A miniaturized piezoelectric Mössbauer spectrometer with feedback control.

A Mössbauer spectrometer was built and evaluated using an amplified piezoelectric actuator under feedback control for the Doppler velocity drive. The actuator was driven with a quadratic displacement waveform, giving a linear velocity profile. The optimization of the piezoelectric Doppler drive under feedback control was performed with measurements from a laser Doppler vibrometer. 57Fe Mössbauer spectra of α-iron in transmission geometry show minimal peak distortions. The performance of this piezoelectric Doppler drive makes Mössbauer spectrometry possible in applications requiring small size, mass, and low cost.

Tuning the Magnetic Quantum Criticality of Artificial Kondo Superlattices CeRhIn_{5}/YbRhIn_{5}.

The effects of reduced dimensions and the interfaces on antiferromagnetic quantum criticality are studied in epitaxial Kondo superlattices, with alternating n layers of heavy-fermion antiferromagnet CeRhIn_{5} and seven layers of normal metal YbRhIn_{5}. As n is reduced, the Kondo coherence temperature is suppressed due to the reduction of effective Kondo screening. The Néel temperature is gradually suppressed as n decreases and the quasiparticle mass is strongly enhanced, implying dimensional control toward a quantum critical point. Magnetotransport measurements reveal that a quantum critical point is reached for the n=3 superlattice by applying small magnetic fields. Remarkably, the anisotropy of the quantum critical field is opposite to the expectations from the magnetic susceptibility in bulk CeRhIn_{5}, suggesting that the Rashba spin-orbit interaction arising from the inversion symmetry breaking at the interface plays a key role for tuning the quantum criticality in the two-dimensional Kondo lattice.

[Aortic root replacement using cryopreserved allograft for an infected aorta patient associated with mediastinitis].

We herein report a case of aortic root replacement using cryopreserved allograft. A 52-year-old man received aortic valve replacement using a mechanical prosthesis for aortic stenosis. He was complicated by postoperative methicillin-resistant staphylococcus aureus mediastinitis involving the ascending aorta. Surgical therapy including debridement, omental transposition, patch closure using pericardium had not achieved satisfied result. Aortic root replacement using cryopreserved allograft was mandatory for refractory aortic infection. He had an uneventful postoperative course. The cryopreserved allograft was effective for a patient with refractory aortic root infection due to postoperative mediastinitis.

Effect of a neutrophil elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using the left-sided heterotopic canine heart transplantation model.

BACKGROUND: Ischemia/reperfusion injury is a major cause of transplanted heart dysfunction. Several reports have demonstrated that polymorphonuclear neutrophil (PMN) elastase derived from the activated neutrophils might play an important role in this injury. Herein, we investigated the protective effects of PMN elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using a left-sided canine heterotopic heart transplantation model. METHODS: We used 10 pairs of adult beagle dogs. The donor heart was transplanted heterotopically into the left thoracic cavity of the recipient without cardiopulmonary bypass. A bolus of ONO-5046 Na (10 mg/kg) was introduced intravenously to 5 recipients (group II) at 15 minutes before reperfusion and was followed by continuous infusion (10 mg/kg per hour) for 180 minutes. Five dogs (group I) did not receive ONO-5046 Na and thus served as a control. After reperfusion, we evaluated transplanted heart function and obtained blood samples from the coronary sinus over a 360-minute period. RESULTS: E(max) and pre-load recruitable stroke work in group II showed significantly better recovery than group I. Blood levels of PMN elastase, creatine kinase MB, lactate and inflammatory cytokines (tumor necrosis factor-alpha, interleukin-6, interleukin-8) were significantly lower in group II. Depletion of myocardial concentration of adenosine triphosphate at 120 minutes after reperfusion and myocardial water content was significantly lower in group II. CONCLUSIONS: ONO-5046 Na, which inhibits PMN elastase, could reduce ischemia/reperfusion injury in heart transplantation. These results indicate that clinical application of ONO-5046 Na should be considered.

Thoracoabdominal aortic aneurysms repair under abdominal cavity cooling with visceral shunting technique--a case report.

Mild hypothermia induced by abdominal cavity cooling together with a selective visceral shunting technique can be a useful adjunct for thoracoabdominal aortic aneurysm repair. The authors adopted this combined technique for repair of selected Crawford type III and type IV aneurysms to reduce visceral ischemic damage and minimize the incidence of postoperative complications.

Double left renal vein associated with abdominal aortic aneurysm.

