Retrograde cerebral perfusion has been a useful technique for preventing brain damage during hypothermic circulatory arrest. To determine the optimum conditions for retrograde cerebral perfusion utilizing a fluorescence vital microscope, male Wistar rats weighing 100 to 300g were used for infusing saline with contrast medium (0.01% FITC-albumin) through the external jugular vein. A closed cranial window was prepared over the pial surface of the brain at the medial part of the right parietal cortex in order to observe the blood flow of tributaries from the middle cerebral artery to the superior cerebral vein. Intracranial pressure was controlled at 3±2cmH₂O for comfortable visualization. The observation of retrograde cerebral perfusion was performed under hypothermic conditions. Cerebral blood flow could not be observed under retrograde pressure of 5-15mmHg, mainly due to venovenous shunt flow. But retrograde cerebral perfusion was observed with a driving pressure of 15-30mmHg, and flow velocity measured by the video tracing method (n=5) in arterioles (mean diameter 37±10μm) was -12±5μm/sec, in venules (mean diameter 64±17μm) was -14±9μm/sec, which was 405±92μm/sec and 220±150μm/ sec under hypothermic beating heart conditions respectively. Under retrograde pressure of 30-50mmHg, cerebral microcirculation was deteriorated with increasing cerebral volume, and cerebral blood flow was consequently interrupted. In conclusion, the optimal condition for retrograde cerebral perfusion was determined under retrograde perfusion pressure of 15-30mmHg and intracranial pressure of 3±2cmH₂O, whenever cerebral microcirculation from venule to arterioles was best. Retrograde cerebral perfusion has some advantage for cerebral protection compared with hypothermic circulatory arrest, but might not supply sufficient cerebral blood flow to prevent brain damage.

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For treatment of Stanford type A aortic dissection, we have operated only on the ascending aorta out of consideration of operative invasions and complications. However, if only the ascending aorta is replaced, the residual distal false lumen and its dilatation become problematic. We examined the risks of postoperative dilatation of the distal false lumen in terms of the following three factors (1) patency of the distal false lumen, (2) Marfan's syndrome, (3) aortic medial degeneration. Between 1984 and 1993, 55 cases of acute and chronic type A aortic dissection were treated surgically at our hospital, and a total of 33 survivors were subsequently followed up. The mean follow-up period was 92 months. None of the survivors died of late aortic complications. Five patients (15%) had Marfan's syndrome. As a result, all 18 patients (55%) with a closed distal false lumen did not show late distal dilatation or late deaths. Marfan patients had a high incidence of distal dilatation of the aorta and required additional aortic operations. Aortic medial degeneration was a high risk factor for younger onset (>40 years old) of aortic dissection, patent false lumen, and late dilatation, not only for Marfan patients but for non-Marfan patients. Non-Marfan patients with onset of aortic dissection under 40 years of age, showed significantly high incidence of medial degeneration. In conclusion, patent false lumen and medial degeneration of non-Marfan patients is a high risk factor of late dilatation as well as those of Marfan patients. On the other hand, patent false lumen is not a risk factor of late dilatation for non-Marfan patients without medial degeneration. Therefore, in both Marfan and non-Marfan patients with onset under 40 years of age, concomitant aortic arch repair should be performed because the rate of reoperation is significantly high.

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Perioperative changes in thyroid function and hemodynamic state were studied in 6 hypothyroid patients and 15 euthyroid patients who underwent coronary artery bypass grafting. Serum free T₃ and total T₃ concentrations declined significantly in hypothyroid patients after the surgery. Serum total T₃ concentration decreased significantly also in euthyroid patients, indicating the occurrence of“euthyroid sick syndrome”in this group. Hypothyroid patients resulted in significantly lower left ventricular stroke work index despite greater central venous pressure and pulmonary capillary wedge pressure, and greater requirements of dopamine and dobutamine compared with those in euthyroid patients. The results indicated poorer postoperative cardiac performance in hypothyroid patients. Serum free T₃ concentration after cardiopulmonary bypass demonstrated a significant positive correlation with left ventricular stroke work index measured simultaneously. Preoperative serum free T₃ concentration showed a significant negative correlation with the postoperative dopamine and dobutamine requirements. Therefore, the results suggest that free T₃ has inotropic effects and the concentration of this hormone can be a predictor for a incidence of postoperative low cardiac output. In conclusion, since hypothyroid patients undergoing coronary artery bypass grafting are prone to have low cardiac output status, careful perioperative management, including hormone replacement therapy, is required for the patients.

