Neuroprotective effect of 1-aminocyclopropanecarboxylic acid in a rabbit spinal ischemia model.

BACKGROUND: Postoperative paraplegia remains a serious complication after repair of a thoracoabdominal aortic aneurysm. The release of the excitatory neurotransmitter glutamate might be responsible for ischemic neuronal damage. We investigated the effect of 1-Aminocyclopropanecarboxylic acid (ACPC) on the prevention of paraplegia in a rabbit model of spinal cord ischemia. METHODS: The infrarenal abdominal aorta was clamped in eighteen rabbits. Saline (group A), 20 mg/kg of ACPC (group B), or 10 mg/kg of ACPC (group C), was injected into the clamped aorta. The animals were neurologically evaluated by Tarlov's score. The spinal cord was obtained for histopathologic examination, including hematoxylin and eosin staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) staining method. RESULTS: Postoperative complete paraplegia with marked neuronal necrosis appeared in group A animals. Four of the six group C animals showed intact neurological function. Scattered TUNEL positive neurons were seen within areas containing necrotic cells in sections from paraplegic animals in group A. CONCLUSIONS: ACPC can prevent spinal cord injury in a rabbit model of spinal cord ischemia.

[Stickler syndrome with rapidly progressive mitral valve regurgitation: report of a case].

A 36-year-old man with Stickler syndrome who underwent mitral valve replacement for rapidly progressive mitral regurgitation due to prolapse of an anterior leaflet. Stickler syndrome is a relatively rare condition caused by a defective collagen gene and characterized by high myopia, sensorineural-hearing deficit and flattened facial features. The prevalence of mitral valve prolapse in Stickler syndrome is reported to be much higher than in the general population because of its connective tissue dysplasia. Mitral regurgitation rapidly and refractorily progresses. Prompt surgical treatment should be recommended to mitral regurgitation in Stickler syndrome, and mitral valve replacement with a prosthetic valve is a better selection than mitral valve plasty for tissue fragility.

Effect of left ventricular assist device on circulatory autonomic nervous activity.

PURPOSE: For evaluation of the autonomic nervous system (ANS) activity of patients with mechanical circulatory support including LVAD, IABP and PCPS, arterial pressure variability (APV) was examined. APV is the power density values of pressure signals. High frequency (0.15 to 0.4 Hz) and low frequency (0.04 to 0.15 Hz) components of APV are regarded as a function of the autonomic nervous system. METHODS: Arterial pressure signals were acquired every 2 hours at 100 Hz for 6 minutes. Power spectral analysis was carried out, and APV was observed in 18 patients with IABP and/or PCPS. APV was also observed in 3 patients with LVADs (Xemex, Zeon Medical, Japan) before their discharge from ICU for transfer to another hospital for cardiac transplantation. RESULTS: Although the value gradually increased in 18 patients with IABP and/or PCPS, sustained low values of LFAnorm of APV in 6 patients were related to prolonged mechanical support, and 4 patients among them died consequently. The normalized power spectral component with low frequency (LFAnorm) was maintained at relatively high values in 3 patients with LVADs. CONCLUSION: The study results suggest that power spectral analysis of systemic arterial pressure offers a reasonable means for the evaluation of the severity of patient cardiovascular condition and for the prediction of clinical outcome. It also suggested that LVAD support exerts a favorable effect on ANS in patients with severe heart failure before cardiac transplantation.

[Leaflet extension technique in a congenital aortic valve regurgitation].

A 17-year-old boy who was diagnosed as congenital aortic valve regurgitation underwent the leaflet extension technique in 3 aortic leaflets using glutaraldehyde-preserved autologous pericardium. Intraoperative transesophageal echocardiography and postoperative cardiac catheter revealed grade I regurgitation and the patient has been doing well for more than 4 months after the surgery. The leaflet extension technique is considered to be an acceptable surgical treatment for aortic valve disease especially in young patients to whom valve replacement or Ross procedure might not be suitable. A careful long-term follow-up will be necessary to evaluate the durability of the leaflet extension technique with autologous pericardium.

[Management of mediastinitis after pediatric cardiac surgery with continuous closed irrigation method].

