Biomedical subjects

M Ohmi

Publications and source records attributed to M Ohmi.

At least 73 records · Page 4Linked to original sources

PubMed1993

Risk analysis of low cardiac output syndrome after valve replacement.

In order to obtain a better understanding of the pathogenesis of the postoperative low cardiac output syndrome (LOS), a multivariate regression analysis was performed, evaluating predictive risk factors quantitatively as a function of plural preoperative variables. A total of 145 cases including 76 MVR (MS 36 MR 40), 42 AVR and 27 DVR were analyzed in this study. Ten historical, 10 hemodynamic and 4 operative risk factors were collected to compose the data file with corresponding status of postoperative cardiac function which was classified as follows. Patients who were not associated with postoperative LOS (Score 1), associated with the LOS which required and responded to ordinal dosage of a catecholamine (Score 2) associated with the LOS which required and responded to maximal dosage of the catecholamine and/or mechanical circulatory support (Score 3), and died of LOS (Score 4). Variables with significant relationships to postoperative LOS, regression equation to LOS score and their multiple correlation coefficients (R) of each group were as follows. MVR group: technical trouble (TT), extracorporeal circulation time (ECCT), change of myocardial preservation methods, delta LVSWI/delta LVEDP, diseased duration, aortic cross clamping time, CTR, Y = -1.16 + 1.01 (TT) + 0.05(ECCT) + 0.16(delta LVSWI/delta LVEDP) + 0.02(CTR), R = 0.76. AVR group: LVMMI, ECCT, cardiac failure, NYHA, Y = -0.71 + 0.03(LVMMI) + 0.004 (ECCT) + 0.22(NYHA), R = 0.78. DVR group: delta LVWI/delta LVEDP, LVMMI, NYHA, LV diastolic eccentricity ratio, ECCT, Y = -0.50 + 0.60 (delta LVWI/delta LVEDP) + 0.003(LVMMI) + 1.18(NYHA) + 0.38(delta LVSWI/delta LVEDP) + 0.003(ECCT), R = 0.87. It was demonstrated that preoperative ergometer exercise study during cardiac catheterization was useful in prediction of postoperative outcomes, especially in the MVR (MS) group.

Adult↗

PubMed1993

[Surgical treatment in the patients with ocular type myasthenia gravis associated with thymoma].

During past 16 years, 192 patients underwent surgery for myasthenia gravis including 40 patients with pure ocular symptoms in our institute. In these 40 patients, 8 were associated with thymoma. The clinical stages of the thymomas were registered into Stage I (n = 5), Stage II (n = 1), Stage III (n = 1), Stage IV (n = 1) according to the classification of Masaoka and colleagues. All patients underwent extended thymothymectomy. The patient in stage III had been well until generalized myasthenic symptoms appeared 4 years after the surgery. Since the chest X-ray film revealed the tumor shadow on the right diaphragm, removal of the tumor was performed. Although he developed myasthenic crisis postoperatively, he is well controlled medically. Other 7 patients have been doing well. We concluded that a close postoperative follow up should be performed for the patients with ocular type myasthenia gravis associated with thymoma.

Adult↗

PubMed1993

[Management of myasthenia gravis (MG) associated with thymoma].

From June 1975 to June 1992, we experienced 203 patients with MG. Sixty patients had associated thymoma, registering stages I (n = 31), II (n = 18), III (n = 9), and IV a (n = 2), according to the classification of Masaoka and colleagues. Fifty patients had generalized MG and 10 had ocular MG. Histopathological findings indicated round-oval, polygonal cell type in 46 patients and mixture of round-oval and spindle cell type in 11 patients and invasive thymomas had a tendency to have a predominantly epithelial type with and increased epithelial element as compared with non-invasive thymomas. An extended thymectomy including thymoma was performed in all patients. Three patients in stage II, 7 patients in stage III, and 2 patients in IV a received postoperative radiation therapy. Twenty-one patients needed prolonged respiratory care for respiratory crisis. Fifty-three patients have been doing well with the alternate-day corticosteroid therapy, however, 4 patients had an excavation of myasthenic symptoms associated with recurrence of thymoma on the pleura. In conclusion, early extended thymectomy including thymoma is markedly effective therapy for MG with thymoma and a careful attention should be paid for recurrence in the patients with invasive thymoma.

