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Biomedical subjects

H Koyanagi

Publications and source records attributed to H Koyanagi.

At least 55 records · Page 3Linked to original sources
PubMed1999

Use of arterial grafts for coronary revascularization. Experience of 2987 anastomoses.

OBJECTIVES: The aim of this study was to evaluate the performance and the quality of arterial grafts for coronary artery bypass grafting at The Heart Institute of Japan, Tokyo Women's Medical University. PATIENTS AND METHODS: From January 1970 to March 1998, 2987 arterial grafts, including left and right internal thoracic arteries, gastroepiploic artery, radial artery and inferior epigastric artery, were used in 1673 patients. In the same period, 1225 saphenous vein grafts were used. Early graft patency was angiographically determined. Also, histological evaluation of operative specimens and preoperative angiographic evaluation of arterial grafts were performed. RESULTS: The total number of hospital deaths was 38 (2.3%). Of 4212 grafts, 3919 grafts (93%) were evaluated angiographically and 3714 of 3919 grafts were patent (94.8%). The patency rate of internal thoracic artery was better than that of gastroepiploic artery (p < 0.0001), radial artery (p = 0.0005) and saphenous vein grafts (p < 0.0001). However, the patency rate of gastroepiploic artery was better than that of saphenous vein grafts (p = 0.04), while no significant difference was detected between gastroepiploic artery and rdial artery. Only one internal thoracic artery specimen obtained at surgery showed atherosclerotic change, but all gastroepiploic artery specimens had moderate to severe atherosclerotic changes with CD68-positive cell infiltration. Only one patient's left internal thoracic artery out of 200 was not angiographically useable as a conduit, while multiple stenotic lesions in gastroepiploic artery were observed. CONCLUSIONS: In the graft selection for CABG, the primary choice is internal thoracic artery and the secondary choice is right internal thoracic artery, from the standpoint of histological and angiographic evaluation, gastroepiploic artery and/or radial artery, depending on the target anastomotic site, degree of stenosis, and in situ or free use is the third choice.

Aged↗
PubMed1999

A noninvasive method of measuring wave intensity, a new hemodynamic index: application to the carotid artery in patients with mitral regurgitation before and after surgery.

Wave intensity (WI) is a new hemodynamic index, which is defined as (dP/dt)(dU/dt) at any site of the circulation, where dP/dt and dU/dt are the time derivatives of blood pressure and velocity, respectively. Arterial WI in normal subjects has two positive sharp peaks. The first peak occurs during early systole when a forward-traveling compression wave is generated by the left ventricle. The magnitude of this peak increases markedly with an increase in cardiac contractility. The second peak, which occurs towards the end of systole, is caused by generation of a forward-traveling expansion wave by the ability of the left ventricle to actively stop aortic blood flow. The interval between the R wave of the ECG and the first peak of WI (R-1st peak interval) and the interval between the first and second peaks (1st-2nd interval) are approximately equal to the preejection period and left ventricular ejection time, respectively. Using a combined Doppler and echo-tracking system, we obtained carotid arterial WI noninvasively. We examined the characteristics of WI in 11 patients with mitral regurgitation (MR) before and after surgery, and 24 normal volunteers. In the MR group before surgery, the second peak was decreased and the (1st-2nd interval)/(R-R interval) ratio was reduced, compared with the normal group (140 +/- 130 vs 750 +/- 290mmHg m/s3. P < 0.0083; 20.7% +/- 3.4% vs 26.7% +/- 2.8%, P < 0.083). There were no significant differences in the first peak between the normal group and the MR group before and after surgery. The second peak in the MR group was increased significantly (P < 0.016 vs before surgery) to 1,150 +/- 830mmHg m/s3 in the early period after surgery (stage I), and to 1,090 +/- 580mmHgm/s3 in the late period after surgery (stage II). These values did not differ significantly from that of the normal group. At stage I, the (R-1st peak interval)/ (R-R interval) ratio was increased from 13.4% +/- 2.7% to 20.6% +/- 5.6% (P < 0.016 vs before surgery). At stage II, this ratio decreased to 16.2% +/- 2.8% (P < 0.016 vs stage I). but was still significantly higher than that before surgery. The (1st-2nd interval)/(R-R interval) ratio increased significantly after surgery (P < 0.016 vs before surgery) to values (27.0% +/- 4.5% at stage I and 28.9% +/- 2.6% at stage II) which did not differ significantly from that of the normal group. The recovery of the second peak after surgery suggests that the left ventricle had recovered the ability to actively stop aortic blood flow. Wave intensity is useful for analyzing changes in the working condition of the heart.

Adult↗
PubMed1999

Retrograde cerebral perfusion for aortic arch surgery: analysis of risk factors.

