Takahiko Uesaka

Giant mediastinal bronchial artery aneurysm mimicking benign esophageal tumor: a case report and review of 26 cases from literature

Mediastinal bronchial artery aneurysm is rare but potentially life-threatening, and requires prompt treatment to avert rupture with catastrophic results. A 78-year-old man was referred to our hospital with a benign esophageal tumor, which appeared as an extrinsic, extramucosal filling defect on an esophagogram. Chest computed tomography and selective bronchial arteriography led to a definitive diagnosis of mediastinal bronchial artery aneurysm. Aneurysmectomy and closure of the ostia of both the afferent and efferent bronchial arteries was performed via standard posterolateral thoracotomy. Postoperative course was uneventful, and the patient was discharged on the seventh postoperative day.

Leukocyte and platelet depletion with a blood cell separator: Effects on lung injury after cardiac surgery with cardiopulmonary bypass

This study was undertaken to assess the effects of leukocyte and platelet depletion on postoperative lung injury in 42 patients who underwent heart operations. Blood was serially sampled before, during, and after cardiopulmonary bypass, and leukocyte count, platelet count, and thromboxane B2 6-keto-PGF1 alpha, leukocyte elastase, thrombin-antithrombin III complex, and D-dimer levels were determined. Postoperative respiratory function was assessed based on analyses of oxygenation and carbon dioxide elimination. Leukocyte and platelet depletion was performed in 21 patients (experimental group) but not in another (control group). In the experimental group, leukocytes and platelets were removed continuously by means of the blood cell separator CS-3000, beginning immediately after the start of the operation and ending 1 hour after the release of aortic occlusion. Leukocyte elastase, thromboxane B2, ratio of thromboxane B2 to 6-keto-PGF1 alpha, thrombin-antithrombin III complex, and D-dimer were significantly lower in the experimental group than in the control group. Of the various indexes of oxygenation, arterial oxygen tension was significantly higher in the experimental group and the alveolar-arterial oxygen pressure difference and respiratory index were significantly lower in the experimental group. The positive end-expiratory pressure needed to achieve an appropriate arterial oxygen tension was significantly lower in the experimental group. The elimination of carbon dioxide was lower in the experimental group. Depletion of leukocytes and platelets reduced respiratory dysfunction after heart operations with cardiopulmonary bypass. It was particularly effective in patients with a low preoperative oxygenation capacity and in those for whom an extended period of cardiopulmonary bypass was required.

Surgical outcome of infectious aneurysm of the abdominal aorta with or without SIRS

The surgical outcome of infectious abdominal aortic aneurysms was evaluated based on the preoperative presence or absence of systemic inflammatory response syndrome (SIRS). Nine patients were divided into two groups according to the criteria for SIRS such as body temperature, heart rate, respiratory rate, and white blood cell count. In the group with SIRS, rupture and impending rupture of aneurysms occurred in three of the four patients (75%). All aneurysms were resected with a small part as a remnant; two in situ and two extraanatomic reconstructions were performed. Three patients died after surgery: one after in situ (cerebral infarction) and two after extraanatomic reconstruction (sepsis and multiple organ failure). In the group without SIRS, closed en bloc resection in two patients and resection of the aneurysm with a small part as a remnant in three patients were performed. In situ reconstruction in all patients and omentum wrapping in two patients were performed. One of the five patients died of massive hematemesis 70 days after surgery. The overall mortality rate was 75% in the group with SIRS versus 20% in the group without SIRS. The surgical outcome of infectious abdominal aortic aneurysm depends upon the severity of underlying infection. A possibility exists that SIRS is a useful indicator for predicting the surgical outcome of patients.

