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Biomedical subjects

A Taira

Publications and source records attributed to A Taira.

At least 37 records · Page 2Linked to original sources
PubMed1999

Application of a manifold system for temporary reperfusion during proximal anastomoses in conventional coronary bypass surgery.

We report the application of a manifold system which is attached to saphenous vein grafts after the completion of distal coronary anastomosis. This technique permits not only the direct delivery of cardioplegic solution into the distal coronary artery, but also the reperfusion of revascularized coronary arteries via saphenous vein grafts by changing the connection to the arterial circuit during proximal anastomosis under a partial occlusion of the aorta in conventional coronary artery bypass surgery.

Cardioplegic Solutions↗
PubMed1999

Repair of an acute type A dissection: fate of the remnant false lumen and preserved aortic valve.

From January 1992 through March 1997, 75 patients (DeBakey type I/II = 56/19) underwent a surgical repair of a type A acute dissection. The patients included 37 men and 38 women ranging in age from 23 to 83 years with a mean of 65 years. All patients were admitted to our hospital with a mean interval of 2.2 days from the episode of onset. The overall hospital mortality rate was 25% (19/75). There were three late deaths among the 56 patients discharged from the hospital. The actuarial survival rate for the patients surviving the operation was 87% at 5 years after repair. A subsequent aortic operation was necessary in 6 patients, while 3 other patients who had late aortic complications were put on medical therapy alone. As a result, the aortic event-free survival rate was 54% at 5 years. For a type I dissection the false lumen was completely thrombosed after repair in 34%. The descending thoracic aorta with a patent false lumen was markedly enlarged in proportion to the follow-up time. After a conservative approach to the aortic valve, all but one patient demonstrated an adequate valve function throughout this study period. This experience with a midterm follow-up showed an acceptable durability of the preserved aortic valve and a progressive enlargement of the persistent false lumen with a high rate of aortic complications. Hence, all patients with a type A dissection need a close follow-up to assess the aorta for complications of either recurrent or residual aneurysms and dissections.

Acute Disease↗
PubMed1999

Myxoma of mitral valve associated with infective endocarditis.

A 20-year-old man was hospitalized for persistent fever, embolism, and syncopal attack. Echocardiography demonstrated a tumor on the mitral posterior leaflet. It was removed under extracorporeal circulation following extirpation of thrombus in the right common like artery. The tumor consisted of myxoma and vegetation with bacterial colony. Myxoma and/or vegetation had destroyed the mitral posterior leaflet. Accordingly, it was necessary to perform mitral valve replacement. The postoperative course was uneventful. This is the 14th surgical case of mitral valve myxoma, and the first case of that associated with infective endocarditis.

Adult↗
PubMed1999

Coronary artery aneurysm after stent implantation.

A coronary artery aneurysm that developed 6 months after coronary stent implantation in the left anterior descending artery, was treated by double coronary artery bypass grafting due to restenosis of the affected vessel and progression of right coronary artery stenosis. Although the poststenting aneurysm initially remained postoperative angiography showed that it had disappeared. In addition to thrombotic occlusion, another mechanism behind its disappearance may be that geometric changes of the implanted stent caused by heart retraction during surgery closed the entrance to the aneurysm.

Adult↗
PubMed1999

Is direct closure dangerous for treatment of doubly committed subarterial ventricular septal defect?

BACKGROUND: We performed direct closure of doubly committed subarterial ventricular septal defects with aortic cusp prolapse. Postoperative echocardiographic studies showed that this method improved coaptation of the prolapsing aortic cusp, especially in patients with mild aortic regurgitation (AR). METHODS: Twenty-one patients (mean age, 7.8+/-4.3 years; range, 2 to 18 years) with doubly committed subarterial ventricular septal defect underwent direct closure alone. Aortic valve prolapse was observed in all 21 patients, with mild AR found in 13 patients but not in the remaining 8. The site of the prolapsed aortic valve was in the right coronary cusp in all patients. We inserted an interrupted 4-0 or 5-0 polypropylene suture with a pledget from the lower margin of the ventricular septal defect to the pulmonary ring to increase protrusion of the prolapsed cusp by pushing it back and to improve coaptation of the aortic cusp. RESULTS: The interval between surgical treatment and the last postoperative evaluation ranged from 3 to 24 months (median, 11 months). No residual ventricular septal defect was detected in any patient. In the 8 patients who had aortic valve prolapse without AR preoperatively, no AR was found at follow-up. Of the 13 patients who had mild AR associated with aortic valve prolapse preoperatively, AR diminished in 7 and did not progress in the remaining 6. Furthermore, no anatomic changes in either the aortic or pulmonary annulus were found on follow-up echocardiography. In the group of 13 patients with mild preoperative AR, AR significantly persisted in patients who were more than 10 years old at operation (p<0.05). CONCLUSIONS: Our findings suggest that direct closure for this type of ventricular septal defect is safe and reliable in improving mild AR and that direct closure is more effective for younger patients in whom the prolapsing aortic cusp is mobile enough to be protruded. However, further long-term follow-up studies will be needed to ascertain the adequacy and usefulness of the method.

