of the aortic arch (exceeded diameter of 50 mm), and/or (5) patient age less than 60 years. If patients are not candidates for TAR, such as in cases of old age or preoperative patient status, hemi-arch replacement is performed to minimize the invasiveness of the surgery and maximize survival rates. Thus, the aim of the current study was to compare the short- and long-term outcomes of aortic arch surgery using our two surgical strategies in patients with DeBakey type I AADA.

The main finding of the present study was that there was no significant difference in the rate of long-term cumulative survival between the two surgical strategies. The rate of freedom from aortic reintervention was higher in the PR group than in the ER group with close to significance.

The present study showed that the 5-year survival rate between the two groups was not statistically different, though slightly lower in the PR than in the ER group (66.4% ± 7.1% vs. 76.1% ± 7.4%, p = 0.515). This result is in line with those of previous studies. Uchida et al. reported a higher survival rate in TAR at 5 years (69.0% in hemi-arch replacement vs. 95.3% in TAR, p = 0.03) (11), and Omura et al. reported favorable 5-year survival rates in discharged patients (83.8% in hemi-arch replacement vs. 88.6% in TAR, p = 0.54) (2). Other studies also showed that ER can be performed safely without increasing operative mortality and morbidity compared to PR (1, 4, 5, 7, 12, 13). However, Kim et al. (6) pointed out that the previous studies mentioned above (11–13) lack a control group and did not make adequate adjustment for baseline characteristics between the study and control groups. Therefore, more acceptable outcomes in the ER group may reflect a more favorable preoperative risk profile in the ER group compared with the PR group. After adjusting for multivariate variables, they reported that PR afforded better survival at 5 years than ER (83.2% vs. 65.8%, p = 0.01). The tendency for patients to have more favorable preoperative risk profiles in the ER group was also observed in the current study. The PR group was older and had a greater proportion of patients with preoperative shock, impaired consciousness, cardiac tamponade, or requiring CPR. At our institute, the surgical strategy was selected based not only on the location of the intimal tear, the range of dissection, the status of the true lumen, the diameter of aortic arch, and the age of the patient, but also on preoperative patient status. Therefore, with this unavoidable selection bias, preoperative patient status in the PR group was less favorable than that in the ER group and had more risk factors for mortality (such as need for CPR) (2, 14, 15). Thus, the lower long-term survival rate in the PR group could be explained by an unfavorable preoperative status.

The PR group had a higher free from reintervention rate than the ER strategy group (92.9% ± 4.6% vs. 72.6% ± 10.8%, p = 0.134), which has not been reported previously. Theoretically, incomplete resection of the dissected aortic arch may necessitate distal aortic reintervention (2, 12, 16). Typically, TEVAR is performed following hemiarch replacement because of progressive aortic dilatation. However, in our experience, although three cases of reintervention TEVAR were performed, the PR strategy did not correlate with an increased risk of future surgical reintervention. This result may be explained by two factors that were not uniform between the two groups: age and the location of the intimal tear. First, intimal tearing sites were more likely to be confined to the ascending aorta in the PR group. As complete resection of the intimal tear is the basis of treatment, this advantageous factor may explain the low rate of aortic reintervention in the PR group. Second, patients in the PR group were significantly older than those in the ER group. Considering the time to reintervention, a certain percentage of patients in the PR group may have died of other causes before experiencing progression requiring reintervention. PR can be performed less invasively than ER, and it usually allows a significant period without reintervention. As a result, PR is appropriate for elderly patients in circumstances requiring urgent life-saving intervention.

Conversely, ER was associated with a high risk of reintervention, which may be accounted for by the contents of late reintervention. As listed in Table 4, there were three patients who underwent TEVAR following TAR with FET. The FET technique is a concomitant procedure in TAR that was introduced more than a decade ago and has been widely adopted (13, 17, 18). It is generally accepted that FET can result in favorable aortic remodeling. However, it is also associated with the development of distal stent graft-induced new entry (dSINE) postoperatively (19). In all three cases, enlargement of the aneurysm diameter was observed, and these results were considered to be a consequence of dSINE. Although there was an aspect as a secured landing zone provided by FET may contribute for preferring TEVAR, dSINE provoked unwanted late reintervention. The other four cases of reintervention following TAR were all considered complications that were necessitated by a highly invasive and complex ER approach. As shown in Table 2, in comparison with PR, more operative time and a greater amount of human blood derivatives were required in ER. With the increased preference for more invasive surgical approaches, the incidence of postoperative complications requiring reoperation may be unavoidable.

Our institute services a large area in northern Hokkaido, covering an area of 18,000 km² and populated by approximately 650,000 people. Because this area is large and has a low population density, long-distance transfers of patients with AADA to our institute are common. Although Andrew et al. (8) reported that interfacility transfer of patients with AADA, even with delay in surgery, did not affect the operative mortality rate; the desirable onset-to-operation time should theoretically be as short as possible. This is particularly important as the risk of death is estimated to be 1%–2% an hour (20). Caleb et al. showed that the time intervals between symptom onset, diagnosis, and surgery had a significant effect on mortality in patients with AADA (21), which supports the theory described above. As documented by the Japan Registry of Aortic Dissection (JRAD) (22), the median time from onset to arrival at hospital and the percentage of patients arriving within 6 h in Japan were 199 min and 67.4%, respectively, compared with 221 min and 60.9% in our study (Table 1). The percentage of octogenarians reported in the JRAD was 16.9%, compared with 30.4% in the current study. This suggests that a greater proportion of patients with a relatively unfavorable preoperative status are transferred to our institute.

Our study found that PR is less invasive than ER strategy and did not correlate with an increased risk of future surgical reintervention. In addition, reintervention in the PR group was performed electively. There was no perioperative mortality observed. Although the optimal extent of surgical resection and reconstruction of the arch in AADA is still under debate, and the surgical strategy should be selected taking into consideration multiple factors, our results suggest the adequacy of a limited approach for patients with a high risk profile, in preference for urgent life-saving therapy. In particular, in circumstances of relatively unfavorable preoperative patient status and a regional facility, limited aortic resection would be acceptable as not a palliative but a reasonable strategy.

No significant differences were found in the rates of long-term cumulative survival and freedom from aortic reintervention between the two surgical strategies. These findings support the theory that limited aortic resection achieves acceptable patient outcomes.