Naomichi Uchida

Operative Strategy for Acute Type A Aortic Dissection: Ascending Aortic or Hemiarch Versus Total Arch Replacement With Frozen Elephant Trunk

BACKGROUND This report compares long-term results with total arch replacement with frozen elephant trunk (FET) to ascending aortic or hemiarch replacement (AHR) for acute type A aortic dissection. METHODS The subjects were 120 consecutive patients, including 65 who received FET and 55 who had AHR for acute type A aortic dissection from 1997 to 2008. The late results after surgery were retrospectively compared between the FET and ARH groups. RESULTS Three patients in the FET group died, and 2 patients in the AHR group died. In long-term follow-up (mean, 67 months), the survival rate after 5 years was 95.3% for the FET group and 69.0% for the AHR group (p = 0.03). The event rate for the thoracic aorta after 5 years showed a significant difference between the FET and AHR groups (95.7% versus 73.0%, p = 0.01). A false lumen at the proximal descending aorta was patent in 16 patients (29%) in the AHR group, but it was thrombosed in all in the FET group. CONCLUSIONS In patients with acute type A aortic dissection, it is possible to perform extensive primary repair using the FET technique with relative safety. FET may reduce the necessity for further operations to manage a residual false lumen.

Flow competition of the right gastroepiploic artery graft in coronary revascularization

BACKGROUND In recent years, there has been a substantial increase in the use of arterial grafts for coronary revascularization. Arterial grafts are more vulnerable than saphenous vein grafts to hypoperfusion syndrome. The purpose of this study was to examine flow competition between the right gastroepiploic artery and native coronary arteries in patients undergoing coronary artery bypass grafting. METHODS Between December 1989 and July 1995, 182 patients underwent coronary artery bypass grafting using the right gastroepiploic artery. Coronary flow patterns were examined in 172 patients by postoperative angiography. Flow patterns were divided into four types: right gastroepiploic artery dependent (n = 128), balanced (n = 24), native dependent (n = 18), or occluded (n = 2). RESULTS All grafts with an old myocardial infarction (n = 75) and 94% of grafts with 99% stenosis (n = 16) were classified in the right gastroepiploic artery-dependent category. In patients with angina pectoris, flow patterns were more frequently classified as right gastroepiploic artery dependent, with increasingly severe native coronary artery proximal stenoses (99% > 90% > 75%) or with stenoses more distal in location. CONCLUSIONS Flow competition depended on three factors: the viability of the revascularized area, the degree of proximal stenosis, and the location of stenosis. Right gastroepiploic artery grafts should be selected for coronary artery bypass grafting with consideration of these three factors.

Frozen elephant trunk technique and partial remodeling for acute type A aortic dissection

OBJECTIVE The aimed to describe the frozen elephant trunk (FET) technique and partial remodeling (PR) for acute type A aortic dissection (ATAAD), considering the long-term prognosis on the basis of our 13 years of experience. METHODS There were 80 consecutive patients (mean age: 66.4 years) with an FET and PR technique for ATAAD between September 1997 and February 2010. We indicated a PR for all 80 patients without dilatation of the sinuses and a FET for 20 patients with a distal entry in the descending aorta, 14 patients with a dilatation more than 4cm on the distal arch and 46 patients with a narrow true lumen younger than 70 years with a narrow true lumen. During moderate hypothermic circulation with selective cerebral perfusion and distal perfusion from the femoral artery, a stent graft (mean diameter: 27.7mm, mean length: 9.9mm, mean distal depth: thoracic vertebra (Th) 6.0th) was inserted through the transected proximal aortic arch. The plication of the sinotubular junction (N=42) or partial remodeling for right and/or non-coronary cusp (N=38) was performed after total arch replacement with a four-branched prosthesis. RESULTS Four patients died in hospital. Early morbidity included two (2.5%) strokes but no spinal cord injury. In long-term follow-up (mean 94.6 months), five patients died of non-aortic events and two re-operations (Bentall and stent grafting to the descending aorta) were required. No patients had patent false lumen on the stent graft and residual aortic regurgitation, according to late follow-up computed tomography (CT) and echogram. The 10-year survival was 75% and the overall 10-year re-operation free rate on the thoracic aorta was 95%. CONCLUSION FET and modified PR techniques could be effective for improving the long-term outcome on the distal and proximal aorta in an ATAAD.

