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Biomedical subjects

M Sueshiro

Publications and source records attributed to M Sueshiro.

At least 19 recordsLinked to original sources
PubMed1998

Combined coronary artery bypass, mitral valve plasty, and abdominal aneurysmectomy in an 80-year-old patient: report of a case.

An 80-year-old man suffering from angina on exertion due to stenosis of the left main coronary artery, heart failure due to mitral valve regurgitation, and an abdominal aortic aneurysm (AAA) was successfully operated on with simultaneous surgical procedures. A coronary cineangiography revealed 90% stenosis of the left main coronary artery in segment 5, and 99% and 90% stenosis in segments 2 and 4AV, respectively, of the right coronary artery. Left ventriculography and aortography showed moderate mitral valve regurgitation and the presence of a fusiform-shaped AAA with a maximum diameter of 6 cm. It was thought that insertion of an intraaortic balloon pump (IABP) would prove difficult due to AAA; therefore, simultaneous surgery combining triple coronary artery bypass grafting (CABG), mitral valve plasty, and prosthetic replacement of the AAA was undertaken. The patient's postoperative course was uneventful, and subsequent angiography showed good patency of all coronary bypass grafts and the abdominal prosthesis, along with the disappearance of mitral regurgitation. This patient's clinical course suggests that an extended surgical procedure is effective for the treatment of complicated cardiovascular disease, even in very elderly patients.

Aged↗
PubMed1998

Eccentric roller type total artificial heart designed for implantation.

In the process of developing a completely implantable total artificial heart system, we have made an eccentric roller type total artificial heart and evaluated it by means of a mock circulatory system and by an acute animal experiment. The actuator of the artificial heart consists of 2 cylindrical drum type rollers which squeeze 2 blood chambers. The blood chambers are made of silicone rubber and are torus in shape. There is no valve used in this artificial heart. The artificial heart appears to be a nearly circular cylinder, approximately 10 cm in length and 8 cm in diameter. In the Donovan mock test, the artificial heart worked at a roller speed of 100-125 rpm with flow rates of 2.5-3.0 L/min for the right side and 3.2-3.8 L/min for the left side, respectively. The electric power consumption was 19.0-24.7 W. Our artificial heart is characterized by an ejection of blood alternatively in the pulsatile mode without need for reversing the motor. In the ex vivo evaluation, circulation of an adult sheep was maintained with this artificial heart for 4 h.

Animals↗
PubMed1998

Accidental entry of an implantable cardioverter defibrillator lead into the left hepatic vein detected by transesophageal echocardiography.

We report a case of accidental entry of an implantable cardioverter defibrillator lead into the hepatic vein, which was not noted on fluoroscopy but was apparent when transesophageal echocardiography (TEE) was used incidentally. The lead was depicted in the hepatic vein as strongly echogenic, accompanied by an acoustic shadow. Additional bending of the stylet was helpful for successful advancement of the lead. TEE provides additional information in such cases, although indications for its use should be explored because of its possible complications.

Adolescent↗
PubMed1998

Simple right atrial procedure for chronic atrial fibrillation with atrial septal defect and aortic valvular regurgitation in an elderly patient.

A right atrial separation procedure was performed to eliminate atrial fibrillation (AF) during concomitant repair of an atrial septal defect and aortic valve regurgitation in an elderly patient. This procedure consisted of a Y-shaped incision in the right atrium, followed by cryoablation of the tricuspid annulus and the atrial septum. Only excision of the left atrial auricular appendage was performed in the left atrium. Although this procedure was devised to eliminate chronic AF associated with a solitary atrial septal defect, it was effective to eliminate chronic AF associated with atrial septal defect and aortic valve regurgitation in an elderly patient.

Aged↗
PubMed1998

Assessment of a new silicone tri-leaflet valve seamlessly assembled with blood chamber for a low-cost ventricular assist device.

