Hiroya Kano

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.

Aggressive Surgical Treatment of Acute Pulmonary Embolism With Circulatory Collapse

BACKGROUND Acute high-risk pulmonary embolism is a life-threatening condition with high early mortality rates resulting from acute right ventricular failure and cardiogenic shock. We retrospectively analyzed the outcomes of surgical embolectomy among patients with circulatory collapse. METHODS Between July 2000 and September 2011, 24 consecutive patients (17 women and 7 men; mean age, 59.9±17.2 years) underwent emergency surgical embolectomy to treat acute pulmonary embolism with circulatory collapse. Nineteen (79.2%) patients were in cardiogenic shock, and 16 (66.7%) patients received preoperative percutaneous cardiopulmonary support. Eleven (45.8%) patients were in cardiac arrest. The preoperative pulmonary artery obstruction index was 76.9%±16.4% (median, 88.9%; range, 44.4%-88.9%). The indications for surgical intervention were cardiogenic shock (n=16 [66.7%]), failed medical therapy or catheter embolectomy (n=4 [16.7%]), or contraindication for thrombolysis (n=4 [16.7%]). Follow-up was 100% complete with a mean of 6.8±3.9 years (median, 5.6 years). RESULTS The in-hospital mortality rate was 12.5% (n=3). One patient underwent a repeated embolectomy on postoperative day 6. The postoperative course was complicated by cerebral infarction and by mediastinitis in 1 patient each. The 5-year cumulative survival rate was 87.5%±6.8%. Mean right ventricular pressure significantly decreased from 66.9 to 28.5 mm Hg among the survivors. CONCLUSIONS Surgical pulmonary embolectomy is an excellent approach to treating acute pulmonary embolism with circulatory collapse. Providing immediate percutaneous cardiopulmonary support to patients with cardiogenic shock could help to resuscitate and stabilize cardiopulmonary function and allow for a good outcome of pulmonary embolectomy.

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.

Strategies for the treatment of aorto-oesophageal fistula

OBJECTIVES Presenting a surgical strategy for aorto-oesophageal fistula (AEF). METHODS From October 1999 to August 2013, 16 patients with AEF were treated at Kobe University Hospital. The mean age was 65.5 ± 10.2 years, and the male/female ratio was 13/3. Eight patients had non-dissecting thoracic aneurysm, 3 had chronic aortic dissection, 5 had oesophageal cancer and 1 had fish bone penetration. Five patients were in shock. Four patients had previous thoracic endovascular aortic repair (TEVAR) in the descending aorta and 1 had hemi-arch replacement. As treatment for AEF, 8 patients underwent TEVAR, 2 had a bridge TEVAR to open surgery, 2 had extra-anatomical bypass (EAB) and 5 had in situ reconstruction of the descending aorta. The oesophagus was resected in 8 patients, and an omental flap was installed in 7 patients. For the 4 most recent cases, simultaneous resection of the aorta and oesophagus, in situ reconstruction of the descending aorta using rifampicin-soaked Dacron graft and omental flap installation were performed. RESULTS Hospital mortality was noted in 4 patients (25.0%; persistent sepsis n = 3 and pneumonia n = 1). However, since 2007, only 1 of 5 patients died (pneumonia). All patients with oesophageal cancer died during follow-up. Two patients underwent oesophageal reconstruction using a pedicled colon graft and one is on the waiting list for oesophageal reconstruction. CONCLUSIONS Bridging TEVAR is a useful adjunct in treating AEF patients with shock. One-stage surgery consisting of resection of the aneurysm and oesophagus, in situ reconstruction of the descending aorta and omental flap installation provided a better outcome in the AEF surgical strategy compared with conservative treatment.

Controlled Earlier Reperfusion for Brain Ischemia Caused by Acute Type A Aortic Dissection

Brain malperfusion caused by acute type A aortic dissection is a life threatening situation that should be relieved as early as possible with minimal reperfusion injury prior to aortic repair. The patient was 72-year-old woman with acute type A aortic dissection. She was referred to us 2.5 hours after onset of chest pain, and she was unconscious with a complete left paralysis. The true lumen of internal carotid artery was severely stenosed. A simple bypass circuit was installed from the femoral artery to the true lumen of the right common carotid artery, which consisted with a roller pump and cold bath for blood cooling. Regional oxygen saturation of the right frontal brain was immediately raised after initiation of the bypass, and she underwent emergency ascending hemi-arch replacement. The postoperative course was complicated with a right brain stroke; however, brain computed tomography and magnetic resonance imaging disclosed minimum brain edema. She was discharged on foot on the 35th postoperative day, and she was walking with a stick after 7 months.

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.

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.

Controlled low-flow reperfusion after warm brain ischemia reduces reperfusion injury in canine model

Background: Acute occlusion of the carotid artery caused by acute type A aortic dissection (AAD) induces on-going warm brain ischemia. The purpose of this study was to elucidate the hypothesis that low-flow reperfusion could mitigate reperfusion injury after warm ischemic damage to the brain. Methods: Experiments were performed using a canine global brain ischemia model, with 15 minutes of ischemia followed by 3 hours reperfusion, which was established by a simple brain reperfusion circuit with a roller pump. The right common carotid artery (RCCA) flow ratio was determined as the mean RCCA flow during reperfusion divided by the mean RCCA flow during pre-ischemia. Animals were divided into two groups according to the RCCA flow ratio; low RCCA flow ratio of 0.3 to 0.6 (Group L, n=5) and control RCCA flow ratio of 1.0 to 1.4 (Group C, n=5). At the 3-hour reperfusion time point, physiological and histopathological assessments were performed in both groups. Results: Electroencephalographic activity recovered in four of five animals (80%) animals in Group L, whereas no recovery (0%) in activity was observed in Group C. Brain water content in Group L animals was significantly less than that in Group C. Apoptosis, number of perivascular edematous regions and NFκB expression were apparently suppressed in Group L compared with Group C. There were significant positive correlations of RCCA flow with brain water content, apoptosis and number of perivascular edematous regions. Conclusions: Controlled low-flow reperfusion mitigated reperfusion-induced brain edema and apoptosis, leading to rescue of brain function in the canine model.

Surgical techniques of total arch replacement using selective antegrade cerebral perfusion

This detailed illustrated article describes our preferred surgical technique of total arch replacement using selective antegrade cerebral perfusion (SACP). Our current approach includes: (I) meticulous selection of arterial cannulation site and type of arterial cannula; (II) SACP for neuro-protection; (III) whole body hypothermia with minimal tympanic temperatures between 20 and 23 °C and minimal rectal temperatures below 30 °C; (IV) early re-warming after distal anastomosis with SACP flow adjustment while monitoring brain oxygenation by near infrared spectroscopy (NIRS); and (V) after 2006, maintaining strict fluid balance below 1 L by the extracorporeal ultrafiltration method (ECUM) during cardiopulmonary bypass (CPB), with the expectation of more rapid pulmonary functional recovery.