BACKGROUND: Retrograde cerebral perfusion (RCP) has been widely adopted during aortic arch surgery under hypothermic circulatory arrest (HCA). However, the risks in terms of mortality and morbidity in aortic arch surgery using HCA with RCP have not yet been confirmed. METHODS: The present study is a retrospective review of 249 patients who underwent aortic arch surgery at three Japanese cardiovascular centers where RCP is a routine adjunct. The median age was 65 years, and 38 patients were more than 75 years old. The pathology in the aortic arch was atherosclerotic aneurysm in 133 patients and dissection in 116. Seventy patients had surgery on an emergency basis. Surgery was performed through a median sternotomy in 182 patients and through a left thoracotomy in 67. Using HCA with RCP, graft replacement of the total aortic arch was performed in 109, the distal arch in 63, and the ascending aorta and hemi-arch in 66; 11 patients had patch repair. RESULTS: The overall hospital mortality was 25/249 (10%), and 12/70 (17%) in emergent surgery. Stroke developed in 11 patients (4%). The median duration of RCP was 46 minutes (range, 5 to 95). Univariate analysis of risk factors revealed that an age of 75 years or more (p < 0.001), and urgency of surgery (p = 0.02) affected hospital mortality. Multivariate logistic analysis revealed that pump time (p = 0.0001), age (p = 0.0001) and RCP time (p = 0.05) are the most significant risk factors for mortality. The risk factors for mortality and neurological morbidity combined are pump time (p = 0.0001), age (p = 0.0002), and urgency of surgery (p = 0.07); RCP time is marginally significant (p = 0.15). CONCLUSIONS: The dominant risk factors for mortality and morbidity are pump time, urgency of the surgery, and age. RCP is a simple and useful adjunct for aortic arch surgery with up to 80 minutes of HCA, although prolonged RCP is a risk factor for mortality and morbidity.

Adult↗
PubMed1999

Extensive aortic reconstruction for aortic aneurysms in Marfan syndrome.

BACKGROUND: Marfan syndrome patients frequently develop aneurysms or dissections involving multiple segments of the aorta, and occasionally require staged replacement of the entire aorta. This study reviews the surgical outcome of patients with Marfan syndrome who underwent extensive aortic reconstruction. Extensive reconstruction is defined as reconstruction of more than two segments of the ascending, arch, descending thoracic, or abdominal aorta. METHODS: From March 1973 to December 1997, 101 patients with Marfan syndrome underwent aortic operation. Twenty-six patients (25.7%) had extensive aortic reconstruction. All 26 patients suffered from aortic dissection: 13 patients had Stanford type A and 13 had type B dissection. Twenty-three patients (88.4%) had annuloaortic ectasia and aortic regurgitation. Surgical procedures included composite valve graft replacement (n = 23, 88.4%), aortic arch reconstruction (n = 15, 57.7%), graft replacement of the descending thoracic aorta (n = 6, 23.1%), and graft replacement of the thoracoabdominal aorta (n = 16, 61.5%). Five patients (19.2%) had total thoracoabdominal aortic replacement, and three patients (11.5%) had replacement of the entire aorta. Twenty-one patients (80.8%) required multiple operations. RESULTS: Follow-up was complete in all patients. The 30-day survival rate was 88.5%. None of the survivors had paraplegia or paraparesis. The overall long-term survival rate was 88.5 +/- 6% at 1 year, and 81.7 +/- 9% at 9 years. CONCLUSIONS: Aortic surgery prolongs survival in patients with Marfan syndrome, and currently there is a relatively low associated morbidity and mortality even for aggressive surgical treatment.

Adult↗
PubMed1999

Current strategy of temporary circulatory support for severe cardiac failure after operation.

BACKGROUND: After open heart operations about 1% of patients still need temporary circulatory support for severe cardiac failure, and over half of those patients die during or after the support. This study assessed the efficacy of the current strategy of circulatory support. METHODS: We assessed clinical outcome of 64 consecutive patients (1.5% of pump cases) who had temporary circulatory support associated with perioperative variables. The results were analyzed by logistic regression analysis. RESULTS: The weaning and discharge rates were 50.0% and 26.7% with venoarterial bypass, 76.2% and 57.1% with biventricular bypass, 87.5% and 37.5% with isolated left ventricular bypass, and 60.0% and 40.0% with pulsatile left ventricular assistance, respectively. Logistic regression analysis identified presupport cardiogenic shock (odds ratio, 9.922) and support type (14.684) as factors significantly associated with nonweaning from the temporary support, and cardiogenic shock (28.268), support duration (2.948), and support type (14.184) as factors significantly associated with mortality during or after the circulatory support. CONCLUSIONS: The current strategy of temporary circulatory support improved clinical outcome of patients with severe cardiac failure. Early application of circulatory support before profound cardiogenic shock and proper selection of the support type might be key factors for successful circulatory support postoperatively after operation.

