[Successful management of ruptured aortic arch aneurysm infected with methicillin-resistant Staphylococcus aureus].

A 64-year-old woman was admitted due to back pain and dyspnea. She was suffering from fever of unknown origin for a few weeks without aortic aneurysm by enhanced chest computed tomography (CT). Chest CT taken 1 month later revealed rupture of aortic arch aneurysm. Total arch replacement was performed with in situ grafting under selective cerebral perfusion combined with deep hypothermic circulatory arrest. Rifampicin (RFP) was sprinkled on the graft at operation and omentopexy was done 5 days after the 1st operation. Methicillin-resistant Staphylococcus aureus (MRSA) was isolated on the culture of the aneurysmal wall, therefore, polymyxin B immobilized fiber with direct hemoperfusion (PMX-DHP) was also conducted with antibiotic therapy. Her clinical course after the 2nd operation was uneventful with no infective complication. We report a successful case of ruptured aneurysm of aortic arch infected with MRSA and review our strategy as one of feasible options without using homograft or preparative RFP-bonded vascular prosthesis.

[Atrial rupture due to blunt chest trauma].

Atrial rupture by blunt trauma is lethal and one of controversial problems for cardiovascular surgeons, because of complexed conditions due to multiple organ injuries. Some papers recommend strategy of early diagnosis and treatment at an acute phase for better clinical course, but high mortality rate has not been improved yet, especially that of left atrial rupture. Three patients were reffered to our hospital by blunt chest trauma, one of whom died due to hemorrhagic shock before receiving surgical or interventional treatment. The remaining 2 patients had surgical operations at an early phase and were discharged without severe complications. We review our strategy of atrial rupture of blunt chest trauma. At an acute phase, atrial rupture alone should be repaired urgently unless use of cardiopulmonary bypass is contraindicated by severe hemorrhage of the other organs.

Analysis of 2-carbon-11-thymidine blood metabolites in PET imaging.

UNLABELLED: Carbon-11-thymidine labeled in the ring-2 position was used with PET to image tumor and tissue proliferation. Since thymidine is rapidly degraded in the body, one must consider the generation of metabolites to fully interpret the PET data. METHODS: We have measured the blood time-activity curves of thymidine and its metabolites in arterial blood samples. Blood was processed to obtain three input curves, including the total activity, the activity with CO2 removed and the fraction of CO2-free activity in intact thymidine (% Tdr). RESULTS: We found that CO2 reached a plateau of 65% (+/- 12%) of total blood activity by 11 min after injection. When a 1-min infusion of labeled thymidine is used, the time to 50% degradation to thymine and metabolites other than CO2 (measured in acidified samples by HPLC) was 2.9 +/- 0.6 min. We fit the results of the blood metabolism with a compartmental model. We found that we could accurately determine the % Tdr curve with as few as three measured points with an root mean square (RMS) error of 2% in the integrated curve, compared to the curve using all blood samples (mean of seven samples per patient). The integral of thymidine blood activity serves as the input to thymidine models, so similar errors could be expected in calculations of DNA synthetic rates. We found that the determination of CO2 could be accomplished with as few as five samples, with an RMS error of 4% in plateau %CO2 value. CONCLUSION: While it is essential to take metabolites into account when interpreting results obtained with 11C-thymidine, the reproducibility of these degradation curves may allow the use of a limited number of samples to measure the catabolic products of thymidine. These data from the blood, along with tissue kinetic models, are needed to calculate DNA synthetic rates.

Contribution of labeled carbon dioxide to PET imaging of carbon-11-labeled compounds.