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To evaluate the role of interleukin-8 (IL-8) and interleukin-10 (IL-10) in reperfusion injury following acute arterial occlusion, an experimental study was carried out using Wistar strain rats. The reperfusion injury model was conducted in 4 rats, in which the infra-renal aorta and the bilateral common femoral artery were ligated for 6 hours and then released (Group I). In controls, only preparation of these arteries without clamping were performed in 4 rats (Group II). In both groups, creatine phosphokinase (CPK), IL-8 and IL-10 were measured and compared. In group I, CPK was significantly higher than in Group II after the ligation and the reperfusion. After the reperfusion, IL-8 increased significantly, remaining at a high value in group I. The IL-10 of Group I also increased significantly and indicated high 6 hours after the reperfusion, however, it significantly decreased 12 hours after the reperfusion. These results suggests that the high value of IL-8, which is inflammation-linked cytokine, and the low level of IL-10, an anti-inflammatory cytokine, may prolong the systemic inflammatory response. The imbalance of these two kinds of cytokines may play an important role in the incidence of reperfusion injury and myonephropathic metabolic syndrome, which is a fatal complication after acute arterial occlusion disease.

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We investigated the effects of milrinone administered during cardiopulmonary bypass (CPB) for open heart surgery. Ten patients (group M) received milrinone after aortic declamping during CPB. Ten other patients served as controls with no administration (group C). Soon after the bolus infusion of milrinone, the perfusion pressure dropped significantly in the M group, however, after CPB and at the end of operation, aortic pressure showed no difference between the two groups. There were no differences in heart rate, pulmonary artery pressure and pulmonary capillary wedge pressure. After CPB, cardiac index was high and systemic vascular resistance index was low in the M group. The need for cathecholamine and time for rewarming showed also no significant differences. No adverse reaction was recognized. During CPB, a single administration of milrinone was useful for peri- and post-operative management of patients undergoing open heart surgery.

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Two types of skin incision, pararectal and transverse, in the retroperitoneal approach to aorto-iliac region were compared. For the last 3 years, 34 abdominal aortic aneurysms, excluding ruptured cases, and 43 cases of aorto-iliac occlusive disease were all operated on by a retroperitoneal approach in our hospital. Of these, 36 patients underwent pararectal incision (P group) and 41 patients transverse incision (T group). An Octopus^® retractor yielded a wide operative field in all cases. The mean interval from the start of the operation to the aortic cross clamp were almost equal in the two groups (89.7 and 91.1 minutes). The mean amount of intraoperative bleeding was significantly smaller in the T group (749ml) than in the P group (1, 096ml). The mean interval after surgery to beginning peroral alimentation, weaning from analgesics and discharge from the hospital were all significantly shorter in the T group (1.6, 3.3 and 10.8 days) than the P group (2.8, 4.8 and 15.8 days). Transverse incision for a retroperitoneal approach to the aorto-iliac region is preferable for an early recovery and short hospital stay.