Adolescent↗
PubMed1999

Effectiveness of preoperatively obtained autologous platelet concentrates in open heart surgery.

BACKGROUND: Autologous blood components have been widely introduced in open heart surgery. However, the effectiveness of autologous platelet products remains controversial. METHODS: Autologous platelet concentrates (PC) were collected from patients (n = 35) scheduled for primary valvular heart surgery 1 to 3 days before the operation and were transfused immediately after cardiopulmonary bypass. Blood loss and platelet-related factors were compared with the control patients who had no PC (n=35). RESULTS: There were no serious complications in harvesting, preservation, and transfusion of autologous PC. The maximal platelet aggregation response significantly improved after its transfusion and tended to be higher with autologous PC stored 1 day than with ones stored 2-3 days. Activation of coagulation and fibrinolytic factors did not significantly differ between the groups. Postoperative blood loss was significantly less in autologous PC group, and seemed to have a negative correlation with platelet aggregation response. CONCLUSIONS: Autologous PC can be safely prepared and are clinically effective in reduction of postoperative blood loss in open heart surgery.

Aged↗
PubMed1999

Effects of sarpogrelate hydrochloride on platelet aggregation, and its relation to the release of serotonin and P-selectin.

Inhibitory effects of sarpogrelate hydrochloride (sarpogrelate), a 5-HT2 receptor antagonist, on platelet aggregation was examined as well as the relationship to serotonin and P-selectin, a platelet alpha-granule membrane glycoprotein. Platelet aggregation was induced by simultaneous addition of collagen (0.06-0.12 microg/ml), which did not induce aggregation alone, and serotonin (0.88 micromol/1) to platelet-rich plasma (PRP). The PRP was obtained from healthy volunteers and percentage maximum aggregation (MA) was measured. Serotonin levels and P-selectin levels in the supernatant of PRP after aggregation were determined. When vehicle-treated PRP was stimulated in the aforementioned manner, platelet aggregation dependent on collagen concentration was induced. Serotonin levels and P-selectin levels were also dependent on collagen concentration. Sarpogrelate (10(-6) to 10(-4) mol/l) inhibited such aggregation dose-dependently, and decreased serotonin levels and P-selectin levels in a dose-dependent manner. There were close correlations between MA and serotonin levels, MA and P-selectin levels, as well as serotonin and P-selectin levels. These results suggest that extracellular release of serotonin and P-selectin from platelets was caused by induction of aggregation, and these responses were suppressed by sarpogrelate.

Adult↗
PubMed1999

Experimental His-bundle pacing: histopathological and electrophysiological examination.

His-bundle pacing gives a more physiological ventricular contraction in comparison to right ventricular apical pacing. However the problems of lead fixation and stability of long-term His-bundle pacing are yet unsolved. We used six adult beagles, in which a screw-in lead was anchored in the His-bundle region for observation of the pacing conditions and histopathologic changes of the conduction system over the course of 2 months. In the results, a satisfactory fixation was obtained using a conventional screw-in lead and no histological influence on the conduction system was observed. The pacing threshold at the time of implantation was 1.15 +/- 0.69 V (3.23 +/- 3.08 mA) in the pulse width of 0.5 ms. R wave amplitude, the impedance and slew rate were 7.28 +/- 2.04 mV, 409 +/- 102 Ohm, and 0.65 +/- 0.41 V/s, respectively. Two months later, these parameters changed to 2.83 +/- 1.06 V (10.4 +/- 5.71 mA), 5.63 +/- 1.62 mV, 310 +/- 71.3 Ohm, and 0.49 +/- 0.22 V/s, respectively. These results suggest the feasibility of clinical application of permanent His-bundle pacing.

Animals↗
PubMed1999

Ultrasonic evaluation of congestive liver after tricuspid annuloplasty.

To assess the effect of tricuspid annuloplasty (TAP), the authors measured the size of the liver by using echography in the patients undergoing tricuspid annuloplasty. From April 1989 to August 1996, 18 patients underwent TAP. The authors measured preoperatively and postoperatively the hepatic index (HI) by echography, defined as follows: HI=L x D/BSA (L: the top-to-bottom length of the left hepatic lobe; D: the front-to-back length of the left hepatic lobe; BSA: body surface area). They also calculated the reducing rate (RR) of HI. The mean HI decreased after TAP; preoperative HI: 39.7+/-11.8 vs postoperative HI: 33.8+/-10.5 (p=0.0069). The RR of the patients with postoperatively residual tricuspid regurgitation (TR) over 2 degrees (n=4) was significantly lower than that of the other patients (n=14): -11.0+/-6.0% vs 20.2+/-3.2% (p=0.0003). They conclude that the use of echography to measure the HI is a good method of assessing congestion after TAP.