We have developed a practical, low-cost ventricular assist device (VAD) comprising a newly designed blood chamber with a silicone lenticular sac and two silicone tri-leaflet valves (STV), made en bloc. This new VAD is seamless, can be made cost-effectively and assembled with the blood chamber and valve as one body. This novel design should reduce the incident of thrombus formation because of the absence of a junction at the connecting ring and because of the use of flexible silicone materials which have both antithrombogenecity and biocompatibility. In in vitro hemodynamics testing, a batch of 3 consecutively manufactured VADs with STVs underwent hydrodynamic functional testing. These showed less regurgitation, a lower value of water hammer phenomenon, and a slightly greater pressure gradient across the valves than a mechanical valve (MV) [Björk-Shiley monostrut valve]. The flow and pulsatile efficiency were adequate and similar to that of a VAD with MVs. In in vitro durability and hemolysis tests, a VAD with STV functioned well for 54 days and showed similar hemolytic profiles to a VAD with MVs. In an in vivo acute experiment using an adult sheep, our device was problem-free providing sufficient output as a left ventricular assist device (LVAD). Although it will be necessary to decrease the pressure gradient across this STV in the future, our device showed efficient performance as a practical land cost-effective VAD for short term use.

Adult↗
PubMed1997

Efficacy of a simple left atrial procedure for chronic atrial fibrillation in mitral valve operations.

BACKGROUND: We have devised a simple surgical procedure to be performed on the posterior wall of the left atrium for the treatment of chronic atrial fibrillation (AF) associated with mitral valve disease. The effectiveness of this procedure for serial mitral valve operations was then evaluated. We postulated that chronic AF associated with mitral valve disease could be attributable to a distended left atrium. The refractory period of the distended left atrium was significantly shorter in the left posterior atrial wall, especially at the base of the left atrial appendage and at the orifice of the left posterior pulmonary vein. We hypothesized that the left posterior atrial wall with its shorter fibrillatory cycle length would act as a driver for maintaining the AF, and therefore, surgical ablation of this critical area in the left atrium could terminate the chronic AF. METHODS: The surgical patients were divided into two groups. In group 1 (control group), 15 patients with chronic AF were operated on by the mitral valve procedure only. In group 2, 36 patients underwent this procedure in combination with a concomitant mitral valve operation. The disappearance rate of the AF was estimated by electrocardiography, and atrial function was estimated by transthoracic and transesophageal echocardiography. RESULTS: The chronic AF had been reduced significantly or eliminated at discharge in 4 of 15 patients (26.7%) in the group 1, versus 31 of 36 patients (86%) in group 2 (p < 0.05). In group 2, 29 of the 31 patients (94%) whose AF had disappeared recovered the atrial kick of their right atrium, and 21 patients (22/31; 71%) recovered the atrial kick of their left atrium. CONCLUSIONS: Surgical ablation of the posterior wall of the left atrium was effective in the treatment of chronic AF associated with mitral valve disease. This simple procedure could restore a sinus rhythm and also recovered atrial systolic function. We conclude that the left atrium may act as a driver for sustaining AF in mitral valve disease.

Aged↗
PubMed1997

Flow velocity of central retinal artery and retrobulbar vessels during cardiovascular operations.

OBJECTIVE: Both blood flow monitoring and pressure monitoring are necessary to avoid inadequate cerebral perfusion during cardiovascular operations. Inasmuch as transcranial Doppler ultrasonography does not provide a consistently good signal, especially during cardiopulmonary bypass, we examined the blood flow through the central retinal artery, which has proved to reflect an obstruction of the carotid artery. METHOD: Twenty-eight consecutive cases were examined with a 5 or 7.5 MHz conventional echocardiographic probe. Correlation between the maximal velocity at the central retinal artery and systolic blood pressure was examined. The blood flow of the central retinal artery and retrobulbar vessels was examined during selective or retrograde cerebral perfusion or intraaortic balloon pumping. RESULTS: Blood flow could be clearly visualized but disappeared below a certain pressure in every case. With data from 478 measuring points, systolic blood pressure correlated with maximal velocity (r = 0.6902, p < 0.0001). The blood pressure-axis intercept, known as "critical closing pressure," was 35.8 +/- 14.8 mm Hg, varying among individuals and bilateral eyes. Pulsatility index increased after cardiopulmonary bypass (1.095 +/- 0.245 to 1.525 +/- 0.268, p < 0.0001). Patency of the circle of Willis was confirmed by the blood flow during anastomosis of the ipsilateral artery. During retrograde cerebral perfusion, blood flow was detectable at the retrobulbar vessels. During intraaortic balloon pumping, the central retinal artery flow was augmented on inflation of the balloon. CONCLUSION: Orbital vessel monitoring provides the critical closing pressure of the central retinal artery and confirms patency of the circle of Willis. The eye can be "an acoustic window" into intracranial blood flow during cardiovascular surgery.

