Cryosurgery of Lung with 2.4 mm Cryoprobe: An Experimental in vivo Study of the Cryosurgery in Canine Model / 대한흉부외과학회지

BACKGROUND: The clinical application of cryosurgery for the management of lung cancer is limited because the response of lung at low temperature is not well understood. The purpose of this study is to investigate the response of the pulmonary tissue at extreme low temperature. MATERIAL AND METHOD: After general anesthesia the lungs of twelve Mongrel dogs were exposed through the fifth intercostal space. Cryosurgical probe (Galil Medical, Israel) with diameter 2.4 mm were placed into the lung 20 mm deep and four thermosensors (T1-4) were inserted at 5 mm intervals from the cryoprobe. The animals were divided into group A (n=8) and group B (n=4). In group A the temperature of the cryoprobe was decreased to -120 degrees C and maintained for 20 minutes. After 5 minutes of thawing this freezing cycle was repeated. In group B same freezing temperature was maintained for 40 minutes continuously without thawing. The lungs were removed for microscopic examination on 1 day after the cryosurgery. In four dogs of the group A the lung was removed 7 days after the cryosurgery to examine the delayed changes of the cryoinjured tissue. RESULT: In group A the temperatures of T1 and T2 were decreased to 4.1+/-11 degrees C and 31+/-5 degrees C respectively in first freezing cycle. During the second freezing period the temperatures of the thermosensors were decreased lower than the temperature during the first freezing time: T1 -56.4+/-9.7 degrees C, T2 -18.4+/-14.2 degrees C, T3 18.5+/-9.4 degrees C and T4 35.9+/-2.9 degrees C. Comparing the temperature-distance graph of the first cycle to that of the second cycle revealed the changes of temperature-distance relationship from curve to linear. In group B the temperatures of thermosensors were decreased and maintained throughout the 40 minutes of freezing. On light microscopy, hemorrhagic infarctions of diameter 18.6+/-6.4 mm were found in group A. The infarction size was 14+/-3 mm in group B. No viable cell was found within the infarction area. CONCLUSION: The conductivity of the lung is changed during the thawing period resulting further decrease in temperature of the lung tissue during the second freezing cycle and expanding the area of cell destruction.

A Clinical Experience of Korean Artificial Heart(AnyHeart) / 대한흉부외과학회지

Korean artificial heart(AnyHeart) is a single-pieced and implantable bi-ventricular pulsatile pump adapting a moving actuator mechanism. The authors report a case of clinical application of AnyHeart as a life-saving device for the patients with end-stage heart disease combined with biventricular failure.

Evaluation of the Potential of Retrograde Flow Competition in the Right Gastroepiploic Artery Graft for Coronary Artery Bypass Grafting / 대한흉부외과학회지

BACKGROUND: Due to the concern of flow competition or retrograde steal, it has been generally suggested that the right gastroepiploic artery(RGEA) pedicled graft should be used in critical coronary stenosis lesion. The study was designed to evaluate the potential of retrograde flow competition in the RGEA pedicled graft by measuring the native pressure differences(PD) between the normal coronary artery and celiac arterial pressure, which would be compared with trans-stenosis pressure gradients(TSPG) in coronary artery occlusive disease. MATERIAL AND METHOD: Between July, 1998 and February, 1999, pressures of the right coronary artery and the right gastroepiploic artery(or the celiac artery) were measured in patients with the patent right coronary artery(n=12). The PD between the arteries was compared with the TSPG in the occlusive coronary arteries(n=32). RESULT: The pressures of the normal right coronary artery and celiac artery were 143+/-23 vs. 134+/-17mmHg in systole(p<0.005), 74+/-13 vs. 73+/-14mmHg in diastole(p=NS), and 100+/-16 vs. 97+/-15mmHg in mean (p0.05). The PD between the arteries were -8~25mmHg in systole, -4~7 mmHg in diastole, and -1~10mmHg in mean. The TSPG measured in the occlusive coronary arteries were -4~19(7+/-5.8)mmHg in the lesion less than 75% stenosis vs. 7~74(27+/-18.3)mmHg in the 75% or over stenosis lesion(p0.005). The normally existing pressure difference between the coronary arteries and RGEA(15~20mmHg) was significantly less than the TSPG in the occlusive coronary artery with 75% or over stenosis(p0.001). CONCLUSION: If the pressure gradient between the RGEA and the coronary artery distal to the stenosis is the main determinant of development of retrograde flow competiton in the RGEA pedicled graft, the above data suggests that there will be little chance of competition when it is used in the coronary lesion with 75% or over stenosis.