Atsushi Omura

Recent advancements of total aortic arch replacement

OBJECTIVE Recent advancements in total aortic arch replacement achieved by our approach were presented. METHODS From January 2002 to December 2010, 321 consecutive patients (mean age 69.8 ± 13.3 years) underwent total arch replacement through a median sternotomy at our institute. Aortic dissection was present in 94 (28.3%) patients and shaggy aorta in 36 (11.2%), with emergency/urgent surgery required in 106 (33.0%). Our current approach included the following: (1) meticulous selection of arterial cannulation site and type of arterial cannula; (2) antegrade selective cerebral perfusion; (3) maintenance of minimal tympanic temperature between 20 °C and 23 °C; (4) early rewarming just after distal anastomosis; (5) after 2004, bolus injection of 100 mg of sivelestat sodium hydrate into the pump circuit at the initiation of cardiopulmonary bypass; (6) after 2006, maintaining fluid balance below 1000 mL during cardiopulmonary bypass. RESULTS Overall hospital mortality was 4.4% (14/321) and was 1.9% (4/215) in elective cases. Permanent neurologic deficit occurred in 4.4% (14/321) of patients and in 2.8% (6/215) of elective cases. Prolonged ventilation was necessary in 53 (16.5%), with a significant reduction after 2006 (22.8% vs 12.6%; P = .02). Multivariate analysis demonstrated that risk factors for hospital mortality were octogenarian (odds ratio, 4.32; P = .03), brain malperfusion (odds ratio, 21.2; P = .001) and cardiopulmonary bypass time (odds ratio, 1.01; P = .04). Survival at 3 and 5 years after surgery was 82.4% ± 2.5% and 78.5% ± 3.1%, respectively. CONCLUSIONS Our current approach for total aortic arch replacement was associated with low hospital mortality and morbidities and with favorable long-term outcome.

Total arch replacement using antegrade cerebral perfusion

OBJECTIVE The technical details of total arch replacement using antegrade cerebral perfusion are presented. METHODS From January 2002 to May 2012, 423 consecutive patients (mean age, 69.2 ± 13.1 years) underwent total arch replacement using antegrade selective cerebral perfusion through a median sternotomy. Acute aortic dissection was present in 81 patients (19.1%; 75 type A, 6 type B), and a shaggy aorta was present in 37 patients (8.7%). Emergency/urgent surgery was required in 135 patients (31.9%). Our current approach included meticulous selection of the arterial cannulation site and type of arterial cannula, antegrade selective cerebral perfusion, maintenance of the minimal tympanic temperature between 20 °C and 23 °C, early rewarming immediately after distal anastomosis, and maintenance of the fluid balance at less than 1000 mL during cardiopulmonary bypass. A woven Dacron 4-branch graft was used in all patients. RESULTS The overall hospital mortality was 4.5% (19/423): 9.6% (13/135) in urgent/emergency surgery cases and 2.1% (6/288) in elective cases. Permanent neurologic deficits occurred in 3.3% patients (14/423). Prolonged ventilation was necessary in 57 patients (13.4%). A multivariate analysis demonstrated the risk factors for hospital mortality to be age (octogenarian; odds ratio, 4.45; P = .02), brain malperfusion (odds ratio, 22.5; P = .002), and cardiopulmonary bypass time (odds ratio, 1.06; P = .04). The follow-up was completed in 97.2% of patients (mean, 29 ± 27; 1-126) and included 2.3 patients per year. Survival at 5 and 10 years after surgery was 79.6% ± 3.3% and 71.2% ± 5.0%, respectively. In the acute A dissection group, the 10-year survival was 96.6% ± 2.4%. In the elective nondissection group, the 5- and 10-year survivals were 80.3% ± 4.2% and 76.1% ± 5.7%, respectively. CONCLUSIONS Our current approach for total aortic arch replacement is associated with low hospital mortality and morbidity, thus leading to a favorable long-term outcome.

