Biomedical subjects
Publications and source records attributed to K Minatoya.
The diagnosis of low grade prosthetic graft infection or aorto-enteric fistula is difficult using conventional radiographic imaging modalities. We report a case of aorto-enteric fistula to the sigmoid colon diagnosed by the new technique of 18-fluorodeoxyglucose positron emission tomography.
A 35-year-old man with constrictive pericarditis underwent pericardiectomy. The pericardium was dissected with a Harmonic Scalpel (Ethicon Endo-Surgery, Cincinnati, OH). This new device has many advantages including no muscular stimulation, low heat, a smokeless field, and easy hemostasis. The Harmonic Scalpel is beneficial for dissection of thickened pericardium.
BACKGROUND: The purpose of this study was to compare the results of total aortic arch replacement using two different methods of brain protection, particularly with respect to neurologic outcome. METHODS: From June 1997, 60 consecutive patients who underwent total arch replacement through a midsternotomy were alternately allocated to one of two methods of brain protection: deep hypothermic circulatory arrest with retrograde cerebral perfusion (RCP: 30 patients) or with selective antegrade cerebral perfusion (SCP: 30 patients). Preoperative and postoperative (3 weeks) brain CT scan, neurological examination, and cognitive function tests were performed. Serum 100b protein was assayed before and after the cardiopulmonary bypass, as well as 24 hours and 48 hours after the operation. RESULTS: Hospital mortality occurred in 2 patients in the RCP group (6.6%) and 2 in the SCP group (6.6%). New strokes occurred in 1 (3.3%) of the RCP group and in 2 (6.6%) of the SCP group (p = 0.6). The incidence of transient brain dysfunction was significantly higher in the RCP group than in the SCP group (10, 33.3% vs 4, 13.3%, p = 0.05). Except in patients with strokes, S-100b values showed no significant differences in the two groups (RCP: SCP, prebypass 0.01+/-0.04: 0.05+/-0.16, postbypass 2.17+/-0.94: 1.97+/-1.00, 24 hours 0.61+/-0.36: 0.60+/-0.37, 48 hours 0.36+/-0.45: 0.46+/-0.40 microg/L, p = 0.7). There were no intergroup differences in the scores of memory decline (RCP 0.74+/-0.99; SCP 0.55+/-1.19, p = 0.6), orientation (RCP 1.11+/-1.29; SCP 0.50+/-0.76, p = 0.08), or intellectual function (RCP 1.21+/-1.27; SCP 1.05+/-1.15, p = 0.7). CONCLUSIONS: Both methods of brain protection for patients undergoing total arch replacement resulted in acceptable levels of mortality and morbidity. However, the prevalence of transient brain dysfunction was significantly higher in patients with the RCP.
OBJECTIVE: We sought to investigate the durability and mechanism of the Carpentier-Edwards pericardial xenograft in the mitral position in comparison with that of the Ionescu-Shiley pericardial xenograft. METHODS: A total of 284 patients who received the Ionescu-Shiley pericardial xenograft in the mitral position between 1980 and 1984 and 84 patients who received the Carpentier-Edwards pericardial xenograft in the mitral position between 1984 and 1999 were included in the study. The freedom from reoperation rates for both graft types were determined. For morphologic study, the pathologic findings of 23 valves of 123 explanted Ionescu-Shiley pericardial xenografts with structural valve deterioration, nonstructural valve deterioration, or both were determined and compared with those of 20 explanted Carpentier-Edwards pericardial xenografts with structural valve deterioration, nonstructural valve deterioration, or both. Each pathologic finding was graded and assigned a score. Both types were matched for age at reoperation (50-75 years) and duration of valve function (8-11 years). RESULTS: Freedom from reoperation caused by structural valve deterioration, nonstructural valve deterioration, or both was significantly better for Carpentier-Edwards pericardial xenografts than for Ionescu-Shiley pericardial xenografts at 8 years after the operation (Carpentier-Edwards pericardial xenografts: 91.3% vs Ionescu-Shiley pericardial xenografts: 71.9%, P =.0061), but it was similar for both types at 12 years (Carpentier-Edwards pericardial xenografts: 43.6% vs Ionescu-Shiley pericardial xenografts: 43.6%, P =.2865). No severe leaflet tears were seen among Carpentier-Edwards pericardial xenografts. The mean area percentage of tissue overgrowth was 15.3% in Carpentier-Edwards pericardial xenografts and 3.4% in Ionescu-Shiley pericardial xenografts (P =.0001). The mean calcification area percentage was 13.6% in Carpentier-Edwards pericardial xenografts and 31.5% in Ionescu-Shiley pericardial xenografts (P =.0001). CONCLUSIONS: Tissue overgrowth on the atrial surface, ventricular surface, or both was the cause of structural valve deterioration, nonstructural valve deterioration, or both of Carpentier-Edwards pericardial xenografts in adults. This was different from Ionescu-Shiley pericardial xenograft failure, which resulted from severe calcification and leaflet tears. Organized thrombi on cusps, in addition to valve design, may have contributed to such tissue overgrowth on Carpentier-Edwards pericardial xenografts.