Transmyocardial laser revascularization induced angiogenesis correlated with the expression of matrix metalloproteinases and platelet-derived endothelial cell growth factor

OBJECTIVE Transmyocardial laser revascularization (TMLR) has been widely evaluated as a treatment for ischemic myocardium. However, its mechanism remains unclear. One mechanism is angiogenesis. This study examines the relationship between TMLR and angiogenesis from the viewpoint of matrix metalloproteinases and platelet-derived endothelial cell growth factor. METHODS The left anterior descending coronary artery (LAD) was ligated permanently in 12 beagle dogs. TMLR was accomplished in six of the 12 dogs using a carbon dioxide laser. No laser treatment was done in the six control dogs. Two weeks after the initial operation, dogs were euthanized and transmural samples (each of approximately 0.5 g) were cut from the center of the infarcted LAD territory, right ventricular wall, left circumflex artery perfuse area and interventricular septum except the LAD perfuse area. They were snap-frozen in liquid nitrogen for matrix metalloproteinases and platelet-derived endothelial cell growth factor activity analysis. Hematoxylin and eosin staining, double immunohistologic staining with anti-proliferating cell nuclear antigen and von Willebrand factor antibody, and immunohistologic staining with antibody against platelet-derived endothelial cell growth factor were performed for histologic studies. The activities of matrix metalloproteinases were examined by gelatin zymography. The activity of platelet-derived endothelial cell growth factor was examined by a spectrophotometric method. RESULTS The channels were found to be infiltrated with granulation tissue and fibrosis. In the laser group, the active matrix metalloproteinase-2 and platelet-derived endothelial cell growth factor activity in the area of the left anterior descending coronary artery was significantly higher than in the control group (P<0.0001 and P=0.037, respectively). Within the channel remnants or close to these areas, the number of von Willebrand factor positive microvessels and proliferating cell nuclear antigen with correlating von Willebrand factor positive microvessels were significantly higher than in the control group (P=0.001 and P=0.0006, respectively). These increases in microvessels significantly correlated with the expression of matrix metalloproteinases and platelet-derived endothelial cell growth factor. CONCLUSION Based on these findings it was concluded that transmyocardial laser revascularization induced angiogenesis correlated with the expression of active matrix metalloproteinases-2 and platelet-derived endothelial cell growth factor.

Effects of Depletion of Leukocytes and Platelets on Cardiac Dysfunction After Cardiopulmonary Bypass

BACKGROUND This study examined the effects of the depletion of leukocytes and platelets from circulated blood on cardiac function after cardiopulmonary bypass in 37 patients who underwent coronary artery bypass grafting or aortic valve replacement. METHODS Leukocytes and platelets were removed continuously using a blood cell separator, beginning immediately after the start of the operation and ending 1 hour after the release of the aortic cross-clamp in 19 patients (LPD group), but not in the remaining 18 patients (control group). Blood cell counts and levels of thromboxane B2, 6-keto-prostaglandin F1alpha, leukocyte elastase, complements C3a and C4a, thrombin-antithrombin III complex, and D-dimer were determined periodically during and after the operation. The cardiac index, the difference between the central and peripheral core temperatures, and the doses of catecholamines and vasodilators required to support the circulation in the early postoperative period also were assessed. RESULTS Leukocyte and platelet counts and levels of leukocyte elastase, thromboxane B2, thromboxane2/6-ketoprostaglandin F1alpha, thrombin-antithrombin III complex, and D-dimer were significantly lower in the LPD group than in the control group before and after the release of the aortic cross-clamp and during the perioperative period. There were no significant differences in the levels of 6-keto-prostaglandin F1alpha or complements C3a and C4a between the two groups. The catecholamine dose was significantly lower in the LPD group than in the control group (1.1 +/- 2.5 versus 5.0 +/- 5.2 mg/kg, respectively). Fewer patients required the use of nitroprusside as a vasodilator in the LPD group than in the control group (1/19 versus 12/18, respectively). CONCLUSIONS The depletion of leukocytes and platelets using a blood cell separator prevents the deterioration of cardiac function after cardiac operations using cardiopulmonary bypass.