Aortic regurgitation after valve-sparing aortic root replacement: modes of failure.

BACKGROUND Despite the positive clinical results of valve-sparing aortic root replacement, little is known about the causes of reoperations and the modes of failure. METHODS From October 1999 to June 2010, 101 patients underwent valve-sparing aortic root replacement using the David reimplantation technique. The definition of aortic root repair failure included the following: (1) intraoperative conversion to the Bentall procedure; (2) reoperation performed because of aortic regurgitation; and (3) aortic regurgitation equal to or greater than a moderate degree at the follow-up. Sixteen patients were considered to have repair failure. Three patients required intraoperative conversion to valve replacement, 3 required reoperation within 3 months, and another 8 required reoperation during postoperative follow-up. At initial surgery 5 patients had moderate to severe aortic regurgitation, 6 patients had acute aortic dissections, 3 had Marfan syndrome, 2 had status post Ross operations, 3 had bicuspid aortic valves, and 1 had aortitis. Five patients had undergone cusp repair, including Arantius plication in 3 and plication at the commissure in 2. RESULTS The causes of early failure in 6 patients included cusp perforation (3), cusp prolapse (3), and severe hemolysis (1). The causes of late failure in 10 patients included cusp prolapse (4), commissure dehiscence (3), torn cusp (2), and cusp retraction (1). Patients had valve replacements at a mean of 23 ± 20.9 months after reimplantation and survived. CONCLUSIONS Causes of early failure after valve-sparing root replacement included technical failure, cusp lesions, and steep learning curve. Late failure was caused by aortic root wall degeneration due to gelatin-resorcin-formalin glue, cusp degeneration, or progression of cusp prolapse.

Early and late outcomes of repaired acute DeBakey type I aortic dissection after graft replacement

OBJECTIVE The present study aimed to determine the impact of the extent of graft replacement on early and late outcomes in acute DeBakey type I aortic dissection. METHODS Between October 1999 and July 2014, 197 consecutive patients were surgically treated for acute DeBakey type I aortic dissection. The extent of graft replacement (hemiarch, partial, or total arch replacement) was mainly determined by the location of the primary entry. Early and late results were compared in patients after total arch replacement (n = 88) and combined hemiarch and partial arch replacement: non-total arch replacement (n = 109). RESULTS The in-hospital mortality rates of the total arch replacement and non-total arch replacement groups were 10.2% and 14.7%, respectively (P = .47). Multivariate analysis revealed preoperative cardiopulmonary resuscitation and visceral organ malperfusion as significant risk factors for in-hospital mortality, but not total arch replacement. During a mean follow-up period of 60 ± 48 months, the 5-year survivals in the total arch replacement and non-total arch replacement groups were 88.6% ± 4.2% and 83.8% ± 4.4%, respectively (P = .54). Rates of distal aortic events (defined as freedom from surgery for distal aorta dilation or distal arch diameter expanding to 50 mm) at 5 years were significantly better in the total arch replacement group than in the non-total arch replacement group (94.9% ± 3.5% vs 83.6% ± 4.9%, P = .01). CONCLUSIONS The operative mortality of patients with acute DeBakey type I aortic dissection treated by total arch replacement was acceptable with good long-term survival after both total arch replacement and non-total arch replacement. The frequency of distal aortic events might be reduced in patients after total arch replacement compared with non-total arch replacement.