Expanded PTFE (ePTFE) sutures have been used widely as a mitral chordal substitute. We present a structural analysis of ePTFE sutures implanted as artificial chordae for 7.5 years and 8.6 years in patients with mitral regurgitation. No calcification was found either macroscopically or microscopically, and the ePTFE suture retained its normal flexibility. The suture was totally encapsulated with host tissues composed of dense fibrous tissue covered with endothelial cells.
A successful case with liver cirrhosis underwent re-tricuspid valve replacement (TVR) using right heart bypass is reported herein. A 59-year-old lady previously undergone tricuspid valve replacement with bioprosthetic valve had suffered from exertional fatigue as the feature of congestive heart failure. She also presented severe liver dysfunction owing to chronic hepatitis and cardiac liver cirrhosis. She was diagnosed with structural deterioration of bioprosthesis in tricuspid position. She underwent re-TVR with right heart bypass consisted of centrifugal pump, heparin coating circuit and blood reservoir. This system lacked of membranous oxygenator in order not to activate various kinds of chemical mediator which leads to postoperative liver dysfunction. Postoperative course was uneventful and she is doing well 1 year after the operation. Although the mortality of the TVR in the patient with cirrhosis remains still high, this new technique seems to provide better outcome in this kind of patients.
BACKGROUND: Mitral valve repair is the procedure of choice to correct mitral regurgitation (MR). Although chordal replacement with expanded polytetrafluoroethylene (ePTFE) has been widely accepted to repair anterior mitral prolapse and other difficult situations, the long-term results of the repair and the fate of ePTFE have not been delineated. METHODS AND RESULTS: From July 1988 to April 1999, 74 patients (49 males, 25 females) aged 17 to 77 years (mean age 55. 3+/-14.8 years) underwent mitral valve repair with chordal replacement with ePTFE. The follow-up period was from 6 months to 11. 3 years (mean 4.6+/-3.2 years). The causes of MR were degenerative in 65 patients (88%) and infective in 9 (12%). Three patients had active infective endocarditis. Valve lesions were anterior in 35 patients, posterior in 10, and both anterior and posterior in 29. Various procedures for plasty of leaflets were necessary in 37 patients (50%). Atrial fibrillation was associated in 38 patients (51%), and the maze procedure has been performed in a selected group of 30 patients (41%) since July 1992. There was 1 in-hospital death (1.4%) and 3 late cardiac deaths (4.1%). More than moderate MR developed in 12 patients (17%) during the follow-up period. Three of these patients required early reoperation within 1 year due to hemolysis. Two patients underwent mitral valve replacement at 6 and 8 years after repair, respectively. The actuarial reoperation-free rates at 5 and 10 years were 94.3+/-2.8% and 81.7+/-9.1%, respectively. Sinus rhythm was restored in 21 patients (70%) with the maze procedure. There was only 1 thromboembolic episode (0. 3%/patient-y) in a patient with atrial fibrillation who did not undergo the maze procedure. Event-free survival rates as assessed by the freedom from cardiac death, thromboembolism, reoperation, and anticoagulation-related hemorrhage at 5 and 10 years were 91.3+/-3. 4% and 71.6+/-9.7%, respectively. There was no relationship between recurrent MR and the change of ePTFE. Structural analysis of the ePTFE resected during reoperation revealed no calcification and showed remaining flexibility and pliability. Protein infiltration was observed in the ePTFE, and collagenous proliferation was recognized at the site of fixation to the valve leaflet and the papillary muscle. The surface of the ePTFE was completely endothelialized, which may induce antithrombogenicity. CONCLUSIONS: The long-term durability and biological adaptation of ePTFE as artificial chordae for mitral valve repair of MR were proved for >10 years.
