[Staged total cavopulmonary connection following Starnes operation]

A three-year-old boy with Ebstein's anomaly, who had received Starnes operation in the neonate state, successfully underwent staged total cavopulmonary connection. Despite of hypoplasticity of the pulmonary artery, the postoperative cardiac catheterization showed no elevation of pulmonary artery pressure and good cardiac performance. Although he suffered from supraventricular tachycardia in the early postoperative period, subsequent course was uneventful.

[Multi-vessel dissection; report of a case]

We report an extremely rare case of multi-vessel dissection including left carotid artery, ascending aorta and thoracoabdominal aorta independently. A 65-year-old man suffered from cerebral infarction due to left carotid artery dissection. Five days later, he complained of severe back pain and was diagnosed as acute DeBakey type IIIb aortic dissection. He had been treated medically. One month later, computed tomography (CT) scan demonstrated DeBakey type II as well as type IIIb aortic dissections. The ascending aorta was replaced on August 8, 2001. Then replacement of the descending thoracic aorta with reconstruction of the eighth and tenth intercostal arteries was performed on September 26, 2001. The left carotid artery dissection has been treated medically.

[Spinal cord ischemia complicated with acute aortic dissection and intramural hematoma; report of two cases]

Spinal cord ischemic injury is one of te most serious complications in patients with aortic dissection. We experienced 2 cases with severe upper back pain and paraplegia of the lower extremities as initial manifestations of acute DeBakey type IIIb aortic dissection (case 1) and aortic intramural hematoma (IMH) from ascending aorta to abdominal aorta (case 2). Paraplegia was permanent and spinal cord atrophy was proved at Th 9-10 by the magnetic resonance imaging (MRI) in case 1. The aortic IMH regressed rapidly and paraplegia was transient in case 2. The MRI obtained 18 days after the onset showed scattered small lesions within the spinal cord at Th 4-7.

[Pericardiectomy for post-coronary artery bypass grafting constrictive pericarditis; strategy for safe and complete pericardiectomy]

Surgery for constrictive pericarditis after coronary artery bypass grafting (CABG) needs complete pericardiectomy without injury to bypass grafts. We performed pericardiectomy for post-CABG constrictive pericarditis 15 months after the first surgery. Preoperative multislice helical 3-dimensional computed tomography (CT) clearly demonstrated the patent bypass grafts and anatomical relationship between grafts and surrounding organs. Among surgical approaches, we chose bilateral thoracotomy to avoid injury to the bypass grafts and to obtain a good surgical exposure, especially for pericardiectomy of the left side of the heart. Additionally, with the use of intraoperative doppler ultrasound blood flowmetry, we could safely achieve complete pericardiectomy. We conclude that the combined application of 3-dimensional CT, bilateral thoracotomy and doppler ultrasound blood flowmetry was a supreme strategy for the operation of constrictive pericarditis after CABG.

[Management of myasthenia gravis in association with thymoma]

From June 1975 to March 2002, we experienced 339 patients with myasthenia gravis (MG). Ninety-four patients (81 generalized MG and 13 ocular type) had associated with thymoma. Extended thymectomy including thymoma was performed in all patients. The thymomas were classified as stage I (n = 46), II (n = 31), III (n = 14), and IV a (n = 3). Histopathological findings of the thymoma indicated polygonal cell type in 75 cases, mixture of polygonal and spindle cell type in 14, and spindle cell type in 3, respectively. Three cases in stage II, 12 in III, and 3 in IV a received postoperative radiation therapy. Twenty-two patients required prolonged respirator management for respiratory crisis. Complete remission of MG was seen in 15 cases (17%), and good therapeutic results were obtained in 55 cases (58%) with combined corticosteroid therapy. On the other hand, recurrences of the invasive thymoma were seen in 12 cases (13%), and six of them (6%) died of the tumor. In conclusion, early extended thymectomy including thymoma is markedly effective therapy for MG associated with thymoma, although careful attention should be paid for recurrence of the invasive thymoma.

[Recurrent low output syndrome after the weaning from mechanical circulatory support for postcardiotomy cardiogenic shock]

We reviewed the cases of recurrent low output syndrome (LOS) after the weaning from mechanical circulatory support for postcardiotomy cardiogenic shock. Twelve patients were divide into 2 groups according to whether low output syndrome recurred or not, consisting of a recurrent low output syndrome (+) group [re-LOS (+) group, n = 6] and a recurrent low output syndrome (-) group [re-LOS (-) group, n = 6]. Between 2 groups, there was no statistical difference in preoperative left ventricular ejection fraction (LVEF), aortic closs-clamping time and cardiac index at the weaning from mechanical circulatory support. Only the LVEF at the weaning in the re-LOS (+) group was significantly less than that in the re-LOS (-) group (0.39 +/- 0.08 vs 0.62 +/- 0.19, p < 0.05). All patients in the re-LOS (-) group survived to discharge, while in the re-LOS (+) group, although 3 patients were re-supported by intra-aortic balloon pumping, 4 of 6 patients died of multiple organ failure and 2 survivors were in New York Heart Association class III. The results suggest that the key to survive to discharge after the weaning from mechanical circulatory support is whether the cardiac contraction could recover or not.

[Surgical treatment of aneurysm of the ductus arteriosus in the adult]

Aneurysm of the ductus arteriosus is rare, however, reports on this lesion have increased recently with the progress of thoracic aortic surgery in Japan. We report 3 male cases aged 58, 59, 73 years. Aneurysms and total aortic arch were replaced by artificial graft through median sternotomy using selective cerebral perfusion in 2 cases. Through left posterolateral thoracotomy using deep hypothermia with circulatory arrest, proximal descending thoracic aorta including the aneurysm was replaced in 1 case. Their postoperative courses were uneventful. Surgery for this lesion is safe and various surgical approaches and circulatory supporting methods can be selected depending on the size of aneurysm and associated lesions.