Aged↗
PubMed1997

Development of an intravascular pumping oxygenator using a new silicone membrane.

A new intravascular pumping oxygenator (IVPO) was developed for intravascular gas exchange and circulatory assistance in critically ill patients with respiratory and circulatory failure. The IVPO utilizes new silicone hollow fibers (diameter, 1 mm; membrane width, 50 microns) and consists of two driving tubes for the oxygenation and pumping of circulating blood. The performance characteristics of the IVPO were studied using an experiment ex vivo model. With a mean hemoglobin concentration of 10.5 +/- 2.3 g/dl, total oxygen transfer was 5.6 +/- 1.5 ml/min at a blood flow of 200 ml/min and 6.3 +/- 2.2 ml/min at a blood flow of 250 ml/min. Total CO2 transfer was 3.8 +/- 1.4 ml/min at a blood flow of 200 ml/min and 4.2 +/- 1.6 ml/min at a blood flow of 250 ml/min. Blood flow increased to a maximum of 250 ml/min during IVPO pumping. This preliminary experiment demonstrated that the IVPO has the capacity to function both as circulatory assist pump and as an intravascular hollow fiber oxygenator.

Animals↗
PubMed1997

Trial manufacture of eccentric roller type total artificial heart.

Working toward a completely implantable total artificial heart, we have designed an eccentric roller type total artificial heart. The actuator of this artificial heart is a drum type eccentric roller that squeezes the blood chambers. The blood chambers are made of silicone rubber and are torus in shape. The shape of the artificial heart is an almost circular cylinder, and its length and diameter are 10 cm and 8 cm, respectively. The 2 main characteristics of this artificial heart are that it discharges blood in a pulsatile mode and that it requires no reversing of the motor. Because we have not completed the artificial heart yet, we have tested the eccentric roller mechanism on the prototype with an overflow type mock circulation with a 100 mm Hg afterload. The prototype worked at the roller speeds of 50, 100, and 150 rpm with flow rates of 1.7, 3.7, and 5.4 L/min, respectively. Next the prototype was connected to a Donovan type mock circulatory system and worked at roller speeds of 88-214 rpm with flow rates of 3.0-8.4 L/min against mean afterloads of 82-120 mm Hg.

Biocompatible Materials↗
PubMed1997

Abdominal aorta and visceral arteries visualized by transgastric echocardiography: technical considerations.

Despite the necessity of information regarding the abdominal aorta and visceral arteries during cardiovascular surgery, there has been no intraoperative modality available. We examined the feasibility and limitations of transesophageal echocardiography (TEE) for this purpose. In 21 consecutive patients, the celiac artery (CEA), superior mesenteric artery (SMA), and left and right renal arteries (LRA, RRA) were examined with TEE, and could be visualized in 21 cases (100%), 20 cases (95.2%), 14 cases (66.7%) and 14 cases (66.7%), respectively. Several attempts were needed for successfully visualizing the LRA and the RRA in 2 and 1 case(s), respectively. Three specific manipulations of the probe were helpful for visualizing these vessels: 1) an appropriate counterclockwise rotation and an upward flexion of the probe when the transducer entered the stomach; 2) a stiffening of the flexible portion of the probe at the position of upward flexion by fixing the handle of the TEE probe when the transducer was advanced; and 3) a lateral flexion of the probe to provide a rotation of the image in either the clockwise or counterclockwise direction and to optimize the assessment of the blood flow velocity in the branch artery. Inferior visualization of the renal arteries was a limitation of this method. Two solutions for this problem were 1) repeated attempts at visualization and 2) an examination of the blood flow in the renal parenchyma with color Doppler imaging. Because of possible damage to the gastric wall, it is recommended that this maneuver be conducted by an experienced sonographer.