Double left renal vein is a rare venous anomaly. We operated on 72-year-old man of abdominal aortic aneurysm (AAA) with double left renal vein. Massive hemorrhage was encountered during encircling the tape around the abdominal aorta. One vein passing posterior to the aorta was injured. Further dissection revealed the presence of double left renal vein forming a ring around the aorta. The patient underwent an abdominal aortic replacement following prompt repair of the injured vein. He had an uneventful postoperative course without renal complication. We missed that preoperative computed tomographic (CT) scan had demonstrated double left renal vein. Preoperative contrast-enhanced CT scan is useful and essential not only for evaluation of AAA, but also for establishing the presence of venous anomalies. Venous anomalies should be taken into consideration on the AAA operation.

[Experience of four cases of postoperative pulmonary embolism requiring surgical treatment].

Four patients underwent a pulmonary embolectomy using cardiopulmonary bypass for acute pulmonary embolism which had occurred after various operations. In two cases, dehydration due to either diabetes insipidus or ileus had existed. In two cases, pulmonary embolism suddenly occurred in our hospital. In the remainder, the disease occurred in the previous hospitals and its diagnosis was established on the 6th and 7th postoperative days, respectively. In massive pulmonary embolism, echocardiography and/or enhanced chest CT are useful for prompt and noninvasive diagnosis. Thrombolytic therapy was performed in only one case before surgical embolectomy, which was not effective. Three patients were discharged without any postoperative complications, but one requiring preoperative external cardiac massage died of multiple organ failure 9 days after operation. Acute pulmonary embolism is one of the fatal postoperative complications. Recognition of this entity, and prompt diagnosis and treatment are essential for managing the fatal disease. Even in the early postoperative period, embolectomy using cardiopulmonary bypass is a safe and effective treatment.

Thoracic and thoracoabdominal aneurysm repair under deep hypothermia using subclavian arterial perfusion.

BACKGROUND: Hypothermic circulatory arrest is a valuable adjunct for thoracic and thoracoabdominal aortic aneurysm repair. Retrograde aortic perfusion through the femoral artery, however, carries a risk of cerebral embolism or malperfusion. To avoid these complications we adopted antegrade aortic perfusion through a prosthetic graft attached to the left subclavian artery through a left thoracotomy. METHODS: Ten patients had repair of descending thoracic and thoracoabdominal aortic aneurysm under deep hypothermia with antegrade aortic perfusion through the left subclavian artery. Hypothermic circulatory arrest was used because proximal aortic control was hazardous due to rupture or intraluminal disease, or for spinal cord protection. RESULTS: There was no brain injury and one hospital death. The cause of death was massive bleeding from the gastrointestinal tract not related to deep hypothermia or the perfusion method. All 9 survivors were alive and well after a mean follow-up period of 9 months. CONCLUSIONS: Using the left subclavian artery as a site of aortic perfusion can avoid retrograde aortic perfusion, hence reducing the potential for brain injury due to embolic stroke or malperfusion through a dissected thoracoabdominal aorta.

Penetrating atherosclerotic ulcer.

The pathogenesis of penetrating atherosclerotic ulcer (PAU) in aortic disease remains controversial. Between January 1995 and April 1999, five patients underwent treatment for a PAU in our hospital. All were men, ranging in age from 46 to 74 years, with a mean age of 66.2 years. The PAU was located on the thoracic descending aorta in three patients and on the abdominal aorta in two. Preoperative diagnosis was established by contrast-enhanced computed tomographic scan and aortogram. Surgery was performed in four patients, as graft replacement in three, and patch plasty in one. The remaining patient is being carefully observed on antihypertensive therapy. No connective tissue disorder, trauma, dissection, or infection was seen in any of the patients who underwent surgery, all of whom had uneventful postoperative courses with no perioperative complications or enlargement of the aorta. We conclude that surgical treatment should be performed for patients with PAU to prevent an aortic catastrophe caused by rapid development of the lesion. This report might provide further evidence of the importance of PAU.

Organ malperfusion in acute aortic dissection.

OBJECTIVE: Organ malperfusion in aortic dissection can precipitate a serious condition. The strategy of treatment for it has been controversial. We have focused on the strategy and outcome of acute aortic dissection with organ malperfusion. SUBJECTS AND METHODS: Between January 1995 and December 1998, 134 acute aortic dissection patients were admitted. There were 73 males (65.4 +/- 8.0 years old) and 61 females (66.7 +/- 7.4 years old). There were 83 patients of Stanford type A, and 51 patients of type B. Of them, 24 patients (17.9%) were complicated by organ malperfusion. The brain was affected in 4, the heart in 5, the spinal cord in 2, the liver in 1, the intestine in 1, the kidney in 4, and the lower extremities in 10 patients. Our management strategy for a patient with malperfusion in acute aortic dissection was that the antecedent operation was initially mandatory, and central grafting was secondarily considered. RESULTS: Refusal of operation or lethal conditions excluded 8 of the 24 patients from operation. An antecedent operation was mandatory in eight of the remaining 16 patients. The overall mortality was 33.3% (8/24 patients), and operative mortality was 31.3% (5/16 patients) in the patients with malperfusion. The overall mortality was 11.8% (13/110 patients), and the operative mortality was 11.1% (9/81 patients) in the patients without malperfusion. CONCLUSION: Organ malperfusion is a major component in the management and treatment of acute aortic dissection. Only an appropriate strategy and therapy could result in a satisfactory outcome.