[Follow-up study of myasthenia gravis: evaluation of thymectomy in 300 patients]

From June 1975 to March 1999, 300 patients of myasthenia gravis(MG) have undergone thymectomy. Among these patients, 69 cases were classified as ocular type of MG(including 15 cases with thymoma), and 231 were generalized type of MG(including 86 cases with thymoma). The efficacy of the treatment was investigated by evaluating current patients' life activity, which is classified in 6 groups(Remission, Much Improved, Improved, Unchanged, Worse, and Died). Among the 214 cases without thymoma, Remission was 75, Much Improved was 56, and Improved was 55, namely 86.9% of these cases showed Improved or better. Among 86 cases with thymoma, Remission was 14, Much Improved was 21, and Improved was 32, namely 77.9% of these cases showed Improved or better. We concluded that post-operative outcome of these patients regardless of thymoma were generally satisfactory, but it was necessary to carry out long term careful follow-up.

[Efficacy of modified ultrafiltration in coronary artery bypass grafting]

We evaluated the efficacy of modified ultrafiltration (MUF) in coronary artery bypass grafting. Twenty patients were divide into two groups consisting of a control group (n = 11) and a MUF group (n = 9). MUF was carried out for fifteen minutes immediately after the completion of cardiopulmonary bypass. The blood flow through the ultrafilter was 300 ml/min and about 1,200 ml of water was removed. The hematocrit elevated significantly from 25% to 30% in the MUF group (p < 0.01). Postoperative blood loss in the first 24 hours in the MUF group was significantly less than that in the control group (8 +/- 2 ml/kg vs 12 +/- 4 ml/kg, p < 0.01). There was no statistical difference in the percentage of the increase in body weight after the operation, inflammatory reaction and pulmonary function (A-a DO2, PaO2/FIO2 and duration of intubation) between two groups. In conclusion, MUF is useful to hemoconcentrate and reduce postoperative blood loss in coronary artery bypass grafting.

A probabilistic solution to the MEG inverse problem via MCMC methods: the reversible jump and parallel tempering algorithms

We investigated the usefulness of probabilistic Markov chain Monte Carlo (MCMC) methods for solving the magnetoencephalography (MEG) inverse problem, by using an algorithm composed of the combination of two MCMC samplers: Reversible Jump (RJ) and Parallel Tempering (PT). The MEG inverse problem was formulated in a probabilistic Bayesian approach, and we describe how the RJ and PT algorithms are fitted to our application. This approach offers better resolution of the MEG inverse problem even when the number of source dipoles is unknown (RJ), and significant reduction of the probability of erroneous convergence to local modes (PT). First estimates of the accuracy and resolution of our composite algorithm are given from results of simulation studies obtained with an unknown number of sources, and with white and neuromagnetic noise. In contrast to other approaches, MCMC methods do not just give an estimation of a "single best" solution, but they provide confidence interval for the source localization, probability distribution for the number of fitted dipoles, and estimation of other almost equally likely solutions.

Cleft on tricuspid anterior leaflet

We report a case of isolated congenital tricuspid regurgitation caused by a cleft in the anterior tricuspid leaflet associated with a patent foramen ovale. Preoperative echocardiography revealed severe tricuspid regurgitation resulting from anterior tricuspid leaflet prolapse. The patient underwent successful tricuspid valve repair with simple cleft suture and annuloplasty and direct closure of the patent foramen ovale.

Successful management of secondary aortoesophageal fistula with graft infection

A 60-year-old woman was transferred to our institution after massive hematemesis and the diagnosis of secondary aortoesophageal fistula was made. Five months previously, she had undergone graft replacement from the origin of the left subclavian artery to midthoracic aorta for chonic type B dissection. After an extraanatomic bypass was performed through a sternotomy, the infected thoracic aortic graft was resected through a left thoracotomy. She remained well without evidence of infection.

[Efficacy of modified ultrafiltration in reoperation for valvular disease]

We evaluated the efficacy of modified ultrafiltration (MUF) in reoperation for valvular disease. Fourteen patients were divide into two groups consisting of a control group (n = 6) and a MUF group (n = 8). MUF was carried out for fifteen minutes immediately after the completion of cardiopulmonary bypass. The blood flow through the ultrafilter was 300 ml/min and about 1,200 ml of water was removed. The hematocrit elevated significantly from 25% to 31% in the MUF group (p < 0.05). The percentage of the increase in body weight after the operation in the MUF group was significantly less than that in the control group (3.3 +/- 3.1% vs 8.3 +/- 4.3%, p < 0.05). The PaO2/FIO2 after the operation in the MUF group was significantly higher than that in the control group (376 +/- 125 mmHg vs 242 +/- 79 mmHg, p < 0.05). The duration of mechanical ventilation in the MUF group was significantly less than that in the control group (1.1 +/- 1.1 days vs 5.3 +/- 3.3 days, p < 0.05). In conclusion, MUF is useful to hemoconcentrate, reduce postoperative body weight gain and promote early recovery of pulmonary function in reoperation for valvular disease.

In vitro simultaneous measurement of refractive index and thickness of biological tissue by the low coherence interferometry

We proposed and demonstrated in vitro simultaneous measurement of refractive index and thickness of biological tissue. The technique is based on the low coherence interferometry combined with precise translation stages. Refractive indices were determined with the accuracy of less than 1% for tissue samples of a few hundred micron thickness, including chicken tissue, human tooth and nail. Simultaneous measurement of refractive index and thickness of multilayer tissue are also demonstrated.

Spontaneous rupture of the thoracic aorta

BACKGROUND

Spontaneous rupture of the thoracic aorta without trauma, aneurysm, or dissection is an extremely rare but catastrophic disorder. Two cases of spontaneous aortic rupture are presented, both treated surgically with satisfactory results.

METHODS

A review of the English literature found 16 patients with the diagnosis of spontaneous rupture of the thoracic aorta from 1961 through 1998. Eighteen reported cases, including the 2 cases presented herein, are reviewed.

