Sumio Nitta

Wallstent endovascular prosthesis for the treatment of superior vena cava syndrome.

OBJECTIVE We assessed the clinical outcome of self-expanding Wallstent endovascular prosthesis in the treatment of superior vena cava syndrome due to malignant tumors. METHODS Eleven patients with malignant superior vena cava syndrome were treated by percutaneous implantation of the self-expanding Wallstent endovascular prosthesis across the stricture site. Patency was defined by the absence of symptoms and signs of superior vena cava syndrome. RESULTS Ten of the 11 experienced complete symptomatic relief within 3 days of stent implantation. The remaining 1 did not benefit, and required a second procedure, dying of heart failure 5 days after stent implantation. Ten patients remain symptomatically free of superior vena cava syndrome to date or until death in follow-up lasting 17 to 227 days. CONCLUSION Implantation of the self-expanding Wallstent endovascular prosthesis for malignant superior vena cava syndrome provides rapid symptomatic relief and improves the patients quality of life.

Computer simulation of geometry and hemodynamics of canine pulmonary arteries

Assuming that along the pulmonary arteries, mathematical expectations of branching are equal to matrix (Ei,j; i: parent branch class, j: daughter branch class number), we made computer drafts of patterns of pulmonary arterial branching trees from the published data of canine pulmonary arterial casts with the “Monte Carlo methods” by FORTRAN, calculating from these data, the numbers of branches, size and resistance of the trees. We also analyzed blood flow distribution in a pulmonary branch according to the pathlength from the entrance of the tree. The graphics of the trees were similar to the original arterial casts, and numbers of the branches were nearly the same as the previous reported values. Calculated resistance was reasonable. The rate of blood flow per unit vessel in the short pathlength group was calculated as 1.5 times that of the long pathlength group of the same diameter. We believe that our method of describing the branching pattern matrix (Ei,j) provides a reasonable simulation of complex branching patterns such as pulmonary arteries and a useful means to analyze local hemodynamics.

Nitinol stent for the treatment of tracheobronchial stenosis

OBJECTIVE The purpose of this study was to evaluate the potential utility of implantation of a nickel-titanium alloy (nitinol) stent for the treatment of malignant or benign tracheobronchial stenosis. METHODS We evaluated 18 patients (14 men and 4 women) who received 24 nitinol stents, between November 1997 and May 2000. All 18 patients had severe dyspnea caused by tracheobronchial stenosis. The underlying condition was malignant disease in 15 patients, and benign tracheal collapse in the other 3 patients. RESULTS Implantation of the stent was successfully performed in all patients. Seventeen patients experienced immediate clinical improvement in respiratory symptoms. The remaining 1 patient with a bronchial fistule after lobectomy did not benefit, and died of pneumonia at 16 days after the implantation. In 15 patients, the procedure was performed using a flexible bronchoscope under local anesthesia alone, while the remaining 3 patients needed intravenous sedation. There was no complication resulting from the stent implantation. Among the 3 patients with benign tracheal collapse, 2 patients were alive at 746 and at 401 days after the stent implantation, at the time of this report. One patient with cicatricial stenosis after intubation died of heart failure due to previous myocardial infarction. Among the 15 patients with malignant disease, 4 patients have survived for 177 to 305 days to date, while the other 11 patients have died of primary malignancy with a mean survival duration of 60.2 days. CONCLUSION The nitinol stent was effective in treating malignant or benign tracheobronchial stenosis, and had some remarkable advantages compared with other tracheobronchial stents. In stenting, most procedures can be performed using flexible bronchoscope under local anesthesia.

Pulmonary multiple metastases of ovarian granulosa cell tumor 15 years after initial diagnosis

We report a case of multiple pulmonary metastases occurring 15 years after an ovarian granulosa cell tumor was initially diagnosed. A 62-year-old woman undergoing left salpingo-oophorectomy for a granulosa cell tumor of the left ovary 15 years earlier presented with abnormal chest shadows. Computed tomography of the chest confirmed the presence of 3 well-defined nodular lesions, and Computed tomography of the abdomen and pelvis revealed a 3.5 x 2.5 cm partially solid, cystic pelvic mass. Left thoracotomy was conducted and tumors diagnosed a pulmonary metastases of a granulosa cell tumor. The pelvic mass was resected and infracolic omentectomy then conducted with total hysterectomy and right salpingo-oophorectomy including the adherent rectal segment. The pelvic mass proved to be a granulosa cell tumor. Adjuvant combination chemotherapy was started every 3 weeks and the woman has remained disease-free for 9 months.