The influence of human T lymphotropic virus type I infection on the outcome of cardiovascular surgery.

OBJECTIVE: Human T lymphotropic virus type I infects CD4(+) T cells and affects cell-mediated immunity. Cardiopulmonary bypass transiently alters lymphocyte subsets, resulting in a reduction in CD4(+) T cells and an increase in CD8(+) T cells. We proposed that cardiovascular operations and human T lymphotropic virus type I infection may act synergistically, resulting in serious damage to cell-mediated immunity. METHODS: A total of 517 consecutive patients who were preoperatively screened for anti-human T lymphotropic virus type I antibody and underwent cardiovascular operations with cardiopulmonary bypass were enrolled in this study. Of the 517 patients, 82 (16%) had positive test results for anti-human T lymphotropic virus type I antibody. The surgical outcome of patients with positive and negative results for anti-human T lymphotropic virus type I antibody was analyzed retrospectively. RESULTS: There was no difference between the 2 groups with respect to early mortality. Distribution of survival curve was also not significantly different (P =.5; mean follow-up duration, 2.4 +/- 1.8 years [range, 0-9.4 years] and 3.2 +/- 2.8 years [range, 0-9.8 years]) in the groups with positive and negative antibody results, respectively). In particular, long-term follow-up did not reveal adult T-cell leukemia or human T lymphotropic virus type I-associated myelopathy, and occurrence of neoplasm did not differ between groups. Early infectious complication was, however, significantly higher in the group with positive antibody results than in the group with negative results (P =.02). Logistic regression analysis revealed human T lymphotropic virus type I infection as a significant risk for this complication (P =.04; odds ratio, 2.5; 95% confidence interval, 1. 0-5.8). CONCLUSION: A combination of human T lymphotropic virus type I infection and cardiovascular operation is believed to increase the potential risk of infectious complications shortly after the operation. However, this synergistic effect seems to be transient and has little influence on long-term prognosis.

Preoperative autologous donation of blood for a simple cardiac anomaly: analysis of children weighing under twenty kilograms.

OBJECTIVE: Preoperative autologous donation of blood has been expanded to cardiac operations in children. However, because of problems such as lack of cooperation and hemodilution during cardiopulmonary bypass, its efficacy in small children is unclear. This study clarifies the clinical significance of preoperative autologous donation of blood in small children. METHODS: Thirty-seven patients weighing under 20 kg (age range, 3-9 years; weight range, 13-20 kg) underwent preoperative autologous donation and cardiac operations to treat a simple anomaly. Twenty-five age- and weight-matched patients who were not cooperative or refused preoperative autologous donation served as control subjects. Autologous blood was collected by the simple or leapfrog method and stored as blood components. Each collecting volume was 5 to 10 mL/kg. RESULTS: The donation was performed 6+/-2 times during 50+/-16 days, and the whole storage volume was 48+/-17 mL/kg. There was no serious complication. The minimum hematocrit level negatively correlated with the priming volume of cardiopulmonary bypass (preoperative donation patients: P<.01, r(2) = 0.4; control subjects: P =.5, r (2) = 0.03). Blood loss did not significantly differ between preoperative donation patients and control subjects, and the transfused blood volumes were 43+/-13 mL/kg and 29+/-22 mL/kg, respectively. All of the autologous blood products but fresh frozen plasma were reinfused. Use of homologous blood was significantly less in preoperative donation patients than in control subjects (0% vs 80%, P <.01). In preoperative donation patients postoperative recovery in hemoglobin level was significantly better, which is concurrent with a higher reticulocyte level. CONCLUSION: Preoperative autologous donation can be performed safely with clinical efficacy, even in children under 20 kg. This can be improved further through coupling with another procedure.

[Perioperative risk factors in valve surgery concomitant with coronary artery bypass grafting].

