Six cases without aortic reconstruction for 48 hours were encountered among 22 cases of Stanford type A acute aortic dissection from April, 1990 to July, 1996. They were one man and five women, with a mean age of 60.3 years old (from 52 to 82 years old). According to Hagiwara's definition, acute thrombotic aortic dissection (ATAD) was observed in four and acute opacified aortic dissection (AOAD) in two of six cases of Stanford type A acute aortic dissection without aortic reconstruction. One of the four ATAD cases was well-controlled by medical therapy, but the others could not be controlled and underwent aortic root reconstruction within 1 month. Two AOAD patients died due to rupture within 1 month. It is said in general that the patients with acute thrombotic aortic dissection can be treated medically, but we consider that they should be treated surgically because of the frequency of late rupture.

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Background. In recent years, aortic valve stenosis in the elderly is increasing. To determine the treatment of aortic stenosis in the elderly, we retrospectively evaluated the patients who underwent aortic valve replacement. Method. Between 1992 and 1997, 22 patients older than 70 years underwent aortic valve replacement for aortic stenosis. There were 15 women and 7 men, with a mean age of 73.0±4.0 years. Seven patients underwent concomitant procedures: 5 patients required coronary artery bypass grafts, 1 mitral valve plasty and 1 aortic root plasty. SJM prosthetic valves of sizes 19mm, 21mm and 23mm were used in 11, 8 and 3 patients respectively. Nobody underwent aortic annuloenlargement. Three patients underwent supraannular aortic valve replacement. All patients had New York Heart Association (NYHA) class III or IV symptoms. Results. There was no operative or hospital death. Five patients had atrial fibrillation after operation. There was only one late death, due to a traffic accident, and there was no significant complication during the follow up period. Of the 22, 21 patients improved to NYHA class I or II after operation. There were significant differences between patients who were 70 years or more and those under 70. BSA in these two groups were 1.495 and 1.615m²; p<0.01, and the amounts of blood transfusion were 918±702 and 408±428ml, p<0.01. However, there was no significant difference between these two groups in terms of ACC time (56.8 and 59.9min), CPB time (88.7 and 92.1min), ICU stay (4.0 and 3.3 days) and hospital stay (29.5 and 25.5 days). Conclusion. The results of aortic valve replacement in patients aged 70 years or more, were satisfactory. If the aortic annulus being small, a small mechanical valve prosthesis is suitable, and supraannular positioning yielded good results.

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When performing surgery of the thoracic aorta, several supporting methods must be easily available to facilitate various grafting procedures which are selected as the most suitable method for each case. We report on a practical cardiopulmonary bypass (CPB) circuit which can be used in the surgical treatment of any thoracic aortic disease: aortic dissection, true aneurysm involving the aortic arch, descending aortic aneurysm or thoraco-abdominal aortic aneurysm. The circuit design is based on a percutaneous cardiopulmonary support system. We added some modifications to the system for managing CPB simply. The improved bypass circuit was applied in operations on 26 patients and yielded excellent clinical results. The advantages of the circuit are listed as follows: 1) If massive bleeding occurs during closed-circuit CPB, the blood can be sucked into a built-in hard shell reservoir on the venous side of the bypass, and can immediately be returned back into the bypass circuit. 2) Using clamping forceps it is possible to easily switch between closed-circuit CPB and conventional CPB using gravitational venous return. 3) Selective cerebral or other organ perfusion can be done by a built-in roller pump distal to the oxygenator. The perfusion line using the roller pump diverges from the main line using the centrifugal pump kept in a spinning state. If the hypothermic method is used, the lower body is perfused via a femoral arterial cannulation by the centrifugal pump, and the upper body by the roller pump with right subclavian arterial cannulation. When the cardiac rhythm changes to ventricular fibrillation in cooling the patient, the flow ratio of the lower body to the upper body must be 1:1, since retrograde perfusion from the femoral artery may cause cerebral infarction due to embolism of dislodged debris or thrombi from the aneurysm.