Combined thoracic aortic or upper digestive tract resection for lung cancer and malignant mediastinal tumor

OBJECTIVE We studied possible indications and combined resection in patients with lung cancer and mediastinal tumors requiring combined thoracic aortic or upper digestive tract resection. METHODS Ten patients with lung cancer and malignant mediastinal tumors (9 men and 1 woman aged 39 to 72 years; mean: 60.5) underwent combined aortic or upper digestive tract resection. RESULTS Five--3 [corrected] with primary lung cancer, 1 with thymic cancer, and 1 with liposarcoma--, underwent combined aortic resection. In 2 each, lung cancer and malignant mediastinal tumor had infiltrated the thoracic aorta. The remaining case of lung cancer was complicated by aortic aneurysm in the distal arch. Cardiopulmonary bypass was conducted in 4, and selective cerebral perfusion in 2. Three patients are alive after 11, 22, and 61 months without disease recurrence. Those undergoing combined upper digestive tract resection all had lung cancer, with 4 having tumors infiltrating the esophagus or corpus ventriculi. The remaining patient had both lung and esophageal cancer. The patient treated with combined corpus ventriculi resection has survived 24 months and the patient treated with combined esophageal resection has survived 12 months without disease recurrence. The 1-year survival rate was 60%, 2-year 23%, and 3-year 23%. Prognosis was generally poor with the longest survival 13 months with N2 lung cancer. CONCLUSIONS In combined resection due to malignant mediastinal tumor, T4N0-1 lung cancer, or diseases such as aortic aneurysm, prognosis can be expected to improve. Despite the often poor prognosis in T4N2 lung cancer, surgical intervention may be indicated to avoid complications due to tumor invasion and to lengthen survival and improve quality of life.

Measurement of antiacetylcholine receptor antibody in patients with thymoma without myasthenia gravis complications

OBJECTIVE Some patients with thymoma reported to show higher antiacetylcholine receptor antibody titers without the preoperative occurrence of myasthenia gravis and some have suffered postoperative complications of myasthenia gravis despite being negative for antiacetylcholine receptor antibody preoperatively. We evaluated changes in antiacetylcholine receptor antibody titers and the occurrence of myasthenia gravis in thymoma patients. METHODS Subjects were 31 of 44 patients with thymoma undergoing thymothymectomy at Tokyo Womens Medical University Hospital between 1987 to 1999 in whom antiacetylcholine receptor antibody titers were measured preoperatively. We studied postoperative changes in antiacetylcholine receptor antibody titers and the presence or absence of myasthenia gravis. RESULTS Eight patients were positive for antiacetylcholine receptor antibody preoperatively, suggesting the presence of subclinical myasthenia gravis. Neither postoperative changes in antiacetylcholine receptor antibody titers nor the occurrence of myasthenia gravis was observed in these 8 patients. Recurrent thymoma and rapid elevation of antiacetylcholine receptor antibody titers were observed postoperatively in 1 patient negative for antiacetylcholine receptor antibody preoperatively, resulting in manifestation of myasthenia gravis symptoms. CONCLUSION We found no correlation between preoperative titers and myasthenia gravis symptoms. Rapid titer elevation indicates the occurrence of myasthenia gravis symptoms or the recurrence of thymoma.

Clinical assessment of unilateral pulmonary artery occlusion test with dobutamine infusion. Expansion of surgical indications in patients with primary lung cancer and impaired cardiopulmonary functions.