Adult↗

PubMed1993

Sound spectral analysis of prosthetic valvular clicks for diagnosis of thrombosed Björk-Shiley tilting standard disc valve prostheses.

To evaluate clinical usefulness of sound spectral analysis in the early detection of prosthetic thrombosis, we analyzed specific patterns of thrombus formation in Björk-Shiley tilting standard disc prostheses in relation to the sound spectral analysis of their click sounds. Among a total of 365 Björk-Shiley tilting standard disc prostheses, nine became thrombotic. These consisted of seven prostheses in the mitral position and two in the aortic position, and the affected valves were replaced in all cases. The sound spectral analysis system includes a wide-frequency microphone and a sound spectral analyzer. To quantify the amplitude of the metallic clicks that are specific to the prosthetic valve sounds, we used a normalized maximal frequency as a diagnostic parameter for valve thrombosis. Thrombus formation was localized at the minor strut in two cases, and these demonstrated abnormally low normalized maximal frequency values only on opening clicks. In four cases thrombus formations were noted at both minor and major struts, and these showed abnormally low normalized maximal frequency values on both opening and closing clicks. In two cases with pannus formation, no abnormalities were found by sound spectral analysis. In one case, which had demonstrated abnormally decreased normalized maximal frequency values of both opening and closing clicks, the normalized maximal frequency values were normalized after thrombolytic therapy, suggesting resolved thrombosis. Reoperation, which was performed for concomitant complication of perivalvular leak, revealed no noticeable thrombus formation. The thrombi were seen on the minor strut during surgical procedures in all cases in which valve thrombosis was indicated by the sound spectral analysis. Therefore, the minor strut is considered to be the prevalent area of thrombus formation, and diagnosis could be made after observation of abnormally low normalized maximal frequency on opening clicks. We found the sound spectral analysis to be an extremely useful diagnostic tool for early detection of thrombosis in the Björk-Shiley tilting standard disc prostheses, especially because the opening clicks of the tilting disc valve were too low in amplitude for auscultation to detect the existence of mild abnormality.

Adolescent↗

PubMed1993

[The study of neuropsychological alterations following coronary artery bypass operation as predicted by computed tomography scan of the brain].

The objective of this clinical study is to provide information regarding the association between coexistent cerebrovascular disease and neuropsychological abnormalities after coronary artery bypass operations. Computed tomography scan of the brain was performed in 104 patients pre-operatively, and their post-operative neuropsychological functions were evaluated. The patients were categorized as follows according to the CT findings: Seventy-three patients showed normal or slight cerebral cortical atrophy which usually seen in patients over fifty of age (group A). Sixteen showed moderate or severe cortical atrophy (group B). Fifteen patients demonstrated the characteristic findings of Binswanger type; severe white matter hypodensity especially in frontal horns and dilated ventricles (group C). Overt neuropsychological dysfunction was not observed in patient in groups A and B. Six patients in group C showed a combination of dementia, bizarre behavior, disorientation and gait dyspraxia following bypass operations. The pseudobulbar signs were also found in 3 patients. These clinical abnormalities persisted for six days to three weeks, and were most often reversible. Although the underlying mechanism of these deleterious alterations is not elucidated, the ischemic nature of the characteristic white matter lesions was highly suspected. The arteriosclerotic changes of the arteriole of the cerebral cortex and hypoperfusion during cardio-pulmonary bypass were supposed to be responsible. Therefore it was concluded that special attention should be focused on neurological evaluation for bypass surgery in group C patients.

Adult↗

PubMed1993

[Continuous irrigation followed by combined omental transposition and pectral muscle rotation for treatment of postoperative mediastinitis with DIC in a child].

A 8-year-old boy was complicated with mediastinitis with DIC 20 days after replacement of the stenotic right ventricular outflow conduit. Open drainage and débridement were performed and semi-closed continuous irrigation with 1% povidone iodine was continued for 10 days to control DIC. Thereafter, the pedicled omentum was mobilized to the upper anterior mediastinum, however, it was too thin to obliterate there. To obliterate the upper anterior mediastinum and cover the infected graft, the major pectoral muscle flap was introduced to the anterior mediastinum through the window created by removing a part of left second rib. The sternum was closed primarily. The postoperative course has been well and no recurrence has been proved for 1 year.

