ObjectivePrevention of late type 1a endoleaks is the main concern in thoracic endovascular aortic aneurysm repair (TEVAR) for thoracic aortic aneurysm (TAA). Since 2017, we have performed zone 0 TEVAR with proximal fixation augmentation using a Najuta thoracic fenestrated stent graft in addition to zone 2 TEVAR for distal arch aneurysms. We report the early-midterm outcomes of TEVAR performed using this strategy. MethodsThis single-center retrospective study enrolled 386 cases of TEVAR for thoracic aortic disease between January 2013 and December 2020. Patients with TAA treated by TEVAR landing at zone 2 was referred to as the Standard group (S group), whereas those treated by TEVAR landing at zone 0 using a Najuta fenestrated stent graft in addition to zone 2 TEVAR was referred to as the Augmentation group (A group). We retrospectively compared the clinical outcomes between the two groups. The primary endpoint was secondary intervention for postoperative type1a endoleaks. Secondary endpoints were technical success, aneurysm-related death (ARD), and major adverse events (MAEs) including stroke, paraplegia, endoleaks, and secondary interventions. ResultsWe performed TEVAR in 41 and 30 cases in the S and A groups, respectively. The mean aneurysm sizes in the S and A group were 54.5 and 57.3 mm (p=0.23), and the proximal neck lengths were 16.8 and 17.4 mm (p = 0.65), respectively. The anatomical characteristics appeared to be similar in both groups. The technical success rate in both groups was 100%. Three cases in the S group had MAEs, including two stroke and one brachial artery pseudoaneurysm; whereas, 2 cases had MAEs in the A group, including one stroke and one paraplegia. There was no 30-day mortality or retrograde type A dissection in both groups. The mean observation periods in the S and A groups were 46 (1–123) and 35 (1–73) months, respectively. At 36 and 60 months post-procedure, the freedom from ARD was 97.6% and 97.6% in the S group, 100.0% and 100.0% in the A group (p=0.39); and the freedom from re-intervention for type1a endoleaks was 79.2% and 65.2% in the S group, 100.0% and 100.0% in the A group (p = 0.0087 < 0.05). A statistically significant reduction in re-intervention for type1a endoleaks was observed in the A group. ConclusionsProximal fixation augmentation using the Najuta fenestrated stent graft during TEVAR for distal arch aneurysm is effective in preventing the postoperative late type 1a endoleaks.