A Surgically Treated Case of Stanford Type B Acute Aortic Dissection Extending through Atherosclerotic Abdominal Aortic Aneurysm / 日本心臓血管外科学会雑誌

A 72-year-old man presented with chief complaints of back pain. Medical workup discovered infrarenal abdominal aortic aneurysm (AAA) with Stanford type B acute aortic dissection on CT. The dissection originated distal to the left subclavian artery and extended to the right commom iliac artery. All visceral arteries branched from the false lumen. The maximum diameter of the thoracic aneurysm was 4.8cm and that of the abdominal aneurysm was 6.5cm. Multiple renal infarcts were noted and the right kidney function was decreased. Initial surgery was performed 3 months after presentation using a graft technique. Advanced atherosclerosis and dissection were noted in the aneurysm making the arterial wall quite vulnerable. Hemorrhage was extensive and hemostasis difficult in the defective arterial wall. The patient became unstable so the aneurysm was closed and the surgical procedure was changed to right axillo-bifemoral bypass rather than the original surgical plan of anatomic reconstruction of the AAA. The patient tolerated the procedure well. We report a rare case of acute aortic dissection which extended through the AAA.

One-Staged Operation for Stanford Type A Aortic Dissection, AAE, Mitral Valve Regurgitation and Pectus Excavatum in a Patient with Marfan's Syndrome / 日本心臓血管外科学会雑誌

A 22-year-old man was hospitalized due to severe back pain having being diagnosed as Stanford type A aortic dissection, AAE, mitral regurgitation and pectus excavatum associated with Marfan's syndrome. A single staged operation including ascending aortic replacement, mitral valve replacement and sternal turnover with a rectus muscle pedicle was carried out in order to keep the blood supply to the plastron to reduce the risk of infection during such a long operation. By this approach, it was found that the operative field was excellent and postoperative hemodynamics were stable. However, frail plastron occurred because of difficulties in keeping the patient stabilized because of severe pain thus re-fixation was required. The necessity of strong pain control after such an operation was also recognized.

Use of the Pre-Test Series of the United States Medical Licensing Examination for Undergraduate Medical Examination in University of Tsukuba / 医学教育

A special elective course to prepare for the United States Medical Licensing Examination for 2 hours weekly was introduced for our 3rd-and 4th-year students 3 years ago. The course consists of two parts: one part concerned basic medical knowledge taught by medical faculty with American textbooks and the other part concerned medical English taught by a native English speaker speaking at a natural speed so that students will be able to understand naturally spoken English.

Subepicardial Aneurysm: A Case Report / 日本心臓血管外科学会雑誌

The incidence of ventricular subepicardial aneurysm following myocardial infarction is quite low. We report a case of subepicardial aneurysm that was diagnosed on postoperative pathohistologic examination. A 69-year-old man was admitted to our hospital because of left ventricular aneurysm following myocardial infarction. The patient had left main trunk disease, triple-vessel coronary artery desease and low output syndrome. Under cardiopulmonary bypass with the heart arrested, the aneurysm was resected and the defect was closed. The suture line was reinforced using Teflon felt and GRF glue. A saphenous vein graft was anastmosed to the left anterior descending artery. On pathohistologic examination, the wall of the aneurysm was found to be composed of fibrotic tissue, myocardial fibers, medium-sized pericardial arteries, epicardium and fibrin thrombi. We diagnosed this as subepicardial aneurysm.

Analysis of Results After Introduction of X Type Questions / 医学教育

X type questions have been used for the national medical licensing examination since 1997. At Tsukuba University, X type questions have been used since 1996. We compared X typeand K type questions on the basis of the percentage of correct answers and discrimination power. The average percentage of correct answers was 68.2% for K type questions and 53.1% for X type questions. However, the average discrimination power was +0.227 for K type questions and +0.257 for X type questions. These results indicate that X type questions are more difficult and are suitable for achievement tests. The estimated knowledge quantity was 2.04 for K type questions and 2.32 for X type questions. This suggests that the person writing the questions decreased the essential difficulty of X type questions.