RESULTS

The representative clinical picture is one of a middle-aged hypertensive patient with acute chest pain and collapse, with imaging modalities demonstrating hemopericardium, hemomediastinum, or hemothorax. According to the reported experiences, aortography was accurate for identifying the rupture site although the findings were sometimes subtle. Misdiagnosis or nonsurgical management resulted in the patient's death. All 8 patients who did not undergo aortic repair died within 3 weeks after the onset, whereas 9 of 10 patients who underwent surgical aortic repair survived.

CONCLUSIONS

For patients with a definitive or possible diagnosis of spontaneous rupture of the thoracic aorta, prompt operation is imperative through an optimal surgical approach to identify and repair the rupture site with appropriate circulatory support.

Altered distribution and density of myocardial beta-adrenoceptors during acute rejection in rats

BACKGROUND

A better understanding of altered expression of myocardial beta-adrenoceptors can facilitate the diagnosis of early and late acute rejection of heart transplants.

METHODS

We submitted rats to heterotopic heart transplantation (iso- and allografts) of which one of each were treated with or without cyclosporin A for 4, 7, and 14 days (n=5, respectively). The cardiac sections were incubated in vitro with [3H]CGP 12177, or the hearts were labeled in vivo by intravenous injection of [3H]CGP 12177. Autoradiographic images of both were analyzed digitally and compared with histologic findings.

RESULTS

Beta-adrenoceptor distribution in native hearts and isografts was homogeneous, but highly differential distribution and density in allografts were observed in the left and right ventricular walls and in the interventricular septum despite treatment with cyclosporin A. High-density areas in the progressive course of acute rejection are commonly associated with up-regulation of beta-adrenoceptors in apparently viable myocytes, although histologic findings confirmed many infiltrating mononuclear cells. Low-density areas, which were identified in the right and left ventricular walls as early as 4 days after transplantation, correlated with derangement of myocytes, which was suggestive of early acute rejection. The images obtained by in vivo technique were comparable to in vitro images.

CONCLUSIONS

The alteration of beta-adrenoceptor expression in allografts showed a close relationship with the severity of acute rejection, and the techniques employed in this model were useful in our study of the rejection process and in detecting early and late acute rejection in the rat.

Pedicled pericardial flap for pulmonary artery in adult dogs

OBJECTIVE

Stenosis of extracardiac conduit after reconstruction of right ventricle outflow tract is a serious problem, and the purpose of this study was to identify the suitability of broadly pedicled autologous pericardial flap for the reconstruction of pulmonary artery trunk in adult dogs.

METHODS

Eight mongrel dogs had replacement of a pulmonary artery trunk with extracardiac conduit, in which prosthetic vascular graft formed the posterior wall and pedicled (group P, n = 5) or free (group F, n = 3) autologous pericardium created the anterior wall. Six months after the operation, pressure gradient across the conduit were measured and put to death for pathological examinations.

RESULTS

Pressure gradient across the conduit in groups F and P was 16.0 +/- 16.8 mmHg and 1.4 +/- 1.7 mmHg respectively. In the microscopic examination, flaps of group P had neo-intimal cells in the innermost layer, abundant cellular component with elastic fiber was seen within the middle layer, and collagen tissue within the outer layer. Conversely, the presence of calcification was shown within collagen fiber layer of all patches in group F. Sparse cellular component and the absence of neo-intimal cells were also observed in group F.

CONCLUSIONS

Broadly pedicled pericardial flap is more conceivable to prevent the development of conduit stenosis after right ventricle outflow tract reconstruction, if compared with free pericardial patches.

Pulmonary vascular changes induced by congenital obstruction of pulmonary venous return

BACKGROUND

Pulmonary venous obstruction (PVO) induces pulmonary arterial hypertension, as well as pulmonary venous hypertension, and jeopardizes the repair of cardiac lesions.

METHODS

Four cases of congenital mitral stenosis and 4 cases of cor triatriatum (Lucas type A), ages ranging from 2 months to 16 years, were histologically examined on pulmonary vasculature. Histometrical analysis was performed on medial thickness and intimal changes of both pulmonary arteries and veins. For comparison, the examination of pulmonary vasculature in ventricular septal defect (VSD) cases was also performed.

RESULTS

Medial thickening and intimal fibrosis, in both pulmonary arteries and veins with widespread lymphangiectasia, were characteristic vascular changes of PVO cases. Medial thickness of pulmonary arteries was correlated with preoperative pulmonary arterial pressure (PAP) (r = 0.77, p = 0.03 for systolic PAP), and greater than that of VSD cases. Medial thickness of pulmonary veins was also greater in PVO cases. Intimal fibrosis of pulmonary arteries and veins was seen extensively at the advanced ages, whereas no plexiform lesions or more advanced stages of pulmonary vascular disease were present.

CONCLUSIONS

Congenital PVO induced progressive medial thickening and intimal fibrosis in pulmonary arteries and veins accompanied by lymphangiectasia. However, no plexiform lesions or more advanced stages of pulmonary vascular disease were present, which may explain the reversibility of pulmonary hypertension due to congenital PVO.

Quantitative analysis of cardiac 3-L-nitrotyrosine during acute allograft rejection in an experimental heart transplantation

BACKGROUND

Recent studies have shown that nitric oxide interacts with superoxide to form peroxynitrite, a potent oxidant that modifies cellular proteins producing 3-L-nitrotyrosine (N-Tyr). This study was designed to evaluate N-Tyr quantitatively with high-performance liquid chromatography (HPLC) during cardiac allograft rejection.

METHODS

Rat transplanted hearts (allogeneic or syngeneic grafts) were examined with HPLC analysis, immunohistochemistry for N-Tyr, and histological studies on 0, 1, 3, and 7 days after transplantation.

RESULTS

No histological rejection was found in syngeneic grafts, or day 0 or 1 allografts. HPLC demonstrated that N-Tyr in allografts increased on day 1 and continued to increase through day 7, while N-Tyr was not detected in any syngeneic grafts. Immunostaining of the allografts did not show N-Tyr on day 1.