The first case was of a 27-year-old female, who was diagnosed as having mitral valve stenosis with regurgitation, systemic lupus erythematosus and antiphospholipid syndrome at her previous pregnancy. We performed mitral valve plasty, which included open mitral commissurotomy and Kay's annulo plasty. The second case was of a 53-year-old female, who was diagnosed as old myocardial infarction, mitral regurgitation, systemic lupus erythematosus and antiphospholipid syndrome. She underwent mitral valve plasty and coronary artery bypass grafting. Both cases were treated by administration of methylpredonisolone and heparin perioperatively to avoid thrombosis and aggravation of systemic lupus erythematosus. Both patients showed good postoperative outcome without complications. We consider that it is important to perform the plasty as far as possible, and to administer effective anticoagulation treatment to prevent complications for patients in the setting of systemic lupus erythematosus and antiphospholipid syndrome.
A case of transmural ischemic necrosis of the esophagus secondary to aortic dissection is presented. A 66-year-old woman with acute type A aortic dissection underwent total arch replacement with a technique of deep hypothermic arrest and retrograde cerebral perfusion. Postoperatively she had hematemesis, and endoscopic examination revealed circumferential mucosal necrosis and desquamation of the lower esophagus. She died of multiple organ failure on postoperative day 74. Autopsy demonstrated transmural necrosis of the esophagus secondary to ischemia. Ischemia of the esophagus secondary to aortic dissection is extremely rare.
BACKGROUND: Intermittent delivery of warm cardioplegia provides a bloodless surgical field, but it is clinically important to evaluate the periods of normothermic ischemia. The aims of this study are to compare intermittent antegrade warm blood cardioplegia (IAWBC) with intermittent antegrade cold blood cardioplegia (IACBC) groups in terms of myocardial protection, and also to evaluate whether the length of ischemic time in the IAWBC group has an effect on myocardial dysfunction. METHODS: This study is based on a retrospective review of patients who underwent elective coronary artery bypass surgery: 162 consecutive patients with IAWBC and 107 consecutive patients with IACBC. RESULTS: The creatinine kinase peak was smaller in the IAWBC group compared with the IACBC group (p<0.0001). The cardiac index after cardiopulmonary bypass was higher in the IAWBC group (p<0.02), and the amount of inotropic support required to wean from cardiopulmonary bypass was less in the IAWBC group compared with the IACBC group (p<0.0001). CONCLUSIONS: IAWBC with 30 minutes of ischemia provides to be clinically acceptable myocardial protection for coronary bypass surgery.
