Biomedical subjects
Publications and source records attributed to K Ihashi.
A 63-year-old man complained of chest pain and back pain 16 months after aortic valve replacement. Computed tomography (CT) showed acute aortic dissection (Stanford A) and we decided to perform operation. We found an entry at aortotomy on operative findings. Under hypothermic circulatory arrest graft replacement of ascending aorta was performed. Postoperative course was uneventful.
This paper describes the relationship between knee extension force and EMG signals detected by multiple bipolar wire electrodes inserted into the human vastus lateralis muscle under isometric conditions. Six healthy male volunteers participated in this study. Eight pairs of bipolar wire electrodes were inserted into the right vastus lateralis muscle and the EMG data were simultaneously detected and analyzed. The EMG raw data and individual force-IEMG relations were influenced by the location of the electrode inserted into the muscle. The force and IEMG relationship averaged across subjects detected from the eight electrodes, however, showed almost the same linear correlation in spite of different electrode locations. No linear correlation was observed between MdF and the knee extension force. This result suggests that, if all of the muscle fibers participate in the same action at the same time, the averaged normalized IEMG from any places using wire electrodes could reflect the total activities of that muscle even if the muscle is large.
Seventeen hemiplegic patients with chronic shoulder subluxation secondary to a cerebrovascular accident (CVA) were divided into three groups, two of which were subjected to 6 weeks of therapeutic electrical stimulation (TES) for 15 minutes twice a day, in order to assess the effectiveness of the treatment in reducing subluxation, and in improving shoulder abduction function. The third group was used as a control (C group). After 6 weeks of electrical stimulation of the supraspinatus (S group) and deltoid (D group), a significant (p<0.05) reduction in subluxation was observed in both groups when compared to the C group. The maximal force of shoulder abduction showed a tendency to increase in the S group (p<0.10). A significant increase in maximal force was also observed in the D group. In most of the TES-treated muscles, the interference pattern of EMG at maximum voluntary contraction increased. The amplitude of the EMG activity of the stimulated muscle also increased. Thus, we concluded that electrical stimulation therapy of the supraspinatus and the deltoid muscle is an effective treatment modality for shoulder subluxation and shoulder abduction function in hemiplegic patients.
The shoulder joint allows three-dimensional movement. In order to analyze the function of the muscles which act on the shoulder joint, three-dimensional movements, including rotation, must be considered. Among muscles participating in the shoulder joint movement, the supraspinatus muscle is known to have abduction and stabilization effects on the shoulder joint. However, the rotational function of the supraspinatus muscle has not been identified, because few studies have been reported on it. This study investigates the rotating function of the supraspinatus muscle using electrical stimulation, magnetic resonance imaging (MRI) and anatomical examination. Electrical stimulation was applied selectively to the supraspinatus muscle of healthy subjects using percutaneous wire electrodes. The electrical stimulation was given at different positions of the shoulder joint. It was found that the electrically induced rotational movements changed their direction depending on the position of the shoulder joint. When the humerus was relatively in internal rotation, internal rotation resulted. When it was in external rotation, external rotation occurred. Regarding the abduction angle of the shoulder joint, external rotation was induced with an increase in the abduction angle, whereas internal rotation occurred when the abduction angle was decreased. By the dissection of cadavers and MRI examination, it was indicated that the relation between the running direction of the supraspinatus muscle and the center of rotation of the humeral head was dependent on the position of the shoulder joint. Those findings supported the results of electrical stimulation of the supraspinatus muscle at various shoulder positions. These results indicate that the bi-directional rotating function of the supraspinatus muscle is characterized by an anatomical relationship between the running direction of the supraspinatus muscle and the center of rotation of the humeral head.
The aim of this study was to investigate whether the median frequencies (MF) of the electromyogram (EMG) and the integrated EMG (IEMG) of histochemically differentiated ankle plantarflexors, the gastrocnemius and soleus, were force dependent. Bipolar intramuscular wire electrodes were used to measure EMG of the soleus (SO), medial head of gastrocnemius (GM), and lateral head of gastrocnemius (GL) during ramp (single ongoing contractions) with the force increasing linearly from 0 to 100% of maximum voluntary contraction (MVC) and stepwise (steady force levels) ankle plantarflexion at 10, 20, 30, 40, 60, and 80% MVC. EMG and force were measured simultaneously. Power spectral analysis of these signals was performed to calculate MF on 1024-point by fast Fourier transform (FFT) technique. IEMG value of each muscle was also obtained at the same levels of force. While IEMG of three heads of triceps surae in both stepwise and ramp contractions increased significantly with increasing force, MF values of GL during stepwise contraction increased significantly (20, 40, 60, 80% MVC). These results suggest that the sensitivity of EMG power spectrum might be influenced by the proportion of fast twitch muscle fibers, which histochemically corresponds to type II fibers.
