Jong-Myeon Hong

Surgical management of dyslipidemia: clinical and experimental evidence.

Coronary artery disease (CAD) is still a major cause of mortality in developed countries, and dyslipidemia is one of its major causes. In an attempt to reduce both mortality and morbidity from CAD, several dietary, pharmacological, and surgical approaches have been used to reduce plasma cholesterol levels. In this brief review, we summarize the evidence for cholesterol-lowering effects and safety of partial ileal bypass (PIB) procedure in both human and animal studies. The results of the Program on the Surgical Control of the Hyperlipidemias (POSCH), which involved a total of 838 subjects with myocardial infarction, are promising. A 5-year follow-up of this study revealed significant reductions of up to 27% in total cholesterol (TC) and up to 42% in low-density lipoprotein (LDL) cholesterol levels along with an increase of up to 8% in high-density lipoprotein (HDL) cholesterol levels as compared to controls. These changes were associated with other benefits such as increased HDL/TC and HDL/LDL ratios, and a significant decrease in apolipoprotein (apo) B100 and increase in apo AI levels. Similar results were also demonstrated by other studies. PIB surgery is one of the most effective methods for reduction of plasma cholesterol levels, particularly in patients with heterozygous familial hypercholesterolemia. This procedure is also applicable to treatment of sitosterolemia, a rare genetic disorder in which the absorption of plant sterols is abnormally high. Although no major complications of this method have been reported, more extensive studies are required to evaluate its long-term effects on renal and hepatic function. Similarly, long-term impact of this procedure on progression/regression of atherosclerotic lesions must be documented. Finally, indications for this procedure should be carefully considered, particularly in view of availability of other treatments of dyslipidemia.

Left ventricular and papillary muscle rupture following blunt chest trauma

Abstract We report a patient with complete rupture of both papillary muscles developing after blunt chest trauma, and LV rupture occurring as the papillary muscle was torn from the LV wall.

Ischemic Preconditioning to Prevent Lethal Ischemic Spinal Cord Injury in a Swine Model

Objective: Paraplegia is a serious complication of thoracic and thoracoabdominal aortic operations and is the result of ischemic spinal cord injury induced by low perfusion pressure during cross-clamping of the aorta. Ischemic preconditioning (IPC) of the heart or brain with reversible sublethal ischemic injury induces resistance to subsequent lethal ischemia. The aim of this study is to investigate whether ischemic tolerance can be induced by IPC of the spinal cord in a swine model. Study Design: The animals were randomly divided into three groups: the sham group (n = 3), control group (n = 6) and IPC group (n = 8). In the sham group, we performed a left thoracotomy without any ischemic injury. In the IPC group, the swine received a reversible ischemic spinal cord injury by aortic clamping for 20 min, whereas in the control group, no aortic cross-clamping was performed. Forty-eight hours later, the animals in both the IPC and control groups underwent aortic clamping for 30 min. Neurological examination was done 24 h later, and then the animals were euthanized for histopathology and a malonedialdehyde spectrophotometry assay of the spinal cord tissue. Results: A statistically significant difference in neurological outcome was observed between the control and IPC groups at 24 h after ischemic injury. The incidence of paraplegia and severe paresis was 100% in the control group and 62.5% in the IPC group (p =. 028). Between control and IPC groups, there was no statistically significant difference in histopathology and only a borderline statistical difference in the malonedialdehyde assay of the ischemic spinal cord (p =. 0745). Conclusion: In this study, IPC induced protection against a 30-min ischemic insult of the spinal cord, although complete recovery was not achieved (standing up or walking). We expect that combining this IPC with other existing protective methods might lead to a synergistic effect, which warrants further investigation.

High-definition 3D stereoscopic microscope display system for biomedical applications

Biomedical research has been performed by using advanced information techniques, and micro-high-quality stereo images have been used by researchers and/or doctors for various aims in biomedical research and surgery. To visualize the stereo images, many related devices have been developed. However, the devices are difficult to learn for junior doctors and demanding to supervise for experienced surgeons. In this paper, we describe the development of a high-definition (HD) three-dimensional (3D) stereoscopic imaging display system for operating a microscope or experimenting on animals. The system consists of a stereoscopic camera part, image processing device for stereoscopic video recording, and stereoscopic display. In order to reduce eyestrain and viewer fatigue, we use a preexisting stereo microscope structure and polarized-light stereoscopic display method that does not reduce the quality of the stereo images. The developed system can overcome the discomfort of the eye piece and eyestrain caused by use over a long period of time.

Acute aortic dissection in pregnancy with the marfan syndrome.

Acute aortic dissection (AAD) during pregnancy can be fatal to both the pregnant mother and the baby, particularly in patients with the Marfan syndrome. We report a case of the modified Bentall procedure in surgery for AAD in a 31-year-old pregnant woman at 24 weeks of gestation with the Marfan syndrome. The patient recovered well after the operation, but unfortunately, the fetus could not be saved.