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Surgery for abdominal aortic aneurysms (AAA, n=240) was reviewed in subgroups of ruptured AAA (RAAA, n=31), non-ruptured AAA with arteriosclerosis obliterans (AAA w/ASO, n=48), and non-ruptured AAA without ASO (AAA w/o ASO, n=161). The average follow-up period was 4.2 years (maximum 15.8 years) and the follow-up rate was 97%. Overall operative mortality rates were 41.9% in RAAA and 2.9% in non-ruptured AAA. Those were 6.3% in AAA w/ASO and 1.9% in AAA w/o ASO. The main causes of death in the long-term follow-up period were heart disease in 32%, malignant neoplasm in 22%, cerebrovascular accidents in 10% and renal failure in 10%, and miscellaneous. Only renal failure was related to operative risk factors. Relative survival rates excluding hospital death following surgery were 79% at 5 years and 0% at 10 years in RAAA; 74% at 5 years and 52% at 10 years in AAA w/o ASO; 95% at 5 years and 78% at 10 years in AAA w/ASO; 90% at 5 years and 70% at 10 years in non-ruptured AAA. These survival rates were lower than those found in the normal population, especially in AAA w/ASO. AAA w/ASO had more surgical risk factors of ischemic heart diseases and diabetes mellitus. Main causes of deaths were heart diseases, and renal failure during the long-term follow-up period was more predominant in AAA. It is important to follow all patients after surgery for AAA with special attention to heart disease and renal failure.

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A 55-year-old man was admitted with a thoracic aortic aneurysm causing wheezing. Computed tomography and angiography revealed a large distal aortic saccular aneurysm, occupying the retrotracheal space and compressing the trachea. There has been only one report of this type of aneurysm. This patient needed emergency intubation because of severe dyspnea caused by premedication for surgery. Replacement of the distal arch was performed via left posterolateral thoracotomy. Profound hypothermia was used during open proximal anastomosis, which helped to make this procedure safe and simple. This patient recovered uneventfully.

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We operated on two cases of small aorta syndrome (SAS). Case 1 was a 43-year-old man who complained of pain and cyanosis of the left first and second toes and was admitted to our department. Angiography showed narrowing of the infra-renal aorta, 11mm in diameter just above the bifurcation. It also showed stenosis of the right external iliac artery and occlusion of the left external iliac artery. Aorto-bifemoral bypass, using a 12×6mm bifurcated knitted Dacron graft, was performed without incident. Case 2 was a 21-year-old man. He was admitted with a chief complaint of intermittent claudication of his left calf. Angiography showed narrowing of the infra-renal aorta, 12mm in diameter just above the bifurcation. It also showed occlusion of the left superficial femoral artery. A femoro-popliteal bypass, using a 6mm knitted Dacron graft, was successfully performed. Both cases were diagnosed as SAS. In the literature, SAS is characterized by narrowing of the infra-renal aorta and is frequently accompanied by hypoplasia of the iliac arteries. Although SAS is not uncommon in Western countries, there are only a few reports in Japan. SAS has been reported more frequently in women with a relatively early age of onset. The graft patency rate in these patients is observed to be much less than that in the general population of patients who require aortoiliac reconstruction. Therefore, long-term follow-up is important to observe possible deterioration of ischemic symptoms and signs in SAS patients even after apparently curative operations.

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A 74-year-old woman was first admitted to our hospital for orthopnea, and was given a diagnosis of severe congestive cardiac failure caused by myocardial infarction. Coronary angiography revealed severe triple vessel disease, with a totally obstructed left anterior descending artery (LAD) and right coronary artery. First diagonal branch (Dx1) was 90% stenotic, and left circumflex artery was also 90% stenotic in its proximal portion (segment 11; #11). There was no stenotic lesion in the obtuse marginal branch or posterolateral branch, which are the usual target branches for the left circumflex branch (LCx). But they were too small to be grafted. Left ventriculography showed severe left ventricular dysfunction (ejection fraction; 31%). Saphenous vein grafting (SVG) to the distal portion of #11 and sequential SVG to the LAD and Dx1 were performed. Postoperative angiography proved that these grafts were patent. The patient was discharged on the 46th postoperative day after an uneventful course.

