When we surgically treat cases for dissecting aortic aneurysm with an inheritable connective tissue disorder like Marfan's syndrome, we should choose the surgical procedure carefully, paying paticular attention to whether to extend the operation, because there is every possibility that the lesion might be progressive. A 41-year-old woman with Marfan's syndrome, type A chronic aortic dissection, rapidly dilating to 80mm in diameter, and with aortic valve regurgitation was operated on with a total aortic arch replacement and the modified Bentall procedure. In the procedure, the aortic root and valve were replaced with a composite graft with a prosthetic mechanical valve, and the coronary arteries were reconstructed by direct anastmosis. In this case, the infrarenal abdominal aorta had already dilated to 40mm in diameter. In many cases with Marfan's syndrome, it was reported that the lesion was progressive and the residual dissection or new aneurysm would usually dilate and eventually rupture postoperatively. Reoperation involve a high risk. With those factors in mind, we chose total aortic replacement, including the distal aortic arch, to where the dissection would not extend. The most important thing for patients with Marfan's syndrome is the development of new or reccurrent problems. We consider that the operation designed to dissect aortic aneurysm for those patients should be performed as extensively in the surgical field as possible.

Fourteen patients (mean age 17.2 years, range 2 to 39 years) undergoing right ventricular outflow tract reconstruction for a Ross operation were studied between 1998 and 2000. Ten of 14 patients underwent Ross procedures and 4 received Ross-Konno procedures. Echocardiographic examination of the pulmonary homograf t was performed after surgery. The mean follow-up period was 23.1 months, ranging from 14 to 33 months. Mean peak velocity and peak gradient were 1.6±0.4m/s and 11.9±5.2mmHg, respectively. Three patients in whom echocardiography revealed a peak pulmonary gradient of 20mmHg or more were retrospectively analyzed with each catheterization data. All patients had no more than 10mmHg at the distal end of the homograft with no evidence of deformity or shrinkage. Only one patient had a trivial homograft valve regurgitation, however, no patient had more than mild pulmonary regurgitation. Patient age, donor age, and preservation period did not reveal any significant risk factor for homograft stenosis. Pulmonary homograft appears to be an excellent substitute for right ventricular outflow tract reconstruction during the mid-term postoperative period.

When homo- or isograft was used as a right ventricle-pulmonary artery bypass in the Rastellitype procedure for congenital heart disease, reoperation was mandatory due to calcification and conduit stenosis after several years. However, the survival period of intimal cells or smooth muscle cells has not been clarified, nor has the question of whether the calcification is due to an immunoreaction or not. Thus, to observe the geometrical or pathological changes of the grafts, an experimental model of homograft transplantation was established using rats' aorta, where cyclosporine A (CsA) was given after the transplantation. The rats used were 8 or 9 weeks old. Male King rats were the donors, and female Lewis rats were the recipients. The descending thoracic aorta was transplanted to the infra-renal abdominal aorta. There were 2 experimental groups; one in which CsA was not given (n=35), and the other in which CsA was given (n=44). The animals were sacrificed at 1, 2, 4, 6, 8, and 12 weeks after the transplantation, and were examined by an optical microscope after slicing longitudinally. The area of the cross-section, intima and the media of the vessel were calculated by 2 ways; manually, and by computer. These data were used to calculate and analyze the percentage of intima-media area, the ratio of the intima/media area, and the percentage of intima area and media area. The effect of suppression of the percentage of intima-media area and the percentage of the intima area were revealed to be significant at an acute stage after brief high dose CsA administration. From this result, we suggest that there is a possibility of a rejective reaction participating in the intimal hyperplasia in the acute phase after homograft transplantation.

Long-term follow up (10.0yrs on average) is described of 33 patients with coronary aretry fistulae (CAF) without other cardiac disorders. Of 33 patients, nine cases demonstrated some electrocardiographic ischemic changes (group I), and other twenty-four cases showed no significant electrocardiographic changes (group II) clinically. Symptomatic, hemodynamic and angiographic findings showed no significant difference statistically between both groups. Thirty patients of small to moderate left-to-right shunt ratio (<50∼60%) showed hemodynamic and angiographic stability during the 10.0 years retrograde follow-up period on average. Of 33 patients, seventeen cases have underwent surgical closure of CAF since 1973 to 1990. Seven of the seventeen patients had showed significant myocardial ischemic changes before surgical treatments, and five of the seven cases showed definitive improvement of the electrocardiographic changes seemed to be derived from occlusion of the coronary steal blood flow after surgical operations. There were no operative deaths and no appearance of new myocardial ischemia following the surgical repairs. At present since not only it is unclear whether the CAF predisposes correlate coronary arteries to some premature atherosclerosises but also there are several reports of severe late risks of surgical repair of CAF, surgical indication in the patients of CAF with small-to-moderate left-to-right shunt shou ld be limited to the cases with such as definitive myocardial ischemia or evidence of infective endocarditis.

Ionescu-Shiley pericardial xenografts implanted in the mitral position between April 1980 and October 1984 were studied. In some cases the cusp was torn in a relatively early postoperative phase, thus requiring an emergency operation. Functional disorders, such as caused by the calcification of the cusp, advance at a relatively moderate pace, and the prognosis of a second operation in cases with valve dysfunction and a chronic course was favorable. The actuarial probability of freedom from reoperation was 88.5±8.7% at 5 years and 55.7±14.5% at 10 years. The structural deterioration of the pericardial valve increased about 5 years after replacement. This tendency was the same as in other bioprostheses. At 10 years the overall actuarial survival rate was 67.2±12.1%. Freedom at 10 years from thromboembolism was 84.6±9.8%. For cases whose the course is under observation at present, the strategy is to recommend an additional operation as far as possible, while continuously observing the function of the valve.