CONCLUSION

These results demonstrate that N-Tyr shows a time-dependent accumulation in cardiac allografts during acute rejection. N-Tyr detection using HPLC may be an useful maker for early diagnosis of acute rejection before pathological rejection occurs.

Cardioprotective effect of orally administered angiotensin-converting enzyme inhibitor against ischemia. Reperfusion injury in the isolated rat heart

Angiotensin-converting enzyme inhibitors are reported to be cardioprotective against ischemia/reperfusion injury. Few studies have been made, however, on the cardioprotectiveness of orally administered angiotensin-conrerting enzyne inhibitors. Wistar rats were pretreated with oral delapril--30 mg/kg/day in the low-dose group and 90 mg/kg/day in the high-dose group--for one week. Cardiac function recovery was assessed after ischemia/reperfusion in the isolated working heart model. Rat hearts in the high-dose group were also reperfused with a solution containing nitro-L-arginine methyl ester, a nitric-oxide synthase inhibitor. Oral pretreatment of delapril did not affect baseline cardiac function. The percentage of cardiac output recovery for controls was 22 +/- 4.5%, for the low-dose group 44 +/- 6.5% (P < 0.05 versus controls), and for the high-dose group 76 +/- 5.3% (P < 0.001 versus controls and low-dose). Although coronary vascular resistance at the end of reperfusion showed no difference, mean coronary vascular resistance early after reperfusion was significantly lower (P < 0.0001) in both delapril groups than in control. In the high-dose group, reperfusion with L-NAME significantly increased coronary vascular resistance after ischemia/reperfusion and attenuated the cardioprotectiveness of delapril (P < 0.05 versus without nitro-L-arginine methyl ester). We thus found that oral administration of delapril was cardioprotective dose-dependently against ischemia/reperfusion injury. Nitric oxide appeared to be involved in the mechanism behind this cardioprotective effect.

Remnant omental transfer for the mediastinitis after coronary bypass surgery with right gastroepiploic artery

A one-stage procedure for the treatment of mediastinitis after coronary bypass surgery utilizing the right gastroepiploic artery is described. This procedure consists of thorough debridement of mediastinal pus and necrotic tissue, excision of infected sternal bone, mediastinal irrigation, and immediate transfer of the "remnant" omental pedicle based on the "left" gastroepiploic artery without postoperative drainage or irrigation. Recently, this procedure was applied to our patients followed by excellent results.

Gaze orientation during full-field and peripheral field passive optokinesis

During full-field optokinetic nystagmus the mean position of gaze shifts the eyes in the direction of the fast phase. The driving force for this, pre-supposes that the preferred locus for the position control system, is shifting gaze into the direction where the motion is coming from. In this study, six subjects were examined to determine whether the absence of the central visual field would influence the mean position of gaze during passive optokinesis. Our findings indicate that a full field and a central field restricted to 20 deg, evoked gaze shifts of up to 7 deg into the direction of the fast phase. However, when the central field was masked by either 12.5 deg or 25 deg the mean gaze position was found to be significantly reduced (p < 0.05). This effect was not influenced by the velocity of the stimulus (p > 0.05). These results lead us to conclude that gaze orientation during optokinesis is strongly influenced by the area of retina stimulated. The role of the slow eye movement control system and possible cognitive strategies adopted during selective spatial attention are discussed in the light of this finding.

[Acquired pulmonary stenosis caused by mediastinal mature teratoma: a case report]

A 13-year-old girl was admitted with a sudden onset of chest oppression. Mediastinal teratoma was suspected on chest X-ray and CT scan. A grade 2/6 systolic murmur was heard at the upper left sternal area and cardiac catheterization showed mild pulmonary stenosis. After resection of the tumor, the murmur disappeared and histopathological diagnosis was mature teratoma. This is a rare case report of pulmonary stenosis caused by mediastinal mature teratoma.

Fontan with pedicled pericardium

Pedicled pericardium is a useful viable material for cardiac surgery. In an adolescent case, the extracardiac lateral tunnel of a Fontan connection was successfully constructed with pedicled pericardium. This procedure is expected to allow the growth of the tunnel and to need no anti-coagulant therapy, while careful long-term follow-up is necessary.

Brain damage after aortic arch repair using selective cerebral perfusion

BACKGROUND

Selective cerebral perfusion is one of the most popular methods for cerebral protection during aortic arch repair. However, causes of postoperative brain damage are not fully understood. We analyzed brain damage after aortic arch repair using selective cerebral perfusion for true aortic arch aneurysm in regard to preoperative cerebral infarction and intracranial and extracranial occlusive arterial disease.

METHODS

Over a 9-year period, 60 patients with true aortic arch aneurysm underwent aortic arch repair using selective cerebral perfusion. Postoperative brain damage was evaluated in regard to preoperative cerebral infarction detected by computed tomography, magnetic resonance imaging, or both in 50 patients and intracranial and extracranial occlusive arterial disease detected by digital subtraction angiography, magnetic resonance angiography, or both in 35 patients.

RESULTS

Seven (12%) of the 60 patients died within 30 days of operation. Postoperative brain damage occurred in 6 (10.5%) (3, coma, and 3, hemiplegia) of 57 patients; 3 patients who died without awakening were excluded. Preoperatively, old cerebral infarction was detected in 9 patients (18%), and silent cerebral infarction (lacunar infarction and leukoaraiosis) was diagnosed in 26 patients (52%). Postoperative brain damage occurred in 3 (33%) of the 9 patients with preoperative cerebral infarction and in 3 (23%) of 13 patients with negative preoperative brain findings; this excludes 2 patients who died without awakening. No patient with silent cerebral infarction had postoperative brain damage. Occlusive arterial disease was detected in 7 patients (20%). The incidence of brain damage in these patients was 71% (5/7), which was significantly greater than that of 4% (1/28) in patients without occlusive arterial disease (p < 0.001).

CONCLUSIONS

Silent cerebral infarction may not be a risk factor for postoperative brain damage. Preoperative evaluation of intracranial and extracranial occlusive arterial disease provides important information as to whether a patient might sustain brain damage after aortic arch repair using selective cerebral perfusion.