Major Hemorrhage from the Lung after Surgery of Congenital Heart Defects: Catastrophic Complication / 日本心臓血管外科学会雑誌

Seven patients with congenital heart defects suffered from multiple major hemorrhages from the lung after surgery and 5 of them died at 8 to 54 postoperative days because of respiratory insufficiency. In a patient with tetralogy of Fallot associated with pulmonary atresia, bleeding occured after the second shunt operation, presumably from rupture of bronchial collateral vessels. The clinical diagnoses of the other 6 patients were coarctation of the aorta (CoA) with common atrioventricular canal (CAVC) in 1, triple shunt in 1, persistent truncus arteriosus in 2, total anomalous pulmonary venous connection in 1 and CAVC in 1. Subclavian flap aortoplasty was performed without pulmonary artery banding in the patient with CoA and CAVC, whereas complete repair was performed in the other 5 patients. As these patients were associated with severe pulmonary hypertension preoperatively and 4 of them encountered pulmonary hypertensive crisis, the hemorrhage from the lung may be related to pre and postoperative high pressure of the pulmonary artery. Dilatation and rupture of the pulmonary capillary net was demonstrated in the patient with CoA and CAVC. These findings suggest the hypothesis that bleeding occurred due to rupture of the capillary net as a result of transmission of high pressure. Major bleeding from the lung is a rare but catastrophic complication after repair of congenital heart defects. As the treatment is difficult, early surgical intervention and treatment of postoperative pulmonary hypertension are important in complex lesions with severe pulmonary hypertension.

The Postgraduate Careers of the Graduates of the School of Medicine, University of Tsukuba, and Evaluation of the School Curriculum by the Graduates / 医学教育

The School of Medicine, University of Tsukuba, was founded in 1974 and had graduated 1, 561 students by 1994. From 1980 through 1987, 44% to 73% of graduates became hospital staff, 16% to 40% became university staff, and 0% to 8% became general practitioners. More than 80% of graduates did a 2-year residency (sotsugo-kenshu) at our university hospital and 40% completed a 6-year residency. Almost 10 years of postgraduate training was required to become an established medical practitioner. This length of time indicates that postgraduate training is the most important part of the medical career. About 80% of graduates earned doctor of philosophy (Ph. D.) degrees, whereas 93% became registered specialists, indicating that graduates tended to become specialists rather than to pursue Ph. D. degrees. This difference is more evident among female graduates: 85% became specialists whereas only 53% received a Ph. D. Most graduates considered the School of Medicine to have a good curriculum, but some younger graduates had complaints. The graduates chose their career specialties on the basis of their own interests and aptitudes. We should take these data into account to prepare a system of life-long education and learning.

Functional Evaluation of Leg Edema after Coronary Artery Bypass Surgery / 日本心臓血管外科学会雑誌

Leg edema following the harvest of great saphenous vein (SV) is sometimes recognized after coronary artery bypass surgery (CABG). Maximum venous outflow (MVO) is one of the parameters of leg venous function which is measured by straingauge plethysmography. To clarify the mechanism of the development of leg edema after CABG, we measured the perioperative MVO. Six patients had leg edema afer CABG (group I), 4 patients had no edema after CABG (group II). Six patients without edema after cardiac surgery, apart from CABG, were selected as controls (group III). The MVO of both legs was measured before and after the operation. In group I, venous echo or venography of the leg, or both, were performed after the operation. The MVO of legs from which SV had been harvested in group I decreased from 35.0±13.6 (ml/min/ 100ml tissue) to 23.9±7.6 (<i>p</i>=0.04) after the operation, but did not differ from the MVO of the contralateral leg. The preoperative MVO of legs from which SV had been harvested in group I was slightly higher than the legs of other groups. There was no significant change of MVO in group II or III after surgery. No deep vein thrombosis was shown in group I by venous echo and venography. Left ventricular ejection fraction, blood cell count and serum chemistry indicated no changes in any of the three groups after the operation except for the hemoglobin level in group I. These results suggested that the leg which had edema had a relatively high MVO before the operation. This MVO significantly decreased to the level of leg from which SV had not been harvested after the operation, and the edema appeared. In conclusion, postoperative edema in the leg from which SV was harvested was the result of a decrease in venous function due to removal of the SV. SV which causes leg edema might play the greater part of the venous return than others and the total function of the venous return was higher than normal at the point of preoperation.