Early and Late Results of Graft Replacement for Dissecting Aneurysm of Thoracoabdominal Aorta in Patients With Marfan Syndrome

BACKGROUND When treating dissecting aneurysm of the thoracoabdominal aorta surgically in patients with Marfan syndrome, we have usually performed graft replacement- including the entire thoracoabdominal aorta and reconstruction of all visceral branches, even if dilatation is mild in some segments-to avoid further aortic operations in the follow-up period. METHODS From October 1999 through July 2011, 20 consecutive patients with Marfan syndrome underwent repair of dissecting aneurysm of the thoracoabdominal aorta (median age, 45 years; range, 19-65 years). All patients underwent surgical intervention with cerebrospinal fluid (CSF) drainage and distal aortic and selective organ perfusion. Deep hypothermia was used in 13 patients for spinal cord protection. RESULTS No in-hospital mortality was observed. One patient had temporary spinal cord ischemia but was fully recovered by discharge. Other complications included exploration for bleeding (n=1), prolonged ventilation (n=1), and graft infection (n=1). At a mean follow-up of 54 months (range, 9-129 months), 1 patient had died of interstitial pneumonia at 38 months postoperatively. Survival at 8% years was 91.2±9.0%. Two patients required additional aortic procedures (total arch replacement and aortic valve-sparing surgery). Actuarial rate of freedom from aortic operations at 8 years was 83.9%±10.5%, but no patient needed required repeated thoracotomy for an aortic procedure. Neither false nor patch aneurysms were observed using computed tomography (CT) during follow-up surveillance. CONCLUSIONS Graft replacement for dissecting aneurysm of the thoracoabdominal aorta in Marfan syndrome offers good early and long-term results. We believe total aortic replacement including the entire thoracoabdominal aorta and reconstruction of all visceral arteries should be recommended for selected patients with Marfan syndrome.

Augmentation of systemic blood pressure during spinal cord ischemia to prevent postoperative paraplegia after aortic surgery in a rabbit model

OBJECTIVE Paraplegia from spinal cord ischemia remains an unresolved complication in thoracoabdominal aortic surgery, with high morbidity and mortality. This study investigated postoperative effects of systemic blood pressure augmentation during ischemia. METHODS Spinal cord ischemia was induced in rabbits by infrarenal aortic occlusion for 15 minutes with infused phenylephrine (high blood pressure group, n = 8) or nitroprusside (low blood pressure group, n = 8) or without vasoactive agent (control, n = 8). Spinal cord blood flow, transcranial motor evoked potentials, neurologic outcome, and motor neuron cell damage (apoptosis, necrosis, superoxide generation, myeloperoxidase activity) were evaluated. RESULTS Mean arterial pressures during ischemia were controlled at 121.9 +/- 2.8, 50.8 +/- 4.3, and 82.3 +/- 10.7 mm Hg in high blood pressure, low blood pressure, and control groups, respectively. In high blood pressure group, high spinal cord blood flow (P < .01), fast recovery of transcranial motor evoked potentials (P < .01), and high neurologic score (P < .05) were observed after ischemia relative to low blood pressure and control groups. At 48 hours after ischemia, there were significantly more viable neurons, fewer terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling-positive neurons, and less alpha-fodrin expression in high blood pressure group than low blood pressure and control groups. Superoxide generation and myeloperoxidase activity at 3 hours after ischemia were suppressed in high blood pressure group relative to low blood pressure group. CONCLUSIONS Augmentation of systemic blood pressure during spinal cord ischemia can reduce ischemic insult and postoperative neurologic adverse events.

