Yutaka Hino

Oxidative stress in the pathogenesis of thoracic aortic aneurysm : Protective role of statin and angiotensin II type 1 receptor blocker

OBJECTIVE The pathogenesis of thoracic aortic aneurysms (TAA) is still unclear. A recent investigation indicated that angiotensin II, a potent activator of NADH/NADPH oxidase, plays an important role in aneurysmal formation. We investigated the potential role of p22phox-based NADH/NADPH oxidase in the pathogenesis of TAA. METHODS Human thoracic aneurysmal (n=40) and non-aneurysmal (control, n=39) aortic sections were examined, and the localization of p22phox, an essential component of the oxidase, and its expressional differences were investigated by immunohistochemistry and Western blot. In situ reactive oxygen species (ROS) generation was examined by the dihydroethidium method, and the impact of medical treatment on p22phox expression was investigated by multiple regression analysis. RESULTS In situ production of ROS and the expression of p22phox increased markedly in TAA throughout the wall, and Western blot confirmed the enhanced expression of p22phox. The expression was more intense in the regions where monocytes/macrophages accumulated. In these inflammatory regions, numerous chymase-positive mast cells and angiotensin converting enzyme-positive macrophages were present. Their localization closely overlapped the in situ activity of matrix metalloproteinase and the expression of p22phox. Multiple regression analysis revealed that medical treatment with statin and angiotensin II type 1 receptor blocker (ARB) suppressed p22phox expression in TAA. CONCLUSION Our findings indicate the role of p22phox-based NADH/NADPH oxidase and the local renin-angiotensin system in the pathogenesis of TAA. Statin and ARB might have inhibitory effects on the formation of aneurysms via the suppression of NADH/NADPH oxidase.

Transbrachial arterial insertion of aortic occlusion balloon catheter in patients with shock from ruptured abdominal aortic aneurysm.

OBJECTIVE Of 125 surgical patients with abdominal aortic aneurysm (AAA) treated from 1999, 11 patients with deep shock from ruptured AAAs who underwent aortic occlusion balloon catheter (AOBC) insertion before laparotomy were studied. METHODS With the patients under local anesthesia, the brachial artery was exposed and the balloon catheter was inserted into the thoracic aorta. The balloon was inflated halfway and pulled back gently to the orifice of the left subclavian artery, and was advanced with the aid of blood flow down to the abdominal aorta. After full inflation of the balloon, the catheter was pulled until the balloon was fixed at the proximal shoulder of the AAA. RESULTS AOBC insertion was completed within 16.1 +/- 5.1 minutes. Systolic blood pressure at presentation was 84.1 +/- 31.7 mm Hg, deteriorated to 60.9 +/- 15.4 mm Hg on arrival in the operating room, and increased significantly (P <.0001) to 123.4 +/- 25.3 mm Hg after AOBC insertion. The balloon burst in three patients. Embolic complications were observed in two patients. There were three deaths, two associated with the balloon bursting. In nine patients whose shock was successfully controlled by AOBC, operative mortality was 11%. CONCLUSION Transbrachial arterial insertion of an AOBC may be useful to ameliorate hemorrhagic shock in patients with ruptured AAAs.

Deep Vein Thrombosis Caused by Congenial Interruption of the Inferior Vena Cava A Case Report

Congenital interruption of the inferior vena cava is an uncommon vascular anomaly. In this setting, the appearance of deep vein thrombosis is very rare because associated azygous or portal continuation develops as a collateral system for venous return. The authors present a case of infrahepatic interruption of the inferior vena cava in a 21-year-old man who presented with symptoms of deep vein thrombosis. Clinical features and prognosis of this entity are discussed.

Endovascular stent-graft repair for penetrating atherosclerotic ulcer in the infrarenal abdominal aorta

PURPOSE Penetrating atherosclerotic ulcer (PAU) is an ulceration of an atherosclerotic plaque penetrating through the intima, which may lead to intramural hematoma, aneurysm formation, or rupture. This disease is predominantly found in the thoracic aorta and is uncommon in the infrarenal aorta. The effectiveness of endovascular repair of PAU in the infrarenal aorta was retrospectively investigated. METHODS From 1999 to 2002, PAU was diagnosed with computed tomography and magnetic resonance imaging in the abdominal aorta in four patients. All patients were men; their average age was 78 years. All four patients had hypertension, and two patients had concomitant coronary artery disease. Three patients had abdominal pain or lumbago. RESULTS All patients underwent endovascular grafting with a Gianturco Z-stent covered with thin-wall woven Dacron graft. Indications for endovascular intervention were aneurysm formation with or without intramural hematoma in two patients and contained rupture with extraaortic hematoma in two patients. The postoperative course was uneventful in all cases, and no endoleak or aneurysm expansion was recognized during follow-up (4-32 months; average, 14 months). CONCLUSIONS Infrarenal aortic lesions caused by PAU were generally localized, and endovascular grafting appears to be a feasible alternative to surgical repair.

Surgical intervention for isolated dissecting aneurysm of the superior mesenteric artery--a case report.

A 44-year-old man with abdominal pain was diagnosed as having a spontaneous isolated dissection of the superior mesenteric artery. The patient was successfully treated with endoaneurysmorrhaphy 5 months after the onset and has been symptom free 15 months after surgery. In view of the excellent surgical outcome in the literatures, surgical intervention for this rare pathology should be considered.

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.

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.

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.

Multiple Penetrating Atherosclerotic Ulcers of the Aorta: Report of a Case

A 69-year-old hypertensive man who had 7 pseudoaneurysms caused by penetrating atherosclerotic ulcers underwent 2-staged endovascular grafting in the thoracic and thoracoabdominal aorta and a conventional graft replacement of the abdominal aorta. He had an uneventful postoperative course; follow-up computed tomography demonstrated that all aneurysmal lesions treated by endovascular grafting completely disappeared. He has been free from any aortic events 20 months after the last surgery.