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During the past 7 years from January 1991 through October 1997, we treated 30 cases of aortic root reconstruction by the Carrel patch method. The cases included annulo-aortic ectasia (AAE), root aneurysm with aortic regurgitation (AR), aortic dissection with AR, and true aneurysm (ascending and arch) with AR. The surgical treatment consisted of 28 modified Bentall operations and 2 aortic root remodelings, similar to the Yacoub operation. The aortic root and valve were resected, the coronary arteries were dissected free, mobilized, and then implanted into the composite graft. Coronary anastomosis was performed by mattress suture reinforced by Teflon felt strips. In 5 cases it was necessary to undergo coronary artery bypass grafting for myocardial ischemia. Blood transfusion was unnecessary in 11 cases. Post operative death was seen in only one patient who underwent an emergency operation for cardiac tamponade due to aortic dissection on the 25th postoperative day. The operative mortality rate was 3.3%. The complications of anastomosis, for example leakage and dilatation of the coronary ostia, were not seen in our experience. Reoperation and late death were not observed during the follow-up period (average 23 months). Cerebral hemorrhage occurred in only one case, at 5 years after the operation, and all other patients had an uneventful postoperative course. The event-free rate is 75% (n=1) at 6 years. The operative procedure is considered feasible in any anatomic variation of aortic root diseases, even if dislocation of the coronary ostia is minimal, and this method holds hope for the prevention of anastomotic pseudoaneurysm formation and long-term survival. Although further long-term follow-up study is necessary, our experience suggests that the Carrel patch procedure has few late term complications.

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To identify the factors affecting the high mortality rates associated with ruptured abdominal aortic aneurysm (rAAA), a review was made of the records of 35 consecutive patients (33 males, 2 females, mean age 69.9yr.) treated surgically between 1988 and 1997. Preoperatively profound shock (systolic pressure less than 70mmHg) was seen in 19 patients and loss of consciousness in 9. Maximum diameter of the AAA was 79±20mm and the preoperative hemoglobin level was 9.1±2.4g/dl. Proximal aortic clamp was performed at the intrathoracic aorta in 3 cases, the suprarenal aorta in 6, balloon occlusion in 4, and the infrarenal aorta in 22. Since 1994, diltiazem and nitroglycerin have been routinely given for latent myocardial ischemia and early induction of continuous hemodialysis for renal failure was attempted postoperatively. The overall hospital mortality rate was 20%. Multisystem failure was the most frequent cause of hospital death (57.1%), followed by pneumonia with sepsis in 28.6%, and intraoperative cardiac arrest (14.3%). By univariate analysis of various factors associated with the mortality rate, loss of consciousness, abnormality on electrocarciogram (ECG) and duration of shock for more than five hours were statistically significant. Multivariate analysis with stepwise logistic regression demonstrated that an ECG abnormality and duration of shock more than five hours were associated with high mortality, but not at statistically significant levels. These findings suggest that factors that are predictive of death (loss of consciousness and ECG abnormality) may be a reflection of shock in this patient population.

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This experimental study was conducted to histopathologically determine whether the low-dose irradiation of donor hearts before transplantation can inhibit graft vasculopathy. Immediately after donor F 344 rat hearts were removed, they were treated with a single dose of radiation using 7.5Gy, 15Gy, or no radiation (control group). The F 344 hearts were transplanted into Lewis rats heterotopically, and cyclosporine A was injected intramuscularly for 20 days after transplantation in all groups. The hearts were harvested 90 days after transplantation, and examined for intimal thickening using elastica van Gieson staining. Severe intimal thickening was observed in both the irradiated groups, the percent intimal area of the coronary arteries was significantly increased in both these groups, to 34.3±12.9 in the 7.5Gy group and 37.0±8.9 in the 15Gy group, compared with 23.1±9.8 in the control group (p<0.01). In conclusion, these findings show that low-dose irradiation to donor hearts before transplantation does not inhibit graft vasculopathy.