[Long-term surgical results of acute aortic dissection]

Between 1988 and 1997, 69 patients underwent surgery for acute aortic dissection: 65 patients had an acute type A (AcA) and 8 an acute type B (AcB) aortic dissection. The hospital mortalities were 16.9% for AcA and 25% for AcB. Actuarial survival rates including hospital deaths after 5 and 8 years were 70% and 58% for AcA patients and no late death or cardiovascular event occurred in AcB patients during follow-up periods. Freedom from cardiovascular events was 88% and 70% at 5 and 8 years, and freedom from reoperation was 94% at 5 and 8 years for operative survivors of AcA. There were no differences on actuarial survival rates between ascending aortic repair and arch repair, ringed-graft and suture anastomosis, and postoperatively patent false lumen and closed false lumen. There were no differences on freedom from cardiovascular events between ascending aortic repair and arch repair, and ringed-graft and suture anastomosis, however, patients with postoperatively patent false lumen showed significantly lower freedom from cardiovascular events registering 85% and 59% at 5 and 8 years compared with 94% at 5 and 8 years in patients with closed false lumen.

[Open distal anastomosis or aortic balloon occlusion technique during complete aortic arch replacement]

The technique of open distal anastomosis or application of aortic balloon occlusion catheter designed to occlude the descending thoracic aorta have been used in 33 and 19 patients, respectively, to control bleeding during the procedure of distal anastomosis for complete aortic arch replacement with a prosthetic graft. These two techniques allowed us a simple approach to the lesion and the avoidance of clamp injury to the fragile aortic tissue. Open distal anastomosis was applied for 91% patients of operated aortic dissection and all emergent cases, it's duration ranged from 10 to 110 minutes with an average of 58 minutes under 18.2 degrees C of lowest esophageal temperature. On the other hand, aortic occlusion balloon was inserted for mainly true aortic aneurysm patients without an emergency, and helped to maintain the perfusion pressure on a lower part of body around 50 mmHg by the 1550 ml/min in an average of perfusion flow femoral artery under 21.2 degrees C of temperature. The difference of postoperative renal and liver function evaluated by serum enzyme levels of total bilirubin, GOT, GPT, LDH, creatinine and BUN did not reach to statistical significance between the patients using open distal anastomosis and balloon occlusion, however, the incidence of postoperative complication including either renal, liver dysfunction, abdominal problem or paraplegia was significantly higher in the patient group with open distal technique. Either open distal anastomosis or aortic balloon occlusion technique would be appropriately selected according to the patient's characteristics or the condition of aortic disease to be operated.

Simultaneous measurement of the phase and group indices and the thickness of transparent plates by low-coherence interferometry

We propose and demonstrate a novel technique for simultaneous measurement of the phase index, n(p) , the group index, n(g) , and the thickness, t , of transparent plates by use of a low-coherence interferometer. The output light from a superluminescent diode is focused upon the front plane of a transparent plate that is used as the sample. The sample stage is subsequently moved until the light is focused upon the rear plane of the plate. Measurement of the stage movement distance and the corresponding optical path difference allows us to determine both n(p) and n(g) . By placing the sample between two glass plates, we measured n(p) , n(g) , and t simultaneously, with an error of 0.3% or less, for nearly 1-mm-thick transparent plates, including glass and electro-optic crystals.

Sutureless ringed graft replacement of descending thoracic aorta with extensive calcification

A 79-year-old hypertensive woman, with fusiform shaped atherosclerotic aneurysm in the descending thoracic aorta whose medial layer was maintained by an extensive solid calcium plate (porcelain aorta), was successfully treated using a sutureless intraluminal ringed graft. Spools of the ring were fixed by circumferential ligatures at both proximal and distal sites of anastomosis and a dilated segment of the aorta was replaced with the tube graft.

Replacement of the ascending aorta and aortic valve with a composite graft: operative and long-term results

The purpose of this study is to analyze our treatment experience on patients with ascending aortic aneurysms, with aortic regurgitation. From January 1974 to December 1995, 49 patients underwent replacement of the aortic valve and ascending aorta with a composite graft, in which primary operation cases were 44 and reoperation ones were 5. The Bentall technique was used in 20 patients, the button technique in 11, the interposition graft technique in 11, and a combination of the interposition graft and button technique in 7. All but one reoperation cases underwent the interposition graft technique. Hospital mortality was 30% for the Bentall technique, and 9.1% for the button technique and 9.1% for the interposition graft technique; there was no hospital mortality in the combination of the interposition graft and button technique. Hospital mortality of interposition graft technique in primary operation cases was 9.1%, and that in reoperation cases was 0%. Hospital mortality in patients underwent from 1974 to 1985 was 30.8%, 27.8% from 1986 to 1991, and 0% from 1992 to 1995. Five late deaths occurred in the Bentall group (35.7%) and one late death in the button technique (9.1%). Not late deaths in the other groups have occurred. In summary, operative mortality in Bentall technique group was higher than that of the other groups. Operative results were improved by the change of operative methods. The interposition graft technique is preferable for patients undergoing reoperation or when tension on the ostial anastomoses may occur. The button technique is best for patients with aortic dissection or inflammation involving the coronary ostia.

Successful management of left main bronchial stenosis as a rare complication of pericardiectomy

We present a rare complication of pericardiectomy and the effective management thereof. A 67-year-old female with dyspnea and upper abdominal pain was received at our department upon referral. Chest roentgenogram and cardiac catheterization preceded a diagnosis of constrictive pericarditis. Pericardiectomy was performed subordinate to median sternotomy and left anterolateral thoracotomy. Extubation was carried out on day 2 but reintubation was necessitated on the same day as a result of progressive dyspnea. Chest roentgenogram revealed an atelectasis of the left lung. Fiberoptic bronchoscopy showed left main bronchial stenosis resulting from a pulsating external structure. A postoperative computed tomogram substantiated the stenotic left main bronchus between the dilated left pulmonary artery and the thoracic descending aorta. An expandable metallic stent for the treatment of this complication was selected over other invasive procedures. Two years of follow-up reveal no complications. Accordingly, an expandable metallic stent has demonstrated its effectiveness not only on bronchial stenosis due to malignancy or tuberculosis but on benign cases such as this as well.

