Biomedical subjects
Publications and source records attributed to Min-Ho Song.
Side-to-side anastomosis was employed by just ten proportional stitches while performing distal anastomosis during coronary artery surgery. This technique is simple and quick. Here this simple technique is described in detail and the postoperative status of grafted conduits is reported.
A 62-year-old woman underwent aortic valve replacement for aortic stenosis. Her hemodynamics deteriorated with ST-T depression 6 hours postoperatively. Emergency coronary catheterization showed diffuse right coronary artery spasm. The spasm persisted despite intracoronary infusion of nitrates and calcium antagonists. Intracoronary adenosine triphosphate infusion finally resolved the spasm and stabilized the cardiac function.
Because a suction-type stabilizer does not move once it is attached to the heart in either on-pump or off-pump coronary surgery, we have been using a simple method of stabilizing mammary radial, or epigastric artery grafts with a suction stabilizer in anastomosis of coronary artery grafts. This method excludes the need for assistants to hold the graft, which can bel cumbersome, thereby reducing graft movement. This experience prompted us to report this method.
To provide supplementary training for trainee cardiac surgeons, a simple method is required to simulate coronary anastomoses. By stretching 2 gloves over a towel, a model can be made that can be used to simulate a small coronary arteriotomy (including anterior and posterior walls). The graft can also be simulated using the fingers of the gloves.
OBJECTIVE: Case-volume has been believed to be of paramount importance in becoming a good cardiac surgeon. However, for a training cardiac surgeon there is no evidence regarding the specific number of necessary cases to attain the medico-legally acceptable level. We attempted to observe the learning curve in performing coronary surgery with the use of the cumulative sum (CUSUM) method to provide some evidence. METHODS: From April 2000 to March 2004, a cardiac surgeon, being board-certified but not being on the attending staff, performed 50 coronary artery bypass grafting (CABG) under supervision of three different chief attending surgeons at three different hospitals. His learning curve was analyzed with the use of CUSUM. Mortality and morbidity and the average time of crossclamp and operation at each hospital were examined. Also, the learning curve of 100 left internal mammary artery (LIMA) harvestings were analyzed via CUSUM in terms of harvesting time and injury rate. RESULTS: The CUSUM curve tended to come closer to the alert line (0.80 confidence) until the 23rd case, but never reached the alert line thereafter until the 50th case. The CUSUM curve never transgressed the alarm line (0.95 confidence) throughout 50 cases. The CUSUM curve of LIMA harvesting approached the alert line in the 38th case and the 59th case, but thereafter never reached the alert line and remained below the reassurance line from the 73rd case. CONCLUSION: Tentatively, it is inferred that approximately 23 cases of CABG may be sufficient to allow for independent practice and that 73 cases of LIMA harvesting are sufficient to allow independent practice.
BACKGROUND: The new evolving multidetector computed tomography (MDCT) is thought to be promising in imaging of coronary disease. We compared the evaluating power of MDCT to that of conventional coronary artery angiogram in patients with coronary artery bypass grafting surgery. METHODS: From April 2002 to December 2003, 50 patients underwent both MDCT and coronary artery angiogram after coronary artery bypass surgery. Overall, 170 grafts were studied. Two weeks after the surgery, 8-row MDCT was taken using contrast medium to observe the grafts patency. Three weeks after the surgery, conventional coronary angiogram was done to verify the graft status. The graft status was classified according to Fitzgibbon classification. Sensitivity, positive predictive value, and negative predictive value were calculated and compared. RESULTS: Multidetector computed tomography succeeded in high-quality imaging of all grafts except for one (less than 1 mm gastroepiploic graft to posterior descending artery). This graft was the only graft that was interpreted differently. Overall patency rate was 97.8%. The diagnostic power of MDCT was as follows: the specificity was 99.4%, the sensitivity was 100%, the positive predictive value was 100%, and the negative predictive power was 80%. CONCLUSIONS: In this study, 8-row MDCT showed reliable imaging power in verifying grafts status. Since MDCT is much less invasive for patients, conventional coronary artery angiogram will be substituted by evolving MDCT.
