Biomedical subjects

H Koyanagi

Publications and source records attributed to H Koyanagi.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Early and mid-term results of elephant trunk method using stent graft during total arch replacement].

Combined therapy of stent graft implantation and open surgery is an alternative method for aortic aneurysm. Seven patients with aortic aneurysm [annulo aortic ectasia (AAE) + Marfan syndrome (4), AAE + arch aneurysm + s/o Behçet disease (1), acute dissected aneurysm (type A) (1), thoracic aortic true aneurysm (1)] were successfully treated by means of elephant trunk method using a stent graft during total arch replacement. There was no complication related to the stent graft during the perioperative period. Postoperative computed tomographic scans were performed 1 and 6 months later. There was no endleak and no migration, and the aortic diameter around the stent graft was not changed in six patients. However, one patient showed thrombus around the stent graft, because of endleak 2 months after the operation. Such patients should therefore have careful long-term follow-up.

Adult↗

PubMed2001

[A re-operative case of bentall operation and aortic arch replacement using a stent graft for a Marfan syndrome, post sternum turnover and post mitral valve replacement].

A 36-year-old male with Marfan syndrome succesfully underwent Bentall operation and aortic arch replacement using a stent graft as an elephant trunk. He had received MVR with sternum turn over 14 years previously. Median sternotomy was performed. Under circulatory arrest with rertograde cerebral perfusion we performed Bentall operation and aortic arch replacement using a stent graft. The sternum was cured well. Retractive breathing was not detected. This surgical procedure was effective for cardiovascular disease with Marfan syndrome.

Adult↗

PubMed2001

[Transmyocardial laser revascularization: overview of clinical and experimental data].

Transmyocardial laser revascularization (TMLR) using carbon dioxide and Holmium YAG laser has been approved by FDA and is now under clinical evaluation in patients with refractory angina who are not candidate of CABG or PTCA. Original concept of TMLR was direct perfusion from left ventricle through channel created by laser. However, pathological analysis showed closed channel in almost all cases, and most possible mechanism of TMLR are now thought to be angiogenesis following to inflammatory response of laser injury. Most prospective randomized trial comparing TMLR and conservative medical treatment demonstrated significantly less angina in TMLR patients and better exercise tolerance and angina-free survival rate during follow-up period. On the other hand, no significant differences were demonstrated in overall mortality rate, myocardial perfusion or cardiac function.

Angina Pectoris↗

PubMed2001

[Mitral valve stenosis due to primary cardiac granulocytic sarcoma relapsing 8 years after complete remission: a case report].

A 28-year-old man was admitted because of dyspnea on effort. His tricuspid valve had been affected by granulocytic sarcoma and manifested tricuspid valve stenosis 8 years previously. After chemotherapy and radiation therapy, the tumor had disappeared and the tricuspid valve stenosis was relieved. Echocardiography showed that the posterior leaflet of the mitral valve was affected by the tumor, and Doppler ultrasonography revealed mild mitral valve stenosis. Biopsy of the anterior chest wall detected granulocytic sarcoma. Chemotherapy was started. The tumor size was reduced and the mitral valve stenosis became slight. Primary cardiac granulocytic sarcoma is very rare and stenosis of the atrioventricular valve by relapse of this tumor after complete remission is extremely unusual.

Adult↗

PubMed2001

[Cardiovascular effects of colforsin daropate hydrochloride for acute heart failure after open heart surgery].

Colforsin daropate hydrochloride (COL) is a novel drug for the treatment of acute heart failure. COL stimulates adenylate cyclase directly and produces positive inotropic and vasodilator effects accompanied by the increase in cellular cAMP. We investigated its cardiovascular effects for 9 patients who showed low cardiac index (< 3.0 l/min/m2) after open-heart surgery in ICU. After 2 or 3 hours from administration of COL, heart rate and cardiac index increased, and pulmonary artery pressure and central venous pressure decreased significantly, but blood pressure and systemic venous oxygen saturation did not show significant change. In conclusion, COL improved hemodynamics through positive inotropic and vasodilator effects without hypotension. We should investigate more proper usage of this drug to avoid such side effects as tachycardia and arrhythmia, which occurred in some cases.

Acute Disease↗

PubMed2001

[A case report of extended thoracoabdominal graft repair for dissecting aneurysm (DeBakey Type IIIb) with visceral ischemia].