[Brain damage following aortic arch repair with regard to techniques of selective cerebral perfusion and preoperative cerebral lesions]

One hundred and twenty-nine aortic aneurysm patients (true 68 and dissection 61) underwent aortic arch repair from January 1987 to December 1995. Postoperative brain damage was evaluated regarding both preoperative brain lesions and techniques of selective cerebral perfusion (SCP) in that one pump for SCP until April 1992, then two pumps were employed, one for right and the other for left hemisphere of the brain. Overall hospital mortalities were 21% in true and 13% in dissecting aneurysms. Ten patients were complicated with postoperative brain damages (coma 8 and hemiplegia 2), registering 7.8% of total patients. Both history of stroke and silent cerebral infarction (SCI) detected by CT and/or MRI were considered to be positive in the mean of having preoperative brain lesions. Although there was no significant difference between incidences of postoperative brain damage in true and dissecting aneurysms, registering 11% and 4% respectively, preoperative brain lesions in true aneurysm (68%) was significantly greater than dissecting aneurysm (32%). Furthermore, the incidence of postoperative brain damage was 22% in one-pump SCP which was significantly greater than 3% in two-pumps SCP in the patients with a true aneurysm. But there was no postoperative brain complication in patients with SCI even using either one two pumps for SCP. The present data suggest two-pumps SCP is better technique for cerebral protection compared to one-pump SCP for aortic arch repair.

Tricuspid valve closure for neonatal Ebstein's anomaly

A respirator-dependent 11-day-old boy with Ebstein's anomaly is presented. His cardiac anomaly with progressive cardiomegaly was first noticed at 24 weeks' gestation on fetal echocardiography. After birth, he required mechanical ventilation because of massive tricuspid regurgitation and restricted pulmonary blood flow. The operation of tricuspid valve patch closure, resection of right atrial wall, and central shunt successfully weaned him from the respirator on postoperative day 13. Cavopulmonary anastomosis was performed without problem when the patient was 8 months of age.

[Early and late results of replacement of the ascending aorta and/or aortic arch using selective cerebral perfusion]

From 1987 to 1994, 116 patients received replacement of the ascending and/or aortic arch using selective cerebral perfusion. They were 82 male and 34 female, with average age of 64 years. There were 63 dissecting and 53 true aneurysms. Extent of replacement was: ascending aorta in 13, aortic root in 2, aortic arch in 93, and aortic root and complete arch in 8. Aortic arch replacements were composed of: 29 partial proximal aortic arch replacements, 44 complete aortic arch replacements, and 20 partial distal aortic arch replacements. Nineteen (16.4%) hospital deaths occurred. Univariate testing of pre-, intra-, and post-operative variables followed by stepwise logistic regression analyses identified elderly, ischemic heart disease, postoperative neurologic complication, cardiac dysfunction, renal failure, and massive bleeding as factors having independent association with hospital mortality. Neurologic complication was found in 10 patients (8.6%), and risk factor for this complication was preoperative peripheral vascular disease. Follow-up of hospital survivors documented an overall cumulative 5-year survive rate of 69%. There was no significant difference between dissection and true aneurysms in 5-year survive ratios, which were 63% and 82%, respectively. During follow-up periods, 18 patients died. Half of these cases were vascular deaths, caused by rupture, sudden death and secondary operation. Univariate analyses followed by stepwise Cox testing indicated that chronic obstructive pulmonary disease and a history of postoperative massive bleeding were associated with decreased later survival. Our experience suggests that selective cerebral perfusion is a safe technique for the repair of ascending aorta and/or aortic arch problems. High-risk subgroups of patients with these aortic problems can be identified by risk factors. Aggressive and careful management is necessary for such subgroups to improve early and late survival rates.

Vection with Degraded Real-World Stimuli

Psychophysical studies have revealed that the retinal periphery plays a dominant role in inducing vection, ie the visually induced sensation of self-motion. This suggests that the quality of the visual stimulus is not an important factor for vection. However, since abstract stimuli were used in these studies, it is not clear whether the quality of real-world visual stimuli could still play a critical role in inducing vection. We investigated how vection induced by real-world visual stimuli was affected when the stimuli were spatially or temporally degraded.

Stereoscopic video clips were taken through the windshield of a car driven on a sharply curved and hilly road. These clips were degraded spatially by using a mosaic effect, or temporally by using a strobe effect on a video editing system. The perceived direction and strength of vection were measured while subjects were viewing these visual stimuli presented on a 63 deg wide and 38 deg high video projection monitor. Degradation of the visual stimuli was found to have little effect on the assessment of direction in horizontal vection. Assessment of the direction of vertical vection, however, was significantly disturbed by both spatial and temporal degradation of the stimuli. Temporal degradation reduced the strength of vection significantly for both horizontal and vertical motion. In contrast, although spatial degradation of visual stimuli reduced the strength of vection in both dimensions slightly, the effect was not statistically significant. We conclude that the spatial quality of real-world visual stimuli does not play a significant role in inducing vection.

[Redo operation after surgery for aortic aneurysm and dissection]

Thirteen patients who underwent redo operation after surgical treatment of aortic aneurysm and dissection were presented. In 8 patients, redo operations were performed for aortic dissection following aortic valve replacement. A-C bypass, the Koster-Collins operation and replacement of thoracic aorta. In the other 5 patients, the reasons for redo operation were aortic root enlargement after replacement of ascending aorta and aortic valve replacement, pseudoaneurysm and aneurysmal dilatation around coronary button for the Bentall operation and recurrent aneurysm after patch aortoplasty and thoracoabdominal replacement using the Crawford's maneuver. To prevent these redo operation, adequate selection of surgical procedures and meticulous operative techniques should be required in primary operation.