A 19-year-old woman with thoracic aortic aneurysm complicating coarctation of the aorta was treated successfully. Aortography and 3D-CT showed the thoracic aortic aneurysm resembling a cluster of grapes. Coarctation of the aorta was seen between the aortic aneurysm and the descending aorta, and there was a 40mmHg pressure gradient between the ascending aorta and the descending aorta. At operation, the wall of the cluster-shaped saccular aortic aneurysm was very thin. We could see the blood flow through the wall, and we thought this patient was at high risk of ruptured aneurysm. The aneurysm was excised and replaced by a Hemashield tube graft, 16mm in diameter. The left subclavian artery was also constructed using a Hemashield tube graft, 8mm in diameter. Ruptured aneurysm in a patient with aortic aneurysm complicated by coarctation of the aorta has a high risk of death, so surgical intervention should be performed as soon as possible.

With multiple-choice questions presenting one, two, or three of five choices (types A, K or X), the expected probability of a correct answer (P) can be obtained with a five-dimensional equation for the knowledge level (q), which is the probability of discriminating correct and incorrect items. From equations for each question type, we inversely estimated the q value (the estimated knowledge level), replacing P with the raw score rate in the actual examinations for promotion. The distribution and mean value of the raw score rate of type X differed from those for types A and K. However, distributions of estimated q values for the three question types were similar. This method can be used to estimate the actual knowledge level of students without the question type affecting the raw score but cannot be used to estimate incorrect knowledge.

After bleeding is controlled with hemostats during surgery, the residual material should be resorbed without adverse effects such as inflammation, infection or scar formation. To evaluate the biocompatibility of hemostats, three kinds of commercially available collagen hemostats, cotton type (Integran^®), microfibrillar type (Avitene^®), and sheet type (TachoComb^®), were examined. A rabbit ear chamber (REC), a system for viewing materials in vivo, was applied to the auricle of male Japanese white rabbits. The REC was designed to leave a 50-μm-thick and 6.4mm-diameter chamber, and 0.5mg of each specimen (Integran; n=8, Avitene; n=6, TachoComb; n=6) was placed in the chamber. Macroscopic and microscopic observations were performed every week up to 5 weeks without anesthetizing or stressing the animal. In the Integran group, capillaries infiltrated between the collagen fibers, and the vasculature in the REC field was complete in 6 out of 8 animals at 5 weeks. Cotton type collagen fibers of Integran became thinner every week without effusion. In the TachoComb group, capillaries were directed toward the effusion at 2 weeks, while in the Avitene group, a similar phenomenon was not observed. The vasculature was incomplete, with either effusion or infection at 5 weeks in the Avitene and TachoComb groups. Material was recognized up to 4 weeks in the TachoComb group, whereas the space occupied by material remained vacant without vasculature in the Avitene group. Our results suggest that cotton type configuration is excellent as a collagen hemostat, with smooth capillary infiltration, rapid resorption of material and promotion of the healing process.

A 3-year-old girl was given a diagnosis of coronary arteriovenous fistula associated with a single right coronary artery on cardiac catheterization. The left coronary artery arose from the proximal part of the right coronary artery. The dilated left coronary artery ran in front of the right ventricular outflow tract and then divided into the left anterior descending branch and the left circumflex artery. A coronary arteriovenous fistula was in the left main coronary artery and opened into the right ventricular outflow tract. Under cardiopulmonary bypass and cardiac arrest, a transverse incision was made at the right ventricular outflow tract 1cm below the dilated vessel and the 5-mm oval-shaped orifice of the fistula was identified. This fistula was closed with a pledgetted mattress suture reinforced with over-and-over suture. Catheterization 8 months after surgery demonstrated no residual shunt and she has been doing well.

When local hemostatic agents are used in surgery, rapid dissolution followed by prompt absorption without adverse effect after successful hemostasis are essential qualities. Residual hemostatic materials greatly influence host cells during the wound healing process. Biocompatibility of material is also essential. Furthermore, hemostatic agents also should be free of cytotoxicity that may block mitosis and migration of host cells, so that wound healing can proceed smoothly. For the evaluation of biocompatibility and cytotoxicity, 4 commercially available hemostatic agents; oxidized regenerated cellulose (Surgicel^®), gelatin sponge (Spongel^®), microfibrillar collagen (Avitene^®) and cotton type collagen (Integran^®) were tested in vitro and in vivo. The hydrogen ion concentration (pH) of culture medium containing hemostatic agents was measured. Fibroblasts were cultured with the hemostatic agents in petri dishes for 5 days. A rabbit ear chamber (REC) model was used to evaluate tissue compatibility and the healing process. Each hemostatic agent was placed in the REC and evaluated macroscopically once a week up to 5 weeks. At 72h, the pH of the culture medium containing Surgicel was low at 7.2, while they stayed between 7.7-7.8 with the other agents. In the fibroblast culture containing Surgicel, cell detachment occurred and the cell numbers decreased, while no particular changes occurred with other hemostatic agents. In the REC model, after 5 weeks Surgicel was dissolved and remained in the effusion, and the healing process was disturbed by inflammation. Spongel was dissolved and absorbed, with normal vasculature. Avitene was dissolved and remained in the effusion, but did not induce strong inflammation. With Integran, the healing process was prompt but the material was still recognizable at 5 weeks. The 4 hemostatic materials tested showed differences in biocompatibility and cytotoxicity. The ability of hemostasis is important; however, after hemostasis is achieved, unused hemostatic material should be eliminated, leaving as little hemostatic agent as possible to avoid postoperative complications.