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Biomedical subjects

H Sekii

Publications and source records attributed to H Sekii.

At least 19 recordsLinked to original sources
PubMed2003

[The surgical technique of heart displacement during off-pump coronary artery bypass grafting in the exposure of the anastomotic site of posterior descending artery].

Heart displacement during off-pump coronary artery bypass grafting (OPCAB) is necessary to expose the anastomotic site. However, such displacement causes hemodynamic deterioration especially in the exposure of the circumflex branches and posterior descending artery (PDA). In this study we present two different cardiac positioning for the exposure of the anastomotic site of PDA. To expose the mid-portion of PDA the heart is vertically displaced by fixing the suction cup of the heart positioner on apex. To expose the proximal portion of PDA the suction cup is attached on the acute margin of the right ventricle (off apex). By using these 2 different techniques properly, hemodynamic deterioration can be avoided during OPCAB for PDA.

Anastomosis, Surgical↗
PubMed1993

Malignant schwannoma of the intrathoracic vagus nerve: report of a case.

We report herein the case of a 48-year-old man with malignant schwannoma of the intrathoracic vagus nerve associated with von Recklinghausen's disease. Malignant intrathoracic vagal tumors are extremely rare and to our knowledge, only four other cases have been documented in the literature, none of which were associated with von Recklinghausen's disease.

Cranial Nerve Neoplasms↗
PubMed1993

A surgical procedure for the prevention of complete right bundle branch block following total correction of tetralogy of Fallot.

Complete right bundle branch block (CRBBB) has been reported as the most common sequelae following total correction of tetralogy of Fallot. A review of previous reports and our own experience have led us to believe that it may be related to the fatal ventricular dysrhythmias which often occur during the postoperative follow-up period. Therefore, we have been trying to reduce the incidence of CRBBB, and we describe herein our surgical procedure for the prevention of CRBBB and its results. Of a total 28 consecutive patients who underwent intracardiac repair by this procedure, only 4 (14%) developed surgically induced CRBBB, none of whom developed a left anterior hemiblock. At the time of this report, no severe ventricular arrhythmias have been found in this series during the postoperative follow-up period. These results suggest that our operative procedure is feasible for the prevention of CRBBB. With regard to the relationship between ventricular dysrhythmia and CRBBB, careful observation is necessary throughout the patients' lifetime.

Adolescent↗
PubMed1992

Left main coronary trunk compression by dilated main pulmonary artery in atrial septal defect. Report of three cases.

Narrowing of the left main coronary trunk, which was compressed by the dilated pulmonary artery, was associated with atrial septal defect in three adults. One of them had severe pulmonary hypertension. Coronary angiograms revealed localized narrowing of the left main coronary trunk, and the left main coronary trunk had a concave shape. No stenosis of other coronary arteries was observed. In all patients the atrial septal defect was closed with a polytetrafluoroethylene patch. In the patient with 75% narrowing of the left main coronary trunk, aorta-coronary bypass was performed; it was not performed in the two with 50% narrowing. In two survivors postoperative coronary angiograms showed that the narrowing of the left main coronary trunk improved or disappeared. These results suggest that markedly dilated pulmonary arteries easily compress the left main coronary trunk and cause narrowing, which improves after atrial septal defect closure.

Constriction, Pathologic↗
PubMed1992

[The superior approach technique for total anomalous pulmonary venous return (type I b)].

Two infants with total anomalous pulmonary venous return (type I b) were operated on successfully through the superior approach. The technique of anastomosis was designed for making large anastomosis between the common pulmonary vein and left atrium according to each pattern of pulmonary venous drainage. In these patients, the angiocardiogram at one year after the operation showed no stenosis between pulmonary vein and left atrium and electrocardiogram revealed no arrhythmias, postoperatively. The operative procedures which used in these patients are described.

Anastomosis, Surgical↗
PubMed1991

Long-term respiratory assistance using a right ventricular assist device system and a membrane oxygenator.

A new method for long-term respiratory assistance using a right ventricular assist device (RVAD) system and a membrane oxygenator (MO) was designed and evaluated. An air-driven RVAD was implanted between the right atrium and the pulmonary artery in five goats and an MO was set on the outlet conduit of the RVAD 2 weeks postoperatively. Two types of MOs [the SciMed (Life Systems) silicone sheet MO and a prototype MO using a novel multilayered composite membrane] were used in this study. Respiratory support with this system under systemic heparinization could be conducted for 4-8 days without major problems accompanied with conventional extracorporeal membrane oxygenation (ECMO) such as surgical bleeding, destruction of the blood components, serum leakage, insufficient bypass flow, and fatal systemic thrombosis. This method opened the possibility for ECMO to be used as a bridge before lung or heart-lung transplantation.