Perioperative Anticoagulation Therapy for Patient with Abdominal Aortic Aneurysm after Heart Valve Surgery / 日本心臓血管外科学会雑誌

Under scheduled anticoagulation therapy, surgery for abdominal aortic aneurysm was performed in 4 patients who had undergone heart valve surgery and implantation of a mechanical prosthesis. Warfarin and antiplatelet agents were prescribed in all cases preoperatively. Antiplatelet agents were discontinued from seven to 10 days before operation. Warfarin was stopped from two to three days before operation and heparin (200IU/kg/day) was administered by continuous intravenous infusion to produce an activated clotting time of around 150 seconds. Bolus intravenous heparin of 3, 000 IU was added before aortic crossclamp. Oral anticoagulants were resumed from the beginning of oral intake, and heparin was stopped when the prothrombin time reached therapeutic levels (% PT=40%). In three patients perioperative courses were uneventful. Intraperitoneal hemorrhage occurred in one patient who simultaneously underwent cholecystectomy and aneurysmectomy with Y-grafting. He required blood transfusion and interruption of anticoagulation. Brain thromboembolism occurred in this patient 26 days after the operation. We believe that scheduled anticoagulation for the operation of abdominal aortic aneurysm is safe and useful in patients with prior prosthetic heart valve surgery. However, the coexistence of coagulopathy requires more intensive anticoagulation therapy.

Surgical Treatment for Airway Obstructions Associated with Congenital Heart Disease / 日本心臓血管外科学会雑誌

We performed surgical treatment for 21 patients of airway obstructions associated with congenital heart disease from December 1986 to March 1993. In all patients perioperative bronchoscopy demonstrated the cause and site of airway obstructions. Seven patients with corrective cardiac surgery (7/7), 7 with palliative cardiac surgery (7/10) and 2 with surgery for airway diseases (2/4) could be weaned from respirators following surgical treatment. Five patients died postoperatively. A respirator was required in 16 patients (76%) preoperatively. The suspension of pulmonary artery with intraoperative bronchoscopy was carried out in 6 patients. Five (5/6) were successfully extubated earlier postoperative day (mean 8.4 days), whereas only five in 10 patients without that procedure could be weaned from the respirator at a mean of 2 months. Identification of potential airway obstruction and early extubation is needed to reduce the mortality and morbidity caused by airway obstruction associated with congenital heart disease. Preoperative bronchoscopy is useful for diagnosis of airway obstructions and essential for decision making concerning surgical treatment. To early extubation in patients with marked airway obstructions, we recommend appropriate choice of the surgical procedure combined the suspension of pulmonary artery.

Investigation on Improvement of Peripheral Circulation by Continuous Use of Prostaglandin E1 during Open Heart Surgery. Evaluation with Peripheral Blood Flow by Laser Doppler Flowmeter and Temperature Difference between the Periphery and Core / 日本心臓血管外科学会雑誌