OBJECTIVE: Investigating the possibility of magnetic resonance angiography (MRA) to visualize the Adamkiewicz artery of as a preoperative study of thoracic aortic aneurysms. METHODS: From February 1998 to March 1999, 26 consecutive patients who had aneurysms of the thoracoabdominal or descending aorta underwent preoperative MRA to visualize the Adamkiewicz artery. Mean age was 60.5+/-11.5 years. Fifteen patients had non-dissecting aneurysm and 11 had aortic dissections. Nineteen patients underwent replacement of the aneurysms, four patients underwent endovascular stent-graft repair, and three patients were discharged without treatment of aneurysm. MRA was performed on a 1.5-T system (Magnetom, Siemens) and data acquisition was repeated two times following injection of gadolinium-DTPA. Source images were reconstructed with multiplanar reconstruction and maximum intensity projection. Criteria for the Adamkiewicz artery of were that the artery ascends from the dorsal branch of the intercostal or lumbar artery to the anterior mid-sagital surface of the spinal cord in the early phase. RESULTS: The Adamkiewicz arteries were demonstrated in 18 patients (69%). These arteries were originated from the left intercostal or lumbar arteries in 13 (72.2%) patients and from the right in 5 (27.8%) and from the Th8 branch in three, Th9 in seven, Th10 in two, Th11 in four, and L1 in two. All patients had graft replacement of the aorta using a partial bypass. All intercostal or lumber arteries, which were visualized as the origin of the Adamkiewicz artery, were reattached to the grafts. No spinal cord injury occurred. CONCLUSION: Preoperative detection the Adamkiewicz artery was possible by MRA and was very useful to reduce the incidence of ischemic injury of the spinal cord during surgery of the thoracoabdominal or descending aorta.
During the past 2 years since new legislation for organ transplantation from brain-dead donors came into effect in Japan, 3 cardiac transplants have been carried out, 2 of which were performed at the National Cardiovascular Center (NCVC). The recipient cases were 46- and 25-year-old male patients who suffered from end-stage dilated cardiomyopathy and had been listed for cardiac transplantation in the Japan Organ Transplantation Network as status I candidates. The first patient was supported by the use of a paracorporeal air-driven left ventricular assist device of the NCVC type, and had a moderate degree of renal and hepatic dysfunction at the time of transplantation. Donor hearts were transported from distant hospitals (Tokyo and Miyagi prefecture) and the transportation time was 1 h 33 min and 2h 4 min, respectively. The operation was performed by the standard technique (Lower-Shumway) in the first patient and by the bicaval anastomosis technique in the second patient. Reperfusion of the transplanted heart was performed retrogradely through the coronary sinus utilizing leukocyte-depleted blood with a gradual increase in temperature. Total ischemic time was 3 h 34 min and 3 h 35 min, respectively. Weaning from the cardiopulmonary bypass was easy and uneventful in each patient. Immunosuppressive therapy was conducted with OKT-3 induction in the first patient because of the coexisting renal dysfunction and with a triple immunosuppressive regimen for both patients. Routine endomyocardial biopsy showed acute rejection of less than grade Ib, and the patients were discharged on the 65th and 46th postoperative day, respectively. At present, both patients are in the NYHA class I state and are ready to return to work. The uneventful recovery seen in these patients shows the advances made in transplant medicine, including the progress and improvement of immunosuppressive therapy, surgical techniques, myocardial protection, and detection and treatment of infection. Further efforts are required to fully establish the cardiac transplantation program in Japan.
Eight patients, 4 males and 4 females ranging in age from 10 to 54 years (mean 27 +/- 13 years) underwent the Ross operation using a cryopreserved pulmonary homograft harvested by and cryopreserved in our institutional "Tissue Bank". Seven patients had a congenital bicuspid aortic valve and 3 patients had had healed infective endocarditis of the aortic valve. Four young female patients wanted to have a baby after operation. The Ross procedure was carried out utilizing aortic root replacement techniques in all patients. All patients survived and are currently in NYHA class 1, but 2 cardiac events occurred in 2 patients during the mean follow-up term of 29 +/- 19 months. The one was the anastomic stenosis between the homograft and distal pulmonary artery treated by balloon dilatation and the other was ventricular tachycardia eventually managed by the insertion of an ICD. Pulmonary autograft valve regurgitation is present in 3 patients, but it is not progressive up to the present time. Pulmonary homograft valves function well in all patients. The Ross operation for adolescents and young adults should become more popular along with more easy availability of homograft valves based upon the establishment of the "Homograft Valve Bank" system in Japan.