Thymidine Phosphorylase Gene Transfer Inhibits Vascular Smooth Muscle Cell Proliferation by Upregulating Heme Oxygenase-1 and p27KIP1

Objective—Thymidine phosphorylase (TP) reportedly promotes endothelial cell migration and induces heme oxygenase (HO)-1 expression. However, its effect on vascular smooth muscle cells (VSMCs) is poorly understood. In this study, we examined the effect of TP on VSMCs in vitro and in vivo. Methods and Results—Phagemid vector encoding human TP gene was transfected into rat VSMCs, and a clone overexpressing TP was selected (C2). C2 showed a slower migration and proliferation than VSMCs cloned with empty vector (pC) under basal, serum-stimulated, and hypoxic conditions. This decrease in proliferation correlated with TP-induced HO-1 expression and was reversed by inhibitors of either TP or HO activity. Furthermore, in C2, the cyclin-dependent kinase inhibitor (p27KIP1) was much more abundant than in pC, and the cell cycle was arrested at the G1 phase. TP or HO activity inhibitors decreased p27KIP1 expression in C2 to the level seen in pC. Adventitial TP gene delivery significantly reduced neointimal VSMC migration and neointima formation in balloon-injured rat carotid arteries. Conclusions—TP overexpression upregulated HO-1 expression and consequently increased p27KIP1 in cultured VSMCs, and inhibited VSMC migration and proliferation in vitro and in vivo. TP represents a promising target for treating vascular obstructive disease.

Hyperamylasemia and subclinical pancreatitis after cardiac surgery.

Hyperamylasemia after cardiac surgery is common but typically causes no clinical concern because it consists mainly of the salivary isoenzyme. In this study we evaluated the incidence, source, and time course of postoperative hyperamylasemia with special attention to the possibility of subclinical pancreatitis. In 88 patients prospectively tested for serum amylase and lipase concentrations, elastase 1 activity, and amylase isoenzyme characteristics, 57 (64%) showed hyperamylasemia during the early postoperative period. In most cases early hyperamylasemia was not of pancreatic origin, but two patients were diagnosed with subclinical pancreatitis. Among the last 23 patients, 5 of 10 patients with early hyperamylasemia exceeding 1000 IU/L showed late hyperamylasemia on the seventh postoperative day, when it represented mainly the pancreatic isoenzyme. Lipase concentrations and elastase 1 activities were elevated in these cases. Late hyperamylasemia following cardiac surgery may be of pancreatic origin and indicative of subclinical pancreatitis, even if early hyperamylasemia was of salivary origin.RésuméL’hyperamylasémie après chirurgie cardiaque est fréquente mais entraîne habituellement peu de soucis car il s’agit le plus souvent de l’isoenzyme salivaire. Dans cette étude, nous avons évalué l’incidence, la source et l’évolution dans le temps de l’hyperamylasémie postopératoire en tenant compte particulièrement de l’éventualité d’une pancréatite postopératoire infra-clinique. Chez 81 patients, analysés prospectivement pour l’amylase et la lipase sériques, l’activité en élastase l et les caractéristiques de l’isoenzyme, 57 (64%) avaient une hyperamylasémie en période postopératoire immédiate. Dans la plupart des cas, l’hyperamylasémie précoce n’était pas d’origine pancréatique, mais on a fait le diagnostic de pancréatite infraclinique chez deux patients. Parmi les 23 autres patients, 5 des 10 patients ayant une hyperamylasémie précoce au-dessus de 1000 IU/L avaient également une hyperamylasémie tardive au septième jour postopératoire, mais il s’agissait principalement d’enzyme d’origine pancréatique. Les concentrations en lipase et l’activité en élastase 1 étaient élevées dans ces cas. En conclusion, une hyperamylasémie tardive après chirurgie cardiaque peut être d’origine pancréatique et indique une pancréatite infra-clinique, même si l’hyperamylasémie précoce est d’origine salivaire.ResumenLa hiperamilasemia tras cirugia cardiaca es habitual pero no tiene repercusión clinica pues se trata sobre todo de la isoenzima salival. En este estudio evaluamos la frecuencia, el origen y la duración de la hiperamilasemia postoperatoria, prestando especial atención a la posible aparición de una pancreatitis subclinica. En 88 pacientes se determinó prospectivamente la concentración sérica de amilasa, lipasa, actividad de la elastasa l y las caracteristicas de la isoenzimas de la amilasa. 57 (64%) de los pacientes presentaron hiperamilasemia en el postoperatorio precoz. En la mayoria de los casos esta hiperamilasemia no reconocía una etiología pancreática, pero 2 pacientes fueron diagnosticados de pancreatitis subclínica. Entre los 23 últimos pacientes, en 5 de 10, que presentaron hiperamilasemia precoz superior a los 1,000 IU/L, se constató hiperamilasemia al séptimo día del postoperatorio, debido, sobre todo, a la isoenzima pancreática. La concentración de lipasa y la actividad de la elastasa l también estaban elevadas en estos casos. La hiperamilasemia tardía, tras cirugía cardiaca puede tener un origen pancreático reflejando una pancreatitis subclínica, incluso si la hiperamilasemia precoz reconoce un origen salival.