OBJECTIVES We evaluated the possibility of expanding indications for pulmonary resection based on an assessment of the pressure-flow relationship in pulmonary circulation. METHODS In 6 of 28 lung cancer patients whose total pulmonary vascular resistance index exceeded the threshold during unilateral pulmonary artery occlusion testing, we conducted unilateral pulmonary artery occlusion testing with dobutamine administration, followed by lung resection. We studied hemodynamics during testing and derived a new indication for pulmonary resection from the postoperative course. RESULTS Cardiac output was 3.82 +/- 0.74 l/min before testing, 3.66 +/- 0.76 l/min during pulmonary artery occlusion testing, and 5.92 +/- 1.78 l/min during unilateral pulmonary artery occlusion testing with dobutamine infusion. The total pulmonary vascular resistance index was 890 +/- 350 dyne.sec.cm-5.m2 before testing, 1170 +/- 320 dyne.sec.cm-5.m2 during testing, and 800 +/- 160 dyne.sec.cm-5.m2 during testing with dobutamine infusion. Cardiac output increased (p = 0.014) during unilateral pulmonary artery occlusion testing with dobutamine infusion, and the total pulmonary vascular resistance index significantly decreased (p = 0.034). Of the 4 patients eligible for lobectomy, 2 underwent the procedure--one undergoing segmentectomy in which pulmonary metastasis was found during surgery and the other undergoing radiotherapy for cN2 disease with chest wall invasion. Of the 2 initially ineligible for lobectomy, one underwent partial pulmonary resection and the other underwent lobectomy because the total pulmonary vascular resistance index was less than 800 dyne.sec.cm-5.m2 during selective pulmonary artery occlusion testing with dobutamine infusion, indicating eligibility for lobectomy. No severe complications of cardiopulmonary function failure after surgery occurred in any of the 5 cases. CONCLUSIONS Unilateral pulmonary artery occlusion testing with dobutamine infusion is useful in determining patient eligibility for pulmonary resection.

Bilateral endobronchial metastasis in postoperative stage I pulmonary adenocarcinoma.

We reported a case of bilateral endobronchial metastasis in postoperative synchronous adenocarcinoma. Twenty months ago, a 63-year-old man underwent combined operation. Biopsy was performed, histological diagnosis of pulmonary adenocarcinoma. When surgery is not indicated because the patient has decreased pulmonary function and contralateral metastatic lesions, the Nd–YAG laser has been used to treat focal malignancy of the trachea and mainstem bronchi, and the laser has been effective, especially in patients with inoperable lesions.

Does Potassium Ion Concentration Affect Lung Preservation

+, 0 mmol/l K+; (2) 150 mmol/l Na+, 5 mmol/l K+; (3) 20 mmol/l Na+, 135 mmol/l K+; and (4) 0 mmol/l Na+, 155 mmol/l K+. All four solutions possessed the same osmolarity, the same pH in the same temperature, and the same buffer action. Lungs were preserved at 7°C in these solutions for 24 h and evaluated in a rat lung perfusion system with perfluorochemical emulsion. Pressure-limited perfusions with pressure-limited ventilation were carried out for 20 min before and after preservation. Thereafter, the recovery ratios of pulmonary arterial flow (Q˙), tidal volume (VT), oxygen tension of the pulmonary venous effluent (PPVO2), and wet-to-dry ratios were compared. The recovery ratios of Q˙ were better in low, but not zero, potassium solutions, whereas wet-to-dry ratios were kept lower in high potassium solutions. No difference in pulmonary compliance or gas exchange was observed against a great change in potassium ion concentration. Therefore, the potassium ion concentration did not play a major role in lung preservation.

Long-Term Results of Aortic Valve Replacement Using a 19mm Bileaflet Valve.

大動脈弁位19mm二葉弁術後5～10年の遠隔期心機能および予後について検討した.術後10年以上(最長16年)10例と,術後5～9年まで(最長9年)の7例,計17例を対象とし予後について検討した.さらに心臓超音波断層法を施行しえた10年以上および5年以上経過の各6例でLVEF,%FS,LVDd,LVDs,PWT,IVST,人工弁圧較差(PG)をそれぞれ計測し,左室心筋重量(LVm)および体表面積(BSA)を加味した左室心筋重量係数(LVMI)を算出した.圧較差では10年以上および5年以上の両群とも高値となる症例もあったが,心機能に関しては保たれNYHAの悪化もなかった.圧較差が高値だった症例はBSAが1.53m2以上であった.LVMIは遠隔期で増加傾向を示した.19mm AVRは症例を選択すれば遠隔期においても良好なQOLを得られると考えるが,圧較差の増加やLVMI増加の可能性もあるため注意深い精査観察が必要である.