Long-term influence of mild or moderate ischemic mitral regurgitation after off-pump coronary artery bypass surgery

BACKGROUND The issue of mild to moderate ischemic mitral regurgitation (IMR) is controversial after conventional surgery, and has not been specifically studied after off-pump coronary artery bypass graft (OPCAB) surgery. OBJECTIVE To review the influence of mild or moderate IMR on longterm survival and recurrent cardiac events after OPCAB surgery. METHODS A total of 1000 consecutive and systematic OPCAB patients who underwent operations between September 1996 and March 2004 were prospectively followed. Sixty-seven patients (6.7%) had mild to moderate IMR at the time of surgery. Operative mortality, actuarial survival and major adverse cardiac event-free survival were studied to assess the effect of IMR. RESULTS The mean (+/- SD) follow-up period was 66+/-22 months and was completed in 97% of the cohort. IMR patients were older (P<0.001), and had lower ejection fractions (P<0.001) and more comorbidities. More female patients presented with IMR (P=0.002). Operative mortality (P=0.25) and prevalence of perioperative myocardial infarction (P=0.25) were comparable for both groups. Eight-year survival was decreased in IMR patients (P<0.001), but after adjusting for risk factors in the Cox regression model, mild to moderate IMR was not found to be a significant risk factor of long-term mortality (P=0.42). Major adverse cardiac event-free survival at eight years was significantly lower in IMR patients (P<0.001) and, more specifically, in patients with 2+ IMR. After adjusting for risk factors, IMR remained a significant cause of poor outcome (hazard ratio 2.09), especially for recurrent congestive heart failure and myocardial infarction. CONCLUSIONS OPCAB patients with preoperative mild or moderate IMR had a higher prevalence of preoperative risk factors than those without IMR. They had comparable perioperative mortality and morbidity but, over the long term, were found to be at risk for recurrent cardiac events.

Comparing Risk-adjusted Hospital Mortality for CABG and AMI Patients

The objectives of this study were to compare the risk-adjusted mortality of coronary artery bypass graft (CABG) and acute myocardial infarction (AMI) patients simultaneously in six hospitals in Seoul, Korea, and to investigate the relationship between these performance measures by developing a predictive model of mortality. The medical records of 749 AMI and 564 CABG patients were reviewed. A predictive model was developed using logistic regression, including 170 variables selected as risk factors for risk adjustment. The validity of our predictive model was demonstrated to be within an acceptable range. The results showed that one hospital with a significantly low AMI mortality rate also had a low CABG mortality rate, while another hospital with a significantly high AMI mortality rate also had a high CABG mortality rate. Our results implied that hospitals providing good-quality medical management of coronary artery disease also provided a good-quality surgical service.

Left Ventricular Apical Lipoma Resected Under the Guidance of a Mediastinoscope

We report a 57-year-old man who was found to have a left ventricular apical mass during a routine check-up. He previously had neither any subjective symptom nor hemodynamic problem. The mass was located deeply in the left ventricular cavity. With exploration using a mediastinoscope, we successfully resected the tumor, which was a yellowish lipoid mass that adhered to the trabeculae near the apex. Histopathologic examination of the tumor was consistent with a lipoma, a very rare benign primary cardiac tumor. The mediastinoscope can be useful for surgical resection of tumors located deeply in the left ventricle.

Primary Pulmonary Amyloidosis with Mediastinal Lymphadenopathy

We report a case of inadvertent hoarseness after surgery for primary pulmonary amyloidosis. A 55-year-old male was transferred to our facility due to a lung mass. Chest computed tomography revealed a solitary pulmonary nodule. Positron emission tomography–computed tomography showed fluorodeoxyglucose uptake in the main mass and in the mediastinal lymph nodes. To confirm the pathology of the mass, wedge resection and thorough lymph node dissection were performed via video-assisted thoracic surgery (VATS). No complications except for hoarseness were observed; hoarseness developed soon after surgery and lasted for 3 months. The main mass was diagnosed as amyloidosis, but this was not found in the lymph nodes. In conclusion, VATS wedge resection for peripheral amyloidosis is a feasible and safe procedure. However, mediastinal lymph node dissection is not recommended unless there is evidence of a clear benefit.

Unintended Pulmonary Artery Ligation during PDA Ligation

A 10-day-old boy was transferred to our hospital due to tachypnea. Patent ductus arteriosus (PDA), 4.8 mm in diameter, with small ASD was diagnosed on echocardiography. Surgical ligation of the ductus was performed after failure of three cycles of ibuprofen. However, the ductus remained open on routine postoperative echocardiography on the second postoperative day, and chest CT revealed inadvertent ligation of the left pulmonary artery (LPA) rather than the PDA. Emergent operation successfully reopened the clipped LPA and ligated the ductus on the same (second postoperative) day.Mechanical ventilator support was weaned on postoperative day 21, and the baby was discharged on postoperative day 47 with a normal left lung shadow.