A 62-year-old man diagnosed as dissecting aneurysm (DeBakey type IIIb) with visceral is chemia was transferred to our hospital. He had suffered from abdominal pain and the absence of right femoral pulse. Emergent laparotomy revealed no evidence of visceral infarction. Right axillo-femoral bypass was performed. However, visceral ischemia gradually progressed. Enhanced CT and angiography showed that celiac artery and supramesenteric artery (SMA) were collapsed. He underwent graft replacement of thoracoabdominal aorta involving visceral arteries with femoro-femoral bypass with a centrifugal pump as an ajunct. The visceral arteries were reconstructed. Postoperative CT revealed sufficient flow of branch arteries. He recovered well without complication and then discharged.

Aortic Dissection↗

PubMed2000

Mid-term follow up results of Japanese heart transplant patients operated in UCLA Medical Center.

UNLABELLED: Japanese candidates have been accepted for heart transplantation by the UCLA Medical Center in the US since 1993 due to the lack of donors available from brain-dead patients. OBJECTIVES AND METHODS: We monitored to patients who underwent such heart transplantation and have been seen at the out-patient clinic at Tokyo Women's Medical University following transplantation. Pre-operative diagnosis was dilated cardiomyopathy in all patients. One patient underwent Novacor implantation as a bridge to heart transplant. All patients underwent cardiac echocardiography and cardiac catheterization including intraluminal echography. RESULTS: All patients survived with an actuarial survival curve of 100% at 1 year, 100% at 3 years and 87% at 5 years in 4.15 years of average follow-up. Two patients died due to liver dysfunction and cerebral emboli. The postoperative functional status of patients was New York Heart Association classification I in 8 (100%). Immunosuppressive therapies included triple drug therapy using either cyclosporin or tacrolimus. The incidence of acute rejection (/pt) exceeding grade 3 was 4% within three months, 3.5% in 3-6 months, and no significant rejection episode more than 6 months after transplantation. Posttransplantation coronary artery disease was seen in 2 patients, but no progression was seen after diltiazem therapy. CONCLUSION: Our postoperative follow-up after cardiac transplantation appears to be satisfactory.

Adult↗

PubMed2000

St. Jude Medical prosthetic aortic valve malfunction due to pannus formation.

According to the literature, the incidence of pannus formation with the St. Jude Medical prosthetic aortic valve has been reported at 0.03% and 0.14% (per patient-year), with no case report of St. Jude Medical prosthetic aortic valve malfunction due to pannus formation. Between 1980 and 1999, 1,186 patients underwent aortic valve replacement at our institute. We encountered 2 aortic valve malfunctions due to pannus formation, including the case of a 53-year-old woman who suffered a St. Jude medical aortic valve malfunction 13 years after the initial operation. A second aortic valve replacement was successful and the postoperative course was uneventful. The possibility of pannus formation on St. Jude Medical aortic valves must thus be considered and its mechanism clarified.

Aortic Valve↗

PubMed2000

The heart string: a simple, inexpensive exposure of the heart during coronary artery operations.

A method of heart retraction during coronary artery bypass operations is described. The technique improves exposure of the coronary arteries, especially of the circumflex and posterior descending coronary branches during grafting. In addition, it is simple, safe, and inexpensive. Furthermore, this technique can be applied for off-pump coronary artery bypass surgery.

Cardiac Catheterization↗

PubMed2000

Continuously maintaining positive flow avoids endocardial suction of a rotary blood pump with left ventricular bypass.

This study showed the usefulness of maintaining positive pump flow to avoid endocardial suction and as an assist bypass. Three calves were implanted with centrifugal pumps. Hemodynamics and pump parameters were measured at varying pump speeds (from 1,100 to 2,300 rpm). In each test pump, speed was adjusted to create 3 hemodynamic states: both positive and negative flow (PNF), positive and zero flow (PZF), and continuously positive flow (CPF). The pump flow volume was determined during systole (Vs) and diastole (Vd). Vs in PNF was 29.6 ml and was not significantly different from Vs in PZF (p > 0.15). Vd in PNF was significantly different from Vd in PZF (p < 0.05). All bypass rates of PNF were over 30% of pulmonary flow. All PZF bypass rates were between the PNF rate and the CPF rate. These data showed that PZF satisfied the minimum requirement of assist flow and was under 100% bypass. Thus, PZF may avoid endocardial suction.

Analysis of Variance↗

PubMed2000

Effects of reduced pulse pressure to the cerebral metabolism during prolonged nonpulsatile left heart bypass.