Cardiac Surgical Procedures↗

PubMed1992

Permanent pacemaker implantation in premature infants less than 2,000 grams of body weight.

Pacemaker implantation in premature infants presents technical problems because of the relatively larger size of the pulse generator compared with their bodies. A new technique with which successful generator implantation was performed in 2 premature infants less than 2,000 g of body weight is described. The generator is wrapped in a Gore-Tex surgical membrane. A piece of membrane overlying the electrical contact surface of the generator is removed, and the generator is fixed to the abdominal wall in the peritoneal cavity. The technique is simple to perform and would give relative ease in generator exchange.

Birth Weight↗

PubMed1992

Thoracic aortic operations in patients aged 70 years or older.

Thirty-one patients over the age of 70 years (group A) and 72 patients less than 69 years (group B) underwent a variety of thoracic aortic surgical procedures. Early and long-term results and cerebral function were compared between the two groups. Preoperative and postoperative cerebral function was evaluated using mini mental state-Himeji and Wechsler adult intelligence scale tests. The operative mortality of groups A and B was 12.9% and 11.1%, respectively (not significant). There were no significant differences in postoperative complications between the two groups. The late mortality rates of groups A and B were 11.1% and 9.3%, respectively (not significant). There were no significant differences between the two groups in the mini mental state-Himeji test, digit symbol, vocabulary, and total Wechsler adult intelligence scale scores before and after operation. We conclude that thoracic aortic surgical procedures in patients over 70 years of age can be performed with acceptable mortality and morbidity risks. Most patients showed symptomatic improvement.

Adult↗

PubMed1992

Changes in myocardial beta-adrenergic receptors during acute rejection of heterotopically transplanted rat hearts.

To evaluate changes of the myocardial beta-adrenergic receptors in acute cardiac graft rejection, the density and binding affinity value of the myocardial beta-adrenergic receptors in heterotopically transplanted rat isografts and allografts were analyzed. Hearts from Fisher rat donors were transplanted either to the Fisher rats (isografts) or to Lewis rats (allografts). Histologic examination of the allografts showed mild to moderate rejection on the seventh and fourteenth days and showed severe rejection on the twenty-first day after transplantation. The density values in the allografts and isografts similarly increased significantly (p < 0.05) above the normal level on the seventh and fourteenth days after transplantation. The density in allografts on the twenty-first day decreased significantly (p < 0.05) below the normal level, while that in isografts remained at the normal level. In contrast, the binding affinity value of myocardial beta-adrenergic receptors in both isografts and allografts did not change after transplantation. These results demonstrated that myocardial beta-adrenergic receptors presented upregulation in mild to moderate rejection, whereas these receptors presented downregulation in severe rejection. The data suggested that downregulation of myocardial beta-adrenergic receptors plays a major role in decreased cardiac contractility during severe rejection, but not during mild and moderate rejection.

Abdomen↗

PubMed1992

[Malfunction of prosthetic valves: pathogenesis and diagnostic measure].

Modality of the malfunction of prosthetic valve often reflects the specific features of its design and materials of the prosthesis. During past 17 years, a total of 499 cases of valve replacements were performed in our institute and among them, 50 cases received redo surgery, in which 52 prosthetic valves were replaced due to their malfunctions. Those replaced prosthetic valves were analyzed in terms of their pathogenesis, onset durations and diagnostic methods of each type of malfunction. The malfunctions included hemolytic anemia, thrombosis or tissue overgrowth and tissue failure of bioprostheses. Hemolytic anemia was experienced in 8 cases with Starr-Edwards (S-E) 2320 (n = 7) and Omni-Science (n = 1) both in the aortic position and those prostheses were replaced at 1-9.6 (mean 4.5) postoperative years (POY). The linearized rate of the complication with the S-E 2320 was 3.0%/patient-years (p-y) and its actuarial event free rate was 62% at 11 POY. Operative findings disclosed cloth wear in 5 and perivalvular leakage in 5 cases. Fourteen Hancock (H) and 3 Angell-Shiley (A-S) bioprostheses experienced tissue failure of valves and they were subjected to reoperation at 3.2-10.0 (mean 6.5) POY. The linearized rates were 4.1%/p-y for H and 4.5%/p-y for A-S with actuarial event free rates at 12 POY of 59 and 56%, respectively. Prosthetic valve thrombosis and/or tissue overgrowth were seen in 17 valves at 1.6-15.1 (mean 9.1) POY.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

[Result of surgical treatment of true or dissected thoracic aneurysm: determinants analysis in operative mortality and morbidity].