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A 70-year-old man was found to have aortic regurgitation and underwent aortic valve replacement. About 10 minutes after disconnection from the cardiopulmonary bypass, cardiac arrest occurred suddenly and the bypass was immediately resumed. At this point, a Stanford type A aortic dissection was detected by transesophageal echocardiography, and the orifice of the left coronary artery was considered to be occluded by invasion of a hematoma. Although ascending aortic replacement with a prosthesis was performed under hypothermic circulatory arrest with selective cerebral perfusion, the heart did not resume vigorous beating. Therefore, saphenous vain graftings to the left anterior descending artery and the right coronary artery were performed. Finally, the patient could be weaned from the cardiopulmonary bypass. On postoperative digital subtraction angiography, neither occlusion nor stenosis in both coronary arteries was observed. We conclude that it would be considered to perform coronary artery bypass graftings in this particular condition.

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Cardiac fibromas are rare tumors. A 12-year-old girl who had no cardiac symptoms was evaluated because of her abnormal ECG. Physical examination revealed a grade 1/6 systolic murmur. Routine laboratory examination results and the chest X-ray films were normal. The ECG showed a negative T wave at leads II, III, aVF and V_3-4. Two-dimensional echocardiography demonstrated a tumor in the lower right ventricular free wall. Operation was performed on July 12, 1990. Sharp dissection was used to remove the tumor through right ventriculotomy. She had an uneventful postoperative course and is well 7 years later with no evidence of recurrence. Pathological findings including immunohistochemical studies revealed cardiac fibroma. The 22 reported cases of cardiac fibroma in Japan were reviewed.

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Four cases of tricuspid regurgitation (TR) developing late after mitral valve surgery for mitral stenosis (MS), which required surgical management, are reported. Two of the 4 patients underwent open mitral commissurotomy (OMC), and the other two underwent mitral valve replacement (MVR) at the initial operation. The time course of the changes in the effective mitral valve orifice area (MVA) and tricuspid regurgitation grade were assessed by pulsed and color Doppler echocardiography. In the former 2 patients, the TR grade gradually increased as recurrent MS progressed after OMC, and operation for TR was done 10 and 12 years after the initial mitral surgery respectively. In the latter 2 patients MVA became moderately narrow about 2.0 to 2.5cm² after MVR, and operation for TR was done 14 and 17 years after initial mitral surgery respectively. The operative procedure for TR was tricuspid annuloplasty in 2 patients and tricuspid valve replacement in 2 patients. These results suggest that recurrent TR late after mitral valve surgery is caused by gradually progressive and chronically prolonged mild recurrent MS, even in cases with MVR. Thus, before surgery for recurrent TR, mitral valve function should be assessed in detail. Also, it is necessary that reliable operative procedures for TR, including tricuspid valve repair and replacement, should be selected, considering the possible necessity of mitral valve reoperation.

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We report a 71-year-old man who was successfully treated with simultaneous coronary artery bypass grafting (CABG) and abdominal aortic repair. The patient presented with a combination of long segmental stenosis of the left anterior descending coronary artery and large infrarenal abdominal aortic aneurysm (diameter in 7.8 cm). Because both lesions were serious, one-stage operation of coronary artery and abdominal aorta was carried out. First, CABG was performed under the beating heart without cardiopulmonary bypass. After completion of CABG, the median sternotomy incision was extended down to the pubic symphisis, and abdominal aortic replacement was performed using a standard technique with a gelatin-coated bifurcated graft (Gelseal). The operation was uneventfully finished in 6hr 18min without requiring the use of homologous blood products. Postoperative course was uneventful and he was discharged 15 days after the operation. CABG without cardiopulmonary bypass is a safe and effective method not only in patients with left ventricular dysfunction or calcified aorta, but also in patients requiring a one-stage approach for both myocardial ischemia and abdominal aortic aneurysm.

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Primary cardiac tumors are comparatively rare. Primary cardiac angiosarcoma is the most common cardiac malignant tumor and the most common site of this tumor is in the right atrium. It is usually difficult to diagnose and treat this condition before death. The present case of primary cardiac angiosarcoma was located in the left atrium, which is very rare. A cardiac malignant tumor was suspected in this 56-year-old man based on chest MRI examination. The operation was performed successfully but its outcome was very poor.

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