Masaaki Sugawara

Limited Resection for Noninvasive Bronchioloalveolar Carcinoma Diagnosed by Intraoperative Pathologic Examination

BACKGROUND The establishment of limited resection procedures for non-small cell lung cancer is expected. Many groups have suggested noninvasive bronchioloalveolar carcinoma (BAC) to be a potential indication for limited resection. METHODS We designed a prospective phase II study evaluating limited resection for noninvasive BAC diagnosed by intraoperative pathologic examination. From 1999 to 2007, limited resection was the procedure in 46 patients (16 men and 30 women; median age, 69 years; range, 49 to 83) who were diagnosed intraoperatively as having noninvasive BAC. The first end point was the predictive value of the intraoperative pathologic examination for noninvasive BAC diagnosis. The second end point was overall survival, disease-free survival, and cancer-specific survival, calculated using the Kaplan-Meier method. RESULTS We performed wedge resections for 44 patients and segmentectomy for 2 patients. Permanent pathologic examination revealed 3 patients had primary lung adenocarcinomas other than noninvasive BAC. The predictive value of intraoperative pathologic examination for noninvasive BAC diagnosis was 94%. During a median 51-month follow-up, there were only 2 cancer unrelated deaths. The 5-year overall survival rate and the disease-free survival rate were 93%, and the 5-year cancer-specific survival rate was 100%. CONCLUSIONS The results of our prospective phase II study indicate that limited resection, mainly by wedge resection, is a potentially curative surgical procedure and may be an acceptable alternative to lobectomy for patients with noninvasive BAC. Furthermore, an intraoperative pathologic diagnosis of noninvasive BAC is strongly predictive and allows for an intraoperative decision to perform a limited resection in these patients.

Experimental application of microwave tissue coagulation to ventricular myocardium.

BACKGROUND It is difficult to create transmural lesions in a beating, normothermic perfused heart. The aim of this study was to evaluate the effect of microwave tissue coagulation on a beating heart. METHOD We used a microwave tissue coagulator that emits microwaves of 2,450 MHz. Studies were conducted on 30 mongrel dogs weighing between 9 and 13 kg, and microwave tissue coagulation was performed at the free wall of the left ventricle in a beating heart without cardiopulmonary bypass. RESULTS Microwave tissue coagulation created transmural degenerated lesions in the left ventricle without risk of ventricular rupture. The lesion width of microwave ablation increased from 10 to 60 seconds. Histologic examinations revealed well-demarcated areas of heat degeneration consisting of coagulation necrosis and contraction band necrosis of the myocardium. The lesion healed to hard scar tissue, which was sharply demarcated from the normal myocardium. No animals had inducible ventricular tachycardia through programmed ventricular stimulation. CONCLUSIONS Microwave ablation with a monopolar antenna created transmural lesions with only a few proarrhythmic events occurring during ablation.

Closure of Isolated Ventricular Septal Defect with Detachment of the Tricuspid Valve

Detachment of the septal leaflet of the tricuspid valve is an alternative technique for obtaining complete visualization of a perimembranous ventricular septal defect (VSD) in cases where the VSD is obscured by the chordae tendineae or a pouch formation of the septal leaflet. This method presents theoretical concerns because it has the potential for causing postoperative valvular insufficiency. We therefore evaluated valvular function in patients who underwent VSD closure with detachment of the tricuspid valve. In a consecutive series of 153 patients who underwent VSD closure using a transatrial approach, 13 had incision of the tricuspid valve. Follow‐up echocardiographic studies were performed on these patients at least 1 year following operation. There were no operative deaths. Color Doppler echocardiography revealed no residual shunt in any of these patients. Ten patients had no evidence of tricuspid stenosis or regurgitation. One patient had trivial tricuspid regurgitation. Moderate tricuspid regurgitation was observed in two patients of these, one patient was a small infant who had a VSD complicated by pulmonary hypertension. The other patient had a VSD with a mitral cleft, pulmonary hypertension, and Downs syndrome. The incised tricuspid valve was resus‐pended by solely running sutures. In conclusion, detachment of the tricuspid valve is a safe and useful method for adequate exposure of a VSD. However, this method should be avoided in patients with Downs syndrome and in small infants. Furthermore, repair of the incised valve should not be performed using only running sutures.

Biocompatibility of a silicone-coated polypropylene hollow fiber oxygenator in an in vitro model

BACKGROUND A silicone-coated microporous hollow-fiber membrane oxygenator has been developed to prevent plasma leakage during long-term use. The objective of this study was to evaluate the biocompatibility of the oxygenator. METHODS A silicone-coated oxygenator was compared with an uncoated oxygenator in an in vitro model of cardiopulmonary bypass. Simulated circulation was maintained for 6 h at 37 degrees C. RESULTS Platelet counts decreased significantly (p < 0.05) and leukocyte counts tended to decline; however, the differences between groups were not significant. Concentrations of C3a increased significantly in both groups (p < 0.05), but levels were significantly less in the silicone-coated oxygenator (p = 0.008). In contrast, concentrations of C4a, beta-thromboglobulin, and granulocyte elastase increased significantly (p < 0.05), but the differences between groups were not significant. CONCLUSIONS Silicone coating over a microporous hollow-fiber membrane may improve biocompatibility by reducing C3a activation.

Limited vertical skin incision for median sternotomy

The cosmetic deformity of the vertical skin incision for median sternotomy was decreased by using a mechanical traction system to increase exposure at the superior margin of a shorter wound. The limited vertical skin incision did not impede technical surgical maneuvers and produced a scar that was more acceptable than submammary incision or right anterior thoracotomy. The limited skin incision is especially useful in young women with congenital heart disease.