Female↗
PubMed1999

Inhibitory effects of H2-receptor antagonists on platelet function in vitro.

To evaluate in vitro inhibitory effects of four types of histamine H2-receptor antagonist (H2-receptor antagonists), famotidine, roxatidine, cimetidine and ranitidine, on platelet function, we examined aggregating potency and P-selectin levels with agonist-induced aggregation. Ranitidine and cimetidine inhibited, in concentration of 0.35 mM, the secondary aggregation induced by 5 microM adenosine diphosphate (ADP), the aggregation induced by 1 microg/mL collagen and 3 microM arachidonic acid. All of H2-receptor antagonists inhibited, in concentration of 1.4 mM, the aggregation induced by ADP, collagen and arachidonic acid. Ranitidine and cimetidine reduced markedly, in same concentration, P-selectin levels after induction of aggregation by 5 microm ADP, 1 microg/mL collagen and 3 microM arachidonic acid. When classified by the strength of inhibitory action, ranitidine and cimetidine were strong, followed by famotidine and roxatidine. It is considered that inhibitory effects of H2-receptor antagonists on platelet function are weaker than those of acetylsalicylic acid (ASA), since ASA inhibited platelet aggregation in concentration of 100 microM. No relationship was observed between inhibitory effects of H2-receptor antagonists on platelet aggregation induced by above agonists and the presence or absence of imidazole ring in the chemical structure.

Adenosine Diphosphate↗
PubMed1999

Clinical experience of 473 patients with the omnicarbon prosthetic heart valve.

BACKGROUND AND AIM OF THE STUDY: The long-term clinical experience of patients receiving Omnicarbon heart valve prostheses between January 1985 and December 1996 was investigated. METHODS: In total, 473 patients (255 males, 218 females; mean age 57.5 +/- 10.1 years (range: 20n-73 years) received 523 prostheses. These included 253 mitral (MVR), 170 atrial (AVR) and 50 double (DVR) valve replacements. RESULTS: The 30-day mortality rate was 4.7% (n = 22); in addition eight patients died more than 30 days after surgery, but during the same hospital stay. Mean follow up was 3.9 years (maximum 11 years and 7 months). Cumulative follow up was 1,750.1 patient-years (pt-yr); follow up was 97.5% complete. Among 39 late deaths, 20 were valve-related (seven cerebral infarction, seven cerebral bleeding, six endocarditis) and four cardiac-related. The overall five-year cumulative survival rate (excluding early mortality) was 90.2 +/- 11.7% (MVR 88.0 +/- 2.5%, AVR 93.1 +/- 2.3%, DVR 93.7 +/- 4.8%). At 10 years, the overall survival rate was 76.4 +/- 7.7%. Valve-related complications included thromboembolism (n = 13, 0.7%/pt-yr), anticoagulation-related hemorrhage (n = 12, 0.7%/pt-yr) and endocarditis (n = 7, 0.4%/pt-yr). Neither mechanical failure nor clinical hemolysis was observed. The overall valve-related event-free rate after five years was 89.3 +/- 2.0% (MVR 89.8 +/- 2.4%, AVR 93.5 +/- 2.6%, DVR 89.4 +/- 5.7%) and after 10 years it was 87.6 +/- 2.6% (MVR 85.4 +/- 3.7%, AVR 93.5 +/- 2.6%, DVR 82.5 +/-10.1%). CONCLUSIONS: These long-term results with the Omnicarbon valve are excellent; especially satisfactory results were achieved in terms of the low rate of thromboembolic complication.

Adult↗
PubMed1998

Penetrating atherosclerotic ulcers in an abdominal aortic aneurysm: report of a case.

We report the case of a 74-year-old man found to have an extensive intramural hematoma (IMH) in the infrarenal abdominal aorta during a follow-up imaging study performed after repair of a DeBakey type II aortic dissection with an aortic arch true aneurysm. Enhanced computed tomographic scan and angiography revealed an extensive IMH and multiple penetrating atherosclerotic ulcers in the abdominal aorta. The patient underwent a successful replacement of the affected abdominal aorta using a collagen-impregnated woven Dacron graft. Atheromatous ulcers are known to occur frequently in patients with advanced atherosclerosis. Hence, the elderly hypertensive patient, being at high risk of developing a variety of aortic disorders, requires careful follow-up imaging studies to assess the aorta on a regular basis.

Aged↗