Adult↗
PubMed1999

Multiglycosidorum tripterygii, a new immunosuppressant, supresses coronary arteriosclerosis after heart transplantation.

BACKGROUND: Graft coronary arteriosclerosis is the major limiting factor for long-term survival after heart transplantation. In this study, we investigate the effect of multiglycosidorum tripterygii on graft coronary arteriosclerosis and platelet-derived growth factor A mRNA expression of transplanted hearts. METHODS: Three groups of Lewis rats (n = 7/Group) underwent heterotopic heart transplantation from Wistar-King donors and were treated with cyclosporine A (10 mg/ kg/day) for 60 days (Group A) or with multiglycosidorum tripterygii (30 mg/kg/day) for 60 days (Group B) or with cyclosporine A for the first 30 days and followed by multiglycosidorum tripterygii for another 30 days (Group C). Histological evaluations of rejection and coronary arteriosclerosis, as well as Northern blot analysis on graft platelet-derived growth factor A mRNA expression were made 60 days after transplantation. RESULTS: Morphometric results indicated no significant difference in rejection among three groups. However, the extent of graft coronary arteriosclerosis in Group B (1.12 +/- 0.21) and Group C (1.41 +/- 0.19) was significantly less than that seen in Group A (1.72 +/- 0.18) (p < 0.01 andp < 0.05, respectively). Furthermore, the incidence of diseased vessels was significantly less in Group B (29.5% +/- 7.8%) and Group C (42% +/- 9.1%) compared with Group A (69.1% +/- 11%) (p < 0.01 and p < 0.05, respectively). The expression of platelet-derived growth factor A mRNA of cardiac allograft was also significantly suppressed in Group B (25.4 +/- 6.2) and Group C (39.8 +/- 9.4), when compared with Group A (62.2 +/- 12.9) (p < 0.01 and p < 0.05, respectively). CONCLUSION: Multiglycosidorum tripterygii is superior to cyclosporine in prevention and attenuation of graft coronary arteriosclerosis and this efficacy is probably associated with the depressed expression of graft platelet-derived growth factor A mRNA in the multiglycosidorum tripterygii-treated groups.

Animals↗
PubMed1999

Anticoagulation after valve replacement: a multicenter retrospective study.

Anticoagulant therapy after cardiac valve replacement was evaluated retrospectively in 1,200 patients attending 8 cardiac surgery clinics in the Tokyo area as part of the Tokyo Area Study on Anticoagulation After Cardiac Valve Replacement Using PT-INR (TAS). A prospective trial is also in progress and will be reported later. The prothrombin time international normalized ratio (PT-INR) was determined at the time of thromboembolic and bleeding complications in 1,200 patients. During the 5 year study period, thromboembolisms occurred in 21 patients, and bleeding complications occurred in 15 patients. In 71% of patients with thromboembolism and 47% of those with bleeding complications, the PT-INR was within the range of 1.6 to 2.8, which is the accepted therapeutic range in Japan. Therefore, the correct PT-INR therapeutic range for Japanese patients with mechanical heart valves needs to be reexamined, and data from the prospective TAS trial that is currently underway will be used for this purpose.

Adult↗
PubMed1999

Clinical experience of left ventricular assist systems at the Heart Institute of Japan.

The main indications for left ventricular assist system (LVAS) support are postcardiotomy ventricular failure as temporary circulatory support and end-stage cardiomyopathy as chronic circulatory support. To clarify the efficacy of LVAS support, we assessed the clinical outcome of a pneumatic LVAS and an electromagnetic LVAS for patients with severe ventricular failure. As of March 1998, 5 patients with postcardiotomy ventricular failure had received the pneumatic LVAS support, and 2 other patients with end-stage idiopathic cardiomyopathy had undergone implantation of the electromagnetic LVAS. The drive control of the LVAS was mainly counterpulsation in the diastole of the native heart. In the 5 postcardiotomy patients, the duration of pneumatic LVAS support ranged from 30 to 312 h (mean, 109.2). All 3 patients with more than 72 h support were successfully weaned, and 2 of them survived. The other 2 patients with cardiogenic shock and less than 36 h support could not be weaned from the LVAS. In the 2 cardiomyopathy patients, 1 patient was well maintained by the electromagnetic LVAS support and underwent successful heart transplantation 7 months later. The other patient has been chronically supported by the LVAS for 2 months and is doing well so far. These results suggest that selective application of the pneumatic LVAS as a temporary support and the electromagnetic LVAS as a chronic support might be appropriate for maximizing the effectiveness of LVAS treatment for profound cardiac failure.

Adult↗