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We successfully introduced minimally invasive cardiac surgery (MICS) to japan by performing thoracoscopic clipping of a patent ductus arteriosus in July 1992. MICS via a small right parasternal incision (Cosgrove procedure) was applied for one patients with severe rheumatic mitral stenosis, one with severe aortic regurgitation, and one with atrial septal defect (ASD). Mitral valve replacement (MVR), aortic valve replacement (AVR), and direct closure of the ASD were performed successfully by MICS for the the first time in Japan. All three patients required no blood transfusion and had no complications postoperatively, being discharged from hospital at 15, 13, and 9 days after their operations. MICS was satisfactory for mitral valve and ASD operations, but AVR by this approach took much longer than by standard midline sternotomy due to the poor surgical field obtained via the small right parasternal incision. A minimally invasive approach for surgery on the aortic valve and ascending aorta may require transection of the sternum or some other method. MICS has several advantages, including less trauma and pain, faster patient recovery, shorter ICU and hospital stays, a lower cost, and a better cosmetic outcome. Therefore, it is better for the patient when it is feasible. MICS should develop and be applied to more patients with cardiovascular disease in the future. Some of the standard cardiovascular operations may soon be replaced by MICS.

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Oligomerization of alpha-adenosine 5'-phosphorimidazolide (alpha-ImpA) has been done in an aqueous solution using a uranyl-ion catalyst or a poly(U) template as a model process of prebiotic synthesis of RNA with alpha-glycosidic linkage. alpha-Oligoriboadenylates up to hexamer were formed from alpha-ImpA by the uranyl-ion catalyst. 3'-5' Linkage was mainly formed in the oligomerization. The poly(U) template mediated the oligomerization of alpha-ImpA, but to a very low extent. The yield and chain length of the resulting alpha-oligomers were far lower than those of the corresponding beta-oligomer formation under the same conditions. Physico-chemical properties of alpha-oligoriboadenylates are presented along with those of the corresponding beta-oligoriboadenylates. The results indicate that beta-RNA is more advantageous than alpha-RNA from the points of their synthesis and properties.

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Preservation of the donor heart is an important and controversial subject in heart transplantation. The donor's heart function must be maintained at the most viable state possible. This study examined the effectiveness of LHB in cases of brain death and clarified the possibility of this application for donors as a bridge to heart transplantation. Changes in hemodynamic parameters and histological findings in brain-dead dogs were studied. Two groups of brain-dead dogs were involved in this study: group L (n = 10) as a LHB support and group C (n = 10) as a control. Brain death was induced by an ethanol injection into the subdural space of the dogs. This condition was maintained with volume replacement and dobutamine administration (5 micrograms/kg/ min). In group L, LHB that was achieved with a transaortic valve left ventricular drainage cannula inserted from a carotid artery and return via a femoral artery cannula was performed after brain death. A Bio-pump was utilized for the kind of assist device. Left ventricular output assist ratio averaged 60%. The parameters of left ventricular function (Max. dp/dt, Emax) at the time of brain death deteriorated by about 70%. In group L, they could keep this level over the 6-hr study period. On the other hand, the Emax value at 3 hours and the Max. dp/dt value at 4 hours decreased significantly when compared to the time of brain death (0-hr) for group C. At the 6-hr study period, histological findings showed only minimal change in the myocardium with slightly interstitial edema in group L. On the other hand, severe ischemic change in the myocardium with many contraction bands was found in group C. This data suggests that LHB is effective to preserve heart function in cases of brain death. This application may make it possible to maintain the viability of other organs by maintaining circulatory blood flow and pressure.

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Alpha-Adenosine analogs of 2'-5'Oligoadenylates (alpha 2-5 A) were synthesized by uranyl ion-catalyzed oligomerization of alpha-adenosine-5'-phosphorimidazolide in aqueous solution. alpha-Anomeric 3'-5'oligoadenylates were simultaneously formed in the oligomerization reaction. Physicochemical and biochemical properties of the resulting alpha 2-5 A were studied by spectroscopic and enzymatic method.