Between January 1990 and December 1999, 20 patients underwent the valve surgery concomitant with coronary artery bypass grafting. There were 16 males and 4 females, their mean age was 66.5 years. Of the 20 patients, aortic stenosis was noted in 7, aortic regurgitation in 3, mitral stenosis in one, and mitral regurgitation in 9 patients. The cause of mitral regurgitation was considered to be an ischemic change in six patients, including ruptured papillary muscle due to myocardial infarction in two patients. On the contrary, LMT lesion was recognized in 5, LAD lesion in 17, LCX in 16, and RCA in 12 patients. Seven patients had preoperative myocardial infarction, three patients were required preoperative IABP support. AVR was performed in 10, MVR in 5, and MAP in 5 patients. The number of bypass was 1.9 +/- 0.85. Four patients died of LOS and MOF. The remaining 16 patients have been doing well. The significant difference between the survived and the not survived patients was recognized in the factor of emergency, preoperative IABP, papillary muscle rupture due to myocardial infarction, history of PTCA, LAD lesion, and the time of CPB. The factors regarding coronary artery had the influence on the outcome of a patients of valve surgery concomitant with CABG. Therefore, an appropriate myocardial protection and perioperative management for ischemia were mandatory.

Surgical repair of a solitary deep femoral arterial aneurysm: report of two cases.

We report herein two cases of a solitary deep femoral arterial aneurysm that were successfully treated by aneurysmectomy and ligation of the deep femoral artery. The patients were a 69-year-old man and a 73-year-old man, both of whom presented with localized pain and a pulsatile mass in the femoral area showing rapid enlargement. Ultrasonography and arteriography confirmed the diagnosis and revealed no evidence of aneurysm or occlusive disease in the other arteries. Aneurysmectomy and ligation of the deep femoral artery were performed, and no ischemic symptoms or thrombus developed postoperatively in either patient. Preoperative arteriography is essential to delineate not only the state of the aneurysm, but also that of the distal arterial tree. An emergency operation is also mandatory due to the rapid enlargement of this type of aneurysm, even if rupture occurs.

[Traumatic cardiac tamponade due to the nail stabbing].

A 45-year-old man was admitted to our hospital complaining of mild chest pain. The stab wound on the chest was very small and the nail had been completely buried under the skin. Emergency operation was mandatory for cardiac tamponade by the nail stabbing. Contused right ventricular wall was repaired using Teflon felt under cardiopulmonary bypass. It was important to have a suspicion as cardiac tamponade, when the patient showed uncertain hypotension.

Papillary fibroelastoma on the mitral valve.

A 78-year-old woman was admitted with transient unknown fever and old cerebral infarction. An echocardiogram demonstrated mild mitral valve regurgitation and high echogenic mass on the mitral posterior leaflet. Surgery was performed with the diagnosis of a healed infective endocarditis. A sea anemone-like appearance tumor, 8 mm in diameter, was located on the mitral posterior leaflet. Annuloplasty was performed following removal of the tumor. A pathological examination confirmed the lesion was a papillary fibroelastoma. No evidence of infective endocarditis was seen. The cause of the fever remained unknown. The tumor was very fragile. Surgical removal was mandatory for preventing embolism despite the advanced age.

Operation for adult patent ductus arteriosus using cardiopulmonary bypass.

BACKGROUND: Surgical repair of adult patent ductus arteriosus is more hazardous than when performed on young patients. METHODS: Nine adult patent ductus arteriosus patients underwent surgical repair between January 1986 and December 1998. There were 3 male and 6 female patients (mean age 55.0 years). The ratio of pulmonary blood flow to systemic flow was 2.40 +/- 0.95, and pulmonary arterial pressure was 56.0 +/- 26.4 mm Hg. The operation was performed using transpulmonary approach under total cardiopulmonary bypass. Balloon occlusion method was also utilized. RESULTS: Direct closure was made in 5 and patch closure in 4 patients. Cardiopulmonary bypass and balloon occlusion were safely established. Cardioplegic arrest was not required in the 2 most recent patients. No operative death has occurred. Pulmonary arterial systolic pressure decreased to 35.3 +/- 6.6 mm Hg at 6 months after operation. The mean follow-up period for all patients is 55 months. To date, neither recannalization of the ductus nor pseudoaneurysm has been recognized. CONCLUSIONS: Cardiopulmonary bypass with balloon occlusion provides a safe operation for adult patients with complicated patent ductus arteriosus.

Distal arch aneurysm repair using stent-grafting and ascending aorto-left axillary bypass.

BACKGROUND: Transcatheter application of a stent-graft to the angulated aortic segments with critical side branches poses some problems. We report our technique of distal arch aneurysm repairs using stent-grafts inserted through the aortic arch and ascending aortoaxillary bypass. PATIENTS AND RESULTS: Three patients underwent successful distal arch aneurysm repair using a homemade semiflexible stent-graft placed under hypothermic circulatory arrest. The left subclavian artery was reconstructed by an extraanatomic bypass grafting between the ascending aorta and left axillary artery. Postoperative imaging demonstrated reduction of aneurysm size and no endoleaks from an intercostal artery. CONCLUSIONS: Our technique seems to be useful for repair of distal arch aneurysms and is a less invasive procedure.