Prolongation of total permissible circulatory arrest duration by deep hypothermic intermittent circulatory arrest

OBJECTIVE We determined whether the duration of permissible circulatory arrest could be prolonged by deep hypothermic intermittent circulatory arrest. METHODS Twenty-five beagles were cooled on bypass to 18 degrees C to initiate deep hypothermia that was maintained for 3 hours. Five protocols were then studied: group 1, uninterrupted bypass during hypothermia; group 2, arrest for 40 minutes during hypothermia; group 3, arrest for 60 minutes during hypothermia; group 4, arrest for 80 minutes during hypothermia; and group 5, intermittent circulatory arrest, consisting of six cycles of 20 minutes of arrest followed by 10 minutes of systemic recirculation during hypothermia (total, 120 minutes of arrest). The oxyhemoglobin concentration in the brain was measured with near infrared spectrophotometry. RESULTS In groups 2, 3, and 4, the oxyhemoglobin concentration in the brain decreased continuously after arrest, finally reaching a plateau after 24.9 +/- 1.2 minutes. This finding suggested that the available cerebral oxyhemoglobin was depleted. In contrast, the available cerebral oxyhemoglobin was not depleted during hypothermic intermittent arrest in group 5. The mitochondrial respiratory control index was significantly lower in group 4 than in the other groups (p < 0.05). However, there were no significant differences in the respiratory control index for groups 1, 2, 3, and 5. Moreover, the formation of brain edema was significantly lower in group 5 than in the other groups (p < 0.05). CONCLUSIONS These results indicate that deep hypothermic intermittent arrest can increase the duration of total permissible circulatory arrest and will be a useful modality when prolonged arrest is anticipated.

Experimental determination of the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass.

This study investigated the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass in a canine model. The adequacy of cerebral oxygenation was determined from the adenosine concentration, the oxygen saturation of cerebral venous blood and brain oxyhemoglobin level. In experiment 1, nine beagles were cooled on bypass to a nasopharyngeal temperature of 18 degrees C and the perfusion flow rate was reduced in a stepwise fashion every 30 min from 100 to 50, 30, 20 and 10 ml/kg per min. In experiment 2, six beagles were cooled on bypass as in experiment 1, and flow was maintained at 30 ml/kg per min for 120 min. At a perfusion flow rate of 30 ml/kg per min, adequate cerebral oxygenation was maintained for 120 min. In contrast, perfusion flow rates of 20 and 10 ml/kg per min were associated with cerebral ischemia.

Descending Thoracic Aortobifemoral Bypass for Aortoiliac Occlusive Disease

Descending thoracic aortobifemoral bypass was evaluated in 3 patients with Leriches syndrome and 1 with severe arteriosclerosis obliterans. Indications for this approach were lack of a suitable site for aortic clamping in 3 and history of laparotomy in 1. Duration of surgery was 4.5 to 5.25 hours, and blood loss was 450 to 1,900 g. There was no surgical mortality. Major morbidity comprised visceral arterial ischemia postoperatively in 1 patient. During a mean follow-up of 60 months (range, 36 to 84 months), 2 limbs of the grafts became occluded. No patient developed proximal propagation of an aortic thrombus. This approach is recommended in selected patients without impaired pulmonary function, when conventional approaches to the abdominal aorta are considered hazardous.