1. Background (1) ・ In 1998, we developed a modified elephant trunk (ET) technique using a single four-branched arch graft with a sewing “collar” and “long ET” prosthesis to treat extensive thoracic aneurysms. ・ An extensive aortic arch pathology involving the descending aorta remains a surgical challenge and an optimal technique remains controversial. single four-branched arch graft (Kuki S, et.al., Eur J Cardiothorac Surg 2000;18:246-248) (Kuki S, et.al., Circulation 2002;106:I253-258)

2. ・ We have made minor changes to the original technique and applied this technique for a wide variety of aortic pathologies. Background (2) (Hara H, et.al., J Thorac Cardiovasc Surg 2009;137:777-778) (Taniguchi K, et.al., Ann Thorac Surg 2007;84:1729-34) (Shudo Y, et.al., Ann Thorac Surg 2007;84:659-661) Objectives In this study, we investigate the early operative results and long-term outcome of total arch replacement with long ET in 132 consecutive patients since October 1998.

3. Operative strategies On the basis of the “uninvolved” descending aorta diameter (at Th6-Th8), one of the two following strategies was adopted in principle. ・ Descending aorta: 35 mm or less. ・ The first stage procedure was attempted as a “permanent ET”. ・ Single-ET strategy: n=99 ・ Staged-ET strategy: n=33 40mm ・ Descending aorta: greater than 35 mm. ・ Two-stage operation was planned, with the second performed within an appropriate period after the initial operation. 30mm

4. Operative technique (1) CPB is established via the bicaval and right axillary artery cannulae, and the ascending aorta is incised. While cooling the patient, a proximal anastomosis is performed.

5. Operative technique (2) Then the patient cooled to 25°C, a long elephant trunk is inserted into the descending aorta aided by a catching catheter under an open distal condition. ET diameter and length: ET diameter: Undersized by 10- 20% of outer diameter of descending aorta at Th6-Th8. ET length: Determined preoperatively by measuring the aorta from the base of the innominate artery to Th6-Th8. 3-0 Tevdek suture

6. Operative technique (3) The arch vessels are individually reconstructed while re-warming the patient. A distal anastomosis is then performed at the base of the innominate artery between the proximal graft and distal aorta, incorporating the ET tube graft.

7. Concomitant Procedures and Operative Data Cardiopulmonary bypass time (min)204±54 Aortic cross-clamp time (min)100±42 Selective cerebral perfusion time (min)86±26 Open distal time (min) * 25±8 Valve surgery (AVR, MVR, TAP)14 (11%) CABG14 (11%) Aortic root replacement (modified Bentall)13 (10%) Reconstruction of left vertebral artery6 (5%) Others2 (2%) * : Hypothermic circulatory arrest time of the lower body for open distal anastomosis. Operative Data Concomitant Procedures (49 procedures in 46 (35%) patients)

8. Results (1): Early Mortality and Morbidity Operative mortality (≤30 days): 2 ( 1.5%) TAAA rupture: 2 Hospital mortality (>30 days): 7 ( 5.3%) TAAA rupture: 1, Pneumonia: 2, Mediastinitis: 2 MOF from biliary sepsis: 1, Aorto-esophageal fistula: 1 Hemorrhagic complication Re-exploration for bleeding: None Neurological complications Permanent stroke: 3 (2.3%) Paraplegia: 3 (2.3%), Paraparesis: 1 (0.8%) Transient paraplegia (recovered within 24 hours) : 4 (3.0%) Recurrent nerve palsy (new-onset), Phrenic nerve palsy: None Downstream operation (rapid 2-stage surgery) Thoracotomy approach: 12 Transluminal approach (TEVAR):8

9. Results (2): Complete thromboexclusion around ET Single-ET strategyStaged-ET strategy (n=99)(n=33) n=86 (87%) n=13 n=22 (67%) n=11 Failure of thromboexclusion N=13 (13%) Second-stage procedure: 11 Being followed: 2 Aortic rupture: None Failure of thromboexclusion N=22 (67%) Second-stage procedure: 16 Being followed: 2 Aortic rupture: 4* (including the 1 patient who refused the second-stage operation) * Success Failure

10. Results (3): Late Mortality and Morbidity Aneurysm-related mortality: 4 ( 3%) TAAA rupture: 1, Iliac aneurysm rupture: 1 Aorto-pulmonary fistula: 1, ET graft infection: 1 Aneurysm-nonrelated mortality: 14 ( 10.6%) Pneumonia: 3, Stroke: 3, Neoplasm: 3, Heart failure: 2 Neoplasm: 3, Sepsis: 1, Arrhythmia: 1, Unknown: 1 Subsequent operation : 10 ( 7.6%) Thoracotomy approach: 6, Transluminal approach: 1 Thoracoabdominal aortic repair: 2 Abdominal aortic repair (infra-renal): 1 Late complications Aorto-esophageal fistula (alive): 1 Distal aneurysm expansion: None Peripheral thromboembolism: None

11. Results (4): Survivals (Average follow up: 45 ± 37 months) 86% 80% Months after operation Patients at risk: 102 80 67 52 42 36 25 17 Percent survival (%) 100 80 60 40 20 0 68% 77% 89%

12. Most patients assigned to the single-stage strategy showed complete thromboexclusion of the perigraft space around the ET with lowering the need for a second-stage procedure. In addition, most patients assigned to the two-stage strategy showed persistent perigraft perfusion around the ET and required a rapid second-stage procedure. Our procedure with long ET for arch aneurysms using an undersized graft is uniformly applicable for a wide variety of aortic pathologies with achieving satisfactory short-term and long-term outcomes. Conclusion