11CO2 is one of the major metabolites of many [11C]-labeled radiopharmaceuticals, including glucose, thymidine, acetate, amino acids, and fatty acids. Our data contradict the notion that the contribution of labeled CO2 to PET images can be disregarded because of its rapid elimination through the lungs. We have measured the retention and excretion of 11CO2 in dogs after the intravenous injection of labeled CO2/HCO3-, which had been equilibrated ex vivo with blood. Only 58% of the label was exhaled as CO2 over the first 60 min after injection, with the rest retained in the body. The injection of [11C]thymidine labeled in the ring-2 position or [11C]acetate labeled in the carboxylate position resulted in the production of large amounts of labeled CO2 with the exhalation of about 47% and 23%, respectively, of the injected label over 60 min. At 10 min after injection of either [11C]thymidine and [11C] acetate, approximately 60% to 70% of total blood activity was in labeled CO2 or bicarbonate. On the other hand, the use of [1-11C]glucose only resulted in exhalation of 5% of the injected dose and CO2/HCO3- made up less than 10% of blood activity at 10 min. Our results indicate that retention and distribution of labeled CO2 needs to be considered when interpreting PET data obtained from 11C-labeled compounds.

Carbon-11-thymidine and FDG to measure therapy response.

UNLABELLED: This study was performed to determine if PET imaging with 11C-thymidine could measure tumor response to chemotherapy early after the initiation of treatment. Imaging of deoxyriboneucleic acid biosynthesis, quantitated with 11C-thymidine, was compared with measurements of tumor energetics, obtained by imaging with 18F-fluorodeoxyglucose (FDG). METHODS: We imaged four patients with small cell lung cancer and two with high-grade sarcoma both before and approximately 1 wk after the start of chemotherapy. Thymidine and FDG studies were done on the same day. Tumor uptake was quantified by standardized uptake values (SUVs) for both tracers by the metabolic rate of FDG and thymidine flux constant (K(TdR)) using regions of interest placed on the most active part of the tumor. RESULTS: In the four patients with clinical response to treatment, both thymidine and FDG uptake markedly declined 1 wk after therapy. Thymidine measurements of SUV and K(TdR) declined by 64% +/- 15% and 84% +/- 33%, respectively. FDG SUV and the metabolic rate of FDG declined by 51% +/- 9% and 63% +/- 23%, respectively. In the patient with metastatic small cell lung cancer who had disease progression, the thymidine SUV decreased by only 8% (FDG not done). In a patient with abdominal sarcoma and progressive disease, thymidine SUV was essentially unchanged (declined by 3%), whereas FDG SUV increased by 69%. CONCLUSION: Images show a decline in both cellular energetics and proliferative rate after successful chemotherapy. In the two patients with progressive disease, thymidine uptake was unchanged 1 wk after therapy. In our limited series, K(TdR) measurements showed a complete shutdown in tumor proliferation in patients in whom FDG showed a more limited decrease in glucose metabolism.

Skeletonization and harvest of the internal thoracic artery with an ultrasonic scalpel.

A new method to skeletonize and harvest the internal thoracic artery using an ultrasonic scalpel is presented. The technique is simple, safe, and minimally invasive. It is possible to obtain sufficient vessel length for anastomosis to most coronary arteries for bypass grafting.

Retrograde cerebral perfusion versus selective cerebral perfusion as evaluated by cerebral oxygen saturation during aortic arch reconstruction.

BACKGROUND: Time limits for neuroprotection by retrograde cerebral perfusion (RCP) and selective cerebral perfusion (SCP) in aortic arch aneurysm repair or dissection are undergoing definition. METHODS: Using near-infrared optical spectroscopy, changes in regional cerebrovascular oxygen saturation (rSO2) were compared between the two perfusion methods. RESULTS: Immediately before cardiopulmonary bypass, baseline rSO2 was 63.9%+/-6.9% for the RCP and 66.1%+/-5.3% for the SCP group (no significant difference). As patients were core-cooled to 20 degrees C, rSO2 increased to 73.1%+/-8.8% and 74.1%+/-7.9% in the RCP and SCP groups, respectively. With circulatory arrest, rSO2 suddenly decreased. After starting cerebral perfusion, rSO2 returned to prearrest values in the SCP group but continued decreasing steadily in the RCP group, to levels below baseline after about 25 minutes. At the end of perfusion, rSO2 was 57.4%+/-12.2% for the RCP group and 71.7%+/-6.9% for the SCP group, and the ratio of rSO2 to baseline value was 0.89 for RCP and 1.08 for SCP despite a shorter brain perfusion time for RCP (38.8+/-18.0 versus 103.3+/-43.3 minutes). Three of 5 patients whose ratios of rSO2 to baseline at the end of brain protection were 0.7 or less had neurologic deficits. CONCLUSIONS: Although SCP showed no clinically important time limitation, rSO2 continued to decrease with time during RCP. An rSO2 ratio less than 0.7 could represent a critical lower limit.

