The prevalence of descending thoracic aortic pathologies, comprising mainly of aneurysm, dissection, and PAU, which eventually rupture if not recognized and treated appropriately, are increasing among our population . Since, the report on the first successful open repair of a descending thoracic aortic aneurysm with a prosthetic graft in 1953 by De Bakey and Cooley , an open surgical repair for treating descending thoracic aortic disease has been the gold standard for 50 years [13-16]. Despite remarkably improved operative techniques and maximized organ protection, open repair of the descending thoracic aorta is still associated with high complications, including intraoperative and postoperative death, hemorrhage, stroke, and paraplegia [9, 17].
Dake et al.  proposed an alternate method of TEVAR which sought to provide better clinical outcomes in patients who were deemed to be at high risk for open repair or were typically considered nonsurgical candidates. Therefore, TEVAR has shown significantly improved early quality of life versus open repair and a general trend toward better short-term perioperative survival and freedom from major complications [1, 3, 4, 18]. However, TEVAR has anatomic restrictions such as severe thoracic aortic tortuosity, short landing and sealing zones, and extensive mural thrombus. These are the limiting factors, although a seemingly infinite variety of debranching and bypass procedures can be applied to extend either the proximal or distal sealing zones [6, 19]. Furthermore, significant complications related to stent -grafts were always implied [3, 5, 17].
Patients who underwent TEVAR have a tendency to have a worse prognosis and older age, with multiple comorbidities, than patients who underwent open repair. Due to the relative lack of data supporting the long-term reliability of TEVAR, open repair procedure has been preferentially offered to younger patients [4, 12]. Therefore, in this study, to neutralize the effects of age difference that could potentially unmask a mortality benefit, PSM was performed between the two groups to perform an adequately powered analysis.
In the present study, the operative time, postoperative length of stay, and procedure-related complications showed better results with TEVAR before and after PSM. Not surprisingly, TEVAR was considering as the procedure involved no aortic cross-clamping, ischemic time, or thoracotomy . In open repair cases, some disadvantages of deep hypothermia, including coagulopathy which caused difficulty in controlling bleeding, retraction injury to a heparinized lung, cold injury to the lung, and a profound inflammatory response from the bypass circuit . Regarding the in-hospital mortality in the open repair group, in the present study, one patient died of pneumonia. AKI is another important complication and regarded as a marker of increased early or late morbidity and mortality after open repair or TEVAR . Patients who underwent TEVAR were older and tended to receive larger amounts of contrast agent, which was not safe considering the risk of AKI. In the present study, postoperative AKI was higher in the open repair group (42.2%), and dialysis was performed in 13.3% of the patients in this group. Eighteen patients who underwent TEVAR (19.8%) had an AKI, six patients in the TEVAR group experienced AKI requiring dialysis. Before and after PSM, AKI was higher in the open repair group; however, there was no statistical difference in the requirement of dialysis between the two groups.
Although a short-term hospital outcome is more favorable for TEVAR, aorta-related complications are more frequent for TEVAR. Five patients (11.1%) in the open repair group underwent reintervention, and the most common cause of reintervention was new-onset aortic dissection or expansion. In the case of TEVAR, the most common cause of reintervention was endoleaks. Twenty-two (48.9%) patients who underwent reintervention showed no in-hospital mortality in the TEVAR; however, seven patients showed late mortality, one patient died of ABF and one patient died of sepsis due to stent-graft infection. Ascending aortic replacement was performed in one patient with retrograde aortic dissection, four patients with ABF underwent aorta replacement and lobectomy, and one patient with AEF underwent aorta replacement and esophagotomy, and showed late mortality. Additionally, eight patients who were initially offered TEVAR, later crossed over to open repair due to difficult anatomy or other reasons.
In the open repair cases, high-volume centers reported mortality and neurological morbidity rates ranging from 5.4% to 7.2% for mortality, 2.1% to 6.2% for permanent stroke, 5.7% for permanent paraparesis, and 0.8% to 2.3% for permanent paralysis, respectively [22, 23]. In the TEVAR cases, the perioperative results for the three stent- graft trials showed 1.9- 2.1% for mortality, 2.4- 4% for stroke, 4.4- 7.2% for permanent paraparesis, and 1.3- 3% for permanent paralysis, respectively [1, 2, 24]. In the present study, the open repair group showed 63.8% of overall 10-year survival rate, 84.3% of aorta-related 10-year survival rate, 6.7% of stroke, and 4.4% of SCI (after PSM, 65.4%, 88.5%, 5.7%, and 2.9%, respectively). In TEVAR, overall 10-year survival rate was 56.5 %, aorta-related 10-year survival rate 81.3%, 1.1% stroke, and 1.1% SCI (after PSM, 64.2%, 88.7%, 0.0%, 0.0%, respectively). Although mortality was higher than previous large-scale studies, it was difficult to compare our results because previous reports did not have long-term follow-up data.