Effect of atherothrombotic aorta on outcomes of total aortic arch replacement

OBJECTIVE The effect of an atherothrombotic aorta on the short- and long-term outcomes of total aortic arch replacement, including postoperative neurologic deficits, remains unknown. We evaluated this relationship and also elucidated the synergistic effect of multiple other risk factors, in addition to an atherothrombotic aorta, on the neurologic outcome. METHODS A group of 179 consecutive patients undergoing total aortic arch replacement were studied. An atherothrombotic aorta was present in 34 patients (19%), more than moderate leukoaraiosis in 71 (39.7%), and significant extracranial carotid artery stenosis in 27 (15.1%). In-hospital deaths occurred in 2 patients, 1 (2.9%) of 34 patients with and 1 (0.7%) of 145 patients without an atherothrombotic aorta (P = .26). Permanent neurologic deficits occurred in 4 (2.2%) and transient neurologic deficits in 17 (9.5%) patients. Multivariate analysis demonstrated that the risk factors for transient neurologic deficits were an atherothrombotic aorta (odds ratio, 4.4), extracranial carotid artery stenosis (odds ratio, 5.5), moderate/severe leukoaraiosis (odds ratio, 3.6), and cardiopulmonary bypass time (odds ratio, 1.02). To calculate the probability of transient neurologic deficits, the following equation was derived: probability of transient neurologic deficits = {1 + exp [7.276 - 1.489 (atherothrombotic aorta) - 1.285 (leukoaraiosis) - 1.701 (extracranial carotid artery stenosis) - 0.017 (cardiopulmonary bypass time)]}(-1). An exponential increase occurred in the probability of transient neurologic deficits with presence of an atherothrombotic aorta and other risk factors in relation to the cardiopulmonary bypass time. Survival at 3 years after surgery was significantly reduced in patients with vs without an atherothrombotic aorta (75.0% ± 8.8% vs 89.2% ± 3.1%, P = .01). CONCLUSIONS Patients with an atherothrombotic aorta and associated preoperative comorbidities might be predisposed to adverse short- and long-term outcomes, including transient neurologic deficits.

Surgical strategy for aorta-related infection

OBJECTIVES This report describes our experience with surgical management of aorta-related infections. METHODS From November 1999 to April 2013, 70 patients underwent surgical management for aorta-related infection, including aortobronchial fistula in 12 patients, aorto-oesophageal fistula in 14 and aortoduodenal fistula in 4. The location of infection was aortic root to arch in 22 patients, descending aorta in 29, thoraco-abdominal aorta in 12 and abdominal aorta in 7. Forty-seven patients had infections of the native aorta and 23 had postoperative graft infections. In situ replacement [bridge thoracic endovascular aortic repair (TEVAR); n = 1] was performed in 45 patients, endovascular aortic repair in 18 and extra-anatomical bypass (bridge TEVAR; n = 2) in 7. Omental flap was installed in 29 patients and a pedicled latissimus dorsi muscle flap was used in 3. Since 2008, we have been trying to resect not only the infected tissues, but also the surrounding aneurysmal wall as well. RESULTS Hospital mortality was 17.1% (12/70). Late death occurred in 15 patients. Overall survival at 3 years was 60.1 ± 6.7%. Freedom from infection-related death of patients who had in situ graft replacement, endovascular repair or extra-anatomical bypass at 3 years was 88.5 ± 4.9, 75.2 ± 10.9 or 14.3 ± 13.2%, respectively (P < 0.01). In situ graft replacement provided a better freedom from aortic event (recurrent infection and reintervention) at 3 years compared with endovascular repair (85.6 ± 5.5 vs 61.8 ± 12.5%, P = 0.029). Freedom from infection-related death at 3 years improved significantly from 61.1 ± 9.7 (before 2008) to 84.7 ± 5.8% (since 2008) (P = 0.044). CONCLUSIONS Surgical treatment for aorta-related infection is still associated with high mortality and morbidity. However, our current strategy, which is aggressive surgical management, including resection of infected tissues, extensive debridement, in situ graft replacement of the aorta and omental or muscle installation provided a better patient survival.