Repair of the thoracic aorta by transaortic stent grafting (open stenting)

BACKGROUND The late results of direct open stent grafting of the aortic arch for aortic arch repair have not been reported previously. METHODS Between September 1997 and December 2000 19 patients underwent open stent grafting with carotid artery bypass for thoracic arteriosclerotic aneurysms (TAA) of the distal aortic arch. In addition, 21 patients underwent open stent grafting with total aortic arch replacement for Stanford type A acute aortic dissection and 7 patients underwent stenting with carotid bypass for Stanford type B chronic aortic dissection. RESULTS The early mortality rate was 11% for TAA, 10% for type A dissection, and 0% for type B dissection. Whereas none of the TAA or type A dissection required a second operation on the thoracic aorta, 1 TAA patient died 6 months postoperatively after sudden aortic rupture and 1 type B patient required descending aortic replacement because of ulceration caused by the stent graft at 11 months postoperatively. On follow-up computed tomography scan, in TAA patients, true aneurysms excluded by the stent graft showed early thrombosis, but the absorption of thrombosed aneurysms started from 1 to 6 months postoperatively and gradually progressed. In patients with type B chronic dissection, the false lumen showed early thrombosis and the true lumen was dilated at the central portion of the graft, which might increase turbulent flow by interaction with the stent. In patients with type A acute dissection, the false lumen showed both early thrombosis and early absorption. CONCLUSIONS Early and late results of open stenting are acceptable and follow-up computed tomography scan may be able to predict late results of open stenting.

Long-term results of the frozen elephant trunk technique for the extensive arteriosclerotic aneurysm

OBJECTIVES The objective of this report is to elucidate the feasibility of the frozen elephant trunk technique as a one-stage operation for extensive arteriosclerotic aneurysms and to investigate the long-term durability and efficacy of this procedure from our 11 years of experience. METHODS The subjects were 58 consecutive patients who electively received the frozen elephant trunk technique for arteriosclerotic aneurysms involving the aortic arch and the descending aorta between September 1997 and September 2008. Concomitant procedures included 15 coronary artery bypass grafts, 2 aortic valve replacements, 1 aortic root replacement, and 3 maze procedures. The stent graft was delivered to the seventh thoracic vertebra level (Th7) in 22, Th8 in 26, Th9 in 8, and Th10 in 2 patients. Cerebrospinal fluid drainage was administered preoperatively in 10 (17.2%) patients. RESULTS Operative mortality within 30 days was 0 of 58. There was 1 in-hospital death. Perioperative morbidity included strokes and spinal cord injury in 2 (3.4%) patients each. During the mean follow-up period of 54.2 +/- 36.9 months, there were 9 (15.5%) late deaths, and 7 (12.1%) patients required additional intervention. The 8-year survival was 65.5%, the overall 8-year aortic event free survival was 72.8%, and the 8-year event free survival on the site of the stent graft was 94.8%. A follow-up computed tomographic image was available for 86.2% (50/58) of patients who survived longer than 6 months. The size of the aneurysm increased in 1 (2.0%) patient, was not changed in 6 (12.0%) patients, shrank in 34 (68.0%) patients, and was obliterated in 9 (18.0%) patients. CONCLUSIONS The frozen elephant trunk for extensive aortic aneurysms had long-term durability and efficacy and might become the alternative treatment for extended aortic replacement.