Between 1986 and 1990, 69 patients underwent surgery either for thoracic aneurysm (27 patients) or aortic dissection (42 patients). Sixty one patients (88%) survived and 8 patients (12%) died after surgery. Main determinants of deaths in 4 patients with true arch aneurysm were bleeding from the sites of aortic clamping or anastomosis and intraoperative severe LOS. Three patients with acute type A dissection died from bleeding due to clamp injury or myocardial ischemia. The cause of death in the patient with chronic type B dissection was associated with brain damage due to hypoxia developed during left heart bypass. Postoperative cardiac, pulmonary, hepatic and renal functions were analyzed in the operative survivors. Cardiac functions were maintained well in all patients except two patients with chronic type A dissection. Four patients, one with true arch aneurysm, 2 with chronic type A and one with chronic type B dissection, required tracheostomy. The mean of maximum total serum bilirubin exceeded 4 mg/dl in the patients with true arch aneurysm, acute and chronic type A dissection. The level of serum creatinine showed slight increase in all patients but prophylactic peritoneal dialysis was performed in one patient with chronic type A dissection. In conclusion, the cause of deaths in most patients with thoracic aneurysm was due to inappropriate operative techniques and circulatory supports during surgery. Without the complication described above, the patients could tolerate surgery well.

Aged↗

PubMed1992

[Postoperative respiratory dysfunction in patients with Stanford type A aortic dissection].

Between 1986 and 1990, 24 patients with Stanford type A dissection (acute; 14, chronic; 10) underwent surgery through median sternotomy. The patients were divided into two groups by a duration of postoperative ICU stay for respiratory care. Six patients in the long-period group stayed in ICU for more than 15 days and 18 patients in the short-period group stayed for less than 15 days after surgery. Acuity of disease, age, sex, operation time, pump time, aortic clamp time, lowest esophageal temperature, amount of blood transfusion, arch manipulation for cerebral perfusion with or without arch reconstruction, occurrence of phrenic nerve palsy and other postoperative complications, postoperative cardiac, hepatic and renal functions were compared between two groups. Conclusions are as follows: 1) Arch manipulation for cerebral perfusion with or without arch reconstruction, phrenic nerve palsy, other complications (pericardial and pleural fluid accumulation, recurrent nerve palsy, postoperative bleeding and coronary spasm) and high serum creatinine level were main factors for prolonged postoperative ICU stay for respiratory care and 2) arch manipulation in the patients with chronic type A aortic dissection induced high incidence of phrenic nerve palsy.

Adult↗

PubMed1992

[Successful post-left ventricular aneurysmectomy left ventricular assist with a centrifugal pump].

A 71-year-old male with a left ventricular aneurysm underwent aneurysmectomy. The patient could be weaned from cardiopulmonary bypass with high-doses of dopamine and dobutamine, followed by immediate left ventricular failure and systemic hypotension. IABP could not be applied to the patient because of the kinked bilateral common iliac arteries. In this condition a centrifugal pump system was connected between left atrium and ascending aorta. With a pump flow of 2 L/min the patient returned to an intensive care unit. After 48 hours of left heart bypass with minimal anticoagulation with systemic heparinization the device could be removed. The patient recovered without any complications, such as thromboembolism, renal failure or mediastinitis. He discharged in fair condition 3 months after the operation.

Aged↗

PubMed1992

[Experience in the treatment of acute fulminating myasthenia gravis].