To stabilize the hemodynamics before and during ruptured abdominal aortic aneurysmal repair, a mass-infusion system was developed and successfully employed in the treatment of two patients. The system consists of a combination of devices used in cardiopulmonary bypass, namely: suction, a reservoir, a heat exchanger, a bubble trap, and an intracaval large-sized venous femoral cannula for infusion. It proved extremely useful to tide the patients over hypovolemic shock before cross-clamping of the proximal aorta, preventing intraoperative hypothermia, which is known to cause multiple physiologic derangement associated with an adverse outcome. Moreover, the employment of a large-sized cannula allowed for a temporary switch from the preceding venous infusion support to the hypothermic circulatory assist with central aortic cannulation, using the caval cannula for drainage. This system provides an optional advantage for patients requiring an open proximal anastomosis.
BACKGROUND: The trend in coronary artery bypass grafting is for a gradual transition to the more extensive use of arterial grafts. This study was designed to investigate the effects of patient body size on complex arterial grafting in coronary artery bypass procedures. METHODS: Four hundred forty-five patients who underwent coronary artery bypass grafting with two or more distal anastomoses using arterial grafts were divided into two groups according to body surface area: group A (n = 114), 1.60 m2 or less; and group B (n = 331), greater than 1.60 m2. Preoperative patient characteristics and early and long-term results were compared between the groups. RESULTS: The prevalence of female sex (27% in group A versus 0.9% in group B; p < 0.0001) and age (62.7 +/- 8.1 years in group A versus 58.9 +/- 7.0 years in group B; p < 0.001) were significantly different. However, the prevalence of previous myocardial infarction and of left ventricular dysfunction and the extent of coronary artery disease were not significantly different. Three patients (2.6%) in group A and 3 patients (0.9%) in group B died within 30 days of operation (p = 0.18). The 1-month patency rate of arterial grafts was not significantly different (98.7% versus 96.7%; p = 0.16), but that of venous grafts was significantly lower in group A than in group B (88.9% versus 97.7%; p = 0.045). No significant difference was noted in the 3-year actuarial survival rate (93.8% versus 91.6%). CONCLUSIONS: The extensive use of arterial grafts in patients with small body size was associated with excellent long-term results, with no significant increase in operative mortality or morbidity.
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A modified technique to the reattachment of the coronary ostia in the aortic root replacement is described. The left coronary ostium is excised semicircumferentially in an aortic button with its subostial quarter remained as a joint. A collagen impregnated 10-mm Dacron interposition tube graft is sutured rectangularly to the face of the button with the interrupted pledgeted horizontal mattress sutures all running through the button wall in outside-in fashion. The other end of the graft is beveled and sutured end-to-side cephalad to the aortic conduit in order to join each other with straightness assuring the distance between the right coronary button and the aortic conduit to be anastomosed directly. The left coronary button can incline passively with the long axis of the coronary graft, like a "shell", and this allows equivalent distribution of tension on the anastomosis and a straightness of the graft to create the laminar flow in it. The right coronary button is anastomosed to the aortic conduit opposite the ostium with a running over-and-over suture. This procedure has been used in a 35-year-old male with annuloaortic ectasia caused by Marfan's syndrome complicated with type A acute aortic dissection. The patient discharged on the 26th postoperative day without any complications nor angiographic problems. We found this procedure useful in terms of the security of the coronary anastomosis and geometrical arrangement of the conduits.
Stenting seems to be a definitive procedure after failed balloon coronary angioplasty. This report describes a case of redo coronary bypass grafting and concomitant resection of enlarging false aneurysm of a saphenous vein graft that developed secondary to stenting for recurrent stenosis after serial percutaneous transluminal coronary angioplasty. It warns us of a pitfall in catheter intervention in an aged saphenous vein graft.
To improve the ease of driving a centrifugal pump that is afterload dependent, we have developed an automatic flow control system for the Terumo Capiox centrifugal pump system. This system consists of an autoflow cruise control system with a safety cutoff. The Capiox Pump Console 3000 was controlled by a personal computer through a serial communication line. In the usual manual mode, the motor speed knob works as a pump speed control, and in the autoflow mode, the same knob works as a blood flow rate control. After selecting and obtaining the desired flow rate, the mode was changed from manual to autoflow mode. In the autoflow mode, the computer compares the desired flow rate with the actual flow measured by an ultrasonic Doppler flowmeter and adjusts the motor rotational speed accordingly. During both in vivo and in vitro testing, this autoflow mode was able to return the changed flow that was disrupted by either clamping and declamping of the tubing or by the bolus injection of a vasomotor drug to the selected flow rate within 10 s without any significant fluctuation. In conclusion, the newly developed computer controlled autoflow system was able to produce a reliable and effective flow regulation for a centrifugal pump.