Extended replacement of the thoracic aorta

OBJECTIVES We present our experience of total aortic arch replacement. METHODS Twenty-nine patients (21 males and 8 females; mean age 63.3 ± 13.3 years) with extended thoracic aortic aneurysms underwent graft replacement. The pathology of the diseased aorta was non-dissecting aneurysm in 11 patients, including one aortitis and aortic dissection in 18 patients (acute type A: one, chronic type A: 11, chronic type B: six). Five patients had Marfan syndrome. In their previous operation, two patients had undergone the Bentall procedure, three had endovascular stenting, one had aortic root replacement with valve sparing and 12 had hemi-arch replacement for acute type A dissection. Approaches to the aneurysm were as follows: posterolateral thoracotomy with rib-cross incision in 16, posterolateral thoracotomy extended to the retroperitoneal abdominal aorta in seven, mid-sternotomy and left pleurotomy in three, anterolateral thoracotomy with partial lower sternotomy in two and clam-shell incision in one patient. Extension of aortic replacement was performed from the aortic root to the descending aorta in 4, from the ascending aorta to the descending aorta in 17 and from the ascending to the abdominal aorta in eight patients. Arterial inflow for cardiopulmonary bypass consisted of the femoral artery in 15 patients, ascending aorta and femoral artery in seven, descending or abdominal aorta in five and ascending aorta in two. Venous drainage site was the femoral vein in 10, pulmonary artery in eight, right atrium in five, femoral artery with right atrium/pulmonary artery in four and pulmonary artery with right atrium in two patients. RESULTS The operative mortality, 30-day mortality and hospital mortality was one (cardiac arrest due to aneurysm rupture), one (rupture of infected aneurysm) and one (brain contusion), respectively. Late mortality occurred in three patients due to pneumonia, ruptured residual aneurysm and intracranial bleeding. Actuarial survival at 5 years after the operations was 80.6 ± 9.0%. Freedom from the subsequent aortic events was 96.0 ± 3.9% at 5 years. CONCLUSIONS Our treatment method for extensive thoracic aneurysms achieved satisfactory results using specific strategies and appropriate organ protection according to the aneurysm extension in the selected patients.

Open reconstruction of thoracoabdominal aortic aneurysms

Technical details of our strategy for reconstructing the thoracoabdominal aorta are presented. Between October 1999 and June 2012, 152 patients underwent surgery for thoracoabdominal aortic aneurysms (Crawford classification type I =21, type II =43, type III =73, type IV =15). Mean age was 64.6±13.9 years. Sixty-three (41.4%) patients had aortic dissection, including acute type B dissection in 2 (1.2%) and ruptured aneurysms in 17 (11.2%). Eight (5.3%) patients had mycotic aneurysms, and 3 (2.0%) had aortitis. Emergent or urgent surgery was performed in 25 (16.4%) patients. Preoperative computed tomography (CT) scan or magnetic resonance (MR) angiography detected the Adamkiewicz artery in 103 (67.8%) patients. Cerebrospinal fluid drainage (CSFD) was performed in 115 (75.7%) patients and intraoperative motor evoked potentials were recorded in 97 (63.8%). One hundred and seven (70.4%) patients had reconstruction of the intercostal arteries from T7 to L2, 35 of which were reconstructed with the aortic patch technique and 72 with branched grafts. The mean number of reconstructed intercostal arteries was 3.1±2.5 pairs. Mild hypothermic partial cardiopulmonary bypass at 32-34 °C was used in 105 (69.1%) patients, left heart bypass was used in 4 (2.6%), and deep hypothermic cardiopulmonary bypass below 20 °C was used in 42 (27.6%). Thirty-day mortality was 9 (5.9%), and hospital mortality was 20 (13.2%). Independent risk factors for hospital mortality were emergency surgery (OR 13.4, P=0.003) and aortic cross clamping over 2 hours (OR 5.7, P=0.04). Postoperative spinal cord ischemia occurred in 16 (10.5%, 8 patients with paraplegia and 8 with paraparesis). Risk factors for developing spinal cord ischemic complications were prior surgery involving either the descending thoracic or the abdominal aorta (OR 3.75, P=0.05), diabetes mellitus (OR 5.49, P=0.03), and post-bypass hypotension <80 mmHg (OR 1.06, P=0.03). Postoperative survival at 5 years was 83.6±4.5%; 5-year survival was 47.5±8.6% in patients with spinal cord ischemia and 88.9±10.4% in those without spinal cord ischemia.