During past 15 years, 188 myasthenia gravis (MG) patients underwent thymomectomy or thymectomy with extended resection of the adipose tissue around the thymus in our institution. Four of 188 patients (2%) had to be given respiratory support within 2 months after the onset of MG. We defined this MG as the acute fulminating type. There were 2 male and 2 female patients, ranging in age from 22 to 44 years (average, 32.5 years). Three of these patients had thymoma. One of these patients was post-thymomectomy myasthenia gravis and another patient was d-penicillamine induced myasthenia gravis. Two patients admitted on respirator for respiratory crisis. All patients underwent operation within 2 weeks after admission. The duration of respiratory support ranged from 10 to 120 days (mean 44) after operation. The period of the hospital stay ranged from 8 months to 2 years 1 month (mean 1 year 5 months). During acute stage after operation, the patients needed ACTH, steroid, immunosuppressants (azathioprine, Bredinin) and plasma pheresis depending on their severity of myasthenic symptoms. In 2 patients dose of steroid could be reduced without deterioration of the symptoms. They are doing well with small dose of steroid. In one patient plasma pheresis was performed 6 years after thymectomy. Various symptoms due to myasthenia gravis and rheumatoid arthritis has recurred 10 years after thymectomy. The titer of acetylcholine receptor antibody of this patient has been continuing in high level.

Acute Disease↗

PubMed1992

[Effects of coronary artery bypass grafting for patients with totally occluded left anterior descending arteries].

Between April, 1987 and March, 1991, 21 patients with totally occluded left anterior descending arteries (TOLAD) underwent coronary artery bypass grafting (CABG) in our institute. All of them were diagnosed as angina pectoris and 15 (71%) of them have had episodes of myocardial infarction. Graftability of TOLAD was 90% (19/21) and two of the TOLADs were not suitable for CABG because severe atherosclerosis of these arteries were observed intraoperatively. There was no operative death. Short term (1-2 months) patency was 64% (7/11) for saphenous vein grafts (SVG) and 100% (8/8) for left internal thoracic artery grafts (LITA). Left ventricular wall motion assessed by left ventriculography showed impaired regional wall motion in 63% segments of the segment #2, #3 and #6 preoperatively. However, the regional wall with impaired motion decreased to 31% after CABG. Thallium-201 scintigraphy showed impaired perfusion in 62% segments of the left anterior wall, apex and interventricular septum preoperatively. However, the regional wall with impaired perfusion decreased to 42% after CABG. Exercises tolerance assessed by treadmill test was improved from 3.8 +/- 0.7 Mets preoperatively to 6.5 +/- 0.7 Mets with patent coronary bypass grafts. These data suggested that CABG can improve the wall motion of the regions perfused by TOLADs and the LIMA is more suitable than the SVG for CABG to TOLAD.

Constriction, Pathologic↗

PubMed1992

[Separate perfusion of upper and lower body for ruptured thoracoabdominal aortic aneurysm--a case report].

A case of ruptured thoracoabdominal aortic aneurysm was presented. The patient had emergent replacement of thoracoabdominal aorta with an aid of separate perfusion of upper and lower body. The postoperative course was uneventful. It was suggested that separate perfusion of upper and lower body was useful in the patients who require extensive aortic replacement and who are at substantial risk for spinal cord injury.

Aorta, Abdominal↗

PubMed1992

[Surgical treatment of myasthenia gravis associated with Graves's disease].

During past 30 years, we experienced 253 patients who underwent surgery for myasthenia gravis. Among these patients, 9 were associated with Graves' disease. No patients had thymoma. Five patients underwent thymectomy after they had become euthyroid by medical treatment, though four patients required subtotal thyroidectomy before thymectomy. One patient developed myasthenic crisis following thyroidectomy and was treated with respirator for 5 days. But thymectomy was performed without myasthenic crisis in these four patients between 25 days and 60 days after thyroidectomy. They have been doing well and no see-saw phenomenon was presented. Thymectomy is safe and effective even in the patients with Graves's disease, and we recommend to perform it after they become euthyroid by medical or surgical treatment.

Adult↗

PubMed1991

[Serious complication of retrograde perfusion during repair of dissecting aneurysm: compression of the true lumen].

Between 1982 and 1990, 61 patients underwent the repair of dissecting aneurysm. Retrograde perfusion from the unilateral femoral artery were performed for 56 patients and the selective false lumen perfusion occurred in 3 patients. As for those 3 patients, compression of the true lumen and insufficient cerebral perfusion were suspected. Selective cerebral perfusion and antegrade systemic perfusion from the ascending aortic graft were performed. Although 2 patients took uneventful postoperative courses, 1 patient died of massive brain damage. It is very important to accomplish the means to maintain adequate cerebral circulation as soon as possible toward this fetal complication.

Adult↗