Egocentric perception through interaction among many sensory systems

We perceive the egocentric position and velocity of ourselves by many senses, such as vision, proprioception and vestibular sense. Normally the information by these senses is in harmony. However, there are situations in which the information is inharmonious. When we watch a wide-screen monitor or we ride in an accelerating or turning vehicle, visual information conflicts with proprioceptive and vestibular information. Since human egocentric perception has been studied for each separate sense in the previous research, it is not clear how the integration among these senses contributes to perception of human orientation. In Experiment 1, we investigated the contribution of visual, proprioceptive and vestibular information in isolation and in combination to perception of direction of forward self-motion. An observer rode in small vehicle (vestibular information) or walked (proprioceptive information) through a narrow corridor. Many vertical bars were hung from a ceiling of the corridor. When the observer moved forward, she/he viewed expanding optic flow of the bars (visual information) through video cameras and a helmet-mounted stereoscopic display. By fastening the observer and/or the cameras at different angles, consistent or conflicting information about forward direction was given through each sense. It was found that when there was conflicting information about the direction of forward motion (a) vestibular information was more dominant than visual cute, (b) visual and proprioceptive information was linearly added with weighting, and (c) visual information was dominant for backward motion. In Experiment 2, we investigated sensory integration when we moved forward with linear acceleration. Direction of the acceleration was either forward or sideways, namely corresponding to a ride in an accelerating or turning vehicle. We developed a new method to measure sensation or self-motion more objectively by using the three-dimensional position-sensor system. Positions of observer's head, shoulder, waist and ankle were measured to find body tilt accompanied by sensation of self-motion. It was found that the body tilted towards the opposite direction of the self-acceleration and the angle of body tilt was in good agreement with the subjective amount of the accelerating sensation. The body tilt was even induced by solely visual information. This implied that visual information contributed to perception of self-acceleration as well as self-motion.

Effects on visual functions during tasks of object handling in virtual environment with a head mounted display

This study examined the effects on visual functions of a prolonged handling task within the helmet-mounted display environment. Both version eye movement and accommodative response became gradually slower during the 40-min task. Although delayed presentation of display after head movement noticeably worsened both visual responses, presentation delay after hand movement did not significantly change the sluggishness of responses. Therefore it is suggested that decreasing time delay after head movement is a more important factor in order to improve human performance of handling tasks within the HMD environment.

Extracardiac conduit composed of gutter-shaped prosthesis and pedicled pericardial valved patch for pulmonary trunk reconstruction

A conduit for reconstruction of the pulmonary trunk is presented. A Gelseal vascular prosthesis (Vascutek Ltd, Inchinnan, Scotland) was split longitudinally in two halves, and one half was used as a posterior wall of the conduit like a gutter. The anterior wall was constructed by a pedicled pericardial valved patch. Finally, the proximal anastomosis of the conduit was completed with a gusset cut from the Gelseal prosthesis. This conduit can be applied to patients who require the Rastelli procedure, and growth potential of the pedicled pericardial patch may be expected.

Vection with Real-World Stimuli

Psychophysical studies have revealed that retinal and depth periphery play a dominant role in activating vection, or visually induced sensation of self-motion. But since abstract stimuli such as random-dot patterns and vertical stripes have been used in these studies, the results are not always applicable for designing more realistic visual displays in real-world applications. Indeed, it has been shown that for human orientation, a real-world display is more effective than an abstract one (Howard and Childerson, 1994 Perception23 753 – 762). We investigated how vection was controlled by the peripheral part of a stimulus consisting of a real-world display. Stereoscopic and nonstereoscopic video clips were taken through a windshield while driving on (i) a straight, (ii) a gradually curved, and (iii) a sharply curved road at slow and fast speeds. Vection was measured with these stimuli which were presented on a 63 deg wide and 38 deg high video projection monitor. The results showed that although the stereoscopic display generally activated more forward and sideways vection than the nonstereoscopic one, the difference was barely statistically significant. When only the central 18 deg diameter of the display was presented, similar vection was activated as with a full field display. When the central 40 deg diameter of the display was occluded, vection did not change significantly, though observers found difficulty in assessing the direction of self-motion. It is concluded that retinal and depth periphery of real-world stimuli do not play a significant role in activating vection.

Effects of cardiac surgery on intellectual function in infants and children

Intellectual function was evaluated by Gesell's developmental quotient (DQ) and Binet's intelligence quotient (IQ) in 161 infants and children (61 ventricular septal defects, 49 tetralogies of Fallot, 15 transpositions of the great arteries, seven atrial septal defects, five complete atrioventricular canals, five double outlet right ventricles and 19 shunt cases; average age 3.6 years) before and after cardiac surgery. There were no significant differences in preoperative DQs and IQs among the patient groups. Although average DQ scores in 21 infants with hypothermic (13-24 degrees C) total circulatory arrest (36-70 min) were not significantly different from the preoperative values, 13 patients with an arrest time > 50 min showed a significant decrease in DQ scores. The postoperative DQ and IQ scores in patients without circulatory arrest or in shunt cases were not significantly impaired after surgery. It was concluded that cardiac surgery did not impair intellectual function in infants and children, although cerebral dysfunction might occur if circulatory arrest was > 50 min.

[Acute aortic dissection with leg ischemia]

From January of 1987 to July of 1994, 83 patients with acute aortic dissection were treated at our institution. Of these, 7 patients (8%) sustained acute leg ischemia. Angiography showed that one patient had arterial occlusion at the abdominal aorta, three had occlusion at the right common iliac artery, and one had severe right common iliac artery stenosis. Four patients with acute type A dissection underwent emergency replacement of the aortic arch and/or ascending aorta. Three of them were discharged, but one patient died due to renal failure and multiple organ failure. In three patients with acute type B dissection, one with aortic rupture was successfully treated by replacement of the descending thoracic aorta; of the other two who received bypass operations for leg ischemia, one died due to myonephropathic metabolic syndrome and sepsis which were caused by a delay in surgery. In conclusion, emergency thoracic aortic repair should be performed in acute type A dissection with leg ischemia, whereas bypass operation for ischemic leg should be considered in patients of acute type B dissection with leg ischemia when they are not complicated with rupture or visceral ischemia.