The existing literature on TEVAR versus open surgical repair suggests that the short-term benefit of TEVAR is lost as early as within 1–2 years from the surgery [3-7]. For mid-term outcomes, analysis of the Medicare database from 2004 to 2007 showed that TEVAR offered a significant perioperative survival advantage when compared to open repair, regardless of the indication for repair. However, the 5-year survival in the Medicare population was similar between the two cohorts . In another study, Goodney et al.  reported patients with intact thoracic aortic aneurysm who underwent TEVAR had a significantly worse survival at 1 year than patients who underwent open repair (87% for open repair and 82% for TEVAR; p =0.001) and 5 years (72% for open repair and 62% for TEVAR; p =0.001).
Chiu et al.  reported that open surgical repairs of descending thoracic aortic aneurysms between 1999 and 2010 were associated with increased odds of early postoperative mortality, but reduced late hazard of death. Despite the improved durability of open surgical repair, the initial mortality advantage of TEVAR over open surgical repair persisted for until nine years post-operatively, resulting in a significant survival benefit associated with TEVAR. They proposed TEVAR ought to be considered as first-line therapy among Medicare beneficiaries, and open surgical repair be restricted to high-volume centers and patients with a low risk of perioperative mortality. However, Desai et al.  reviewed their series of patients who had descending thoracic aortic aneurysms repaired by either TEVAR or open repair. They concluded that 105 patients in the TEVAR group clearly had undergone more reinterventions than 45 patients who underwent open repair. The TEVAR cohort had a trend towards a decreased 30-day mortality as well as decreased rates of neurologic complications; however, none of these findings reached statistical significance. During a long-term follow-up from 1995 to 2007, the choice between TEVAR and open approach did not influence survival (p =0.5).
In our study, TEVAR was more prevalent in terms of postoperative short-term outcomes. However, we could not conclude that TEVAR was superior to open repair in terms of SCI, 30-day mortality, and in-hospital mortality. Furthermore, there was no significant difference in the long-term follow-up survival between the two approaches. We hypothesized that these advantages of TEVAR, i.e., less invasiveness and ease of use, will provide improved long-term results for the patients.
Similar to the previous study, our findings indicated that TEVAR was better than open repair in terms of short-term outcomes; however, the long-term results were similar in both groups. Considering the fact that the previous studies had data older than in this study and there were discrepancies in the age or number of patients between the two groups, we believe that this study, which used PSM to neutralize the effects of confounding independent variables, presents more accurate data on the long-term results of the two groups.
In case of reintervention rates, there were significantly reinterventions in the TEVAR group than in the open repair group. Moreover, although long-term survival of the two groups did not differ significantly, more reinterventions occurred in the TEVAR group; the costs of additional graft modules to treat endoleaks and follow-up CT scans increase hospital cost, attributing to the disadvantage of TEVAR. Furthermore, while TEVAR had lesser procedure-related complications than open repair; patients had more adverse events, such as re-dissection, fistula formation and stent-graft infection. This should be considered in the choice of approach.
Some authors have proposed that TEVAR does not change the natural history of the disease, and although less invasive, may be inferior to open therapies . In our present study, the maximal aortic size decreased more in the open repair group than in the TEVAR group, but not dramatically. This supports the report that it does not alter natural history of aortic pathologies, and, emphasizes the importance of long -term follow up. For this reason, in patients requiring TEVAR, the establishment of a precise TEVAR indication will reduce the requirement for further reintervention; better results are expected with improvements in debranching skills and stent- graft development.
Our study has several limitations. First, it was a single-center retrospective study that included a small number of patients, with a possible selection bias that might have affected our results. Second, the difference of follow-up duration and frequency can affect the survival rate of both groups. We performed PSM attempts to reduce the bias due to confounding variables. However, since TEVAR was introduced in 2007, it has a relatively short follow-up duration, whereas more frequent follow-up to monitor stent- grafts is expected to affect the results. Finally, the functional status of patient information influenced treatment strategy; there was no data interpretation, and studies on cost analysis, which is an increasingly important consideration for treatment strategy, have not been conducted. The results, which include all of these, may influence the final assessment of quality of life and longer life expectancy.