Aged↗
PubMed1996

Pooled air in open heart operations examined by transesophageal echocardiography.

BACKGROUND: The clinical significance of pooled air detected by transesophageal echocardiography during open heart operations is not clear. METHODS: Thirty-eight consecutive patients undergoing an open heart operation or an operation on the ascending aorta were divided into two groups on the basis of the absence (group 1, n = 14) or presence (group 2, n = 24) of pooled air. They were examined for intramyocardial echo contrast, ST segment elevation, conduction disturbances, and regional wall motion abnormalities. RESULTS: Echo contrast was found in no patient in group 1 and 66.7% of group 2 patients (p < 0.001). New regional wall motion abnormalities were detected in no patient in group 1 versus 33.3% of group 2 patients (p < 0.05), and ST segment elevation was seen in 33.3% of group 2 patients versus no group 1 patients (p < 0.05). Intramyocardial cardial echo contrast was newly detected after the appearance of pooled air more frequently in patients with ST segment elevation (p < 0.001). Atrioventricular block and sinus arrest appeared in 3 patients and 2 patients, respectively. Postoperative regional wall motion abnormalities were found in 25.0% of patients and were not closely related to intraoperative echo contrast findings. CONCLUSIONS: Pooled air, which is often detected in open heart operation by means of transesophageal echocardiography, is related to several cardiac events, including ST segment elevation, conduction disturbances, and regional wall motion abnormalities, although most of these are transient.

Adolescent↗
PubMed1996

Simple left atrial procedure for chronic atrial fibrillation associated with mitral valve disease.

BACKGROUND: A computerized 48-channel mapping system was used to investigate the characteristics of an atrial epicardial electrogram during chronic atrial fibrillation (AF) in patients with solitary mitral valve disease. We have devised a simple left atrial procedure to eliminate the chronic AF during a mitral valve operation. METHODS: Using this mapping system, we performed intraoperative atrial mapping in 11 patients with chronic AF associated with mitral valve disease. The AF duration ranged from 0.4 to 15 years (mean, 8.0 +/- 4.5 years). A simple surgical ablation of the AF on the left atrium only was performed during the mitral valve operations. RESULTS: The mean AF cycle length of the atria ranged from 129 to 169 milliseconds in the right atrium and from 114 to 139 milliseconds in the left atrium. The mean AF cycle length of the left atrium was shorter than that of the right atrium. Regular and repetitive activation was found in the left atria of 7 of 11 patients. The AF disappeared in all patients immediately after the operation, and 10 of these patients continued to have a sinus rhythm postoperatively (AF-free rate, 91%). CONCLUSIONS: Computerized intraoperative mapping revealed a shorter mean AF cycle length in the left atrium. A simple left atrial procedure was effective in eliminating chronic AF associated with solitary mitral valve disease.

Adult↗
PubMed1996

Coronary artery fistula to bronchial artery on contralateral side of coronary atherosclerosis and myocardial insufficiency. A case report.

Among coronary vessels anomalies is the rare coronary artery fistula. Myocardial insufficiency resulting from fistula steal phenomenon can not be clinically distinguished from that of coronary atherosclerosis, if these conditions coexists in the same patient. The authors present a case of extracardiac left coronary artery fistula connecting the circumflex branch and left bronchial artery, with inferior wall myocardial insufficiency attributable to the right coronary artery atherosclerosis.

Aged↗
PubMed1996

[Efficacy of left atrial only procedure for the treatment of chronic atrial fibrillation associated with mitral valve disease].

We supposed that chronic atrial fibrillation originated as a result of discontinuity of the refractory period of the dilated left atrium in the mitral valvular disease. We then performed left atrial only procedures to treat the chronic atrial fibrillation (AF) associated with mitral valve disease. These procedures were the left atrial isolation and the modified left sided maze procedure, consisting of isolation of all pulmonary veins and cryoablation to the posterior wall of the left atrium, in addition to excision of the left atrial appendage. Twenty-eight patients underwent these procedures over the past thirty months. Patient ages and the duration of AF ranged from 37 to 71 years and from 0.5 to 26 years, with an average of 8.3 years, respectively. Chronic AF disappeared in twenty-four patients (86%) at discharge. Three patients with severe tricuspid insufficiency had sustained AF and one patient had atrial flutter postoperatively. Three patients showed sick sinus syndrome postoperatively and two of these required a DDD pacemaker. Severe tricuspid regurgitation (p < 0.020) was the factor in recurrence of AF. Left atrial only procedures were effective in the treatment of chronic AF associated with mitral valvular disease.

