Kuniyoshi Yagyu

Application of a new tactile sensor to thoracoscopic surgery: Experimental and clinical study

BACKGROUND We developed a new tactile sensor that could quantify the hardness of objects as changes in the resonance frequency of the sensor (delta f). We have applied it to thoracoscopic operations for the localization of small invisible nodules in the lung. METHODS When the sensor probe was moved over the lung surface, a delta f curve was depicted on the computer screen. When the sensor tip reached a point directly above a hard object, a sudden upward jump of the delta f curve was evoked. After experimental studies using pigs, the sensor was applied in 8 patients. More recently we produced a needle sensor to distinguish small nodules from bronchi that may evoke similar upward jumps of the delta f curve. Eight nodules and four bronchi in resected human lungs were probed directly using this sensor. RESULTS In all of the patients, the hardness of various thoracic structures could be quantified. A total of 10 nodules were found using the sensor and resected thoracoscopically. The needle sensor distinguished nodules from bronchi, as the mean delta f of the bronchial walls (-64 +/- 45.9 Hz) was significantly higher than that of nodules (-526 +/- 168 Hz, p < 0.001). CONCLUSIONS Thoracoscopic detection of small and invisible pulmonary nodules using our new tactile sensor is feasible.

Tuberculous Pseudoaneurysm of the Thoracic Aorta

Tuberculous pseudoaneurysm has been reported to be a fatal, but rare complication of tuberculosis. We report a case of a 68-year-old man who underwent successful surgical treatment for a tuberculous pseudoaneurysm of the thoracic aorta with bronchial communication, and review previous reports of patients who also underwent operation for similar lesions, focusing especially on the pathway of infection to the aorta.

Successful management of massive pulmonary tumor embolism from renal cell carcinoma

Renal cell carcinoma occasionally invades the inferior vena cava and rarely extends to the right atrium. However, despite the frequency of venous extension, it is unusual to recognize patients with massive pulmonary tumor embolus clinically. We describe a 60-year-old man who underwent pulmonary tumor embolectomy using cardiopulmonary bypass combined with profound hypothermia and intermittent low-flow perfusion. The patient is currently alive and well without implantation metastasis 6 months after the operation.

Cine computed tomography for evaluation of tumors invasive to the thoracic aorta: Seven clinical experiences

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Midterm results of the rotation-advancement flap method for correction of partial anomalous pulmonary venous drainage into the superior vena cava.

Since 1986, a rotation-advancement flap method has been used in 11 patients with partial anomalous pulmonary venous drainage into the superior vena cava. This method consists of atrial partitioning, enlargement of the superior vena cava, and protection of the sinus node. The midterm postoperative sinus node function and hemodynamic changes were examined in this study. Postoperative angiograms showed normal pulmonary venous pathway and no stenosis in the superior vena cava. Cardiac rhythm was normal and no clinical symptoms appeared.

Four-channeled aortic dissection and rupture

A four-channeled aortic dissection is quite rare, which is a highly life-threatening situation predisposing to aortic rupture. We report a successful management of a four-channeled aortic dissection and an aortic rupture in a 59-year-old woman with Marfans syndrome 11 years after an initial Bentall procedure for DeBakey type I dissection. The total arch and the descending thoracic aorta were replaced under deep hypothermia and circulatory arrest.

Hemolysis after mitral valve replacement with mechanical valve prostheses.

OBJECTIVE We evaluated effects of type, size, and orientation of mechanical mitral valve prostheses on hemolysis. METHODS Subjects were 84 patients who had undergone mitral valve replacement. Lactate dehydrogenase was mainly used as a marker of hemolysis and was measured before surgery, 1 month after surgery, and in the late postoperative period. RESULTS Valves used included 16 Medtronic-Hall, 32 St. Jude Medical, and 36 CarboMedics valves. Medtronic-Hall valves caused less hemolysis than St. Jude Medical or CarboMedics valves in the late postoperative period. This resulted because hemolysis due to Medtronic-Hall valves was more severe 1 month after surgery than in the late postoperative period and because hemolysis due to St. Jude Medical or CarboMedics valves was more severe in the late postoperative period than 1 month after surgery. One reason for this finding is that cardiac output was greater in the late postoperative period than 1 month after surgery, making regurgitation through the pivots of bileaflet valves more severe. The orifice area and the orientation of prostheses did not affect hemolysis. CONCLUSION St. Jude Medical or CarboMedics valves caused more severe hemolysis than Medtronic-Hall valves in the late postoperative period.

Pulmonary-to-systemic blood flow ratio oriented management after repair of obstructive total anomalous pulmonary venous connection in neonates with single ventricle

Caval oxygen saturation was monitored to estimate pulmonary-to-systemic blood flow ratio after relief of obstructive total anomalous pulmonary venous connection in two neonates with single ventricle. Distribution between systemic and pulmonary blood flow was manipulated by pharmacologic, ventilatory, and surgical interventions aimed at achieving pulmonary-to-systemic blood flow ratio of 0.5 to 1.0. Monitoring of pulmonary-to-systemic blood flow ratio facilitates appropriate balancing between tissue perfusion and oxygenation, and detects redundant ventricular volume-load.

HEMOPTYSIS FROM AN EMPHYSEMATOUS BULLA DEVELOPING AFTER OPEN-HEART SURGERY: REPORT OF A CASE

We present herein the case of a 62-year-old woman with an emphysematous bulla who developed intractable hemoptysis 16 days after undergoing mitral and aortic valve replacement with tricuspid annuloplasty. A bronchoscopic examination with balloon occlusion of the bronchial lumen revealed that the blood source was the right middle lobe bronchus. A computed tomographic (CT) scan of the chest subsequently demonstrated a blood-filled emphysematous bulla in the right middle lobe. A right middle lobectomy was performed and the bulla was observed to be swollen with clotted blood. The respiratory tract bleeding stopped immediately after the lobectomy. Pathohistological examinations suggested that disruption of the pulmonary vessels in the wall of the bulla had caused the respiratory tract bleeding.

Mitral Valve Replacement after Percutaneous Transvenous Mitral Commissurotomy

Percutaneous transvenous mitral commissurotomy is widely performed as the first choice of the non-pharmacological treatments for mitral stenosis. Five patients have been identified who required mitral valve replacement after percutaneous transvenous mitral commissurotomy. The causes leading to mitral valve replacement were mitral regurgitation in three cases and insufficient commissurotomy in two. Massive mitral regurgitation is one of the most serious complications of percutaneous transvenous mitral commissurotomy. This report aims to elucidate the mechanism of massive mitral regurgitation occurring during percutaneous transvenous mitral commissurotomy. In every such case, there was a large tear in the posterior leaflet without any split in the commissures. The Japanese literature reports that 16 patients have undergone mitral valve replacement for massive regurgitation after percutaneous transvenous mitral commissurotomy: 14 of these cases had a tear in one of the leaflets and no evidence of splitting of the posterior commissure. These facts indicate that relative fragility of the leaflets as compared with rigidity of commissural fusion, especially in the posterior commissure, is an important factor of massive mitral regurgitation during percutaneous transvenous mitral commissurotomy.