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A new video-assisted thoracoscopic surgery was applied to patients with patent ductus arteriosus (PDA). After the ductus was carefully dissected and exposed, two or one titanium clips which were 11 mm in length were used to interrupt the ductus completely. Eight patients with PDA were successfully treated by the new technique between July 1992 and September 1993, which was the first successful series in Japan. Mean age was 4.3 years (range 1.7 approximately 6.7 years) and mean weight was 15.6 kg (range 10.0 approximately 24.0 kg). All patients had immediate complete PDA closure after the procedure which was proved to be successful by an esophageal stethoscope and color doppler echocardiogram. One patient had mild left recurrent laryngeal nerve dysfunction which was completely cured on 7th postoperative day. There were no other complications and the usual hospital stay was 4 or 5 days. No residual PDA shunt in all cases was revealed by color doppler echocardiogram during follow-up periods (range 3 approximately 12 months). The advantages of thoracoscopic surgery for PDA are: less postoperative pain and discomfort, early recovery and short hospital stay, and cosmetic preservation. Availability of smaller sized surgical instruments should allow this technique indicated for smaller children and premature infants.

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A 5-year-old girl with patent ductus arteriosus (PDA) was successfully treated by thoracoscopic surgery, which was the first successful case in Japan. The operation was carried out under general anesthesia with the usual endotracheal intubation. Short trocars were inserted through the left intercostal spaces to introduce a flexible video thoracoscope and adequate surgical instruments. After the ductus was carefully dissected and exposed, two titanium clips, 11 mm in length, were applied to interrupt the ductus completely. The continuous heart murmur of PDA disappeared, as confirmed by an esophageal stethoscope. Postoperative course was uneventful and the patient was discharged on the 6 postoperative day. Eighteen months after surgery, no residual PDA shunt was revealed by doppler echocardiogram. The advantages of thoracoscopic surgery for PDA are less postoperative pain and discomfort, early recovery and short hospital stay, and cosmetic preservation. Availability of smaller sized surgical instruments should allow smaller children or newborns with PDA to be treated with this method.

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A five-year-old girl with patent ductus arteriosus (PDA) was successfully treated by thoracoscopic surgery, which was the first successful case in Japan. The operation was carried out under general anesthesia with usual endotracheal intubation. Short trocars were inserted through the left intercostal spaces to introduce a flexible video thoracoscope and adequate surgical instruments. After the ductus was carefully dissected and exposed, two titanium clips which were 11 mm in length were applied to interrupt the ductus completely. The continuous heart murmur of PDA was confirmed to disappear by an esophageal stethoscope. Postoperative course was uneventful and the patient was discharged on 6 postoperative day. No residual PDA shunt was revealed by doppler echocardiogram 8 months after surgery. The advantages of thoracoscopic surgery for PDA are: less postoperative pain and discomfort, early recovery and short hospital stay, and cosmetic preservation. Availability of smaller sized surgical instruments should allow this method indicated for smaller children or newborns with PDA.

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A 67-year-old man with mitral regurgitation underwent mitral valvoplasty and annuloplasty successfully. Combined superior transseptal approach was adopted to expose the mitral valve, because the left atrium was small. The exposure of the mitral valve was excellent. But this approach cannot avoid damaging the sinus node artery, so that why the sinus node function was examined electrophysiologically before and after the operation. Sino-atrial conduction time (SACT) and corrected sinus node recovery time (CSRT) were measured as the indices of the sinus node function. Both SNCT and CSRT after the operation was within normal range. As far as this case, combined superior transseptal approach, which gave good exposure of the mitral valve but needed to cut the sinus node artery, did not deteriorate the sinus node function.

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An adult case of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) was presented. A 37-year-old male was admitted for ventricular arrhythmia and chest pain. The catheterization, left ventriculography and coronary arteriography revealed ALCAPA with anterolateral ventricular aneurysm and mild mitral regurgitation. An operation using Takeuchi procedure was performed. The postoperative course was uneventful and the results of the catheterization, left ventriculography and coronary arteriography performed immediately and five years after the operation were excellent except mild supravalvular pulmonary stenosis. Six years later, the patient is asymptomatic and well.

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A case of aortic stenosis complicated with complete atrioventricular block preoperatively was reported. The patient was a 73-year-old woman who had been suffering from dyspnea and fatigability. Preoperative echocardiography revealed severe left ventricular hypertrophy, marked left ventricular-aortic pressure gradient (144 mmHg), and the impairment of left ventricular distensibility. Therefore, DDD pacemaker was implanted in addition to aortic valve replacement. Postoperative cardiac catheterization revealed that cardiac output was increased about 25% by DDD pacing compared with VVI pacing. It is more reasonable to employ DDD pacemaker to the case of which distensibility is impaired.

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