Prostaglandin E₁ (PGE₁) was used continuously in adults from immediately after induction of anesthesia, during extracorporeal circulation, to the acute phase after open heart surgery. Using blood flow in the toe determined by laser Doppler flowmeter and the temperature difference between periphery and core as indices, the effects of afterload reduction and improvement of peripheral circulation were investigated. Subjects were 17 adults who underwent open heart surgery. PGE₁ was used in 7 patients and not used in 10. In the group using PGE₁, continuous injection of 0.015μg/kg/min of PGE₁ was started immediately after induction of anesthesia and was maintained during extracorporeal circulation until the acute phase after surgery. During extracorporeal circulation, perfusion pressure was kept at 50∼60mmHg and PGE₁ injection was controlled within the range of 0.015∼0.030μg/kg/min. At completion of extracorporeal circulation, the dose was fixed at 0.015μg/kg/min again. The degree of improvement of peripheral circulation was evaluated on the basis of hemodynamics, blood flow in the toe determined by laser Doppler flowmeter and the temperature difference between periphery and core, at induction of anesthesia (before using PGE₁) on completion of extracorporeal circulation, and in the acute phase after surgery. The value of blood flow in the toe determined by laser Doppler flowmeter was significantly higher in the PGE₁ group than in the non-PGE₁ group, from completion of extracorporeal circulation to the acute phase after surgery. Moreover, peripheral temperature was significantly higher in the PGE₁ group than in the non-PGE₁ group at completion of the extracorporeal circulation as well as immediately after surgery, and the temperature difference between periphery and core was significantly smaller. Continuous injection of PGE₁ enabled smooth control of perfusion pressure during extracorporeal circulation. Although there was no significant difference in peripheral vascular and total pulmonary resistance, the coefficients tended to be lower in the PGE₁ group. The use of PGE₁ during open heart surgery seems to be an effective method to improve peripheral circulation.

A Fourteen-Day-Old Neonate with Congenital Aortic Valve Stenosis Successfully Treated with Open Valvular Commissurotomy / 日本心臓血管外科学会雑誌

A thirteen-day-old neonate was admitted because of systolic heart murmur, tachycardia, tachypnea and sucking weakness. The chest X-ray film demonstrated remarkable cardiomegaly and pulmonary congestion. Echocardiography detected marked thickening and stenosis of the aortic valve, and left ventricular dysfunction (EF=10%). The pressure gradient between left ventricle and ascending aorta was presumed 130mmHg with pulsed Doppler echocardiography, Since he did not respond to conservative treatment, an emergency open aortic valvular commissurotomy under cardiopulmonary bypass was performed the day after admission. We made incisions of 1mm in the left side and 0.5mm in the right side commissure of the adherent bicuspid aortic valve. After the procedure, left ventricular function improved (EF=57%), and the pressure gradient was reduced to 62mmHg. He showed good recover from the congestive heart failure. There are few reports about operative treatment of congenital aortic valve stenosis in neonates. This is considered to be the third youngest successful operative case of open aortic valvular commissurotomy in Japan.

A Case Report of Successful Surgical Treatment of High Aortic Occlusion with Acute Ischemia of Intrapelvic Organs and Bilateral Lower Extremities / 日本心臓血管外科学会雑誌

This is a case report of a 57-year-old woman with high aortic occlusion (HAO) who had acute symptoms of severe ischemia of the lower extremities and the intrapelvic organs. Generally, HAO is a chronic ischemic disease of the lower extremities and the intrapelvic organs; therefore, acute HAO is relatively rare. Acute thrombotic occlusion of a major collateral artery might be the cause of acute HAO. Laser Doppler flowmetry of the sigmoid colon was useful to evaluate the ischemia of intrapelvic organs. Thrombectomy of the juxtarenal portion with the suprarenal aortic cross clamp was performed within four minutes, then the clamp was moved to the infrarenal portion. The remaining occluded aorta was replaced with a Y-shaped knitted Dacron graft. She had no symptoms after the surgery except renovascular hypertension. Seventy five percent stenosis of the right renal artery was exacerbated to 99%. Vascular clamping of the right renal artery might have been the cause of severe stenosis. Percutaneous transluminal renal angioplasty was successfully performed after the surgery. Aggressive renal artery reconstruction during surgery is recommended in cases with moderate or severe renal artery stenosis.