This paper describes the effects of therapeutic electrical stimulation (TES) on the wasting muscles in a patient with amyotrophic lateral sclerosis. The patient is a 47-year-old male, and he has a history of progressive muscle weakness and atrophy, affected more in the right side. Percutaneously indwelling intramuscular electrodes were implanted to the affected muscles in the right upper and lower extremities but no electrode in the corresponding left region. Within a month of TES therapy, a rapid improvement of extremity motion appeared in the TES treated side. Long-term application of TES more than 3 months increased the strength of the muscle which had been evidently weaker than the non-treated side. CT findings of both the upper and lower extremities with TES therapy showed an increase in the density and a reduction in the moth-eaten image. An increase in the thickness of the muscles was also observed in the TES treated side while deterioration was observed in the muscles on the non-treated side.
A 68-year-old male who had previously undergone aorto-coronary artery bypass grafting was admitted for mitral valve surgery. Because of the presence of anteriorly placed intact coronary artery bypass grafts, we used right thoracotomy to replace the mitral valve. Cardiopulmonary bypass was established after cannulation of the femoral artery and bicaval cannulation, and continuous retorograde cardioplegia with cold blood was infused. Residual air was evacuated through left ventricular vent catheter and aortic air vent hole. Post operative course was uneventful.
According to STS/AATS guidelines 1988, we compared the long-term results after cardiac valve replacement (ReAVR 26, ReMVR 127, ReDVR 35, ReTVR 2, total 190 patients) with those after initial valve replacement (AVR 760, MVR 1, 001, DVR 431, TVR 22, total 2,214 patients). Actuarial survival (AS), reoperation free (RF) and freedom from all valve-related events (EF) at the 10th postoperative year were 74.6%, 100%, 70.1% after ReAVR, 84.2%. 97.8%, 75.8% after AVR, 82.9%, 91.4%, 75.8% after ReMVR, 86.5%, 91.7%, 70.7% after MVR. 78.4%, 92.9%, 63.2% after ReDVR, 82.8%, 95.6%, 73.8% after DVR, respectively. There was no significant difference of AS, RF and EF between ReVR and initial VR in any valve position. These results justify our current strategy of cardiac valve re-replacement.
A case of aortic and mitral regurgitation associated with aortitis syndrome was presented. The patient was a 36-year-old female who admitted for palpitation and dyspnea. Left ventriculography showed moderate MR. Aortography showed moderate AR and multiple occlusive lesion of the aortic arch branches. After the inflammation was controlled, aortic and mitral valve replacement was performed. Postoperative course was uneventful. Histologically, aortic and mitral valve showed capillary increase and infiltration of inflammatory cells, mainly lymphocytes.
To evaluate risks and complications of reoperation on valvular disease, we reviewed data on 186 patients who underwent reoperations because of prosthetic valve malfunctions, pregression of valvular disease after open mitral commissulotomy and previous valvular replacement. Overall hospital mortality was 4.8% (9/186 patients). The common causes of death was low cardiac output syndrome (3 pts.) and respiratory failure (3 pts.) and others (3 pts). Hospital mortality was different according to the risk factors. There was no significant difference between the operative procedures; AVR (6.2%), MVR (3.2%), DVR (8%), TVR (0%) and MVR + TVR (9%). Furthermore, advanced age, valve position, renal failure, preoperative %FS, LVDd and diagnosis of prosthetic valve malfunction did not appear to be significant risk factor. However, preoperative respiratory failure and emergency operation showed significant increase of hospital mortality in comparison with other factors. On the basis of this reports, hospital mortality and late survival indicated that reoperation should be performed early as the potentially safe condition.
A case of successful surgical removal of a primary malignant pericardial mesothelioma was reported. The patient was a 79-year-old man with a complaint of dyspnea at rest. Chest X-ray study showed enlargement of upper mediastinum. Echocardiogram, computed tomography and MRI revealed a giant mass occupying the pericardial space anterior to the heart with marked pericardial effusion. The right ventricle was severely compressed with this tumor. Total resection of the tumor was achieved because the tumor was localized without invading surrounding tissue. The tumor was 17 x 12 x 10 cm in size and 900 g in weight. Rare growth fashion as a distinct isolated mass was a key of successful outcome.
The patient was a 72-year-old woman who was admitted with AMI. On the next day, a systolic murmur of Levine II/VI became audible on the left sternal border of the 5th intercostal space and VSP was diagnosed by the echocardiogram. The hemodynamics was comparatively stable, and so we scheduled the elective operation in the expectation of the healing of the infarction tissue. At the cardiac catheterization just before the operation, L-R shunt ratio was 64.9% and main PA was 41/18 (26) mmHg. Before the operation we marked the VSP position by Swan-Ganz catheter through the left ventricle and VSP closure and 2 CABG was performed. We concluded that this method was useful for the diagnosis and therapy of VSP.