OBJECTIVE: It is widely accepted that both valve and cardiac functions are closely correlated. In order to investigate the relationship between the valve and cardiac functions, we developed a model of an isolated working heart with crystalloid perfusate in swine. We investigated the feasibility of this model to evaluate the precise left ventricular function using the pressure-volume relationship and metabolic measurement. Another objective was as a trial for the imaging and analysis of valvular interventions with a high-speed digital camera on this model. METHODS: Six isolated working hearts were subjected in the pressure-volume study, and additional three hearts were used in the valve imaging study. Measurement of the pressure-volume relationship was undertaken in situ before the heart was removed, and on the working heart mode during the initial 30 min as the baseline, and at every 60 min. Lactate levels were measured at every stage in the working heart mode. Mitral valve interventions were performed in three hearts, and valve motions were observed by a high-speed digital camera via the left ventricle. RESULTS: The end-systolic elastance maintained a baseline level (5.17+/-2.25) until 180 min and decreased at 240 min (3.97+/-1.97, NS) and 300 min (2.85+/-1.29, P<0.01) of the working heart mode as compared with baseline. The Tau maintained a constant level until 180 min and increased at 240 min (62.2+/-13.3, NS) and 300 min (85.5+/-43.4, P<0.05) as compared with baseline (50.3+/-13.6). The slope of the end-diastolic pressure-volume relationship gradually increased with no significance until 180 min and increased significantly (0.147+/-0.066, P<0.01 vs 0.067+/-0.041 at baseline). Lactate increased accumulatively. The total heart energy was reduced from the initial phase of the working heart mode. The valves were well captured by the high-speed digital camera. CONCLUSIONS: The systolic and diastolic functions of an isolated heart were preserved at an acceptable level for 180 min. The practical reliability of the swine working heart model was demonstrated. This model will be used reliably for the investigation of the interaction of valve and cardiac functions.
A 66-year-old woman with a 30-year history of Behcet's disease was referred for coronary surgery because of restenosed stent and crescendo angina. We succeeded in operating on her by off-pump coronary bypass with bilateral internal mammary arteries, which were anastomosed to the left anterior descending artery and diagonal artery. The grafts were patent postoperatively and she became free from angina. Coronary surgery for Behcet's disease is extremely rare and this experience prompted us to report this case.
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Atrial natriuretic peptide and brain natriuretic peptide are known to be indices for heart failure. Atrial natriuretic peptide and brain natriuretic peptide changes in off-pump and on-pump coronary artery bypass grafting is hypothesized to be correlated to clinical implications of coronary artery bypass grafting. 20 consecutive off-pump and 20 consecutive on-pump coronary artery bypass grafting patients were studied. Perioperative atrial natriuretic peptide and brain natriuretic peptide values were measured and statistically analyzed in terms of 14 factors related to myocardial damage and recovery. Postoperative atrial natriuretic peptide plateaued on the third postoperative day and it decreased gradually down to the preoperative level by one month in the off-pump group. Postoperative brain natriuretic peptide plateaued, showed very slow decrease and it never reached down to the preoperative level. The peak brain natriuretic peptide level was correlated with aortic cross-clamp time, postoperative pleural effusion, and postoperative atrial fibrillation (p < 0.01). The atrial natriuretic peptide change reflected surgical prevention of ventricular remodeling. Brain natriuretic peptide > 450 microg.mL(-1) had strong predictive power for atrial fibrillation and pleural effusion and is a useful marker for management of coronary surgery patients.
The feasibility of using transthoracic echocardiography to assess internal mammary artery graft patency and function was examined. Coronary angiography and transthoracic echocardiography was performed in 60 consecutive patients undergoing coronary artery bypass from April 2000 to March 2002. Flow velocity, velocity-time integral, and the ratio of the diastolic fraction of the velocity-time integral to total velocity-time integral were measured by doppler transthoracic echocardiography. A stress test was carried out to detect coronary flow changes by echocardiography. The relationship between the coronary angiogram and the echocardiogram was analyzed. The overall graft patency rate was 98%. The mean diastolic velocity-time integral in patients with patent grafts was 0.64, and it increased up to 0.72 in response to physical stress. The occluded grafts showed diastolic velocity-time integral fractions of less than 0.60 in all grafts. There was a statistical correlation between patency > or = FitzGibbon grade B and diastolic velocity-time integral > 0.60. The diastolic velocity-time integral recorded by transthoracic echocardiography predicted the patency of internal mammary artery grafts. As echocardiography is noninvasive and accurate, it might be a useful method of verifying arterial graft patency.
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