Two cases are presented as a successful management for mediastinitis with the continuous closed irrigation method after pediatric cardiac surgery. The continuous closed irrigation method has significant advantages over conventional open irrigation method or muscle flap in pediatric cases, because the system is simple to handle and easy to wash out any infectious tissue debris without additional invasive intervention. However, adequate duration of the irrigation and subsequent antibiotic regimen is still unclear. We conclude that the continuous closed irrigation method is an effective management which is applicable to most of mediastinitis cases after pediatric cardiac surgery.

Surgical management of a penetrated greenfield inferior vena cava filter.

This is a case report of an IVC filter penetration identified during lymph-node dissection for endometrial carcinoma. Although the spread strut put the adjacent abdominal aorta in danger of penetration, surgical removal of the filter could not be performed because there was still an increased risk of pulmonary embolism. Instead of IVC interruption, we used a wrapping technique as a prophylaxis against major bleeding complication due to IVC filter dislocation and recurrent pulmonary embolism.

Evaluation of stress on the autonomic nervous system of patients on mechanical circulatory assist.

PURPOSE: The power density values of high (HF; 0.15 to 0.4 Hz) and low frequency (LF; 0.04 to 0.15 Hz) components of arterial pressure were adopted for evaluation of stress on the autonomic nervous system of patients supported by mechanical circulatory assist. METHODS: Power spectral analysis (PSA) of arterial pressure signals was carried out, and trends in changes in the spectral components were observed in 12 patients on mechanical circulatory support (IABP and/or PCPS) and without the support (n=10). RESULTS: The normalized LF was depressed initially and increased gradually in both groups of patients except for four patients on mechanical circulatory assist. Three patients among them consequently died. CONCLUSIONS: Depressed LF represented marked stress on ANS and prolongation of the depression was related to poor outcome of patients. PSA of systemic blood pressure offers a reasonable tool for evaluation of stress on the ANS and for prediction of the prognosis of patients with circulatory assist devices.

[A surgical case of atrial septal defect with myotonic dystrophy].

A case report is presented of a 16-year-old woman with myotonic dystrophy, who required open-heart surgery for an atrial septal defect. We successfully repaired an atrial septal defect using normothermic cardiopulmonary bypass and electrically maintained ventricular fibrillation. Anesthesia using fentanyl, vecronium and isoflurane was uneventful and there were no postoperative complications. Anesthetic agents must be selected with care, and ventilation requires meticulous attention.

Late aneurysm of the distal aortic arch after repair of aortic interruption. A case report.

Aneurysm formation after aortic coarctation repair is not a rare complication of post-coarctation of aorta repair. We describe the case of a 43-year-old woman who had undergone repair of an isolated interruption of the aortic arch 30 years earlier, who came to our hospital with progressive chest pain, cough and dyspnea. A giant aortic aneurysm was revealed in the distal aortic arch by CT study. The patient underwent aneurysmectomy with total aortic arch replacement using a Dacron graft through redo median sternotomy. An embryologic explanation of this patient's anomaly and the previous surgical procedure are discussed for defining this rare clinical condition.

[A case of lateral femoral circumflex artery as a free graft for coronary artery bypass surgery].

A 46-year-old man had a three-vessel coronary disease. We performed quadruple coronary artery bypass grafting (CABG) with the left internal thoracic artery (LITA), right gastroepiploic artery (RGEA), saphenous vein and lateral femoral circumflex artery (LFCA). Postoperative coronary angiogram showed that the LFCA bypass graft was patent and supplied sufficient blood to the anastomosed vessel. There was no stenosis at the anastomotic site. However, the LFCA graft showed a string sign. Long-term follow-up and angiographic studies is necessary to establish the use of LFCA as an arterial free graft for coronary revascularization.

Upper extremity vein thrombosis: etiologic categories, precipitating causes, and management.