Development of labeled thymidine analogs for imaging tumor proliferation.

We have sought nucleoside analogs suitable for labeling with F-18 that could be used to image tumor proliferation with positron emission tomography (PET). The following three thymidine analogs were labeled with tritium and screened for their catabolism and biodistribution in vivo in mice: 5-fluoro-1-(2'-deoxy-2'-fluoro-beta-D-ribofuranosyl)uracil (FFUdR), 5-fluoro-1-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-uracil (FFaraU) and 5-methyl-1-(2'-deoxy-2'-fluoro-beta-D-ribofuranosyl)uracil (FTdR). We found that all three compounds were stable to degradation in vivo and when incubated in blood. Of the three analogs tested, only FFUdR showed preferential retention in rapidly proliferating tissues, such as the spleen and implanted tumors, and it attained tissue to blood ratios of 2.1 at 2 h.

Radiosyntheses of labeled beta-pseudothymidine ([C-11]- and [H-3]methyl) and its biodistribution and metabolism in normal and tumored mice.

In order to develop labeled probes for measuring DNA synthetic rates in vivo we investigated [H-3]- and [C-11]methyl labeled beta-pseudothymidine (2a), and report on their radiosyntheses from methyl iodide. We find methylation is rapid and regioselective on N-1 of the acylurea moiety of 2'-deoxy-beta-D-pseudouridine (1a), in the presence of N,N-diisopropylethylamine and N,N-dimethylformamide at 60 degrees C. Although yields are low (11% [C-11]-decay corrected and 4.4% [H-3]), the method is simple and high specific activity tritiated methyl iodide can be used. In contrast to the rapid degradative de-glycosylation of thymidine in blood, beta-pseudothymidine is stable. However, based on biodistribution and metabolite studies, the anticipated uptake of [H-3]methyl-beta-pseudothymidine into mouse DNA of proliferating tissues (e.g. spleen, thymus and duodenum) and implanted tumors was not observed.

Two cases of aorto-gastrointestinal fistula.

We report two cases of aorto-gastrointestinal fistula. Case 1, a 60-year-old man, suffered from repeat hematemesis. He was preoperatively diagnosed as aortoesophageal fistula with thoracic aortic aneurysm and was successfully treated by graft replacement of the aneurysm. Case 2, a 73-year-old man, presented with massive gastrointestinal bleeding, yet repeat endoscopical examination did not reveal the origin of the bleeding. He died of catastrophic hematochezia. The pathological findings at autopsy revealed an aortoduodenal fistula. These two cases suggested the importance to consider an aorto-gastrointestinal fistula in the differential diagnosis of patients presenting gastrointestinal hemorrhage.

Coronary artery bypass grafting using the "Super Pulse" dynamic pulsatile cardiopulmonary bypass device in patients with cerebrovascular occlusive disease.