Long-term results of the frozen elephant trunk technique for extended aortic arch disease

OBJECTIVES This study describes the long-term safety and effectiveness of extended aortic arch replacement with the frozen elephant trunk technique from our 12 years of experience. METHODS Between September 1997 and September 2008, 156 patients (mean age 67.9 years) with different pathologies from the aortic arch to the extended descending aorta in 100 dissections (acute A/acute B/chronic B=66/26/8) and 56 thoracic arteriosclerotic aneurysms (TAAs) had the frozen elephant technique performed upon them. During moderate hypothermic circulation with selective cerebral perfusion, the stent graft was inserted through the transected proximal aortic arch with trans-oesophageal echo guidance. RESULTS Six patients (3.2%) (acute A/acute B/chronic B/TAA=3/2/0/1) died in hospital. Postoperative morbidity induced four (2.6%) strokes (acute A/acute B/chronic B/TAA=2/0/0/2) and three (2.0%) spinal injuries (paraplegia in two and transient paraparesis in one) (acute A/acute B/chronic B/TAA=0/0/1/2). In the long-term follow-up (mean 63.3 + or - 39.2 months, maximum 144 months) 16 patients died. The survival rate was 99.3%, 86.5% and 74.9% at 1, 5 and 10 years, respectively. An additional operation was performed in 15 (9.4%) (ascending aorta/aortic root/descending aorta/abdominal aorta=1/2/5/7) including three stent-graft-related events (2.1%), and the additional repair proved successful. A follow-up computed tomography (CT) image was available for 96.0% (143/149) of patients who survived longer than 12 months. The size of false lumen or aneurysm increased in four patients, was unchanged in 20 patients (14.0%), shrank in 66 (46.2%) and was completely obliterated in 55 (37.1%). CONCLUSIONS The frozen elephant technique could be an attractive treatment for extended aortic arch disease to the extended descending aorta for acute aortic dissection as well as arteriosclerotic aneurysm.

In situ replacement for mycotic aneurysms on the thoracic and abdominal aorta using rifampicin-bonded grafting and omental pedicle grafting.

BACKGROUND The objective of this report is to discuss the efficacy of in situ replacement for treating mycotic aneurysm, particularly using rifampicin-bonded grafts and omental pedicle grafts, on the basis of our 7 years of experience. METHODS Between December 2003 and December 2010, we performed surgical treatments in 23 patients (for the thoracic aorta in 6 patients, for the thoracoabdominal aorta in 8 patients, and for the abdominal aorta in 9 patients; 7 emergency, 10 urgent, and 6 elective operations) with mycotic aneurysm by using rifampicin-bonded grafting and omental pedicle grafting. RESULTS One patient died in hospital because of local recurrent infection. One patient required an additional operation on another aortic site, and 3 patients had spinal cord injuries (2 transient and 1 permanent). Overall survival at 5 years was 95%, and the rate of freedom from aortic events at 5 years was 86%. CONCLUSIONS In situ replacement using rifampicin-bonded grafting and omental pedicle grafting is effective for treating mycotic aneurysms of the thoracic and abdominal aorta.

Total arch replacement with an open stent graft for acute type A aortic dissection: fate of the false lumen

OBJECTIVE To describe the fate of the false lumen remaining in the descending thoracic aorta after extensive primary repair of the thoracic aorta by the modified elephant trunk technique with a stent graft for acute type A aortic dissection, particularly the changes of the false lumen on enhanced CT scanning. METHODS The subjects were 65 consecutive patients who received arch replacement with an open stent graft for type A acute aortic dissection. CT scanning was performed at 1, 3, 12, 36, and 60 months postoperatively to detect thrombus formation, absorption of thrombus, and obliteration of the false lumen after its exclusion by the stent graft. The aorta was measured at four levels, which were the distal border of the stent graft, the middle and distal parts of the descending thoracic aorta, and the origin of the superior mesenteric artery. RESULTS Obliteration was recognized in all patients at the distal border of the stent graft and absorption of thrombus was seen in 90% at the middle of the descending thoracic aorta within 1 year after surgery. However, the false lumen remained patent at the superior mesenteric artery (SMA) level in 50% of the patients. CONCLUSIONS In patients with acute type A aortic dissection, it is possible to perform extensive primary repair of the thoracic aorta with relative safety by stent grafting, and this method may reduce the necessity for further operations to manage a residual false lumen.