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This report describes the results of endovascular stent graft repair for abdominal aortic aneurysms in comparison with conventional open surgery. Endovascular repair of abdominal aortic aneurysm was performed in 21 patients (SG group) and 69 patients were treated with conventional open surgery (OS group). The SG group had a higher preoperative risk than the OS group. The complete exclusion of the aneurysm at 2 weeks after the stent graft treatment was obtained in 16 out of 21 SG cases (76%). On the other hand, in the OS group, 68 of 69 cases underwent successful surgery (99%). The average amount of bleeding during the endovascular stent graft repair was 427ml and the average operation time was 242 minutes. Both blood loss and operation time were significantly lower compared to the OS group. The endovascular stent graft repair was less invasive in comparison with conventional open surgery. However, judging from the initial success rate, open surgery is more reliable than the endovascular stent graft repair. Our data suggested that the endovascular stent graft repair should be performed only in selected cases.

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Between January 1981 and December 1996, we performed valve replacement in 281 patients using bileaflet prosthetic valves in mitral and/or tricuspid positions. Thrombosed valve were seen in 10 patients (7 in mitral, 3 in tricuspid positions). In 5 patients, coumadin had been stopped for several reasons (pacemaker implantation, melena, drug allergy), but in the other 5 patients, anticoagulation was within the therapeutic range at the time of presentation. For thrombolytic therapy urokinase or tissue plasminogen activator were used. The treatment was successful in 5 patients (4 mitral, 1 tricuspid), and unsuccessful in 5 patients (3 mitral, 2 tricuspid). Three of the 5 unsuccessful patients were treated surgically (3 with re-mitral valve replacement, 1 with thrombectomy). Prompt surgical treatment can be used as the first line of therapy for thrombosed valves. Thrombolytic therapy may be useful in some cases of bileaflet valve thrombosis without critical hemodynamic collapse. Doppler echocardiographic assessment of increasing peak velocity and pressure half time is useful for detecting thrombosed valves.

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The purpose of this study is to clarify the appropriateness of axillofemoral bypass for high-risk patients with aortoiliac occlusive disease. From February 1986 through November 1997, 50 axillofemoral bypasses were performed at our institution. The mean age of patients was 70.3± 9.6 years (range 28 to 86 years) and 90% of them had severe associated disease. Twenty-nine grafts had axillounifemoral configuration and 21 grafts had axillobifemoral configuration. The primary and secondary patency rate, during this 11-year period (mean follow-up 47.0±30.1months), were 66.4 % and 78.3% at 5 years, with no change thereafter. The mortality rate within 30days was 2%. During the follow-up period 22 died mainly due to heart disease, cerebrovascular disease or malignant tumor, and the survival rate at 5 years was 56.3%. Fontaine classification evaluation revealed that ischemic symptoms improved in 78% of 28 survivors. According to QOL study 75% of survivors were satisfied with daily life, and their performance status improved after operation. These findings indicate that axillofemoral bypass may be an appropriate procedure for high risk patients with aortoiliac occlusive disease.

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We report a 69-year-old woman with transient mitral valve regurgitation and hemolysis following mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis. She had a history of congestive heart failure caused by mitral valve regurgitation so we performed mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis (Model 6900). Three days after surgery, a systolic murmur became clearly audible and the serum LDH level reached a maximum of 2, 018IU/l on postoperative day 10. Echocardiography showed regurgitant flow through the center of the bioprosthetic valve. It was thought that stent distortion of the implanted pericardial bioprosthesis had occurred and re-operation would be necessary, but the regurgitant flow disappeared suddenly on postoperative day 12. If mitral valve regurgitation occurs following mitral valve replacement with a pericardial bioprosthesis, stent distortion should be taken into consideration.