We investigated changes in the cerebral metabolism with long-term reduced pulse pressure. Nine goats underwent pulsatile left heart bypass (LHB) for 2 weeks while awake, and nonpulsatile LHB was subsequently conducted for 4 weeks. The average pulse pressure during nonpulsatile LHB (13, 10, 11, and 11 mm Hg at the 1st, 2nd, 3rd, and 4th nonpulsatile LHB week, respectively) was significantly lower than that during pulsatile LHB (36 mm Hg). There were no significant differences in either arterio-jugular venous oxygen differences (AJDO2) and cerebral oxygen extraction ratio between the 2nd pulsatile LHB week and the 1st, 2nd, 3rd, and 4th nonpulsatile LHB weeks. The arterio-jugular venous glucose differences, jugular venous-arterial lactate differences (JAD Lactate), and lactate oxygen indexes (JAD Lactate/AJDO2) also remained unchanged during the entire course of the experiments. In conclusion, the cerebral metabolism during nonpulsatile LHB did not change compared to that during pulsatile LHB.

Analysis of Variance↗

PubMed2000

[Late results of SJM and CM valves in bentall procedure].

Recently, Bentall procedure is commonly performed for annuloaortic ectasia with aortic regurgitation or dissecting aneurysm. And the operative results are improving. In this study, we evaluated results of the St. Jude Medical (SJM) and Carbomedics (CM) valves which were used in this procedure. From 1979 to 1994, 87 SJM valves and 22 CM valves were implanted in the aortic position of Bentall procedure. Total follow-up was 528.6 years in the SJM group and 56.5 years in the CM group. According to the Kaplan-Meier actuarial method and the Cox-Mantel statistical analysis, actuarial survival, thromboembolism free rate, reoperation free rate, event free rate were not different between the SJM and CM groups. These results suggest that, current selection of the SJM and CM valves would be acceptable in Bentall procedure.

Adult↗

PubMed2000

[Open heart surgery in three patients receiving dialysis for more than 20 years].

In Japan, the number of chronic hemodialysis (HD) patients is increasing, and there are 7,000 cases with a more than 20 year history of HD. At our institute, we have experienced 135 cases of open heart surgery in patients on HD, including 92 isolated CABG cases and 43 other open heart surgery cases. However, open heart surgery for patients with a more than 20 year history on HD is rare. Open heart surgery on HD patients is rather difficult, since perioperative management can be complicated and special care must be taken for prophylaxis of infection, fluid and electrolyte management and anticoagulation therapy. Many complications have been published in HD patients. At our institute, 3 cases of open heart surgery in patients with more than a 20 year history of HD have been performed. These included triple CABG, double CABG + AVR and double CABG in a post-kidney transplantation patient. They were discharged uneventfully with angiographically patent grafts. It is concluded that for CABG in patients on HD, aggressive use of arterial conduits for revascularization is recommended. For patients with a transplanted kidney, careful management against dysfunction and rejection is necessary.

Angina, Unstable↗

PubMed2000

[Four cases of third time operation of coronary artery bypass grafting].

Reoperative coronary artery bypass operations are increasing in frequency. Consequently, an ever-increasing pool of patients now is being seen with need of coronary revascularization for repeated time. Four cases of second reoperation were retrospectively investigated. Until March 1999, 2,563 cases of isolated coronary artery bypass grafting were done at the Heart Institute of Japan, Tokyo Women's Medical University, Tokyo, Japan. Within those cases, 124 cases (4.8%) were reoperated. And among those 124 cases, 4 cases (3.2%) were secondly reoperated. There were one hospital death and two had a perioperative myocardial infarction. All of them needed intraaortic balloon pump support after operation. Three were discharged with relief of the symptoms. The average age at the primary operation was 51.1 years. All these cases, at the primary operation, no ITA graft was used. Two cases were incompletely revascularized, because of coronary arteries were ungraftable. Both at reoperation and at second reoperation, we are trying to make a complete revascularization by all arterial grafts. But because of limited number of arterial graft at repeated operation, all arterial complete revascularization is not done without difficulty. Therefore it is concluded that saphenous vein graft is still needed at repeated operation.

Aged↗

PubMed2000

[Early and late results of combined valvular and coronary artery operations].