Animals↗
PubMed1990

[Recovery of severely decompensated hearts with a left ventricular assist device].

We evaluated the limits of recovery of decompensated hearts experimentally and clinically and studied the problems of applying a left ventricular assist device (LVAD). In the chronic experiments, 16 adult goats were studied as follows: Group I consisted of seven with left ventricular infarction in a 70-80% area of the free wall induced by the multiple-ligation method; Group II, three with infarcted areas larger than 80% of the free wall; Group III, three with a 30 min anoxic arrest, and Group IV, a 45-min anoxic arrest. An LVAD was applied in all goats, and a right ventricular assist device was applied simultaneously for two goats in Group IV. Clinically, 21 patients receiving treatment with an LVAD from December 1982 to September 1988 in our center were examined. No goat in Groups II and IV could be weaned from the LVAD. Thus, the severity of artificial heart failure in Groups I and III was considered to be the limit for accomplishing restoration. In successfully-weaned cases, both in experimental and clinical settings, periods of LVAD therapy with or without IABP were less than two weeks, which was thought to be the upper time limits for LVAD application. All but one successfully-weaned patients were alive in the experiment, while clinically many patients died of multiple organ failures regardless of the results of the LVAD assistance. Analysis of data suggested that the difference was caused by the durations of the LVAD applications and weanings, the degree of right ventricular failure, the doses of catecholamine used, and the systemic care afforded, especially during tracheal intubation.

Animals↗
PubMed1989

Treatment of acute myocardial infarction with cardiogenic shock using left ventricular assist device.

We have treated ten cardiogenic shock patients after acute myocardial infarction (AMI) with a left ventricular assist device (LVAD). These patients were later divided into three groups: the first group with ventricular septal perforation, the second with aorto-coronary bypass grafting (ACBG) before LVAD implantation and the third group without ACBG. LVAD maintained the systemic circulation in each group, and cardiac function recovered enough to remove LVAD in 70% of the total patients. Two of three patients in the first group were discharged from hospital. Two weaned cases in the second group died of multiple organ failure and one was discharged, and hemorrhagic necrosis was seen in the bypassed area of the myocardium. One patient of the third group could not be weaned from LVAD because of respiratory failure though his heart function began to recover. Another case in the third group underwent bypass grafting after removal of LVAD. However ACBG surgery should be done very carefully because a patient in shock is occasionally intolerant to major surgery. In all groups, the major cause of death was multiple organ failure which was probably caused by the prolonged low output condition prior to LVAD application. In the light of this experience, it appears that LVAD should be applied before irreversible damage occurs to major organs, including the heart itself. To ensure the timely application of LVAD, some way must be found to introduce systematic application of LVAD into the normal course of AMI treatment.

Aged↗
PubMed1989

[Surgical experiences of Cor triatriatum in infancy].

Three operative cases with Cor triatriatum, age ranged from 30 days to 16 months, were presented. All types were IB1 of Lucas-Schmidt's classification and one patient was associated with right upper PAPVC. One patient died of low output syndrome due to preoperative shock. Communication of abnormal diaphragm in left atrium varied from small and multiple to 5 mm in diameter. Their preoperative diagnoses were established by two-dimensional echocardiogram prior to angiocardiogram and the intracardiac communications were well evaluated by color doppler echocardiogram which was superior to angiocardiogram in this evaluation. Postoperatively, no abnormal diaphragm were detected in two survivors. The diagnosis and operative procedure for this anomaly were discussed on.

Angiocardiography↗
PubMedDate not supplied

Regulation of coronary circulation during left ventricular assist.

Regulatory mechanisms of coronary circulation during left ventricular assist (LVA) were studied in chronic experiments using adult goats. In normal heart studies (n = 3), circumflex coronary artery flow (CxF) and endocardial blood flow (MBF) decreased in proportion to decrease of tension time index (TTI). Mean CxF/TTI was constant at 0.22, whether the LVA functioned or not. In the left anterior descending branch ligation model (AMI) study (n = 2), CxF decreased according to decrease of TTI throughout the experiment, if the bypass ratio was kept within a normal range of systemic pressure. Mean CxF/TTI was maintained at approximately 0.21 by LVA, fell to 0.16 when LVA was turned off during the early stages. Coronary circulation during LVA was regulated by oxygen demand if systemic circulation was maintained, and LVA improved oxygen demand-supply balance in failing hearts.