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A 58-year-old diabetic man underwent emergency coronary artery bypass grafting for ischemic heart failure. Although postoperative cardiac function was good but acute renal failure developed. We started continuous hemodiafiltration (CHDF) from 5 hours after the operation and continued it for 7 days without any undue influence on hemodynamics or bleeding side effects. The renal function gradually improved and CHDF was halted. It is reported that CHDF can prevent renal failure caused by inflammatory cytokines produced after cardiac surgery. CHDF appears to be useful for the management of acute renal failure in the early postoperative period after cardiac surgery.

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A 7-year-old boy suffered from isolated interruption of the aortic arch without any other complications or cardiovascular malformations. Cardiac murmur, which had been apparent since one month of age, had been left untreated because of the absence of any symptoms of heart failure. Isolated interruption of the aortic arch was noted during a routine physical examination at school and the patient was referred to our hospital for a complete medical evaluation. Blood-pressure difference was recognized not only between the right side and the left side of the upper extremities but also between the upper and lower extremities. On the basis of the results obtained via magnetic resonance angiography (MRA) and aortography, a definitive diagnosis of isolated interruption of the aortic arch was made. Reconstruction of the aortic arch by synthetic implant was indicated. The blood-pressure difference disappeared and the postoperative course was satisfactory.

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We treated a 62-year-old man with aneurysms of the descending thoracic aorta (45mm: proximal, 60mm: distal). We evaluated the intima of the aorta by intraoperative direct echography using a small probe (finger tip size), which detected floating mural thrombi in the proximal descending aorta. Therefore we chose the proximal and distal open technique with retrograde cerebral circulation under deep hypothermia during graft replacement of the descending aorta. There was no complication during or after surgical treatment.

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Prosthetic grafts have been employed in a limited number of pediatric patients with peripheral vascular lesions. We treated an iatrogenic obstruction of bilateral external iliac arteries in a child. The patient was a six-year-old girl whose chief complaints were intermittent claudication, and lower limb pain when exposed to cold. She had a history of coarctation complex for which she had undergone repeated catheterizations by puncture of both femoral arteries in her infancy. At the age of four, two-stage operation was performed: resection of the coarctation and end-to-end anastomosis, and direct closure of ventricular septal defect. Angiography performed through the brachial artery demonstrated obstruction of the bilateral external iliac arteries. Both right and left femoral artery were visualized through the collateral artery from the ipsilateral internal iliac artery. Because she became afflicted with lower limb ischemia a revascularization procedure was indicated. A 6mm expanded polytetrafluoroethylene (ePTFE) bypass graft was implanted bilaterally between the internal iliac artery and the common femoral artery with end-to-side anastomosis. Ischemic symptoms disappeared postoperatively and MR-angiogram performed nine days after surgery also showed the patency of the graft. It is a great concern, however, that the length of the graft may become relatively shorter with the growth of the patient. It is also anticipated that the lower limbs may suffer relatively insufficient blood flow in the future.

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A 31-year-old woman complained of dizziness. Preoperative aortogram revealed a saccular type of aneurysm of the aortic arch and abnormal origin of the left subclavian artery. She underwent reconstruction of the aortic arch through 4th intercostal thoracotomy on August 10th, 1996. The aneurysm originated distally to the left common carotid artery and its wall was very thin. Aortic arch replacement with woven Dacron prosthesis was performed between the left common carotid artery and the left subclavian artery using the inclusion method under hypothermic circulatory arrest. The post operative course was uneventful. Cystic medial necrosis of the aneurysmal wall, and normal arterial findings of the left femoral artery were recognized by the pathohistological examinations. Kinking of the aorta is a congenital disease due to abnormal embryonal development. The aortic arch elongates between the left common carotid artery and the left subclavian artery, and arch aneurysm originates in this portion, because the aneurysmal wall is very thin and fragile when accompanied with cystic medial necrosis. Therefore, it is important that the left subclavian artery originating distally to the arch aneurysm in this category of the aortic arch aneurysm be recognized. There are 11 cases which were successfully operated for aortic arch aneurysm associated with congenital kinking of the aorta in Japan.

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