Patients with coronary disease complicated by severe carotid or intracranial arterial stenosis underwent coronary artery bypass graft surgery (CABG) using a novel method of dynamic pulsatile cardiopulmonary bypass (Super Pulse CPB). The Super Pulse technique can maintain the systolic pressure and systolic-diastolic amplitude in such a way that they mimic the physiologic circulation. Forty-five patients (33 males and 12 females, mean age 65.1 years) with coronary disease who had a greater than 75% stenosis of the carotid or intracranial arteries were evaluated. Evaluation was performed for the following 3 groups: 8 patients with conventional pulsatile CPB (Group I), 8 patients with conventional pulsatile CPB plus intraaortic balloon pumping (Group II), and 29 patients with Super Pulse CPB. Maximum, minimum, and mean perfusion pressures during CPB were 112.7, 53.6, and 76.9 mmHg (integrated mean), respectively, in Group III. The systolic-diastolic amplitude was significantly better than for Group I and similar to baseline pressures. No patients in Group II or Group III developed perioperative cerebral disorders or myocardial infarction, while in Group I perioperative cerebral disorders developed in 3 patients, myocardial infarction occurred in 2 patients, and 2 patients died during hospitalization. The initial performance of the Super Pulse CPB indicates excellent safety, and is useful for patients with co-morbid cerebral arterial disease.

Minimally invasive direct coronary artery bypass grafting using the gastroepiploic artery for reoperation after the Cabrol procedure.

Obstruction of the right coronary ostial anastomosis is a rare late complication after composite graft replacement of the ascending aorta and the aortic valve with separate Dacron coronary grafts (Cabrol method). Occlusion at the right coronary ostial anastomosis in a 36-year-old woman with aortitis syndrome who underwent a composite graft with a Dacron coronary graft is described. She underwent a third successful operation for right coronary reconstruction by minimally invasive direct coronary artery bypass grafting technique using the right gastroepiploic artery. This approach is likely to be extremely useful in avoiding resternotomy and cardiopulmonary bypass in patients requiring coronary reoperation.

[A case of acute aortic dissection with aortic regurgitation successfully treated by postoperative ECMO].

A case of acute aortic dissection (Stanford Type A) with severe aortic regurgitation successfully treated by postoperative ECMO was reported. The patient was 41-year-old man in shock condition and was transferred to Kobe University Hospital. Chest CT scan and echocardiogram revealed acute aortic dissection with severe aortic regurgitation. An emergent operation by Collins' method and resuspension of aortic valve were carefully performed. Consequent ECMO was necessitated because of postoperative left ventricular and respiratory failure. Thereby, ECMO using heparin-coated CBAS-MAXIMA membrane oxygenator, centrifugal pump, and tubes was established by arterial cannulation via the anastomotic site of the ascending aorta to prevent the obstruction of the aortic true lumen by the false lumen which may be enlarged by retrograde perfusion via the femoral artery. Left ventricular function and pulmonary function were improved after 6 hours and 20 minutes, thus ECMO was successfully weaned without any complications.

[Mitral valve repair for the treatment of ischemic mitral regurgitation].

Twenty-six patients with moderate and severe ischemic mitral regurgitation due to papillary muscle dysfunction underwent mitral valve replacement (MVR) or mitral annuloplasty (MAP) using modified Kay method. Emergent operation was performed in 12 patients of whom 11 had severe congestive heart failure even under IABP, 5 had cardiogenic shock and 9 needed respiratory care with intubation preoperatively. Elective operation was performed in 14 patients of whom 6 had history of congestive heart failure and 1 had episodes of ventricular tachycardia. As intraoperative findings of mitral valve, mural annular dilatation in 84.6%, prolapse of anterior leaflet in 23.1%, papillary muscle scar in 15.4%, chordal elongation in 15.4% and chordal rupture in 3.8% were seen separately or in combination. In 22 patients MAP using modified Kay method and CABG were performed, but in 4 patients MVR was needed because of the prominent prolapse of the anterior leaflet. Fourteen patients who underwent MAP with CABG and one MVR with CABG survived. Hospital mortality was higher in emergent (58.5%) than elective operation (28.6%). In the 15 survivors, mitral regurgitation decreased below Sellers 2, pulmonary wedge pressure decreased significantly (p < 0.01) and NYHA functional class improved to I or II postoperatively. During the follow up period of 15-100 (mean 38.7 +/- 21.6) months, 2 MAP+CABG patients died suddenly, but the remaining 13 patients were in NYHA class I or II and no progression of MR was seen. These results indicated that MAP+CABG is recommendable in the treatment of ischemic mitral regurgitation due to papillary muscle dysfunction, in order to preserve cardiac function and to reduce valve related complications.