The long-term survival rates of patients after repair of abdominal aortic aneurysms

This study was undertaken to examine the longterm survival rates of patients following abdominal aortic aneurysm (AAA) repair in comparison with an age-matched normal population, and to determine by multivariate analysis the factors influencing long-term survival. Of 125 patients who underwent AAA repair prior to July 1986, 13 died during hospitalization. Of these 13 patients, 6 who suffered aneurysmal rupture all died within 30 days. The survival rate of patients with ruptured aortic aneurysms was significantly lower than that of those with nonruptured aneurysms. Of the 112 patients surviving hospitalization, 85 died within 0.48 to 24 years after their operation. The long-term survival rate of patients who had suffered a preoperative cardiovascular event was significantly lower than that of those who had not suffered a preoperative cardiovascular event. The actual survival rate was significantly lower than the expected survival rate. According to a multivariate analysis, the significant predictors of late survival were age, aneurysmal rupture, and chronic renal failure in all the patients, and age, chronic renal failure, and pre- and postoperative cardiovascular events in patients who did not die in hospital. These findings indicate the importance of improving immediate perioperative management of ruptured AAA and that cardiovascular events should be prevented, or treated during long-term follow-up.

Total circular annuloplasty with absorbable suture for the repair of left atrioventricular valve regurgitation in atrioventricular septal defect

To obtain a better control of left atrioventricular valve regurgitation, we applied total circular annuloplasty with the use of absorbable sutures to 14 children with atrioventricular septal defect (six complete forms and eight incomplete forms). In the intraoperative period, a good coaptation of the leaflets was achieved and the regurgitation was minimized or disappeared. Follow-up studies with echocardiography for 13 survivors showed a gradual increase of annular size during the postoperative period. Ten patients of the survivor group (77%) maintained good valvular competency in a long-term period. Total circular annuloplasty is a simple and effective procedure to reduce the regurgitation and prevent the annular dilatation during the immediate postoperative period.

Blalock-taussig operation with an assist of venovenous extracorporeal membrane oxygenation

Three infants with congenital cyanotic heart disease encountered severe hypoxemia during a Blalock-Taussig shunt procedure using a right thoracotomy approach. Pericardiotomy was performed and venovenous extracorporeal membrane oxygenation was instituted using right atrial canulation. The shunt procedure was completed with good oxygenation and hemodynamic stability in all cases. Venovenous extracorporeal membrane oxygenation can be easily established in the right thorax, and is an effective support technique for unexpected hypoxemia encountered during systemic-to-pulmonary artery shunt operations.

The long-term influence of pulmonary valve regurgitation following repair of tetralogy of Fallot: Does preservation of the pulmonary valve ring affect quality of life?

The transannular patch (TAP) repair used in the correction of tetralogy of Fallot (TOF) inevitably causes pulmonary regurgitation. We report herein the results of a long-term follow-up study conducted on 50 patients who had undergone a TAP repair 20–29 years earlier to evaluate the influence of pulmonary regurgitation on their late outcome and quality of life. As a control, 26 patients with an intact pulmonary valve ring and right ventricular outflow patch (RVP) confined to the subvalvular region were also studied. The 25-year survival rates of the TAP and RVP groups were 88.5% and 95.7%, respectively, and the event-free rates at 25 years were 73.3% and 90.9%, respectively. Although the absolute values of these rates were higher in the RVP group, there were no statistically significant differences between the two groups. To assess quality of life, the occupational status, childbearing ability, and late symptoms were evaluated, and found to be comparable between the two groups. Moreover, a treadmill submaximal stress test did not show any differences in exercise capacity between the two groups. In conclusion, the presence of a TAP does not significantly alter the late results or quality of life of patients who have undergone repair of TOF.

The Influence of a Heparin‐Coated Oxygenator During Cardiopulmonary Bypass on Postoperative Lung Oxygenation Capacity in Pediatric Patients with Congenital Heart Anomalies

Abstract Background: Cardiopulmonary bypass (CPB) causes an inflammatory response and remarkably depresses the oxygenation capacity of the lung in pediatric patients with pulmonary hypertension. Although a heparin‐coated circuit is more biocompatible than an uncoated circuit, the beneficial effect of a heparin‐coated circuit on the postoperative lung function in the pediatric patients remains unknown. Methods: Sixty patients younger than 3‐years‐old undergoing heart operations for ventricular septal defect were divided into three groups: group I = children (n = 11) without pulmonary hypertension who underwent CPB with an uncoated oxygenator; group II = children (n = 32) with pulmonary hypertension who underwent CPB with an uncoated oxygenator; and group III = children (n = 17) with pulmonary hypertension who underwent CPB with a heparin‐coated oxygenator. A respiratory index (RI) was used to assess the oxygenation capacity of the lung. Results: RI in group II was significantly higher than in group I and intubation time in group II was significantly longer than in group I. There was a positive correlation between preoperative pulmonary‐systemic blood pressure ratio and RI at 3 hours post‐CPB. Three and six hours post‐CPB, RI in group III was significantly lower than in group II, but there was no significant difference in RI between both groups at 12 hours post‐CPB. Conclusions: Pulmonary hypertensive pediatric patients were vulnerable to postperfusion lung injury. Beneficial effects of a heparin‐coated oxygenator in a CPB circuit was limited to the early hours post‐CPB and the postoperative clinical course was not modified by the heparin‐coating of a membrane oxygenator.