Although an increasing incidence of upper extremity venous thrombosis (U/E-DVT) has been reported, a relative paucity of information regarding the etiologic categories, precipitating causes, and proper management for this disorder is available. To settle on a strategy for the management of U/E-DVT, retrospective analyses were performed using records from the authors' hospital. In 12 patients (seven men, five women), 61 (mean) years of age, diagnosed as having symptomatic venography-proved U/E-DVT and followed up for 41 (mean) months, etiologic factors, precipitating causes, treatments, and outcomes were retrospectively analyzed. As etiologic factors, five of the patients had neoplastic disease, one had hemodialysis, and two had transvenous pacemaker implantations. Among various precipitating causes of U/E-DVT, hypoproteinemia was most frequently noted (67%). Various types of therapeutic management were selected: from thrombolysis with urokinase in six, balloon angioplasty in two, thrombectomy in two, and venous bypass surgery in one patient. Pulmonary embolism did not occur in any of the patients and only three of them complained of mild intermittent arm swelling during the follow-up period. Four patients died of neoplastic disease or heart failure (three within the first 6 months). This study, though limited, suggests that the rate of mortality depends on multiple underlying medical problems in U/E-DVT patients. Low incidences of late postthrombotic sequelae and pulmonary embolism were noted in this series. Symptomatic U/E-DVT patients could be managed conservatively with a revised supplementary therapy for their precipitating causes of U/E-DVT.

Pseudoaneurysm of the subclavian artery due to Xanthomonas pneumonia in a patient with acute myeloid leukemia: its rupture treated by transcatheter coil embolization.

A 52-year-old male with acute myeloid leukemia developed pseudoaneurysm of the subclavian artery. Pneumonia due to Xanthomonas maltophilia, which was multi-drug resistant, progressed to a lung abscess even under administration of antibiotics. This lung infection contiguous to the left carotid and subclavian arteries was suggested to have caused the pseudoaneurysm of the subclavian artery. The rupture of the aneurysm by penetration to the trachea amounted to about 1,000 ml of bleeding; fortunately the bleeding ceased spontaneously. Nonetheless, an emergency transcatheter coil embolization prevented re-bleeding. Endovascular treatment should be considered especially for aneurysms which develop in patients with underlying diseases.

Lower extremity hematoma as a complication of warfarinization in patients with artificial heart valves.

Four cases of lower extremity hematoma in patients undergoing anticoagulant therapy after heart valve replacement are herein reported, with special emphasis on the comparative diagnostic value of ultrasonography and computerized tomography. Although conservative management is sufficient for patients with no neurological impairment, needle aspiration after autolysis of the hematoma, which can be confirmed by CT study, is also recommended.

Low-dose protamine based on heparin-protamine titration method reduces platelet dysfunction after cardiopulmonary bypass.

OBJECTIVE: The heparin-protamine titration method that uses the Hepcon hemostasis management system (Medtronic HemoTec Inc, Englewood, Colo) reduced blood loss in cardiac surgery in previous reports, but the mechanism is not fully understood. This study tests the hypothesis that reduced protamine administration preserves platelet function in human cardiac surgery. METHODS: Platelet count, alpha-granule secretion, and aggregation to thrombin before and after cardiopulmonary bypass in human beings were evaluated. In the control group (n = 14), a fixed dose of protamine (3 mg/kg) was administered. In the titration group (n = 20), protamine doses were based on the heparin concentration measured by the Hepcon system. RESULTS: Heparin concentrations before protamine administration were higher in the titration group (P =.0012), but protamine doses of patients in the titration group were markedly lower than those of the control group (P <.0001). During protamine infusion at a rate of 0.3 mg. kg(-1). min(-1), the percentage of granule membrane protein-140-positive platelets significantly increased in the control group compared with the titration group (18.8% +/- 8.6% vs 13.0% +/- 5.3%, P =.0188). After protamine administration, aggregation of washed platelets to thrombin recovered almost to the preoperative level in the titration group; however, it remained lower in the control group (20% +/- 20% vs 55% +/- 18%, P =.0009). CONCLUSION: Low-dose administration of protamine, based on a heparin-protamine titration method, restores not only the blood coagulation but also the platelet responses to thrombin and attenuates platelet alpha-granule secretion during heparin neutralization. Overdose of protamine activates platelets and may predispose patients to excessive bleeding after cardiac surgery.

[A case of cor triatriatum with atrial septal defect in an adult].