[Closure of patent ductus arteriosus in elderly cases].

A technique for closure of patent ductus arteriosus in the elderly cases is described. We have operated on eleven adult cases of patent ductus arteriosus cases in 10 years. In five cases cardiopulmonary bypass used and in the other six cases it was not used. The cardiopulmonary bypass was used especially for the patients with pulmonary hypertension (pulmonary artery mean pressure greater than 40 mmHg), or high aged (older than 40 years) patients. No operative death have occurred in both groups, and no complication from air embolism or hemorrhage have been encountered. The technique embodies the profound hypothermia, low flow, and direct suture of the pulmonary end of the ductus arterious through a pulmonary arteriotomy. The ductus has been obstructed by using a Hegar's dilator before core cooling was started. Hegar's dilator is useful for establishing profound hypothermia and satisfactory visualization of the operative field.

[Management of coronary artery disease combined with aortic stenosis: how to do with mild aortic stenosis].

A total of fourteen patients with combined operation of coronary artery bypass grafting (CABG) and aortic valve replacement (AVR) for coronary artery disease (CAD) and aortic stenosis (AS) were reviewed to evaluate the indication of the combined operation. Preoperative pressure gradient across the valve and effective orifice area were 21-89 mmHg (mean 64 mmHg), 0.5-1.9 cm2 (mean 0.92 cm2), respectively. The extent of CAD was 1-3 (mean 2.0). Fractional shortening (%FS) ranged from 13% to 43% with mean value of 28%. All patients underwent CABG and AVR. The number of grafts was 1-4 (mean 2.3) with internal thoracic artery used in 7 cases. Mechanical valves were employed for all patients except 1 case with cerebral aneurysm. There was no operative death, although low output syndrome developed in 2 cases. One had poor left ventricular function preoperatively, and the other was emergency case. Fractional shortening improved postoperatively even in two cases with preoperative %FS less than 20%, and all grafts were patent on postoperative coronary angiography. The event-free survival was 100% during 32 months of mean follow-up. Combined AVR with CABG is recommended to avoid risky secondary operation in patients of CAD and AS, even if one of which is relatively mild, because of the fact that operative and late results of the combined surgery are satisfactory.

[Long-term result and its evaluation after aorto-coronary bypass grafting].

Since a first successful A-C bypass using saphenous vein graft was performed in 1970, eighty five patients with severe coronary heart disease were operated on in our clinic. Up to date, A-C bypass was carried out in sixty four cases, and aorto-coronary sinus bypass (Ao-Cs bypass) as an arterialization of the coronary venous system was done in one case in the group of angina pectoris. Three cases among sixty four patients who underwent A-C bypass and a case of Ao-Cs bypass died of low cardiac output syndrome postoperatively. Other two cases died of refractory arrhythmia and cardiomyopathy 6 years after surgery. The remaining fifty nine cases are doing well without any complications during follow up from ranging 2 months to 13 years (mean 3 years 4 months). Recently, no operative death was found during past 8 years with development of surgical technique and myocardial protection. Ventricular function (cardiac index, LVedp, Max LV dp/dt, EF, LVEDVI , double products at rest and during treadmill exercise test) disclosed good results especially in complete revascularization group. Graft patency had a close correlation between a diameter of the coronary artery at the anastomosis site and bypass graft flow after completion of bypass. Subsequently, a good patency rate (84%-86%) was obtained in cases with the coronary artery more than 1.5 mm in diameter. It could be concluded that A-C bypass was useful procedure to improve ventricular function as well as clinical symptoms and longevity of the life.