Animals↗
PubMedDate not supplied

An electrohydraulic ventricular assist system with a linear actuator.

An electrohydraulic ventricular assist system with a linear actuator was developed, and in vitro and in vivo evaluations were performed. During in vitro evaluations this system could yield 5.6 L/min of pump flow against a mean afterload of 100 mmHg. Durability tests were performed for more than 4 months. The system was implanted in three goats and a maximum pump flow of 4.2 L/min was obtained against a mean afterload of 100 mmHg, and 3.2 L/min against 130 mmHg. These evaluations have proven that the system can maintain stable hemodynamics under various conditions.

Animals↗
PubMedDate not supplied

Multi-institutional studies of the National Cardiovascular Center Ventricular Assist System: use in 92 patients.

A ventricular assist system (VAS) developed at the National Cardiovascular Center (NCVC) and produced by Toyobo Company has been clinically evaluated at 32 institutes. The system consists of a pneumatic and diaphragm-type pump, and a control-drive unit with an automatic bypass flow (BF) control system. The VAS was used in 85 adults and 7 children with acute, severe heart failure. Forty-eight patients were weaned from VAS, and 21 were long-term survivors. Heparin was not used when BF was above 2.0 L/min in an adult sized pump, and 0.8 in a pediatric one. Thrombus formation was noticed in the groove around the valve in eight cases, and in the pump in eight. Pump-originated serious complications were not seen. Hematologic and biochemical findings revealed that the VAS did not directly affect the major organs. The control-drive unit, including the automatic BF control system, functioned accurately, with less manpower, securing reliable control over the circulation. Two major causes of death were irreversible heart failure, and multiple organ failure, which resulted from delayed application. In conclusion, the NCVC-type VAS has been found effective and reliable, less thrombogenic, and requiring less manpower for its clinical use.

Adult↗
PubMedDate not supplied

Experimental evaluation and clinical application of a pediatric ventricular assist device.

A pneumatic pediatric ventricular assist device (VAD) with a stroke volume of 20 ml has been developed to treat post-operative heart failure (HF), and maintain transplant candidates. The polyurethane VAD has two #21 Bjork-Shiley valves and the internal diameter of the cannula is either 6 or 8 mm. Hemodynamic effects of a left ventricular assist device (LVAD) on a HF after Fontan's procedure model, and those of a right ventricular assist device (RVAD) on right HF with pulmonary hypertension model, were investigated in acute experiments with four and five dogs, respectively. In the former, the pressure gradient across the lung and cardiac output (CO) increased with an LVAD; right atrial pressure decreased and CO increased with an RVAD in the latter. The pump was implanted as an LVAD in 8 young goats, 9-22 kg in weight, for 4-10 weeks and favorable in vivo performance was demonstrated. The VAD system was applied as an LVAD to two postcardiotomy patients, a 12 kg boy with a ventricular septal defect, and a 13 kg boy with an endocardial cushion defect. In these cases, CO was well maintained at the level of 2.5-4.1 L/min/m2 for three and seven days, respectively, and the pump was removed. In conclusion, this VAD will become a promising circulatory support system for pediatric uses.

Animals↗
PubMedDate not supplied

Left ventricular assist system with a simplified cannulation technique.

A simplified cannulation system was developed without thoracotomy for a ventricular assist system (VAS) that will be applicable even in an emergency. This system consists of an air driven and diaphragm type pump, cannulae, and devices for insertion. The inlet cannula was inserted into the left atrium through the femoral vein using a modified brockenbrough transseptal method. This system was installed without thoracotomy in a chronic experiment in two goats and was removed without any trouble after 14 days of pumping. In a 40 day experiment with this system implanted between the left atrium and the aorta, bypass flow was maintained at 2.7 to 3.3 L/min, and plasma free hemoglobin levels were below 7 mg/dl. When this system was implanted between the left atrium and the aorta, and activated in an induced heart failure goat, output through the pump was 3.0 +/- 0.4 L/min, and mean aortic pressure was increased to 91.7 +/- 15.9 mmHg from 55.8 +/- 15.4 mmHg. This system takes a middle position between an IABP and VAS with thoracotomy in capability of circulatory support and convenience.

Animals↗