[Dislodgement of the ringed-graft--a case report]

A 70-year-old man underwent replacement of the distal aortic arch which contained a huge aneurysm using a ringed graft. He died suddenly of hemoptysis 54 months following the operation. An autopsy revealed dislodgement of the spool on the posterior aspect of the aorta. Histologic examination of the dislodged portion of the ring showed complete disruption of the intima and elastic fibers of the media. There were minimal histologic changes in the anterior portion of the anastomotic site. It is postulated that the long, kinked graft might have caused the late ring dislodgement.

[Separate perfusion of upper and lower body under mild hypothermia during operation on the thoracoabdominal aorta]

During last 7 years, we performed 24 operations on the thoracoabdominal aorta. There were 9 true and 15 dissecting aneurysms. There were two cases of ruptured aneurysm and thoracoabdominal replacement was performed as a last stage operation for total aortic replacement in 4 cases. Three cases with aortic dissection died within 30 days after surgery. Femoro-femoral bypass was used in 4 cases (1 case died of brain damage, paraplegia and MOF), left heart bypass in 5 cases and separate perfusion of upper and lower body (SPULB) under deep hypothermia in 7 cases (2 cases died of LOS and cerebrovascular accident occurred at 2 weeks after operation) and SPULB with mild hypothermia in 8 cases for circulatory support. There was one case of renal dysfunction and transient mild liver dysfunction occurred in 7 cases. There was no evidence on relationship between surgical outcome and methods of circulatory supports, but we recently prefer SPULB under mild hypothermia for thoracoabdominal surgery since intraoperative massive bleeding and cardiac arrest can be easily treated and major organs can be protected by introducing hypothermia in this perfusion technique.

Proposal of a working left heart model with a heterotopic transplantation technique in rats

BACKGROUND

A heterotopically transplanted rat heart model described by Ono and Lindsey in 1969 has been widely used as a fundamental animal model of heart transplantation. However this "nonworking" model is greatly different from the orthotopic heart in view of left ventricular work, in which the experimental results obtained may not always reflect the clinical setting with an orthotopic transplanted "working" heart. We herein propose a new "working" left heart model in rats using a heterotopic abdominal transplantation technique by modifying the method of Ono and Lindsey.

METHODS

First, a donor heart graft and a recipient were prepared in the conventional fashion. Second, the donor heart was tailored by the ligation of main pulmonary artery and the removal of tricuspid valve and interatrial septum. Third, the ascending aorta and right atrium of the donor heart were anastomosed to the infrarenal abdominal aorta and to the inferior vena cava of the recipient, respectively. Consequently, the left atrium and ventricle of heart graft were loaded with the blood from the right atrium through the interatrial communication.

RESULTS

This surgical procedure required an average of 58 minutes and had negligible operative risk. The donor left ventricle produced a systolic blood pressure almost equal to the recipient's aortic pressure and maintained vigorous beat.

CONCLUSIONS

This model is easily reproducible and would be useful for various studies on heart transplantation.

[Hemodynamic response to pericardiectomy in the patients with constrictive pericarditis: with reference to surgical approaches and responses to exercise]

Between 1975 and 1994, we performed 20 pericardiectomies for 19 patients with constrictive pericarditis (CP) through a median sternotomy (13 cases), a left thoracotomy (2 cases), a median sternotomy combined with a left thoracotomy (4 cases) or a median sternotomy under ECC (1 case). One patient died from LOS at 1st POD due to myocardial failure. Pericardiectomy through a median sternotomy decreased RA pressure but PAW pressure did not decrease in some patients. On the contrary, pericardiectomy through either a left thoracotomy or a median sternotomy combined with a left thoracotomy decreased PAW pressure as well as RA pressure significantly. Responses to bicycle exercise demonstrated marked elevation of RA and PAW pressures even in a mild case of CP, so that the exercise testing seems to be useful for early detection of CP and evaluation of the operative results.

Heading judgments during active and passive self-motion

Previous studies have generally considered heading perception to be a visual task. However, since judgments of heading direction are required only during self-motion, there are several other relevant senses which could provide supplementary and, in some cases, necessary information to make accurate and precise judgments of the direction of self-motion. We assessed the contributions of several of these senses using tasks chosen to reflect the reference system used by each sensory modality. Head-pointing and rod-pointing tasks were performed in which subjects aligned either the head or an unseen pointer with the direction of motion during whole body linear motion. Passive visual and vestibular stimulation was generated by accelerating subjects at sub- or supravestibular thresholds down a linear track. The motor-kinesthetic system was stimulated by having subjects actively walk along the track. A helmet-mounted optical system, fixed either on the cart used to provide passive visual or vestibular information or on the walker used in the active walking conditions, provided a stereoscopic display of an optical flow field. Subjects could be positioned at any orientation relative to the heading, and heading judgments were obtained using unimodal visual, vestibular, or walking cues, or combined visual-vestibular and visual-walking cues. Vision alone resulted in reasonably precise and accurate head-pointing judgments (0.3 degrees constant errors, 2.9 degrees variable errors), but not rod-pointing judgments (3.5 degrees constant errors, 5.9 degrees variable errors). Concordant visual-walking stimulation slightly decreased the variable errors and reduced constant pointing errors to close to zero, while head-pointing errors were unaffected.

[Mitral valvuloplasty for an infant with congenital mitral stenosis-- report of a case]

A 7-month-old infant, who underwent repair of coarctation of the aorta four months ago, was readmitted for heart and respiratory failure. Preoperative serial echocardiographic studies revealed progression of mitral valvular and subvalvular stenosis. At operation the mitral valve apparatus was found to be funnel-shaped type of congenital mitral stenosis. Chordae fenestration, papillotomy and commissurotomy were performed. Intraoperative transesophageal echocardiography demonstrated increased inflow through the mitral valve apparatus. Postoperative course was uneventful, and she was discharged 28 days after operation.