BACKGROUND: The incidence of cerebral complications is high in patients with aortic arch aneurysm. METHODS: Between December 1977 and December 1995, 246 patients with arteriosclerotic arch aneurysm underwent operation. Thirty-nine patients had an aneurysm involving the entire arch, 193 had only distal arch aneurysm, and 14 had arch aneurysm extending to the descending aorta. Eighty-seven patients underwent replacement of the total arch, 85 had replacement of only the distal arch, 14 had simultaneous replacement of the descending aorta, 45 had patch repair, and 15 had thromboexclusion. Selective cerebral perfusion was used in 112 patients and partial bypass in 58 in the earlier series of patients, but deep hypothermic circulatory arrest with retrograde cerebral perfusion technique was exclusively applied in the most recent 76 patients. RESULTS: There were 50 (20%) early deaths and 37 (19%) late deaths. Postoperative stroke was found in 26 (11%) patients of which 13 (50%) died. Mutual predictive factors for postoperative mortality and stroke were earlier series, preoperative chronic renal failure, ruptured aneurysm, arch clamping during procedure, and using partial cardiopulmonary bypass. Among 129 patients operated on during the most recent 5 years, early mortality and incidence of stroke decreased to 14.7% and 6.9%, respectively. CONCLUSIONS: Results of operations for arteriosclerotic aneurysms of the transverse aortic arch in 246 patients during a period of 17 years have been improving but are still not satisfactory.
BACKGROUND: We investigated long-term outcomes of the distal false lumen of the aorta and aortic branches after distal anastomosis of the graft only to the true lumen in chronic type B aortic dissection. METHODS: From November 1979 until June 1998, we treated 98 patients without Marfan syndrome who had chronic type B aortic dissection and underwent replacement of the descending aorta, 79 of whom had distal anastomosis to the true lumen only. The celiac artery originated from the false lumen in 11 patients, superior mesenteric artery in 5, right renal artery in 19, and left renal artery in 16. RESULTS: There were 12 (15.1%) early deaths. Spinal cord ischemia was detected in 5 patients. Postoperative follow-up was achieved in 67 patients, and 13 patients died. Postoperative survival at 10 years was 67.6% +/- 7.1%. Eight patients had complete occlusion of the distal false lumen, 54 patients had occlusion of the false lumen down to the celiac artery, and 5 patients had a patent false lumen. Four patients required further replacement of the thoracoabdominal aorta. CONCLUSIONS: In non-Marfan patients with chronic type B aortic dissection, the false lumen distal to the graft anastomosis was likely to be thrombosed when the graft was anastomosed to the true lumen only. Postoperative visceral circulation was not compromised, but spinal cord ischemia is a problem that remains to be solved.
OBJECTIVE: The purpose of this study was to demonstrate early and long-term results of surgery for thoracic aortic aneurysm in patients over 70 years of age compared with those of patients under 70 years and to clarify the clinical problems peculiar to this subset of patients. PATIENTS AND METHODS: Of 1157 patients who underwent surgery for thoracic aortic aneurysm from 1978 to December 1997, 261 who were 70 years or older were selected for analysis. Mean age at the time of surgery was 74.4 +/- 3.5 years. Aneurysms were atherosclerotic in 177 patients and aortic dissection in 84. Acute aortic dissection was found in 25 patients and ruptured aneurysm in 44. The control group consisted of 896 patients under 70 years. Preoperative complications such as AAA, peripheral arterial disease, emphysema, and old cerebral infraction were more common in the older group. Operative procedures consisted of replacement of the ascending aorta or hemiarch in 51 patients, total arch replacement in 75, distal arch replacement in 35, descending aorta replacement in 75, replacement of the thoracoabdominal aorta in 28, and extra-anatomical repair and others in 15. The technique of extracorporeal circulation was selective cerebral perfusion in 69 patients, deep hypothermic circulatory arrest in 90, femoro-femoral bypass in 39, left heart bypass in 12, and temporary aorto-arterial bypass in 30, and others in 21. RESULT: Early mortality was 21% (54 patients), which was greater than that of the control group (113 patients, 13%, P < 0.01). The incidence of postoperative stroke, transient brain dysfunction, and respiratory problems was higher in the study group (P < 0.01 in all). Mean