Multiple factors predict the risk of spinal cord injury after the frozen elephant trunk technique for extended thoracic aortic disease

OBJECTIVES Spinal cord injury (SCI) after the frozen elephant trunk (FET) technique is more frequent than after endovascular aneurysm repair. This study aimed to identify risk factors of SCI after the FET technique. METHODS We performed the FET technique for extended thoracic aortic disease in 224 patients (mean age, 72.1 ± 10.9 years) from September 1997 to December 2011. The patients included those with acute type A aortic dissection (n = 103), acute type B aortic dissection (n = 30), chronic type B aortic dissection (n = 11) and thoracic atherosclerotic aneurysm (n = 80). Cerebrospinal fluid drainage (CSFD) was preoperatively performed for 18 elective cases with a high risk of spinal cord ischaemia from January 2003. RESULTS Postoperative SCI was present in 8 (3.5%), including complete paraplegia in 3, patients and transient or permanent paraparesis in 5 patients. CSFD was not a significant independent risk factor (P = 0.93) for SCI. Univariate logistic regression analysis identified pathology (P = 0.001), diabetes (P = 0.001), previous aortic operation (P = 0.003), atherosclerotic aorta (P = 0.003), distal position of the stent graft below the ninth thoracic vertebral level (Th9; P = 0.001) and low blood pressure after the operation (P = 0.009) as significant independent risk factors for SCI. Stepwise logistic regression analysis identified the distal position of the stent graft below Th9 (P = 0.003; odds ratio [OR], 15.167; 95% confidence interval [95% CI], 2.568-89.578), mean pressure <70 mmHg (P = 0.008; OR, 11.470; 95% CI, 1.920-68.546) and diabetes (P = 0.009; OR, 9.621; 95% CI, 1.779-52.032) as significant independent risk factors for SCI. CONCLUSIONS There were multiple factors predicting the risk of SCI after the FET technique. Paraplegia may be prevented by avoiding deep insertion of the stent graft and by keeping blood pressure elevated after the operation.

The frozen elephant trunk technique for acute type A aortic dissection: results from 15 years of experience

OBJECTIVES We aimed to evaluate the long-term prognosis of prophylactic repair of the descending aorta using the frozen elephant trunk (FET) technique for acute type A aortic dissection (AAAD). METHODS Between 1997 and 2012, 120 consecutive patients (mean age: 64.4 ± 10.9 years) underwent total arch replacement with FET for AAAD; 36 patients had an entry at the descending aorta, 68 patients were aged <70 years and 8 patients had Marfans syndrome. With regard to preoperative morbidity, 23 patients had stroke, 10 had coronary ischaemia and 9 had visceral ischaemia. During intraoperative measurement, the required size and length of the stent graft were determined and inserted under transoesophageal echographic guidance. RESULTS Seven patients (6%) died in the hospital. Four (3%) cases of stroke and 2 (2%) with spinal cord injuries were noted. Computed tomography prior to discharge indicated complete thrombosis of the false lumen by the stent graft in 113 patients, with a mean diameter of 26.0 ± 2.5 mm before discharge and 27.5 ± 2.5 mm at 1 year postoperatively compared with a mean stent graft diameter of 27.8 ± 1.7 mm. During the long-term follow-up (mean period: 104.6 ± 51.9 months), 12 patients died of non-aortic events and 5 distal aortic reoperations were required using endovascular stent grafting of the descending aorta, including 1 case with new tear formation. None of the patients had a patent false lumen on the stent graft at the final follow-up. The 10-year survival rate was 75% and the overall 10-year reoperation-free rate on the thoracic aorta was 93%. CONCLUSIONS The FET technique results in excellent aortic remodelling of the downstream aorta and can improve the long-term outcomes for AAAD.