A total of 122 patients with ischemic heart disease underwent valvular surgery. Thirty-nine had combined CABG and aortic valve surgery (included Bentall method), 72 had CABG and mitral valve operations, and 8 patients had CABG and double or triple valve operations. Only 3 patients for ruptured papillary muscle due to acute myocardial infarction had isolated mitral valve replacement. Early mortality was 5.1% AV, 2.8% MV and 12.5% DTV in the combined groups and 0% in the valve only group. The grafts patency rate was 93.5%. Univariate analysis of risk factors selected in the dialysis patients and the patients age older than 65 years as the strongest predictors for early death. At the mean follow up period of 5.4 +/- 4.8 year after surgery, the 5-year all death free rates were 57.9 +/- 9.6% AV, 69.6 +/- 5.8% MV and 75.0 +/- 15.3% DTV. The 5-year cardiac death free rates were 73.8 +/- 9.0% AV, 77.5 +/- 5.4% MD and 75.0 +/- 15.3% DTV.

Adolescent↗

PubMed2000

[Respiratory function after coronary artery bypass grafting through mini-sternotomy as a factor of early recovery].

OBJECTIVES: Early recovery in patients after minimally invasive coronary artery bypass grafting with mini-sternotomy and cardiopulmonary bypass (MICS-CABG) was compared to standard CABG by assessing preoperative and postoperative (7 to 10 days after) respiratory function. METHODS: Fifteen patients (Group M; mean age 62.1 years) underwent MICS-CABG with a mean of 2.3 distal anastomoses per patient. Ten patients (Group F; mean age 63.8 years) underwent standard CABG through full sternotomy with a mean of 2.4 distal anastomoses per patient. RESULTS: Postoperative coronary angiography showed that the patency rate of the grafts was 97% in Group M and 96% in Group F. Intubation time and hospital stay were significantly shorter (p < 0.01) in Group M (6.2 +/- 2.4 hours, 16.3 +/- 3.1 days) than in Group F (10.8 +/- 2.9 hours, 22.8 +/- 2.5 days). Respiratory function measured as the percentage of postoperative to preoperative values (Group M/Group F; mean +/- standard error) were vital capacity of 95.8 +/- 3.1%/74.6 +/- 3.4% (p < 0.05), 1 sec percentage of forced expiratory volume of 98.8 +/- 2.3%/71.8 +/- 2.8% (p < 0.05) and peak expiratory flow rate of 91.7 +/- 4.2%/89.4 +/- 4.5%. CONCLUSIONS: Quick recovery of the respiratory function after MICS-CABG may be important in the early recovery and short hospital stay of MICS-CABG patients compared with standard CABG patients.

Aged↗

PubMed2000

Effect of ATP-potassium channel opener nicorandil on long-term cardiac preservation.

BACKGROUND: ATP-sensitive potassium channels have been shown to be one of the important protective mechanisms for the ischemic myocardium. The purpose of this study was to evaluate the protective effect of nicorandil, an ATP-sensitive potassium channel opener, on myocardium during 6 hours hypothermic preservation. METHODS: Preserved rat hearts were randomly divided into 4 groups according to cardioplegia and preservation protocols as follows: (1) histidine-tryptophan-ketoglutarate solution (HTK) for both cardioplegic and immersing solutions (group A); (2) nicorandil-added HTK for cardioplegic solution and nicorandil-free HTK for immersing solution (group B); (3) nicorandil-free HTK for cardioplegic solution and nicorandil-added HTK for immersing solution (group C); and (4) nicorandil-added HTK for both cardioplegic and immersing solutions (group D). RESULTS: The recovery of postischemic cardiac function, including left ventricular developed pressure and end-diastolic pressure, was significantly improved in group B and group C as compared with the other groups (p<0.05). Postischemic intracellular calcium concentration was significantly lower in group B and group C than in group A (p<0.05). CONCLUSIONS: We concluded that nicorandil-induced hyperpolarizing arrest could reduce ischemia-derived myocyte injury and inhibit the influx of calcium into the myocytes in long-term cardiac preservation.

Animals↗

PubMed2000

Malfunction of a Hancock bioprosthesis in the mitral position 24 years after initial implantation.

BACKGROUND AND AIMS OF THE STUDY: Although many types of cardiac bioprosthetic valves are currently available, the major disadvantage of their use is limited durability due to progressive structural valve deterioration. Few such valves function beyond 20 years. METHODS: A 61-year-old man was admitted urgently to our institute with acute mitral insufficiency, 24 years after undergoing mitral valve replacement with a 25-mm standard Hancock porcine bioprosthesis for mitral stenosis. RESULTS: Mitral valve reoperation was performed successfully with a mechanical valve. The explanted bioprosthesis showed leaflet perforations and a commissural tear, moderate calcification on the commissures, and pannus overgrowth. CONCLUSION: The findings in this case suggest that individual patient variables, as well as the design and the construction of the valve are major determining factors in the rate of valve failure.

Bioprosthesis↗