Adult↗
PubMed1996

Numerical simulation of nonpulsatile left ventricular bypass.

A computer simulation was carried out to investigate the influence of nonpulsatile left ventricular assistance on hemodynamics. A simulation circuit was constructed to represent the circulatory system. A source of current was added to denote the nonpulsatile blood pump. The left and right ventricles were replaced by variable compliances. Left heart failure was simulated by decreasing the amount of compliance change of the left ventricle. We introduced a pulsatility indicator (PI) to clarify the pulsatility characteristics in the hemodynamics; this PI was defined as the ratio of the pulse pressure (PP) to the mean aortic pressure (AoP). When nonpulsatile bypass flow increased, the mean AoP, tension time index (TTI), and diastolic pressure time index (DPTI) increased, and cardiac output, PP, and PI decreased. When assisted flow increased with the constant total flow rate, the mean AoP and DPTI changed little; the PP, TTI, and PI decreased, and the endocardial viability rate increased. The PI would be helpful in evaluating the effect of pulsatility.

Blood Pressure↗
PubMed1996

[Role of noninvasive graphic diagnosis in acute type A aortic dissection and selection of the adjunct for cerebral protection].

We have evaluated the usefulness of graphic diagnostic modalities (transthoracic echocardiography [TTE], high speed CT, transesophageal echocardiography [TEE], surface echocardiography [SE]) in acute type A aortic dissection and selected the adjunct to protect cerebral damage during operation followed by pre and intraoperative diagnosis. 1) Angiopraphy was undergone in only 5 cases of 22 cases of acute type A dissection. Intimal flap of the ascending aorta was completely diagnosed by TTE and CT. It was sometimes difficult to show the location of the intimal tear by TTE and CT (diagnostic sensitivity 64%, specificity 88%). However, TEE and SE showed the location of intimal tear in all cases (sensitivity 100%, specificity 100%) and also clarified the dissection of the coronary arterial orifice. CT and SE were useful to detect dissection of the cervical branches. 2) The adjunct for cerebral protection was selected by the diagnosis of the distension of the dissection. Retrograde cerebral perfusion was used in the cases with intimal tear in the ascending aorta (10 cases) and selective cerebral perfusion was selected in cases of the distended dissection, in which dissection involved the arch aorta and replacement of aortic arch was required (12 cases). Cerebral perfusion time and operative mortality was 48 min and 10% in the former and 72 min and 17% in the latter, respectively. Operative mortality was not different in both groups.

Adult↗
PubMed1995

[Evaluation of serum granulocyte colony stimulating factor and granulocyte counts in patients with extracorporeal circulation].

To clarify the physiologic roles of granulocyte colony stimulating factor (G-CSF) in increasing granulocyte after extracorporeal circulation (ECC). The serum levels of G-CSF, C3a, granulocyte elastase and granulocyte count were examined in 26 patients undergone open heart surgery. These patients were divided into two groups, the long perfusion group (11 patients) and the short perfusion group (15 patients). Granulocyte increased immediately after ECC and reached maximum 48 hours after ECC in both groups. C3a showed significant increase at the end of ECC and decreased rapidly after ECC in both group. G-CSF showed high levels 3 and 6 hours after ECC in the short perfusion group and moderate increase prolonged until 48 hours after ECC in the long perfusion group. Granulocyte elastase showed high levels 6 hours after ECC and decreased to the normal value 48 hours after ECC in the short perfusion group, and high levels prolonging until 48 hours after ECC in the long perfusion group. Increase of granulocyte count might be affected with increase of compliment (C3a) and G-CSF at the early and late phase after ECC, respectively. Granulocyte elastase increased differently by the duration of perfusion time.

Adult↗