duration in ICU among survivors was 9.3 +/- 20.2 days and that of the control group was 5.9 +/- 2.8 days (P < 0.01). In a recent series (from 1991 to 1997) postoperative mortality improved to 15.6% (30/192 patients) in the study group however this result was still inferior to that of the control group (8.6%, 39/452, P = 0.03) however mortality of emergency surgery during the same periods was still high (31%, 11/35 patients). Logistic regression analysis revealed that significant risk factors for postoperative hospital death were surgery before 1991, age over 70 years, preoperative cardiac problems, aneurysm rupture, postoperative stroke, low output syndrome, bleeding, and acute renal failure. Postoperative follow-up was obtained in 408 patients/year and the longest period was 10.2 years. Late deaths were documented in 31 patients. Five-year and 10-year survival were 61.2 +/- 5.7% and 31.3 +/- 16.4%, respectively. In the control group the 5-year and 10-year survival were 78.0 +/- 2.1% and 62.5 +/- 4.0%, respectively (P = 0.03). However, survival of the early survivors in the study group was similar with that of the age-matched normal population. Aortic reoperation was performed in 13 patients. Freedom from aortic reoperation was 86.7 +/- 4.2% at 5 years and 80.5 +/- 7.1% at 10 years in the study group and 83.4 +/- 1.8% at 5 years and 64.1 +/- 13.3% at 10 years in the control group (P = 0.27). CONCLUSION: Although recent advances have been achieved, early and long-term results of surgery for thoracic aortic aneurysm in patients older than 70 years were less satisfactory compared with those of patients under 70 years of age, especially in patients who required emergency surgery. Preoperative disorder of the vital organ systems was considered to be the main causative factor for high mortality, however, pertinent surgical strategies are necessary to improve the outcome of elderly patients.
A 38-year-old man presented with 2 months' history of a hoarseness and aphthous stomatitis. Image diagnosis showed that he had saccular-type aneurysms of the aortic arch, right subclavian artery, and infrarenal abdominal aorta. Simultaneous total arch replacement, including reconstruction of the right subclavian artery and replacement of the infrarenal abdominal aorta, was performed. Pathologic specimen of each aneurysmal wall revealed that intima and the majority of the medial layer were absent. Chronic inflammatory process was detected in the adventitia that was compatible with diagnosis of Behçet's disease.
The chief benefits of small skin incisions are reduced patient discomfort, accelerated recovery, and cosmetic satisfaction without compromising the quality of surgery. Since April 1997, the lower ministernotomy approach without femoral cannulation has been performed in 43 patients in the authors' institutions. The indications for this approach were initial single valve surgery and secundum-type atrial septal defect. Cases of aortic valve regurgitation that could be repaired, and aortic stenosis that necessitated annular enlargement were excluded. Among patients with mitral valve disease, those with chronic atrial fibrillation were excluded frpm undergoing the Maze procedure and those reguiring chordal reconstruction for anterior leaflet were also excluded. Mitral valve repair for mitral regurgitation was performed in 8 patients, and open mitral commissurotomy in 2. Mitral valve replacement was performed in 3 patients and aortic valve replacement in 13. Closure of an atrial septal defect was carried out in 18 cases. An approximately 10-cm median skin incision was made, and a ministernotomy with a lower semitransverse division (inverted L-shape) was carried out. Cardiopulmonary bypass was initiated with ascending aortic cannulation and right-angled venous cannulae in the superior and inferior vena cava for mitral valve disease. Single venous cannulae from the right atrial appendage was used for aortic valve disease. Surgery was performed with mild hypothermia and intermittent tepid blood cardioplegia with diltiazem. A rigid 30-degree angle scope held by a videoscope holder with a flexible arm was used for mitral valve surgery. There were one hospital death due to perioperative myocardial infarction and pulmonary embolism. There was one reopening for bleeding which resulted in methicillin-resistant Staphylococcus aureus mediastinitis. However, the patients was discharged after rectal muscle flap repair. There was one reoperation for mitral valve repair due to hemolysis. The improvement of surgical instruments and materials will further facilitate this procedure.