A surgical treatment of a 54 year-old female with cor triatriatum was reported. Two dimensional echocardiography had demonstrated an abnormal septum in the left atrium. The abnormal septum had a 2 x 1 cm fenestration and existed between the left and right pulmonary veins. Preoperatively, we had misjudged the septum as ASD and misdiagnosed this case as PAPVC. During surgery we found that there was the accessory atrial chamber posterior to the true ASD. The accessory chamber received right pulmonary veins and connected to the left atrium. The left pulmonary veins connected to the left atrium normally behind the abnormal septum. We diagnosed this case as Lucas-Shmidt IIIA1 type cor triatriatum with ASD. The abnormal septum was resected, and the ASD was closed with a bovine pericardium. The postoperative course was uneventful and she was discharged 19 days after the operation.

A preliminary study of microcapsule suspension for hemolysis evaluation of artificial organs.

A microcapsule suspension, a substitute for animal blood in hemolysis tests, has been developed for evaluation of the absolute hemolytic properties of circulatory artificial organs. The microcapsule suspension was made by dispersing microcapsule slurry into an ethylene glycol sodium chloride solution. The microcapsule slurry was composed of a leuco dye solution and polyurethane membrane made by the reaction between aliphatic poly-isocyanate and polyamine by interfacial polycondensation. The microcapsule was a small particle containing dye inside. The microcapsule suspension was white; the diameter of the microcapsules was from 5 to 100 microns. The specific gravity of the suspension was 1.024, and the membrane was elastic. The fluid showed Newtonian characteristics, different from animal blood, and its viscosity was approximately 5.8 mPa.s. After the microcapsules were destroyed, the leuco dye was extracted with n-hexane from the suspension and was measured by spectroscopy after being colored with acid ethanol. Hemolysis can be regarded as a fatigue fracture of cell membranes rather than a static fracture. The destruction of microcapsules by a Potter type tissue grinder was observed at a low stroke number region and was compared to rat blood. Moreover, hemolysis tests of a commercially available centrifugal blood pump and the prototype of our centrifugal pump for mechanism checks were carried out with bovine blood. The hemolysis level of the prototype pump increased with time while the hemolysis level of the commercial blood pump did not change as much as that of the control when both pumps were tested with the microcapsule suspension. These results are similar to tests utilizing bovine blood. Therefore, hemolysis tests of circulatory artificial organs completed with microcapsule suspension are expected to provide results similar to tests with animal blood.

Atrial fibrillation after coronary artery bypass grafting. An increase in high-frequency atrial activity in patients with right coronary artery revascularization.

The increase in atrial high-frequency activity has been reported as a marker of the risk of paroxysmal atrial fibrillation. The presence of proximal right coronary artery disease is a predictor of atrial fibrillation after bypass surgery, however, the potential mechanism remains controversial. In this study, high-frequency atrial activity to clarify the electrophysiologic background for the predisposition to have proximal right coronary artery disease leading to atrial fibrillation after coronary revascularization was investigated. Before and soon after coronary revascularization, frequency analyses were performed on the 100 ms segment at the end of signal-averaged P waves in 22 patients with right coronary artery disease as opposed to the 23 patients without disease. Under the spectrum curve, area ratio (AR50) and magnitude ratios (MR) were calculated as follows; AR50 = (area 20-50 Hz/0-20 Hz) x 100, and MR = (magnitude at 20, 30, 40 and 50 Hz, respectively/maximal magnitude) x 100. In patients with proximal right coronary artery disease, high-frequency atrial components increased significantly in the 20 to 50 Hz range after coronary revascularization, and the incidence of postoperative atrial fibrillation was higher than in those without disease. In patients without right coronary artery disease, the frequency distribution of P waves was unchanged. Postoperatively, the two groups showed the same atrial frequency distribution. This data suggests that the increase in high-frequency atrial activity after right coronary artery revascularization might be associated with the pathogenesis of postoperative atrial fibrillation.

Aortic dissection complicating cardiac surgery in a patient with calcified ascending aorta.

Aortic dissection is a rare but devastating complication of cardiac surgery. Adequate and early diagnosis of intraoperative aortic dissection and quick therapeutic decision making are the keys for saving patients in such cases. We describe the case of a 68-year-old man referred for CABG and mitral valve replacement with severe calcification of the ascending aorta. Intra-operative transesophageal echocardiography was useful for diagnosis of intra-operative aortic dissection and malperfusion of the true lumen. Immediate switching of the arterial perfusion site established flow in the true lumen with prompt subsidence of the expanded false lumen. CABG, mitral valve replacement and graft replacement of the ascending aorta could be simultaneously performed in this patient.