Causative Factors for Thrombi Formation in Mitral Stenosis / 日本心臓血管外科学会雑誌

Causative factors for thrombi formation in left atria of 38 patients with mitral stenosis who underwent mitral valve surgery (open mitral commissurotomy or mitral valve replacement) alone or in combination with other procedures were studied. There were 9 cases of left atrial thrombosis (LAT). Left atrial diameter was increased in LAT(+) group (6.1±1.6cm) compared with LAT(-) group (4.6±0.7cm). There was significant difference in the left atrial diameter between the two groups of patients (<i>p</i><0.01). Cardiac output was decreased in LAT(+) group (3.04±0.74<i>l</i>/min) compared with LAT(-) group (3.99±1.07<i>l</i>/min). Cardiac output of LAT (-) group was significantly larger than that of LAT(+) group (<i>p</i><0.05). Mean transition time of blood through left atrium (MTT_LA) was calculated using left atrial volume and cardiac output. In LAT (+) group, MTT_LA was significantly increased (6.2±3.9sec) compared with LAT(-) group (2.9±1.6sec). It is considered that, in mitral stenosis, prolongation of MTT_LA is one of the risk factors for thrombi formation in the left atrium.

A Successful Result of One Stage Operation for Atrial Septal Defect and Funnel Chest / 日本心臓血管外科学会雑誌

A 6-year-old boy underwent one stage operation for atrial septal defect (ASD) and funnel chest. The procedure began with removal of cost-sterno complex (plastron) following median skin incision. Plastron was kept in cold saline with antibiotics during ASD closure, and sterno-costal elevation method was performed. Simultaneous operation for heart disease and funnel chest is profitable in preventing postoperative circulatory or respiratory complications, in avoiding problems of two stage operation such as adhesion and mental stress of the patients. In addition, wide exposure and easy approach to the heart is available with this one stage procedure. Although current refinement both of cardiac and thoracic surgery has encouraged the possibility of simultaneous corrections for heart disease and funnel chest, much precautions against bleeding and infection are necessary for the satisfactory surgical result.

Aorto-Renal Artery reconstruction for renvoascular Hypertension Due to takayasu's disease / 日本心臓血管外科学会雑誌

Thirty-nine years old woman had a severe renovascular hyper-tension with Takayasu's arteritis Her left renal artery stenosis was treated with percutaneous transluminal angioplasty (PTA) three times. Six months after the third PTA, the left renal artery was occluded, and left renal failure occurred. Aorto-renal bypass surgery with a prosthetic graft was performed. Blood pressure dropped to normal range, and left renal function began to recover. Although PTA is an effective method in the treatment of renovascular hypertension, an incidence of restenosis after PTA is higher in Takayasu's arteritis rather than atherosclerotic lesions. Five months after renal revascularization, hypertension recurred in this case. However the aorto-renal bypass graft was patent accompanied by no symptoms. This aorto-renal bypass surgery can be considered effective in this condition.

Surgical Repair of Atrial Septal Defect in Adult Patients / 日本心臓血管外科学会雑誌

Fifty-five adult patients with atrial septal defect (ASD) were surgically treated. In the preoperative study, 6 patients showed high pulmonary artery systolic pressure (>50mmHg). However, there was no linear relation between PAP and age, nor between <i>Q</i>_p/<i>Q</i>_s and PAP. As for the additional surgical procedures, MVR (1), MAP (1), TAP (3), OPC (2) were carried out with ASD closure in 7 patients. Post-operative evaluation with echocardiography revealed increase in the left ventricular chamber size, decrease in the severity of tricuspid regurgitation and same grade mitral regurgitation compaired with pre-operative level. From these data, the prediction of the atrioventricular valve regurgitation after ASD closure seemed to be difficult just from the preoperative evaluation, Transesophageal echocardiography was useful for the evaluation of residual atrioventricular valve regurgitation during operation in the cases of ASD with over II grade regurgitation preoperatively.